Comparing Agilent InfiniiVision 2000 and 3000 X-Series Oscilloscopes

[Electro Fan]

Still trying to figure out the "ideal scope".  It could still be a Rigol - we'll see if they get around to introducing their new Logic Analyzer enabled model(s), but maybe the winner could be an Agilent. 

If it's an Agilent, it's either a 2000 or 3000 but not sure which.

Any comments/corrections/thoughts highly welcomed and appreciated....


Here are some links regarding Agilent's I2C, SPI Serial Embedded option for the 2000 series they call DSOX2EMBD:

http://www.home.agilent.com/en/pd-2252460-pn-DSOX2000-LSS/embedded-serial-triggering-and-analysis-ic-spi-for-infiniivision-2000-x-series-oscilloscopes?cc=US&lc=eng



Here is a link regarding Agilent's I2C, SPI Serial Embedded option for the 3000 series scope they call DSOX3EMBD:

http://www.home.agilent.com/en/pd-1951539-pn-DSOX3EMBD/embedded-serial-triggering-and-analysis-ic-spi-for-infiniivision-3000-x-series-oscilloscopes?nid=-35491.970768.00&cc=US&lc=eng

Does anyone know if these two options (DSOX2EMBD and DSOX3EMBD) are identical, or just similar?

One reason for asking is that on pages 377-396 of the Agilent 3000 manual (User's Guide) there is a section specifically on the DSOX3EMBD, but there is no comparable section in the Agilent 2000 manual (User's Guide).

3000 User's Guide (see pg 377-396):
http://cp.literature.agilent.com/litweb/pdf/75019-97073.pdf

2000 User's Guide
http://cp.literature.agilent.com/litweb/pdf/75015-97034.pdf

It appears that the two options (DSOX2EMBD and DSOX3EMBD) both work with the analog channels of each scope (2000 and 3000), ie, in both cases they can work without the MSO options (DSOX2MSO and DSOX3MSO) - Correct?

And the DSO2XEMBD/DSOX3EMBD can work with either 2 channnel or 4 channel analog configurations - Correct?

While the two DSOX"N"EMBD options appear very similar, there are of course some differences between the 2000 series and the 3000 series.  For example, the 2000 (with the DSOX2MSO) only supports 8 digital channels vs. the 16 channels supported by the 3000 (with the DSOX3MSO). This is pretty obvious, but I'm wondering what else might be different that perhaps isn't quite as apparent.

On page 126 of the 3000 Manual there is a reference to the Serial Decode options:  http://cp.literature.agilent.com/litweb/pdf/75019-97073.pdf,
but there is no corresponding section in the 2000 Manual:  http://cp.literature.agilent.com/litweb/pdf/75015-97034.pdf

Also on Page 126 of the 3000 Manual there is a section on the Lister (which the manual says "is a very powerful tool for investigating large amounts of packet level serial data...").  On page 128 there is a brief section on Searching Lister Data.

Although there is no reference in the 2000 Manual regarding the Lister the above video seems to show that the Lister feature is available on the 2000 series scope (if you have the DSOX2EMBD option):  see video at 2:50.

Another possible difference seems to be in the area of search:  on Page 59-60 in the 3000 manual there is section on Search for Events, but no comparable section seems to be in the 2000 manual.

And of course, there is the difference in wfms/s: 50k on the 2000 vs 1 million on the 3000; 1GSa/s per channel on the 2000 vs 2GSa/s on the 3000 and 100kpts memory depth on the 2000 vs 2Mpts on the 3000; and there are definitely additional triggers on the 3000 vs. the 2000.

Maybe the additional triggers are what causes Agilent to claim superior Search and Navigate features on the 3000?
http://wireless.agilent.com/flash/infiniivision/npl/index1.html
Search and navigate:  2000 No, 3000 Yes   ?

Agilent has done a nice job of providing a graceful/incremental upgrade path within each series but it would be nice to know what features and functions can never be reached by heading down the 2000 path vs. the 3000 path.  The performance and memory trade-offs are relatively easy to see between the 2000 and 3000, but some of the functional feature differences seem a bit more obscure - so any advice from forum members would be much appreciated.

Not to be overly OC, but in an effort to try to make the right investment, below is a Table of Contents list of the features referenced in the 3000 manual that seem to not have a corresponding section in the 2000 manual.  Some of the TOC differences might be just documentation differences, but I think most of them reflect feature/function differences.   (Let me know if you see any errors and I'll fix the list - but with the list and the links to the manuals it should be possible to identify most of the differences between the 2000 and 3000):

Searching for Events 59
To set up searches 59
To copy search setups 60
Divide 77
Math Transforms 78
Differentiate 79
Integrate 80
FFT Measurement 83
Square Root 90
Ax + B 90
Square 91
Absolute Value 92
Common Logarithm 92
Natural Logarithm 93
Exponential 93
Base 10 Exponential 94
Math Filters 94
High Pass and Low Pass Filter 95
Math Visualizations 96
Magnify 96
Measurement Trend 97
Chart Logic Bus Timing 98
Chart Logic Bus State 99
Serial Decode Options 125
Lister 126
Searching Lister Data 128
Edge then Edge Trigger 148
OR Trigger 155
Rise/Fall Time Trigger 157
Nth Edge Burst Trigger 158
Runt Trigger 160
Setup and Hold Trigger 162
To set up Generic video triggers 168
Measurements, Statistics 201
Ratio 227
Counter 229
X at Min Y 233
X at Max Y 234
Count Measurements 234
Positive Pulse Count 234
Negative Pulse Count 235
Rising Edge Count 235
Falling Edges Count 235
Mixed Measurements 235
Area 235
Measurement Thresholds 236
Measurement Window with Zoom Display 238
Measurement Statistics 238
16 Digital Voltmeter (not referenced in the 2000 manual, but I think it's an option on both 2000 and 3000)
- WaveGen functions referenced in 3000 manual, but not in 2000 manual
To edit arbitrary waveforms 261
Creating New Arbitrary Waveforms 262
Editing Existing Arbitrary Waveforms 263
To add noise to the waveform generator output 267
To add modulation to the waveform generator output 267
To set up Amplitude Modulation (AM) 268
To set up Frequency Modulation (FM) 269
To set up Frequency-Shift Keying Modulation (FSK) 271
To save Lister data files 281
To recall arbitrary waveforms 285
Browser-Based Remote Front Panel 320

Long story short if you had to live with a 2000 vs a 3000 what would you miss most from the 3000?

[djghost]

Hi, what I'd miss if I had a 2000x instead of a 3000x :

- extra memory
- extra update rate
- extra bandwidth
- serial decode on the digital channels
- advanced triggering capability
- smartprobe interface (support for active/special probes)

Actually for any of the above reasons I would pick a 3000x over a 2000x.

Those features are nice too :
- arbitrary waveform gen
- navigation
- mask testing

And I miss having a 4000x for the USB serial decode.

Of course all this is a matter of budget. All those scopes are top class

Compared to the rigols :
- more expensive
- not in the same league
- more features come as options (including VGA/LAN)
- less memory but faster

[Electro Fan]

Hi, what I'd miss if I had a 2000x instead of a 3000x :

snip

- serial decode on the digital channels

snip

Isn't serial decode on the digital channels the same for both the 2000 and 3000?  Or how is it different?  Thx

[djghost]

I heard someone saying 2000x can do serial decode only on its 2/4 analog channels, and not on its 8 digital channels.

[Lajon]

I heard someone saying 2000x can do serial decode only on its 2/4 analog channels, and not on its 8 digital channels.

Unfortunately this is true, it is documented in the "Serial Bus Options for InfiniiVision X-Series Oscilloscopes" data sheet where the input sources are listed:

Analog channels 1, 2, 3, or 4
Digital channels D0 to D15 (3000 and 4000 X-Series only)

I guess decoding two way SPI will not be possible with a two channel 2000x.

[Electro Fan]

I heard someone saying 2000x can do serial decode only on its 2/4 analog channels, and not on its 8 digital channels.

Unfortunately this is true, it is documented in the "Serial Bus Options for InfiniiVision X-Series Oscilloscopes" data sheet where the input sources are listed:

Analog channels 1, 2, 3, or 4
Digital channels D0 to D15 (3000 and 4000 X-Series only)

I guess decoding two way SPI will not be possible with a two channel 2000x.

This is correct, 4 channels are recommended/needed for SPI on the 2000X - but that seems like it would be true for any 2 channel scope, not just Agilent, right?

Further, to partially answer my own question at the top of this thread, one of the biggest things that I think would be missed with an Agilent 2000 vs. an Agilent 3000 would be the ability to do any serial decoding or serial triggering on the digital channels.  And apparently if you use the analog channels to do serial decoding then you can't use the digital channels at the same time.  Net, net:  I think on the Agilent 2000 I'd miss the ability to use a serious LA; it's kind of a "partial MSO".  The Agilent 3000 looks great if you have the budget.

The more I look at the popular scopes it looks like the Rigol 2000 series is very strong in the 2 channel space, the Agilent 3000 is looking pretty comfy in it's space, and in between things are shaping up for a battle between the Rigol 4000 series and the Agilent 2000 series; and if Rigol really puts the pedal to the metal with their MSO4000, then the Agilent 3000 might become a little less comfy.

[DaveW]

I guess decoding two way SPI will not be possible with a two channel 2000x.

This is correct, 4 channels are recommended/needed for SPI on the 2000X - but that seems like it would be true for any 2 channel scope, not just Agilent, right?

On the Hameg scopes, you can decode point-point SPI (no select line) using the external trigger as a third input; I presume some of the other scopes can do this as well

[ben_r_]

Man, I love my X-2000 series, but I only bought it because I couldnt afford an X-3000 series and can only drool over an X-4000 series. :/

[Lajon]

I heard someone saying 2000x can do serial decode only on its 2/4 analog channels, and not on its 8 digital channels.

Unfortunately this is true, it is documented in the "Serial Bus Options for InfiniiVision X-Series Oscilloscopes" data sheet where the input sources are listed:

Analog channels 1, 2, 3, or 4
Digital channels D0 to D15 (3000 and 4000 X-Series only)

I guess decoding two way SPI will not be possible with a two channel 2000x.

This is correct, 4 channels are recommended/needed for SPI on the 2000X - but that seems like it would be true for any 2 channel scope, not just Agilent, right?

I meant two way SPI decoding will not be possible on a 2000X even when it is an MSO, this is not exactly what one would expect.

[Electro Fan]

I heard someone saying 2000x can do serial decode only on its 2/4 analog channels, and not on its 8 digital channels.

Unfortunately this is true, it is documented in the "Serial Bus Options for InfiniiVision X-Series Oscilloscopes" data sheet where the input sources are listed:

Analog channels 1, 2, 3, or 4
Digital channels D0 to D15 (3000 and 4000 X-Series only)

I guess decoding two way SPI will not be possible with a two channel 2000x.

This is correct, 4 channels are recommended/needed for SPI on the 2000X - but that seems like it would be true for any 2 channel scope, not just Agilent, right?

I meant two way SPI decoding will not be possible on a 2000X even when it is an MSO, this is not exactly what one would expect.

Right, I agree - it is surprising.  In this case it's kind of like Agilent went about 95-99 miles and didn't finish what should have or could have been a 100 mile race because either they didn't quite see the finish line, or maybe they didn't think it was worth going there, or maybe they didn't quite have a good way to get there.

[Hydrawerk]

Keysight Infinii Vision 2000 and 3000 scopes are 5 years old nowadays. I wonder if there is any new model coming?

[Wuerstchenhund]

3000-A became 3000-T, -T provides larger FFT size and touch screen.

The DSOX3000T is essentially a scaled down DSOX4000A. It has the same basic specs (5Gsa/s sampling, 64k FFT, 4M sample memory) but it also suffers from the same limitations (i.e. tiny sample memory, 64k FFT still pretty poor, small low resolution screen, VGA & LAN expensive options) the other members of the X-Series scopes.

[Keysight DanielBogdanoff]

I'll take some time in the next day or two with both a 3000T and a 2000A and go through your full list.

[Keysight DanielBogdanoff]

...and I just saw how old that first post was (2013).  So, I'm not going to break down the whole list right now.  But, if you have any scope related questions feel free to ask.

Key differences between 2000A and 3000T are still:

Bandwidth (70-200 MHz vs 100 MHz to 1 GHz)
Sample rate (2 GSa/s vs 5 GSa/s)
Touch screen standard on 3000T (zone trigger, on screen keyboard, movable windows/tabs etc.)
Memory Depth (2M vs 4M)
Segmented Memory (only on 3000T and up)
Waveform Update Rate (50k vs 1M)
Arbitrary WaveGen w/ built in editor
MSO channel count (8 vs 16)
Serial decode (2000 has I2C, SPI, UART, CAN, LIN; 3000T adds FlexRay MIL-STD1553, ARINC429, I2S, SENT)
Serial decode on digital channels (only for 3000T and up)
Lister
Probing capabilities (use active probes with 3000T and up)
Power analysis application (3000T and up)
Timebase accuracy (25 ppm vs 1.6 ppm)
Measurements (8 extra meas on 3000T and up)
More math (2000 gets "standard" only, get advmath on 3000T)
--link: http://www.keysight.com/en/pd-2020351-pn-DSOX3ADVMATH
Better FFT on 3000T (can do cursor gated, too)
Warranty (5yr on 2000, 3yr on 3000T)

I personally would prefer the 3000T ove rthe 2000 on the merit of the touch screen alone.  It makes navigation and usability skyrocket.
(Bonus article I wrote about touch screens:  http://www.techbriefs.com/component/content/article/ntb/features/feature-articles/21545)

[Keysight DanielBogdanoff]

And while I'm at it, here's the brief differences between the InfiniiVision 3000T vs 4000X

Bandwidth (100M-1G vs 200M-1.5G)
Touch screen (8.1" vs 12.1")
WaveGen w/ arb (1ch vs dual channel)
WaveGen Vpp max (+-5V vs +-10V_
Serial decode (4000X adds USB 2.0)
Simultaneous measurements on screen (8 vs 10)
Included passive probe (500 MHz vs 700 MHz)
Simultaneous active probe usage (2 at once vs 4 at once)
Math functions (2 vs 4)
Simultaneously displayed math functions (1 + FFT vs only 1)
10 MHz ref in/out (no vs yes)
LAN/VGA (option vs standard)

[Keysight DanielBogdanoff]

And wow one more: InfiniiVision 4000X vs 6000X.  Might be overkill, but I have my notes out so here goes.

Bandwidth (200M-1.5G vs 1-6 GHz)
Sample Rate (5 GSa/s vs 20 GSa/s)
Noise (using N7020A probe @ 1.5 GHz bandwidth) (3.34 mV vs 1.32 mV)
-at 20 mHz bandwidth (1.13mV vs 880 uV) (wow!)
Waveform update rate (1M vs 500k)
Color Graded Waveforms (no vs yes)
Multi-touch screen on 6000X (pinch & zoom & scroll waveforms!)
Jitter analysis package on 6000X
Counter (5 digit vs optional 10 digit)
Timebase accuracy (10 ppm vs 1.6 ppm)
Simultaneously displayed math functions (1 vs 4)

[nctnico]

...and I just saw how old that first post was (2013).  So, I'm not going to break down the whole list right now.  But, if you have any scope related questions feel free to ask.

Key differences between 2000A and 3000T are still:

Bandwidth (70-200 MHz vs 100 MHz to 1 GHz)
Sample rate (2 GSa/s vs 5 GSa/s)
Touch screen standard on 3000T (zone trigger, on screen keyboard, movable windows/tabs etc.)
Memory Depth (2M vs 4M)

Actually the useable memory depths is only a quarter of what is specified on Keysight oscilloscopes in common usage scenarios. First of all the memory is divided in half because of double buffering and then it is divided in half again when 2 channels in the same group (1&2 or 3&4) are enabled. And it gets less with reference traces on.

[nctnico]

There are other options out there for around the same price which have way more useable memory like Lecroy's Wavesurfer 3000 series. Some already noted that Keysight's ASICs are getting old and they should work on new ones with support for memories to 500Mpts otherwise Keysight will go follow Tektronix' example. You can't milk a cow forever!

edit: typo

[Hydrawerk]

Siglent and Rigol often have better specs, but when it comes to everyday professional usability, many people go for Keysight or Tektronix.

[nctnico]

Siglent and Rigol often have better specs, but when it comes to everyday professional usability, many people go for Keysight or Tektronix.

And for good reason because those better specs are only better on paper!

[Wuerstchenhund]

Siglent and Rigol often have better specs

Actually, most of the time they only offer more sample memory and a lower price, but the baseline specs are often not better (and sometimes even worse) than big brand instruments.

but when it comes to everyday professional usability, many people go for Keysight or Tektronix.

I certainly agree for Keysight but in terms of the big brands Tek is pretty much bottom-of-the-barrel these days. They were king of the hills back in the analog scope days but their DSOs have never really been particularly good or advanced (their only real highlight was to come up with a combination of entry-level scope and poorly spec'd spectrum analyzer), plus their service has declined a lot since then. They pretty much live from their reputation from the old times, and these days most of their sales go to traditional buyers that for some reason always bought Tek and never looked at the alternatives, because it's mandated (i.e. by contract or by policy), to people who believe just because they were great 30yrs ago that this must still be the case because the T&M market never changes, or the edu market (where Tek seems to be pretty much giving stuff away).

Tek has still some hold in the (corporate) entry-level scope market but the majority of mid-range and high-end sales go to Keysight and LeCroy, as they have been for lots of years already).

[Lajon]

Key differences between 2000A and 3000T are still:
.
.
.
Segmented Memory (only on 3000T and up)
.
.

2000A supports segmented memory (DSOX2SGM option).
/Lars

[fanOfeeDIY]

And wow one more: InfiniiVision 4000X vs 6000X.  Might be overkill, but I have my notes out so here goes.

Bandwidth (200M-1.5G vs 1-6 GHz)
Sample Rate (5 GSa/s vs 20 GSa/s)
Noise (using N7020A probe @ 1.5 GHz bandwidth) (3.34 mV vs 1.32 mV)
-at 20 mHz bandwidth (1.13mV vs 880 uV) (wow!)
Waveform update rate (1M vs 500k)
Color Graded Waveforms (no vs yes)
Multi-touch screen on 6000X (pinch & zoom & scroll waveforms!)
Jitter analysis package on 6000X
Counter (5 digit vs optional 10 digit)
Timebase accuracy (10 ppm vs 1.6 ppm)
Simultaneously displayed math functions (1 vs 4)

Thank you for the list.

I added InfiniiVision 6000X to the Digital Oscilloscope Chart.
https://www.eevblog.com/forum/testgear/digital-oscilloscope-comparison-chart/

[ECEdesign]

I go back and forth on which scope to get.  DS1054Z sure is cheap and good on paper but I hear more and more complaints about them being noisy and hard to use.  I have been considering a used Agilent 2 channel 2000 series scope.  Of course everyone has their opinon but it sounds like I would be much more happy down the road with the Agilent

[Wuerstchenhund]

I go back and forth on which scope to get.  DS1054Z sure is cheap and good on paper but I hear more and more complaints about them being noisy and hard to use.  I have been considering a used Agilent 2 channel 2000 series scope.  Of course everyone has their opinon but it sounds like I would be much more happy down the road with the Agilent

Probably, but at the end of the day it depends on what exactly you plan to do and your budget.

Since you're considering used, have a look at the R&S RTM1054. At the moment there's a seller on ebay that sells them for roughly the same price as a 2Ch 200MHz DSOX2k would roughly go for.

[ECEdesign]

Probably, but at the end of the day it depends on what exactly you plan to do and your budget.

Since you're considering used, have a look at the R&S RTM1054. At the moment there's a seller on ebay that sells them for roughly the same price as a 2Ch 200MHz DSOX2k would roughly go for.

The R&S scope looks like a great deal for the price, still a bit too high for me though, 1k is about my max for a scope.  I also need a few other things and trying to keep the total around 2k.  I watched some videos of the Rigol with 4 channels and it was so unresponsive I'm not sure its even worth having the extra 2 channels.  Used name brand is likely the way I am leaning towards maybe the 2012 Keysight scope

[Muxr]

I go back and forth on which scope to get.  DS1054Z sure is cheap and good on paper but I hear more and more complaints about them being noisy and hard to use.  I have been considering a used Agilent 2 channel 2000 series scope.  Of course everyone has their opinon but it sounds like I would be much more happy down the road with the Agilent

Probably, but at the end of the day it depends on what exactly you plan to do and your budget.

Since you're considering used, have a look at the R&S RTM1054. At the moment there's a seller on ebay that sells them for roughly the same price as a 2Ch 200MHz DSOX2k would roughly go for.

Been pondering the idea of getting that RTM1054 ever since I first saw that listing. Well I pulled the trigger today, we'll see when it gets here. Really from my research it's a pretty decent scope, waveforms per second is the only major handicap (measly 12500), but when you add up everything else like R&S UI and controls, and other specs, something had to give for that price. I'd rather give up on waveforms/s than any other spec in the end I guess.

[Wuerstchenhund]

Been pondering the idea of getting that RTM1054 ever since I first saw that listing. Well I pulled the trigger today, we'll see when it gets here. Really from my research it's a pretty decent scope, waveforms per second is the only major handicap (measly 12500), but when you add up everything else like R&S UI and controls, and other specs, something had to give for that price. I'd rather give up on waveforms/s than any other spec in the end I guess.

I wouldn't worry too much about the waveform rate to be honest, my old LeCroy WaveRunner scopes had similar update rates and I haven't encountered any situation where this presented a real limitation.

On the plus side, the build quality of the RTM is excellent (a big step up even from Hameg stuf which itself isn't exactly shabby), aside from powerup (where the fan spins up for a few seconds) it's absolutely silent, the UI is very good, it has some really nice search functionality, and decent FFT. The R&S probes are pretty nice, too.

And (as a bonus), how many other DSOs have an Y (brightness) input? 

[Muxr]

Been pondering the idea of getting that RTM1054 ever since I first saw that listing. Well I pulled the trigger today, we'll see when it gets here. Really from my research it's a pretty decent scope, waveforms per second is the only major handicap (measly 12500), but when you add up everything else like R&S UI and controls, and other specs, something had to give for that price. I'd rather give up on waveforms/s than any other spec in the end I guess.

I wouldn't worry too much about the waveform rate to be honest, my old LeCroy WaveRunner scopes had similar update rates and I haven't encountered any situation where this presented a real limitation.

On the plus side, the build quality of the RTM is excellent (a big step up even from Hameg stuf which itself isn't exactly shabby), aside from powerup (where the fan spins up for a few seconds) it's absolutely silent, the UI is very good, it has some really nice search functionality, and decent FFT. The R&S probes are pretty nice, too.

And (as a bonus), how many other DSOs have an Y (brightness) input? 

Yeah the Z brightness in XY mode is neat.

Ditto on the waveforms/s, just something to keep in mind when looking for rare glitches I guess (crank up persistence and give it time).
If anything will probably keep my DS2072A around as well, even though it too isn't exactly great in that aspect either.

For the price I can't really complain about the DS2072A it's been a great scope (for the price), but I never really got 100% comfortable with its UI and controls. After a year and a half I still find myself hunting for that one rarely used feature, and just the general UI sluggishness and lag drove me nuts. Shouldn't hate on it too much though, it's really been a good scope to me. Which is why I am really psyched about getting this RTM 1054!

I made a mistake by checking out some RTO vids, heh. There is always that next thing in T&M!

[Wuerstchenhund]

Yeah the Z brightness in XY mode is neat.

Indeed. When I got mine (from the same seller btw) I was surprised to find that the scope offers true XYZ mode, something I can't remember having seen on any other DSO (but then I don't need it so I might well have just missed it).

Ditto on the waveforms/s, just something to keep in mind when looking for rare glitches I guess (crank up persistence and give it time).

I usually just use proper triggers to capture glitches, which is pretty easy plus I don't have to sit there and wait for a rare event to show up on persistence.

If anything will probably keep my DS2072A around as well, even though it too isn't exactly great in that aspect either.

Well, I'd guess your Rigol will see little use as the RTM can do pretty much the same just a bit better.

For the price I can't really complain about the DS2072A it's been a great scope (for the price), but I never really got 100% comfortable with its UI and controls. After a year and a half I still find myself hunting for that one rarely used feature, and just the general UI sluggishness and lag drove me nuts. Shouldn't hate on it too much though, it's really been a good scope to me. Which is why I am really psyched about getting this RTM 1054!

The Rigol DS2000 is certainly not a bad scope, especially when considering the price. Plus it's probably the most mature Rigol scope of all. But yes, it is obviously built to a low cost, and the easiest things to cut cost is software.

The RTM UI is pretty good, it's fluid, and the XGA display (1024x768) is very nice in such a compact scope, too. There are also many details which show the thought that went into the product design, i.e. the dimmable front panel LEDs.

I made a mistake by checking out some RTO vids, heh. There is always that next thing in T&M!

Yes, the RTO Series is cool (and they even offer an OCXO as option). But from what I've seen so far the UI isn't that great, it can do a lot but it's not very intuitive and in some areas not really well thought out. And R&S really is pretty pricey, and for the money they want for an RTO you can find better alternatives from other vendors.

[Hydrawerk]

And (as a bonus), how many other DSOs have an Y (brightness) input? 

Do you mean this?
https://youtu.be/zkaYzYXZ4dI

[Muxr]

You can also do this:


edit: Also I think that HP only has a binary Z axis, either on or off, which is why they called it blanking in that video I assume. The RTM1054 should support Z axis intensity, for grayscale ability like (the analog scope) in the video I posted.

Also I believe there are some headless instruments, like spectrum analyzers that require XYZ support to function on the scope. Basically you use the scope as your screen for the instrument.

[Wuerstchenhund]

And (as a bonus), how many other DSOs have an Y (brightness) input? 

Do you mean this?
https://youtu.be/zkaYzYXZ4dI

Yes, although as Muxr stated the HP only does blanking while a true Z input as the one in the example he provided allows brightness modulation.

The RTM1054 should support Z axis intensity, for grayscale ability like (the analog scope) in the video I posted.

Yes, at least according to the manual (never tried it). Would be interesting to try something like that in your example on the RTM.

Also I believe there are some headless instruments, like spectrum analyzers that require XYZ support to function on the scope. Basically you use the scope as your screen for the instrument.

That's true, but most of them were pretty mediocre so I'm not sure they are still worth bothering with. But hey, at least the LCD screen of the RTM should provide a much better and sharper picture than an old analog scope 

[Muxr]

Yup will have to play with XWZ mode as well  . Sadly I don't own an SA, so it's nice to have that option. Partly because they are kind of bulky and expensive and I wouldn't use them often to be a worthwhile investment. Also they mostly don't cover audio frequencies, which is what I would probably use it for mostly. That and I also own a Keithley 2015, which can measure THD at least.

Curious about the FFT on the RTM1054. The sluggishness and weird UI made the one on DS2072A next to useless.

[nctnico]

I also looked at the RTM1054 but since I needed decoding and didn't want to go on another hacking expedition I choose to buy a different oscilloscope. Pity because I would have liked to play around with an R&S scope for a change.

[Muxr]

I also looked at the RTM1054 but since I needed decoding and didn't want to go on another hacking expedition I choose to buy a different oscilloscope. Pity because I would have liked to play around with an R&S scope for a change.

Yeah I read your quest about getting quotes for decoding. It is pretty expensive $1k per option pretty much? I can live without it though. I usually just use the Saleae for that. And maybe one day I get bored and decide to try and hack it.

But it is a bit annoying, because they have this awesome capability on the scope itself, and even though the scope depreciates in value for us individual enthusiasts to have access to, the software feature unlocks don't scale with the depreciation of the equipment, so the price disparity is a bit ridiculous.

[Wuerstchenhund]

Curious about the FFT on the RTM1054. The sluggishness and weird UI made the one on DS2072A next to useless.

FFT on the RTM is surprisingly fast, and it uses 64kpts which is a lot better than the measly 4kpts max or so found on Rigol scopes (and pretty much on par with the Keysight DSOX3000A/T).

I also looked at the RTM1054 but since I needed decoding and didn't want to go on another hacking expedition I choose to buy a different oscilloscope. Pity because I would have liked to play around with an R&S scope for a change.

Yeah I read your quest about getting quotes for decoding. It is pretty expensive $1k per option pretty much? I can live without it though. I usually just use the Saleae for that. And maybe one day I get bored and decide to try and hack it.

But it is a bit annoying, because they have this awesome capability on the scope itself, and even though the scope depreciates in value for us individual enthusiasts to have access to, the software feature unlocks don't scale with the depreciation of the equipment, so the price disparity is a bit ridiculous.

R&S has a well deserved reputation not just for building great gear but also for being very expensive, and unfortunately that shows. They are generally pretty friendly towards hobbyist and often with some luck one might get features unlocked for an old device if it's for personal use, but as you say they don't drop the prices for options of old gear, which is silly because hardly anyone would pay $5k for a few decoding options for a $2k 2nd hand scope. R&S is missing the trick here.

But then, a solution was found for the Rigols, so I can't imagine why a similar solution couldn't be found for old R&S gear 

[TheSteve]

Hah, you guys are doing a good job comparing scopes but there is a very little 2000 and 3000 X-Series info - maybe start a new thread?

[Wuerstchenhund]

Hah, you guys are doing a good job comparing scopes but there is a very little 2000 and 3000 X-Series info - maybe start a new thread?

What info are you looking for that hasn't been mentioned in this and other threads and Keysight_DanielBogdanoff's posts?

DSOX2k and DSOX3KA aren't exactly new scopes (and the later DSOX3kT is just a slightly upgraded DSOX3kA), and there are several threads about them already, some going back to 2012 (when DSOX2k and DSOX3k came to market). Aside from the DSOX3kT update there hasn't really been much changes to these scopes since then, but what has changed is the competitive landscape (there are some alternatives available today which in many areas are better)

[ECEdesign]

but what has changed is the competitive landscape (there are some alternatives available today which in many areas are better)

Which scopes would these be?  I think im pretty set on a DSOx2012 or if I find a good deal DSOX2022/DSOX2014. 

I saw a Tektronix TDS-2024B pretty cheap.  The bandwidth was a little higher but the Agilent's screen is awesome. 

[nctnico]

I went for a GwInstek GDS2204E as a second (spare) oscilloscope. If you can spend a little bit more then Lecroy's Wavesufer 3000 is definitely worth looking at. If I had not come across a good deal on a used Agilent DSO7104 I probably would have at gotten a Wavesurfer 3000 on loan for evaluation.

[Wuerstchenhund]

but what has changed is the competitive landscape (there are some alternatives available today which in many areas are better)

Which scopes would these be?  I think im pretty set on a DSOx2012 or if I find a good deal DSOX2022/DSOX2014.

For example there's the Rigol DS2000 (if you want a 2ch scope) as a good and by now pretty mature alternative. There's also the R&S HMO1202 which has recently been in one of Dave's tear-down videos. The GW Instek GDS2000E that nctnico mentioned might also be worth a look although I personally have no experience with this brand. The DSOX2k is a good scope but at the end of the day it's a entry-level scope with not that great specifications, and that isn't that hard to beat.

As far as the DSOX3k is concerned, the LeCroy WaveSurfer 3000 Series that nctnico mentioned is a very attractive alternative which is better in most of the relevant areas (i.e. sample memory, functionality, screen size/resolution, ports) while being noticeably cheaper than the DSOX3000 (i.e. some $2k cheaper for the 500MHz variant), and it doesn't look bad even in comparison to the (even more expensive) DSOX4000 Series.
 

I saw a Tektronix TDS-2024B pretty cheap.  The bandwidth was a little higher but the Agilent's screen is awesome.

Well, the TDS2000B is a pretty antique design with measly specs that is pretty much only bought by those that have no other choice than spending money with Tek. Tek is pretty much riding on the reputation from the old analog days when they were still a leading T&M brand and not the shadow they are today.

[ECEdesign]

For example there's the Rigol DS2000 (if you want a 2ch scope) as a good and by now pretty mature alternative. There's also the R&S HMO1202 which has recently been in one of Dave's tear-down videos. The GW Instek GDS2000E that nctnico mentioned might also be worth a look although I personally have no experience with this brand. The DSOX2k is a good scope but at the end of the day it's a entry-level scope with not that great specifications, and that isn't that hard to beat.

As far as the DSOX3k is concerned, the LeCroy WaveSurfer 3000 Series that nctnico mentioned is a very attractive alternative which is better in most of the relevant areas (i.e. sample memory, functionality, screen size/resolution, ports) while being noticeably cheaper than the DSOX3000 (i.e. some $2k cheaper for the 500MHz variant), and it doesn't look bad even in comparison to the (even more expensive) DSOX4000 Series.

I have been looking at the new HMO1202, the education price is around 1100.  Bit more than I wanted to pay but it is a new scope.  I have seen keysight dsox2012 for around 900.  They seem like pretty comparable scopes but the memory is higher on the HMO1202.  From what I can tell the Keysight is super responsive due to their ASIC.  We also learn in the labs on Keysight 2000 series scopes.  I love the big screen.

Im not really looking for an MSO, I plan on using a Saleae 8 for that.  Just something to analyze analog signals and that ill be happy with for a bit in the future (when have a real job and can buy a nice new scope)

[Wuerstchenhund]

I have been looking at the new HMO1202, the education price is around 1100.  Bit more than I wanted to pay but it is a new scope.  I have seen keysight dsox2012 for around 900.  They seem like pretty comparable scopes but the memory is higher on the HMO1202.  From what I can tell the Keysight is super responsive due to their ASIC.  We also learn in the labs on Keysight 2000 series scopes.  I love the big screen.

Im not really looking for an MSO, I plan on using a Saleae 8 for that.  Just something to analyze analog signals and that ill be happy with for a bit in the future (when have a real job and can buy a nice new scope)

As I said, the DSOX2k isn't a bad scope, and just because there are some other scopes available that have some advantages over it doesn't mean it's not a good buy. The truth is that at the lower end of the market there isn't really a world of difference between available scopes, they all are pretty much similar with similar specs and performance figures (it's a different story for the upper low-end/lower mid-range like the DSOX3k, though).

The new HMO is a very good scope but since you don't need MSO then the additional $300 wouldn't really be worth it. Buying the cheaper DSOX2k now and saving for a much better scope later on sounds like indeed the better option.

[ECEdesign]

Thanks for the help on choosing my scope!   

[Faith]

Sorry for resurrecting this old thread again, but I figured it would be the best one to reply to since Daniel from Keysight has wonderfully provided us with a summary comparison between the 2000, 3000 & 4000 X-Series.

So my question is this; ordinarily there would be a US$2,274.00 price difference between the MSOX3024T & MSOX4024A.

But now with the "Free DSO to MSO Upgrade" promotion the difference is down to US$972.00 (when comparing the DSOX3024T & DSOX4024A prices).

And since I also require LAN (which is a US$404.00 module on the 3000T but standard on the 4000A) that brings the difference down to US$568.00.

So is there actually any practical disadvantage of purchasing the 4000A versus the 3000T seeing how the 4000A is actually a slightly older model? I do very much like the larger screen.

The price of the software licenses are the same as long as you purchase the Application Bundle (which I intend on doing).

Other than that, is there anything else I should take note of? Is this even a good time to upgrade given the age of the MegaZoom IV?

From what I can tell the only feature missing from the 4000A which the 3000T has is the 8-Digit Frequency Counter.

[nctnico]

Look at Lecroy's Wavesurfer 3000! The MSOX3000 and MSOX4000 don't have enough memory for the price. What the specs don't say is that the 4Mpts becomes 1Mpts per channel (or even less with the MSO enabled). The 4MPts is the total memory and it is shared between channels and MSO AND it is also used for double buffering. I have an 8Mpts DSO7000A series and I keep running out of memory for some measurements.  All in all the warm & fuzzy fealing of having a Keysight scope will wear off quickly.

[Wuerstchenhund]

Other than that, is there anything else I should take note of? Is this even a good time to upgrade given the age of the MegaZoom IV?

I have to concur with nctnico here. The DSOX aren't bad scopes but at the end of the day you're paying through the nose for an aging entry-level platform with tiny sample memory which was pretty much designed for max waveform rates at the cost of anything else.

Really, have a look at the LeCroy WaveSurfer 3000. It's a lower mid-range scope which comes with a few advantages over the DSOX3000T, for example (copied from an older posting of mine):

• The WaveSurfer comes with 4GSa/s and 10Mpts (the slighly lower sample rate is irrelevant for scopes with <1GHz BW, however the larger memory is a real-life advantage)
• The Wavesurfer comes with a larger screen with higher resolution (10.1" 1024x600 vs 8.4" 800x480 with the DSOX3kT)
• FFT with the WaveSurfer is up to 1Mpts while on the DSOX3kT FFT uses 64kpts only (which is pretty poor in this price class)
• The WaveSurfer allows automatic and manual sample memory/sample rate management while the DSOX3kT is automatic only
• WaveSurfer 3000 has many features that can be found in LeCroy's high-end scopes, i.e. WaveScan and LabNotebook
• The DSOX3kT has nothing comparable to WaveScan, which is a very versatile tool to find rare glitches and other issues and which works 'live' as well as on sampled data.
• The DSOX3kT also doesn't offer anything comparable to LabNotebook, which is a documentation tool and pretty neat if you have to document your measurements in some standardized format.
• The WaveSurfer 3000 uses the same probe interface (ProBus) all midrange and high-end scope from LeCroy use since the mid '90s, which means there's a wide range of suitable active probes out there, including a lot of second-hand ones which often sell for reasonable prices because they don't carry the "Tektronix" or "Agilent" label
• Integrated AWG: 25MHz 125MSa/s 14bit with 16kpts on the WaveSurfer, 20MHz 100MSa/s 10bit with 8kpts on the DSOX3kT (both not great, but still)
• LAN is standard on the WaveSurfer 3000 while it's a $400+ option on the already very expensive DSO3kT
• Not that important, but the WaveSurfer has four (2x front, 2x rear) USB host ports (Keysight two, one front one rear)
• Plus the WaveSurfer 3000 is noticably cheaper than the DSOX3kT

Most of the points remain valid against the DSOX4kA as well.

Also, LeCroy fully supports all its scopes for 7 years after a model goes end-of-sale, and on a "best effort" basis beyond that (they still repair 9300 scopes from the '90s, although getting spares is becoming increasingly difficult). LeCroy also provides software support much longer than anyone else, while Agilent/Keysight often ends software updates while a product is still within mainstream support. LeCroy also doesn't artificially limit probe compatibility between its scope models as Keysight does.

The only case where I'd chose the DSOX over the WaveSurfer would be when one of the serial decode options that aren't (yet) available for the WaveSurfer are required, i.e. MIL-1553 or I2S. As to options, LeCroy often has promos where all options are included, and if you make sure to highlight your interest in a Keysight scope then they most certainly will throw in the options for free.

In any case, if you're going to spend several grands on a scope I strongly recommend to contact the vendors and ask for a loaner which you can take for a spin around the block. Features only go so far if you for some reason can't get on with a scope, so it's important to 'test-drive' them before spending all that money.

[Hydrawerk]

https://www.picotech.com/oscilloscope/6000/picoscope-6000-specifications

10 mV/div to 4 V/div at x1 zoom (1 M? input)

Well, many scopes have 1mV/div or 4mV/div resolution.

Maximum sampling rate (single-shot)
1 channel in use   5 GS/s
2 channels in use  2.5 GS/s
3 or 4 ch. in use      1.25 GS/s

[Faith]

Thank you everyone for your replies and recommendations

The main reason for considering Keysight is because I am already familiar with the 2000A. And you know how it is, some of us don't like to change what we are used to or familiar with

I did take a brief look at Teledyne LeCroy and more specifically their WaveSurfer 3000 but if I recall correctly it does not have a built-in Arbitary Function Generator. This is one feature I would certainly like as it would mean that there is less equipment occupying my limited bench space.

In fact I did rule out quite a few brands based on this requirement alone. I was originally quite keen on a number of offerings by Rohde & Schwarz but ruled them out for the same reason.

I guess one option is to just stick with the MSOX2024A (with its rather sad memory depth) which I have access to every now and then (as it isn't mine) until such time Keysight upgrades their product range with a new MegaZoom. I've always loved their user interface and it has grown on me quite well.

Ahh. Choices, choices. I didn't feel like the memory depth would have been a big issue (especially when using channel one and three on the four channel version) but I can see how it could potentially become a problem in the future. I do recall Dave mentioning in one of his reviews that he quite likes the idea of having memory managed automatically, and coming from a 2000A it was easy for me to agree with him (whether that is justified or not is a separate matter altogether, haha).

[yodhe]

The Wavesurfer 3000 does have an AWG option.

http://teledynelecroy.com/options/productseries.aspx?mseries=472&groupid=144

[Someone]

Ahh. Choices, choices. I didn't feel like the memory depth would have been a big issue (especially when using channel one and three on the four channel version) but I can see how it could potentially become a problem in the future. I do recall Dave mentioning in one of his reviews that he quite likes the idea of having memory managed automatically, and coming from a 2000A it was easy for me to agree with him (whether that is justified or not is a separate matter altogether, haha).

Memory depth controls can be important on scopes where the acquisition rate, measurements, or user interface slow down with longer memory depths, Tek and Rigol in particular but most scopes do this to some extent. The Agilent/Keysight X series didn't need the option to reduce the acquisition depth as they offer so much speed even at full memory depth, its only reduced below maximum when using the segmented capture mode.

[Faith]

The Wavesurfer 3000 does have an AWG option.

http://teledynelecroy.com/options/productseries.aspx?mseries=472&groupid=144

Err no idea how I missed that... think I got that bit mixed up with Rohde & Schwarz at some point >,<"...

Its best to make your own value choices rather than relying on others such as Mr W, he likes to spin all aspects of Lecroy products as advantages even when they are undesirable features. Memory depth controls can be important on scopes where the acquisition rate, measurements, or user interface slow down with longer memory depths, Tek and Rigol in particular but most scopes do this to some extent. The Agilent/Keysight X series didn't need the option to reduce the acquisition depth as they offer so much speed even at full memory depth, its only reduced below maximum when using the segmented capture mode.

Yep, ultimately I will make a purchasing decision based on my own experiences and comfort levels.

While I did some homework here and there I did eventually end up between the MSOX3024T & MSOX4024A; thus my original question, which has been completely derailed by now

Of course 99% of my judgement is based from my familiarity with the 2000A, but I never really found its 1M memory depth to be too big of an issue, and hence why I didn't think much of it when I saw that the 3000T/4000A are 4M.

[nctnico]

Memory depth controls can be important on scopes where the acquisition rate, measurements, or user interface slow down with longer memory depths, Tek and Rigol in particular but most scopes do this to some extent. The Agilent/Keysight X series didn't need the option to reduce the acquisition depth as they offer so much speed even at full memory depth, its only reduced below maximum when using the segmented capture mode.

Speed is relative. With my DSO7000 I have to do some measurements several times because it is not very clear what samplerate is used and how much memory is actually available. All in all I'd be finished quicker using an oscilloscope which has more memory, is clear about the memory length & samplerate even though the UI might be slower.

[Wuerstchenhund]

PicoScope 6000 series excels at every points you have listed.

No, they don't. You get stuff like more in sample memory, and (depending on your computer's monitor) a larger screen. What you don't get are advanced glitch finders like WaveScan, or even so basic things in this class like an active probe interface. And you get an UI that requires having mouse and keyboard on your bench.

We use PicoScopes at work (mostly for automated test systems where they are great), but even their most ardent fans wouldn't suggest them as a replacement for a proper standalone scope.

The main reason for considering Keysight is because I am already familiar with the 2000A. And you know how it is, some of us don't like to change what we are used to or familiar with

I know, and that is a perfectly valid argument.

On the other side, it's a lot of money and I guess most people would want to get the most bang for their bucks, and at the end of the day it helps to know all available options even if you then go for original choice.

I did take a brief look at Teledyne LeCroy and more specifically their WaveSurfer 3000 but if I recall correctly it does not have a built-in Arbitary Function Generator. This is one feature I would certainly like as it would mean that there is less equipment occupying my limited bench space.

It does have an AWG, as stated in the list:
http://cdn.teledynelecroy.com/files/pdf/wavesurfer-3000-datasheet.pdf

Ahh. Choices, choices. I didn't feel like the memory depth would have been a big issue (especially when using channel one and three on the four channel version) but I can see how it could potentially become a problem in the future. I do recall Dave mentioning in one of his reviews that he quite likes the idea of having memory managed automatically, and coming from a 2000A it was easy for me to agree with him (whether that is justified or not is a separate matter altogether, haha).

Back in 2012 when the DSOX came out many low-end scopes required the user to manually select between short and long memory (i.e. you had two choices). The MegaZoom manages the memory automatically, i.e. the user has no choice how the memory is used, and the scope keeps the used amount of memory at minimum required to fill the display to increase the waveform rate.

The WaveSurfer lets you select the amount of sample memory manually, but you don't have to.

Its best to make your own value choices rather than relying on others such as Mr W, he likes to spin all aspects of Lecroy products as advantages even when they are undesirable features.

Memory depth controls can be important on scopes where the acquisition rate, measurements, or user interface slow down with longer memory depths, Tek and Rigol in particular but most scopes do this to some extent. The Agilent/Keysight X series didn't need the option to reduce the acquisition depth as they offer so much speed even at full memory depth, its only reduced below maximum when using the segmented capture mode.

  There's so much wrong with that it's not even funny.

First, you completely ignore that the time it takes to fill a certain amount of sample memory at a certain sample size is fixed:

                  capture time [seconds] = sample memory size [pts] / sample rate [Sa/second]

This basic law hold true even for a Keysight DSOX InfiniiVision scope. So on your (I believe) DSOX3kA, at 4GSa/s it takes 1ms to fill 4Mpts of sample memory. Even if we had a perfect trigger circuit immediately re-arming, the time it takes to fill the 4Mpts alone means that even with that perfect trigger the update rate would be limited to 1000 per second. There's no way around that, it's a physical reality.
 
What MegaZoom does is using windowing to reach its high update rates. Windowing is used during normal operation where the scope only uses enough memory to fill the period shown on screen. That means even if it shows you it's using 2Mpts it's actually just using a few kpts. Only when you stop the acquisition system or enable zoom then the last acquisition uses all of the displayed sample memory. It's pretty much a trick to circumvent the fact that using all the displayed memory at the displayed sample rate would make it physically impossible to attain high sample rates. This is also the reason the InfiniiVision doesn't allow manual controls.

[Someone]

Memory depth controls can be important on scopes where the acquisition rate, measurements, or user interface slow down with longer memory depths, Tek and Rigol in particular but most scopes do this to some extent. The Agilent/Keysight X series didn't need the option to reduce the acquisition depth as they offer so much speed even at full memory depth, its only reduced below maximum when using the segmented capture mode.

  There's so much wrong with that it's not even funny.

First, you completely ignore that the time it takes to fill a certain amount of sample memory at a certain sample size is fixed:

                  capture time [seconds] = sample memory size [pts] / sample rate [Sa/second]

This basic law hold true even for a Keysight DSOX InfiniiVision scope. So on your (I believe) DSOX3kA, at 4GSa/s it takes 1ms to fill 4Mpts of sample memory. Even if we had a perfect trigger circuit immediately re-arming, the time it takes to fill the 4Mpts alone means that even with that perfect trigger the update rate would be limited to 1000 per second. There's no way around that, it's a physical reality.
 
What MegaZoom does is using windowing to reach its high update rates. Windowing is used during normal operation where the scope only uses enough memory to fill the period shown on screen. That means even if it shows you it's using 2Mpts it's actually just using a few kpts. Only when you stop the acquisition system or enable zoom then the last acquisition uses all of the displayed sample memory. It's pretty much a trick to circumvent the fact that using all the displayed memory at the displayed sample rate would make it physically impossible to attain high sample rates. This is also the reason the InfiniiVision doesn't allow manual controls.

If you want to frame it in terms of time period captured on the screen then the update rate does has a ceiling of:
1/capture time
But most scopes will degrade their realtime waveform capture rate below the theoretical maximum when you increase the memory depth, which was the key differentiator of the "always on" memory and not having a memory depth control on the Agilent/Keysight X series scopes since they processed the waveforms to the display in the ASIC and wouldn't run substantially faster if the memory depth was reduced. I even plotted up the collected data from this forum to make it easy to compare:
https://www.eevblog.com/forum/testgear/rigol-mso4000-and-ds4000-tests-bugs-firmware-questions-etc/msg973064/#msg973064
All the data points at whatever the sample rate is gets to the screen, even though on the Agilent/Keysight design it is rendered at a lower resolution and you can only zoom in on the last capture and not the accumulated graduated display. As an alternative method didn't the Wavejets let you zoom and pan the graduated capture along with their segmented captures?

But to say that manual control of memory depth is a better thing to have when its just used to hide other downsides to a product is once again disingenuous. Ideally you would want to operate your scope at maximum memory depth all the time! And Agilent/Keysight delivered this.

[Wuerstchenhund]

But most scopes will degrade their realtime waveform capture rate below the theoretical maximum when you increase the memory depth, which was the key differentiator of the "always on" memory and not having a memory depth control on the Agilent/Keysight X series scopes since they processed the waveforms to the display in the ASIC and wouldn't run substantially faster if the memory depth was reduced.

Most scopes will decrease their update rate because they are actually using the memory they claim to use for every single acquisition.

The DSOX (like it's InfiniiVision predecessors) only manage to reach faster because they are *not* using the full memory most of the time. They have to, as it is physically impossible to reach high waveform numbers while using all of that paltry 4MB memory, as shown in my previous post.

I even plotted up the collected data from this forum to make it easy to compare:
https://www.eevblog.com/forum/testgear/rigol-mso4000-and-ds4000-tests-bugs-firmware-questions-etc/msg973064/#msg973064

All the data points at whatever the sample rate is gets to the screen, even though on the Agilent/Keysight design it is rendered at a lower resolution and you can only zoom in on the last capture and not the accumulated graduated display.

Which is one limitation of the MegaZoom platform.

As an alternative method didn't the Wavejets let you zoom and pan the graduated capture along with their segmented captures?

I believe so, but then I haven't had much contact with them, and since they are essentially Iwatsu rebadges a few things work differently on these scopes than on 'real' LeCroy scopes.

But to say that manual control of memory depth is a better thing to have when its just used to hide other downsides to a product is once again disingenuous. Ideally you would want to operate your scope at maximum memory depth all the time! And Agilent/Keysight delivered this.

No, they did not! They delivered a system which creates the impression to the (uninformed) user that it always uses maximum sample memory when in fact it is cheating its way out. This also has consequences, i.e. for recording pre-trigger events.

I've no doubt that the way MegaZoom works makes it easier for beginners. But spinning the absence of manual controls as an advantage is preposterous. It's like saying a scope that only has an auto-set button is better than one that has manual knobs and buttons because the auto-setup system always produces a stable image (well, it doesn't, but let's ignore that for a moment). The point of the various controls of a test instrument is that the user can setup the instrument to fit the measurement situation, and that works better with more control than with less. I'm not against automatics in scopes (unlike many of my peers), but only as long as they don't get in the way of giving the user control of the instrument. They do become a hindrance when automatics are the only option, even more so when the 'price' for that automatism is a comparably tiny sample memory.

Of course Keysight knows this very well, after all pretty much all of its high-end scopes (aside from the DSOX6004, but that's pretty much just an expensive variant of the DSOX3k which is an entry-level scope) allow manual control of memory and sample rate. The DSOX doesn't because it was pretty much designed for the highest possible update rate at the price of everything else, which was pretty much Agilent's marketing spin back in 2012. But there's a reason why other scopes (even keysight's own scopes) didn't follow that path, and more than compensate their lower waveform rate with advanced triggering and analysis tools.

The more I have to carry my MSOX3104A across lab, home and office, the more I wish I have bought a PS6000. PS have some quite advanced triggers that can automatically analyze something, but I have never really looked into it. Talking about active probe IF, it is really a PITA. However, the active probe IF on my MSOX is also next to useless -- the probes quickly sum up more than the price of the scope. It is common to see a probe selling for $1000, and the tips $4000, which is ridiculous. Thanks to the custom coax interface, even if I have a prove and a scope, without its proprietary tips, it is next to useless.

Well, that's normal as stuff that is labelled Agilent/Keysight is pretty sought after, as is Tek. Simply because when thinking about scopes Agilent/Keysight and Tek are for many people the only names that come to mind. But just because some seller wants $4k for something doesn't mean it's selling. Of course, if its compatible with the DSOX it will fetch extra money, thanks to Agilent/Keysight making some probes artificially incompatible with the InfiniiVision scopes and thereby limiting the choice for InfiniiVision scope users.

On the other side, I've bought several active LeCroy probes (AP033, AP034, HPF Series) for a couple of hundred dollars, as have other forum users. Thanks to most people focussing on Agilent/Keysight and Tek there are a lot more deals for LeCroy probes (although it does require patience). It also helps that LeCroy's active probe interface hasn't changed since the '90s, and because of the unified software stack there are pretty much no compatibility issues with older probes on newer scopes.

But yes, if you have to schlepp around the scope regularly then the PicoScope might be the better option, even more so when you're already using a PC on the bench.

[Howardlong]

So I have set up permanently MSOX3054A, MSOX7104B, MDO3054, and 54832D on the bench. Since I put the MSOX7104B on a slide out swivel mount above the desk, that gets by far the most use, but it used to be the MSOX3054A.

Depite not being able to freely manually set the acquisition sample rate and/or memory depth, by far most of the time, I find the way the MSOX series work are most conducive to my workflow.

With the MDO3054 and 54832D I can manually set those parameters, but I actually find that by far most of the time, having to attend to that step gets in the way of what I'm trying to do, and I do find myself needing to alter the memory depth quite a lot particularly on the Tek where it's a compromise between sluggish performance with long memory or faster response with short memory. To some extent that can also apply to the 54832D, but there are also other problems with the Tek: most notably the UI as a whole which as well as being unresponsive is a bit of a potpourri, the crazy paving of UIs, it feels like everything's a fight.

Although on occasion being able to adjust the memory settings might seem a reasonable thing to want to do, in practice I just find that I use a slightly different workflow depending on the scope. If the proof is in the pudding, almost all the time I find myself using that of the MSOX series, but others may have different needs. I certainly don't find it a limitation -most- of the time.

[Wuerstchenhund]

With the MDO3054 and 54832D I can manually set those parameters, but I actually find that by far most of the time, having to attend to that step gets in the way of what I'm trying to do, and I do find myself needing to alter the memory depth quite a lot particularly on the Tek where it's a compromise between sluggish performance with long memory or faster response with short memory. To some extent that can also apply to the 54832D, but there are also other problems with the Tek: most notably the UI as a whole which as well as being unresponsive is a bit of a potpourri, the crazy paving of UIs, it feels like everything's a fight.

As a fresh owner of a Tek MDO3054 I can certainly understand your plight, but that is pretty much due to the MDO being a very poor scope with a slow platform and a horrendous UI designed by someone who probably hates humans.

As to UI, the 58432D isn't really a lot better with its mouse-driven UI. My DSO8064 uses the same, and although it has a higher resultion display with touch, I find its menu system cumbersome, especially for basic things like changing sample memory. I leave it most of the time on auto as well but, despite all criticism, at least there's the option to change the auto settings manually. 

Just to compare, on my LeCroy it's just a tab on the Acq box in the lower right corner to get to the memory settings.

Although on occasion being able to adjust the memory settings might seem a reasonable thing to want to do, in practice I just find that I use a slightly different workflow depending on the scope. If the proof is in the pudding, almost all the time I find myself using that of the MSOX series, but others may have different needs. I certainly don't find it a limitation -most- of the time.

Completely understandable, but this is probably more down to the fact that neither the Infiniium 54832D nor the Tek MSO3054 are good every-day scopes than to the InfiniiVisions being particular great. But whatever works for you.

[Someone]

Really, have a look at the LeCroy WaveSurfer 3000. It's a lower mid-range scope which comes with a few advantages over the DSOX3000T, for example (copied from an older posting of mine):

• ...
• The WaveSurfer allows automatic and manual sample memory/sample rate management while the DSOX3kT is automatic only
• ...

Since you seem to have wandered way off and reframed the discussion several times to distract from this, can you provide examples of when it is desirable to use less than the maximum memory possible? I can't think of any situation where I would want to use less memory depth on an Agilent/Keysight X series scope, there is no downside to having the maximum memory enabled at all times. There may be downsides on other scopes but there are none here, the absence of a memory depth control is not a negative point and rather points to deficiencies of other products which require it.

[nctnico]

Really, have a look at the LeCroy WaveSurfer 3000. It's a lower mid-range scope which comes with a few advantages over the DSOX3000T, for example (copied from an older posting of mine):

• ...
• The WaveSurfer allows automatic and manual sample memory/sample rate management while the DSOX3kT is automatic only
• ...

Since you seem to have wandered way off and reframed the discussion several times to distract from this, can you provide examples of when it is desirable to use less than the maximum memory possible? I can't think of any situation where I would want to use less memory depth on an Agilent/Keysight X series scope, there is no downside to having the maximum memory enabled at all times. There may be downsides on other scopes but there are none here, the absence of a memory depth control is not a negative point and rather points to deficiencies of other products which require it.

If you forget that on average the actual record length in the Keysight scopes is 10 to 50 times shorter than in other scopes then you are right.

[Someone]

Really, have a look at the LeCroy WaveSurfer 3000. It's a lower mid-range scope which comes with a few advantages over the DSOX3000T, for example (copied from an older posting of mine):

• ...
• The WaveSurfer allows automatic and manual sample memory/sample rate management while the DSOX3kT is automatic only
• ...

Since you seem to have wandered way off and reframed the discussion several times to distract from this, can you provide examples of when it is desirable to use less than the maximum memory possible? I can't think of any situation where I would want to use less memory depth on an Agilent/Keysight X series scope, there is no downside to having the maximum memory enabled at all times. There may be downsides on other scopes but there are none here, the absence of a memory depth control is not a negative point and rather points to deficiencies of other products which require it.

If you forget that on average the actual record length in the Keysight scopes is 10 to 50 times shorter than in other scopes then you are right.

Long memory can be important and/or useful, but that doesn't explain why a scope needs to have a memory depth control. You're welcome to have a crack at the question too rather than derailing the thread further.

[nctnico]

Setting the memory depth can be handy for speeding up things like math traces, measurements, etc. Still it would be a great help if Keysight showed the memory length and samplerate so (especially when using segmented recording) you have an idea on whether the amount memory/samplerate is going to be adequate or not.

[nfmax]

So: memory depth...

If I'm looking at a repetitive signal, one which repeats often enough to fool the eye, then so long as I have enough memory to fill the screen (and handle the pre trigger delay I've set), having more memory doesn't improve anything much. If I want to zoom in or pan, I just adjust the sweep rate control & trigger delay, and the next trigger event fills the memory with my chosen settings. In fact, having too large a memory slows the waveform update rate down (since each trigger must fill all of memory) which brings its own problems, namely the risk of missing transient signal which I'm not triggering on. Operating in this mode, I can set infinite persistence on, and wait for the odd event to happen. If I can see it on screen, I can set a trigger condition for it.

Things are different in single shot mode. Now, I'm triggering on the rare event, and when it happens, I'd like to capture as much of it as possible. Memory depth is now really important, and waveform update rate generally doesn't matter much at all. Memory depth sets the amount I can zoom in, post acquisition, and also the time range I can pan over. Memory depth is king.

So if I'm working in single shot mode, I should set the memory depth to maximum, but if I'm working in repetitive trigger mode, I should set it to minimum (there really doesn't seem to be much case for setting it to any other value).

As I understand it, the MegaZoom 4 system in all the current InfiniVison scopes does this for me, automatically. In single shot mode, I get to use all the memory available - the 1Mpt (2000 series) or 4Mpt (3000/4000 series) per channel is filled by the trigger & I can pan & zoom around as I want (though of course, more memory would be nice, as it decidedly on the small side). In repetitive acquisition (Run mode), the memory is split in two and used in swinging buffer fashion. One half is used for acquisition while the other half is being rendered to screen. The rendering is done by the ASIC and is very fast. In the 2000 series, there is a single ASIC and it takes no more than 50 microseconds to update the screen and free the buffer for the next acquisition. In the 3000 series there is a pair (or maybe a quartet?) of ASICs and the screen is updated inside one microsecond. So there is little benefit to be gained by reducing the memory size below half the maximum value.

Hence neither of these scopes has, or needs, an explicit memory size setting - only as part of the run/single shot configuration.

I've used both 2000 and 3000 InfiniVision scopes, and this seems to be the way they work. If Daniel is following this thread maybe he could confirm/clarify this. What happens in segmented mode I'm not so sure. I've only used the 2000 in segmented mode and it looks as if you only get to use half the total memory to store all your segments, because effectively you are operating in run mode so that the dead time between segment triggers is minimised. This is a pity, because the screen is not being updated, so it looks as if you ought to be able to use it all. Maybe the 3000 series work this way? (We don't have the segmented memory license for the 3000)

[nctnico]

You forget one thing: you don't want to hit the 'single' button for each acquisition. I regulary use the normal trigger mode to capture a signal and only zoom in on the interesting acquisitions. This leaves me with half the memory depth and sometimes this means the signal is not as detailed as I would like.

[nfmax]

I agree, if you just hit 'stop' when you see something interesting, that's what you'll get. Assuming you hit 'stop' fast enough!

Using the run controls as intended, you can get twice the memory. it's a bit like relying on the 'auto set' button instead of setting your channels, trigger and sweep manually (auto setup isn't particularly effective on these scopes, BTW. Oddly enough, the DSO1000  family does it better - presumably it's Rigol software in those instruments!)

[nctnico]

I agree, if you just hit 'stop' when you see something interesting, that's what you'll get. Assuming you hit 'stop' fast enough!

If there is only one event to trigger on (generated by pushing a button manually), then there is plenty of time to hit the 'stop' button.

[nfmax]

I agree, if you just hit 'stop' when you see something interesting, that's what you'll get. Assuming you hit 'stop' fast enough!

If there is only one event to trigger on (generated by pushing a button manually), then there is plenty of time to hit the 'stop' button.

...and plenty of time to push the 'Single' button, too. Think of it as the 'maximum memory' button if that helps.

[nfmax]

I agree, if you just hit 'stop' when you see something interesting, that's what you'll get. Assuming you hit 'stop' fast enough!

Trigger inhibit delay and segmented memory are there to help.

Agreed - these two facilities together are very powerful!

[nctnico]

I agree, if you just hit 'stop' when you see something interesting, that's what you'll get. Assuming you hit 'stop' fast enough!

If there is only one event to trigger on (generated by pushing a button manually), then there is plenty of time to hit the 'stop' button.

...and plenty of time to push the 'Single' button, too. Think of it as the 'maximum memory' button if that helps.

So instead of one button I need to push 2 buttons? Excellent ergonomics! I rather user a different scope with more memory.

[kcbrown]

Memory depth controls can be important on scopes where the acquisition rate, measurements, or user interface slow down with longer memory depths, Tek and Rigol in particular but most scopes do this to some extent. The Agilent/Keysight X series didn't need the option to reduce the acquisition depth as they offer so much speed even at full memory depth, its only reduced below maximum when using the segmented capture mode.

  There's so much wrong with that it's not even funny.

First, you completely ignore that the time it takes to fill a certain amount of sample memory at a certain sample size is fixed:

                  capture time [seconds] = sample memory size [pts] / sample rate [Sa/second]

This basic law hold true even for a Keysight DSOX InfiniiVision scope. So on your (I believe) DSOX3kA, at 4GSa/s it takes 1ms to fill 4Mpts of sample memory. Even if we had a perfect trigger circuit immediately re-arming, the time it takes to fill the 4Mpts alone means that even with that perfect trigger the update rate would be limited to 1000 per second. There's no way around that, it's a physical reality.

Oh yes there is.  Or, there is unless I'm missing something vital.

If the trigger mechanism is based on the actual samples (as is the case with modern DSOs if I'm not mistaken), then the scope can simply treat the memory as a circular buffer and mark the memory locations at which the trigger conditions were satisfied.  The display mechanism can then display the appropriate region of the memory by examining the list of triggered locations and selecting whichever one is most suitable (ideally, it would be a region that is far removed from the region that the sampling mechanism is currently writing to so as to avoid collisions).   With that scheme, hitting the "stop" button would stop the sampling mechanism at something like t + 1/2 * memory-fill-time, where t is the time of the last trigger event, and would cause the display engine to display the waveform at time t.  To get away with this, you'd need to either use dual-ported RAM or RAM that is at least twice as fast as the fastest sampling rate (which implies a memory controller that is also suitably fast).

If you do that, then the trigger rearm mechanism would be completely independent of the buffer size.  It would obviously have to be able to keep up with the current sampling rate in order to ensure that it doesn't miss any events, which means being able to keep up with the maximum sampling rate.  If it can't keep up with the sampling rate, then there would be some chance of missing a triggering event.  Even then, once the sampling is stopped, the triggering mechanism can walk backwards through the samples to find previous occurrences of triggering events that it missed.

What MegaZoom does is using windowing to reach its high update rates. Windowing is used during normal operation where the scope only uses enough memory to fill the period shown on screen. That means even if it shows you it's using 2Mpts it's actually just using a few kpts. Only when you stop the acquisition system or enable zoom then the last acquisition uses all of the displayed sample memory. It's pretty much a trick to circumvent the fact that using all the displayed memory at the displayed sample rate would make it physically impossible to attain high sample rates. This is also the reason the InfiniiVision doesn't allow manual controls.

What's on the screen is just a subsampling of what has been captured.  That clearly has to be the case since the screen is resolution-limited, and thus is guaranteed to be able to display only a limited number of points (whatever the horizontal resolution of the screen is).  But clearly, the sampling interval has to be at most the amount of time the screen represents divided by the horizontal resolution if the screen's resolution is to be utilized to its fullest (if the time base is set small enough, of course, then there will be no choice but to display a smaller number of points than represented by the horizontal resolution, and some sort of interpolation would be needed to fill in the gaps).

Regardless, with the circular buffer model, I see no advantage to using a smaller amount of memory than what the scope actually makes available, since doing so only ensures that the buffer is cycled through more quickly by the sampling engine.  Since manufacturers obviously change the size of the buffer to achieve better performance, I must be missing something crucial here, but I don't have any idea what that is.

[nfmax]

Isn't there a problem with this approach that when you hit Stop, you won't know what memory depth you will get? If the first trigger has only just occurred, then there may only be just enough samples to see what is already on the screen, so while you can zoom, you can't pan outside the screen window. Only if there have been enough triggers to completely fill the sample memory will you get the full depth. This could be very confusing to the user. It seems better to maintain the one trigger = one memory buffer rule for consistency.

If you can search the memory for trigger events after stopping the acquisition, it's difficult to see what practical advantages this approach brings - beyond increasing the data sheet waveforms/sec number, for bragging rights, of course! 

[Keysight DanielBogdanoff]

Isn't there a problem with this approach that when you hit Stop, you won't know what memory depth you will get?

Ok, so the ASIC on the InfiniiVision X-Series uses what we affectionately call "ping pong" memory. With 4M of total space, it uses alternating halves (2M) during normal Run operation. When you hit "Stop" the scope immediately stops capturing and displays the latest 2M capture (or whatever memory applies to the screen time/div settings). At fast time/div settings there's still 2M of data, but the screen may show less info than that. The scope only processes the data that's on the screen, but does this even when it's not actively acquiring data. When you're stopped and then zoom out, if there's more data there it will re-plot the whole 2M signal capture.

If you hit "Single" you get the full 4M of memory, but it will take a new capture instead of keeping the current 2M one.

This might be too basic for you guys, but I did a brief video on "Run/Stop vs Single" that discusses the memory buffer on our YouTube channel:

[kcbrown]

Isn't there a problem with this approach that when you hit Stop, you won't know what memory depth you will get? If the first trigger has only just occurred, then there may only be just enough samples to see what is already on the screen, so while you can zoom, you can't pan outside the screen window. Only if there have been enough triggers to completely fill the sample memory will you get the full depth. This could be very confusing to the user. It seems better to maintain the one trigger = one memory buffer rule for consistency.

That won't be a problem with the circular buffer approach.  That's because with the circular buffer, once enough initial time has passed to fill the entire buffer with samples, the buffer is always full, which means you can always scroll backwards, at the very least, to see what has happened before, for roughly however much time it took to fill the buffer.  The real question is how much additional sampling the scope should do if it is set up to stop on a trigger and it encounters the triggering condition.  For that, it seems logical that it will depend on the amount of memory that has already been filled and the amount of time it would take to fill the remainder.  If the amount of memory that has been filled is small, then there's little point in actually stopping until the remainder is filled, as long as doing so doesn't take too long (that cutoff time is something that could be defined by the user).

If you can search the memory for trigger events after stopping the acquisition, it's difficult to see what practical advantages this approach brings - beyond increasing the data sheet waveforms/sec number, for bragging rights, of course! 

The main advantage is that you're guaranteed to have the maximum possible amount of history at your disposal, while also being able to run the triggering system at its maximum speed.  It makes the speed of the triggering system independent of the memory depth, too.  And it makes it possible to use higher sampling rates with longer timebases.

The approach is so blindingly obvious to me that I must be missing something crucial here, as I would have expected scope manufacturers to already be implementing it if it didn't have some sort of showstopper property that I'm missing.  But it does sound like Keysight does something similar.  Their solution does take care of the case where trigger events are rare, and could be integrated into the single circular buffer approach, by splitting the memory into two pieces in the event you don't see another trigger event after half the buffer fill time since the previous trigger event.

[nctnico]

Because you don't need so much samples to shows on the screen (1024 samples is enough) this memory can be included in the ASIC and can operate independantly of the main memory. Surely circular buffering can be used to fullfill prefill requirements.

@Daniel: the memory is only a quarter (or less) of 4Mpts with 4 channels enabled and in normal run mode on the MSOX4000 series. See pages 220 and 324 of the user manual.

[Keysight DanielBogdanoff]

@Daniel: the memory is only a quarter (or less) of 4Mpts with 4 channels enabled and in normal run mode on the MSOX4000 series. See pages 220 and 324 of the user manual.

You're right, it cuts my above statements in half.

[mikeselectricstuff]

Isn't there a problem with this approach that when you hit Stop, you won't know what memory depth you will get?

Ok, so the ASIC on the InfiniiVision X-Series uses what we affectionately call "ping pong" memory. With 4M of total space, it uses alternating halves (2M) during normal Run operation. When you hit "Stop" the scope immediately stops capturing and displays the latest 2M capture (or whatever memory applies to the screen time/div settings). At fast time/div settings there's still 2M of data, but the screen may show less info than that. The scope only processes the data that's on the screen, but does this even when it's not actively acquiring data. When you're stopped and then zoom out, if there's more data there it will re-plot the whole 2M signal capture.

If you hit "Single" you get the full 4M of memory, but it will take a new capture instead of keeping the current 2M one.

This might be too basic for you guys, but I did a brief video on "Run/Stop vs Single" that discusses the memory buffer on our YouTube channel:

On both the MSOX and older MSO scopes I've always thought it would be useful to be able to override the double-buffering to get maximum memory in "normal" trigger mode, instead of having to keep pressing <SINGLE>

[Hydrawerk]

DSOX2000 scopes were intruduced in early 2011. Is there a next model coming next year or so?

[kcbrown]

Because you don't need so much samples to shows on the screen (1024 samples is enough) this memory can be included in the ASIC and can operate independantly of the main memory. Surely circular buffering can be used to fullfill prefill requirements.

(Naturally what follows is just my thinking on this.  I'm no expert in any of this by any means)

It's important to not confuse screen memory and sample memory.

What you see on the screen is a representation of the samples.  It's the result of processing the samples that exist within the time window represented by the screen boundaries (and whatever samples exist beyond the boundaries that are necessary to give an accurate screen representation).

Because the screen's only purpose is to display something to a human, and humans are relatively slow, the system doesn't have to keep the screen updated with the absolute latest capture.   Update it at 30 times per second and the viewer won't perceive it to be lagging in any way.   That means the triggering mechanism would have to succeed in detecting a trigger event at least once every 1/30th of a second for the display to be perceived as accurate (when trigger events happen more often than that, of course.  When they're less frequent than every 1/30th of a second, then a seemingly laggy display would actually be an accurate reflection of what's happening).  However, for seeing glitches via persistence, obviously the trigger detection mechanism would have to fire with maximum rapidity, and the display processing would have to be very fast as well in order to maximize the probability that a glitch is made visible.

It's because of the glitch detection and persistence implementation that you really want a fast display processing mechanism and fast trigger detection, and it's why you need a memory subsystem that can support simultaneous maximum-speed reads and writes (writes from the sampling mechanism, and reads from the trigger and display processing mechanisms).  The display mechanism would simply follow the pointer list generated by the triggering mechanism and do burst reads of the sections of memory the pointer list entries imply would need to be read (the size of each section would be determined by the sample rate and the visible window size). 

I imagine that getting the memory and bus architectures right for this is crucial.  It has to minimize the possibility of bus contention in the face of simultaneous maximum-speed read and write operations (and when there is contention for the bus, obviously the sampling mechanism is what has to win). 

I imagine the guys who design oscilloscopes must have a lot of fun doing it, because of all the interesting problems that have to be solved.   

[Wuerstchenhund]

@Daniel: the memory is only a quarter (or less) of 4Mpts with 4 channels enabled and in normal run mode on the MSOX4000 series. See pages 220 and 324 of the user manual.

You're right, it cuts my above statements in half.

And there's even less memory available when logic channels are enabled, or even something basic like Reference waveforms, which unlike on many other scopes, reduce the amount of available sample memory even more and could well mean you end up with a few hundred kpts per channel.

Not exactly a lot for a scope in the price class of the DSOX3000 Series.

[nctnico]

I imagine the guys who design oscilloscopes must have a lot of fun doing it, because of all the interesting problems that have to be solved.   

It is fun indeed 

[Keysight DanielBogdanoff]

I imagine the guys who design oscilloscopes must have a lot of fun doing it, because of all the interesting problems that have to be solved.   

It's always a party! Part of why we love our ASICs so much is that it helps us streamline a lot of the plotting/data analysis challenges. It has it's downsides, of course (e.g. no memory controller built into MegaZoom so we only have 4M), but from a performance standpoint it's been great.

And there's even less when logic channels are enabled, or even something basic like Reference waveforms, which unlike many other scopes reduces the amount of available sample memory even more and could well mean you end up with a few hundred kpts per channel.

Yeah, it's definitely not ideal, but for most users it does the job. It's amazing how few people change their Tek scopes out of the default 10 kpts depth. I'm not trying to hide our memory depth or anything but a lot of people don't necessarily need it.

Obligatorily, I must mention segmented memory as a thing. You know, the usual.

[kcbrown]

It's always a party! Part of why we love our ASICs so much is that it helps us streamline a lot of the plotting/data analysis challenges. It has it's downsides, of course (e.g. no memory controller built into MegaZoom so we only have 4M), but from a performance standpoint it's been great.

The 4M of memory is located on the ASICs directly, right?

I can hardly imagine that a memory controller would eat so much ASIC space that you had to put the memory directly into the ASICs instead for that reason, so what was the reason for choosing to put the memory directly onto the ASICs?  Speed?  Reduced latency?

I wouldn't be surprised if the performance of external memory back when the ASICs were designed simply wasn't enough to meet the performance requirements.  Modern computer designs seem to use multiple levels of cache in order to achieve decent throughput, but the nature of the demands on an oscilloscope's memory is such that I don't know that such an architecture would be suitable (indeed, I rather suspect it's not).

It's been quite some time since I've looked at how computers are architected at that level, so something may have changed.   In any case, densities are so high these days that I'm surprised that a substantial amount of additional memory wasn't added to the ASICs for the 3000T series, at least.   Are you guys using an older fab process or something (that would be entirely understandable.  Going to a new fab process is apparently quite expensive)?

[Someone]

And there's even less memory available when logic channels are enabled, or even something basic like Reference waveforms, which unlike on many other scopes, reduce the amount of available sample memory even more and could well mean you end up with a few hundred kpts per channel.

Except we tested that and including reference traces didn't reduce the memory depth. Would you like to bring some more verifiably wrong statements to the thread?

[nctnico]

And there's even less memory available when logic channels are enabled, or even something basic like Reference waveforms, which unlike on many other scopes, reduce the amount of available sample memory even more and could well mean you end up with a few hundred kpts per channel.

Except we tested that and including reference traces didn't reduce the memory depth. Would you like to bring some more verifiably wrong statements to the thread?

See pages 220 and 324 of the  MSOX4000 user manual (for example).

[mikeselectricstuff]

@Daniel: the memory is only a quarter (or less) of 4Mpts with 4 channels enabled and in normal run mode on the MSOX4000 series. See pages 220 and 324 of the user manual.

You're right, it cuts my above statements in half.

And there's even less memory available when logic channels are enabled, or even something basic like Reference waveforms, which unlike on many other scopes, reduce the amount of available sample memory even more and could well mean you end up with a few hundred kpts per channel.

Not exactly a lot for a scope in the price class of the DSOX3000 Series.

Not to mention peak detect mode ( 4x reduction I think)

[Someone]

And there's even less memory available when logic channels are enabled, or even something basic like Reference waveforms, which unlike on many other scopes, reduce the amount of available sample memory even more and could well mean you end up with a few hundred kpts per channel.

Except we tested that and including reference traces didn't reduce the memory depth. Would you like to bring some more verifiably wrong statements to the thread?

See pages 220 and 324 of the  MSOX4000 user manual (for example).

You might have to reference the actual document as the currently served 4000 X users guide doesn't have anything relevant on those pages, and does not state that the memory will be reduced when displaying reference waveforms, it mentions channel bonding and realtime/single capture, and nothing about digital channels or acquisition modes (which are known to reduce memory depth).

[Someone]

It's always a party! Part of why we love our ASICs so much is that it helps us streamline a lot of the plotting/data analysis challenges. It has it's downsides, of course (e.g. no memory controller built into MegaZoom so we only have 4M), but from a performance standpoint it's been great.

The 4M of memory is located on the ASICs directly, right?

I can hardly imagine that a memory controller would eat so much ASIC space that you had to put the memory directly into the ASICs instead for that reason, so what was the reason for choosing to put the memory directly onto the ASICs?  Speed?  Reduced latency?

I wouldn't be surprised if the performance of external memory back when the ASICs were designed simply wasn't enough to meet the performance requirements.  Modern computer designs seem to use multiple levels of cache in order to achieve decent throughput, but the nature of the demands on an oscilloscope's memory is such that I don't know that such an architecture would be suitable (indeed, I rather suspect it's not).

It's been quite some time since I've looked at how computers are architected at that level, so something may have changed.   In any case, densities are so high these days that I'm surprised that a substantial amount of additional memory wasn't added to the ASICs for the 3000T series, at least.   Are you guys using an older fab process or something (that would be entirely understandable.  Going to a new fab process is apparently quite expensive)?

Latency is key to the problem of building a histogram (here rendering waveforms with intensity grading). From back of the envelope calculations you can see why this all adds up quickly, we can take your example below and add some numbers to it.

Isn't there a problem with this approach that when you hit Stop, you won't know what memory depth you will get? If the first trigger has only just occurred, then there may only be just enough samples to see what is already on the screen, so while you can zoom, you can't pan outside the screen window. Only if there have been enough triggers to completely fill the sample memory will you get the full depth. This could be very confusing to the user. It seems better to maintain the one trigger = one memory buffer rule for consistency.

That won't be a problem with the circular buffer approach.  That's because with the circular buffer, once enough initial time has passed to fill the entire buffer with samples, the buffer is always full, which means you can always scroll backwards, at the very least, to see what has happened before, for roughly however much time it took to fill the buffer.  The real question is how much additional sampling the scope should do if it is set up to stop on a trigger and it encounters the triggering condition.  For that, it seems logical that it will depend on the amount of memory that has already been filled and the amount of time it would take to fill the remainder.  If the amount of memory that has been filled is small, then there's little point in actually stopping until the remainder is filled, as long as doing so doesn't take too long (that cutoff time is something that could be defined by the user).

If you can search the memory for trigger events after stopping the acquisition, it's difficult to see what practical advantages this approach brings - beyond increasing the data sheet waveforms/sec number, for bragging rights, of course! 

The main advantage is that you're guaranteed to have the maximum possible amount of history at your disposal, while also being able to run the triggering system at its maximum speed.  It makes the speed of the triggering system independent of the memory depth, too.  And it makes it possible to use higher sampling rates with longer timebases.

The approach is so blindingly obvious to me that I must be missing something crucial here, as I would have expected scope manufacturers to already be implementing it if it didn't have some sort of showstopper property that I'm missing.  But it does sound like Keysight does something similar.  Their solution does take care of the case where trigger events are rare, and could be integrated into the single circular buffer approach, by splitting the memory into two pieces in the event you don't see another trigger event after half the buffer fill time since the previous trigger event.

A hypothetical scope with:
8bit 10GS/s 2GHz bandwidth
1,000,000 samples memory
100us capture
screen with 1000px display for the waveform

"ideal" 10,000 wfms/s 1 trigger+display per 100us (10,000 wfms/s)

acquisition memory:
wr bandwidth 10GB/s
rd bandwidth 10GB/s
filter and pipe to display histogram:
rd bandwidth 0.01GB/s
wr bandwidth 0.01GB/s

2GHz trigger = 200,000 triggers+display per 100us (2,000,000,000 wfms/s)

acquisition memory:
wr bandwidth 10GB/s
rd bandwidth 2,000,000GB/s
filter and pipe to display histogram:
rd bandwidth 2000GB/s
wr bandwidth 2000GB/s

Current histogram memory for 1,000,000 wfms/s peak into approximately 500px window as in the 3000 X discussed in this thread:
rd and wr bandwidth of 0.5GB/s
Overhead for clearing etc, double for zoom window, per channel etc. This would use 16, Probably 32 or more parallel 1MB histogram rams at x00MHz each. The histogram memory needs to be very low latency as the match pipeline grows in resources with latency squared, so to get 3 orders of magnitude increase in performance you're hunting for some magical technology.

[Keysight DanielBogdanoff]

The 4M of memory is located on the ASICs directly, right?

I can hardly imagine that a memory controller would eat so much ASIC space that you had to put the memory directly into the ASICs instead for that reason, so what was the reason for choosing to put the memory directly onto the ASICs?  Speed?  Reduced latency?

Yes, the memory is right on the ASIC to improve the speed (read: fast waveform update rate). I don't remember what nm architecture we used for this one, but the ASIC team is always using the latest tech and fabs. If we could go back in time and do it over again we'd definitely add more memory into the ASIC and potentially a DDR memory controller. When developing a chip trade offs are always made for one reason or another.

Also, the memory takes up a non-trivial amount of chip real estate. More memory means larger chips. As a rule, larger chips mean lower yield and increased overall cost.

[Faith]

I think from an InfiniiVision brochure I've read loooong ago, the chip used in MSOX3kXT/4kX are made with 65nm technology with on die DRAM (why the hell not using external DRAM since you've already used DRAM and already took the complexity a whole level higher compared to SRAM)?

Wow 65nm? That's been around for a good decade already if I remember correctly. Kinda puts the age of the ASIC into perspective >,<"...

I'm guessing they went with on-die memory to reduce latency as much as possible. Possibly similar reasons to why CPU's always possess a decent amount of on-board cache memory as well.

But I would definitely love to know as well if Keysight has anything new coming up in the near future.

I've always maintained however that new equipment doesn't suddenly make old equipment useless, hence why I am still open to buying the 3000T or 4000A despite their age.

From a budgeting and support perspective however it does make me feel better if I know that my product will be supported for another 5-10 years.

I'm loving the discussion that's been going on in this thread however as there are definitely many valid points being made.

For now however I will likely just wait and see what happens first. Me smacking my head on the table when my borrowed scope needs to go back, or Keysight launching something with an updated ASIC.

In the interim however I will get in touch with Teledyne LeCroy and also Rohde & Schwarz (the RTE looks super interesting but seems to lack reviews online) to demo their units.

[Wuerstchenhund]

Yeah, it's definitely not ideal, but for most users it does the job.

No-one doubts that. And aside from the tiny memory, the DSOX are great general purpose scopes.

But at the end of the day the entry-level is a competitive market, and the thing is that there are now other scopes which make similar great general purpose scopes but offer more memory and more functionality for a lower price.

It's pretty much a buyer's market.

It's amazing how few people change their Tek scopes out of the default 10 kpts depth.

True, but that is probably because even with short memory they are generally slow as wading through molasses so I guess these people are just trying to minimize their pain (I got a new Tek MDO3054 recently, it's so slow it's not even funny)

[Wuerstchenhund]

In the interim however I will get in touch with Teledyne LeCroy and also Rohde & Schwarz (the RTE looks super interesting but seems to lack reviews online) to demo their units.

The RTE is certainly interesting but at a starting price of around $6500 for the 2ch 200MHz variant it is a lot more expensive than any of the scopes discussed here (you can almost get two 2ch 200MHz WaveSurfer 3000 for that money). Also, if you're really interested in this scope make sure you trial it as the UI is pretty quirky.

R&S' competitor to the discussed scopes would be the RTM2000 which still starts at $5k (RTM2022 2ch 200MHz). I had the predecessor RTM1054 (500MHz 4Ch) which was pretty much the same aside from the MSO option and slightly lower sample memory. It was a very nice scope and had a few interesting features, and it was worth the <$2k I paid for it, but it's max update rate is just some 11k wfms/s and FFT is limited, too (IIRC 128k on the RTM2000), and while it was good it wasn't nearly good enough to justify anything close to the $5k R&S wants for the smallest model.

And any of the options from R&S will be very expensive, too.

[Someone]

From a budgeting and support perspective however it does make me feel better if I know that my product will be supported for another 5-10 years.

You shouldn't have to worry about that, Keysight have pared back their older promises and advertising of specific service life expectations but we just had a scope 5 years into "extended support" (their new term for the date of discontinuing a product) go in for service and any parts we could need were available. Common with the other major T&M manufacturers discontinuation is usually announced in advance and the older products continue to be sold on for years in support of long term test applications even after a replacement is brought to market. You'll get similar experiences from Tek and Lecroy.

In the interim however I will get in touch with Teledyne LeCroy and also Rohde & Schwarz (the RTE looks super interesting but seems to lack reviews online) to demo their units.

Best option is to demo all you can, you get a feel for the scopes and the level of support you can get locally. Once you've compared a few do return and post your thoughts, its always good to hear what people do and don't like about the different options.

[nfmax]

Comparing the two series, the 3000's offer a maximum of 4Mpts memory, while the 2000's offer only 1Mpt. But it seems there are actually two MZ4 ASICs in the 3000 and one in 2000, so you might expect a 2:1 ratio in maximum memory. That got me wondering if the 2000 was originally designed to be able to use part-good die, as well as lower speed bins (it has 2Gs/s compared to the 3000A's 4Gs/s)? IIRC it was announced before the 3000. The subsequent speed bump (4Gs/s -> 5 Gs/s) between the 3000A & 3000T is another indication that maybe yields in the higher speed bins have improved over the years.

I get the impression that the MZ4 ASIC was a 'stretch' design, that presumably cost a lot of money, hence Keysight are naturally keen to get the most out of it they can. We may have to wait a while for the MZ5. Clearly the MZ4 can be used in pairs: I wonder if an architecture using four of them is possible? Also presumably, if the ASICs going into current production 2000s are fully functional, a firmware offering 2Mts might be possible.

All this is wild, unfounded speculation, but what the heck, this is the Internet, after all! 

[Wuerstchenhund]

The subsequent speed bump (4Gs/s -> 5 Gs/s) between the 3000A & 3000T is another indication that maybe yields in the higher speed bins have improved over the years.

Hardly. The DSOX3000T is pretty much just a DSOX4000A with smaller screen, and the latter already had the faster sample rate right from the start.

I get the impression that the MZ4 ASIC was a 'stretch' design, that presumably cost a lot of money, hence Keysight are naturally keen to get the most out of it they can.

Of course designing and having to manufacture such a special-purpose ASIC isn't cheap, and they wouldn't be a good business if they didn't try to make most of it.

We may have to wait a while for the MZ5. Clearly the MZ4 can be used in pairs: I wonder if an architecture using four of them is possible? Also presumably, if the ASICs going into current production 2000s are fully functional, a firmware offering 2Mts might be possible.

I doubt there are as many imperfect MZ4 ASICs as you imagine, after all as others already mentioned the 65nm process is ancient and already has been when the DSOX came out back in 2011. It's a well controlled process with a very high yield rate.

Also, the MegaZoom architecture itself is not limited to 4Mpts, that is only true for the MZ4 variant used in the DSOX. My Infiniium DSO8064A also has MegaZoom, but with 128Mpts of sample memory (it also has a 4GSa/s sample rate, and funny enough, even allows me to disable automatic memory management and set memory manually). And that is just one Agilent scope of several which offer MZ with more than 4Mpts of memory. Even the DSOX predecessors (InfiniiVision DSO6000/7000) offered MegaZoom with 8Mpts.

The simple reason Agilent went for the MZ4 with small memory was to maximize the waveform update rate. Which to some extend is understandable, as these scopes are often used to replace an analog scope, and if you treat a DSO like an analog scope (i.e. staring on waveforms) then the update rate is quite important (less so if you treat a DSO like a DSO, though, and then sample memory size and analysis tools become much more important than an excessive update rate). That paid out in 2011 when there wasn't the same amount of competition as there is today, and where the big brand alternative consisted of the painfully slow Tek DPO2k/3k Series, or the LeCroy WaveSurfer 300A (a scope that was pretty much a 2003 era design by Iwatsu, with low update rates and limited memory). That is different today of course.

Also, MegaZoom is only really fast with small memory and relative small amounts of data. That's where it excels. It doesn't cope well with large memory, or fast sample rates which increase the amount of data it has to process. So it's bes suited for entry-level scopes like the DSOX2k and DSOX3k (and it would be less of a problem if they were priced more appropriately for a 4Mpts scope). Once you need lots of memory and high sample rates then there are other architectures which offer much better waveform performance than MegaZoom, and without its disadvantages.

[Faith]

But it seems there are actually two MZ4 ASICs in the 3000 and one in 2000, so you might expect a 2:1 ratio in maximum memory.

If I'm understanding everything right I think that the MZ4 ASIC actually has 4M memory points each in the 3000T. Just that in the 3000T you have one MZ4 ASIC taking care of a pair of channels.

Thus I think you won't actually experience a decrease in memory if you are utilizing only two channels as long as you are connected to separate pairs (1 & 3 for instance versus 1 & 2).

It could very well be though that the 2000A is (or was) limited due to having lesser binned parts but you would imagine that after six years they'd be getting incredibly good (near-100%?) yields, especially on such an ancient manufacturing process.

And any of the options from R&S will be very expensive, too.

Yep, noticed >,<"... their options are shockingly expensive. Makes even Keysight look affordable especially when considering the Keysight bundles.

Also my local Rohde & Schwarz online shop is kinda sad with several links 404'ing and options being cryptic which meant that pricing wasn't originally as obvious as it should have been.

It's unlikely I will get one of their products as I am still insisting on having a built-in Arbitrary Function Generator, but hey, they looked interesting so I may as well just have a poke just so that I know what's out there!~

[EEVblog]

Also, the MegaZoom architecture itself is not limited to 4Mpts, that is only true for the MZ4 variant used in the DSOX. My Infiniium DSO8064A also has MegaZoom, but with 128Mpts of sample memory (it also has a 4GSa/s sample rate). And that is just one Agilent scope of several which offer MZ with more than 4Mpts of memory. Even the DSOX predecessors (InfiniiVision DSO6000/7000) offered MegaZoom with 8Mpts.

The reason Agilent went for the MZ4 with small memory was to maximize the waveform update rate.

They went with 4Mpts because that's what size memory is built onto the MZ4 die, that's what makes it crazy fast.
If the higher power scope use more and the same ASIC then they must be bypassing the internal memory and using external.

[EEVblog]

Comparing the two series, the 3000's offer a maximum of 4Mpts memory, while the 2000's offer only 1Mpt. But it seems there are actually two MZ4 ASICs in the 3000 and one in 2000, so you might expect a 2:1 ratio in maximum memory. That got me wondering if the 2000 was originally designed to be able to use part-good die, as well as lower speed bins (it has 2Gs/s compared to the 3000A's 4Gs/s)?

Nope, it's the exact same good die. The limited memory on the 2000 is purely a marketing spec decision. They always reserved the right to up the memory later via a software update to compete with competition.

[EEVblog]

BTW, how old is the 2000/3000 series now? 
Remember when it used to be untouchable?!

[Wuerstchenhund]

They went with 4Mpts because that's what size memory is built onto the MZ4 die, that's what makes it crazy fast.

I'm not sure that putting some DDR2 memory on the same die provides such a performance advantage. What it does though is reduce costs.

If the higher power scope use more and the same ASIC then they must be bypassing the internal memory and using external.

I doubt it's the exactly same ASIC, but yes I'd guess the memory is external.

[Faith]

They went with 4Mpts because that's what size memory is built onto the MZ4 die, that's what makes it crazy fast.
If the higher power scope use more and the same ASIC then they must be bypassing the internal memory and using external.

Yep, and looking at the specs of the higher end Keysight scopes with more memory it seems that their waveform update rate is quite a far cry away from the 1,000,000 wfms/s we see on those with only 4M memory points.

Their sampling rates are still pretty insane though.

[Wuerstchenhund]

BTW, how old is the 2000/3000 series now? 
Remember when it used to be untouchable?!

What do you mean with "untouchable"?

[Faith]

What do you mean with "untouchable"?

I would say that the 3000T has always been quite touchable

Still though, as mentioned earlier, newer models don't necessarily make older models useless. But the market has definitely become really competitive and thus all the more interesting.

Let's see where the wind takes me though!~

[Someone]

We may have to wait a while for the MZ5. Clearly the MZ4 can be used in pairs: I wonder if an architecture using four of them is possible? Also presumably, if the ASICs going into current production 2000s are fully functional, a firmware offering 2Mts might be possible.

I doubt there are as many imperfect MZ4 ASICs as you imagine, after all as others already mentioned the 65nm process is ancient and already has been when the DSOX came out back in 2011. It's a well controlled process with a very high yield rate.

65nm was entering mainstream in 2011:
https://eda360insider.wordpress.com/2011/09/07/where-is-the-mainstream-ic-process-technology-today-28nm-40nm-65nm/
But the megazoom IV ASIC is reportedly on the 90nm node:
http://www.embedded.com/electronics-news/4213152/Agilent-uses-new-ASIC-in-MSO-market-attack
Which was mainstream for fully digital designs of the era. Just because the bleeding edge is 1-2 nodes ahead doesnt make a process ancient.

[Faith]

Just because the bleeding edge is 1-2 nodes ahead doesnt make a process ancient.

I think the original concern was why the 2000A was more severely limited in memory than the 3000A. And while binning could have been a reason, marketing is more likely as yields should've been really good by then and especially now.

[nfmax]

The big advantage of putting the memory on the same die as the logic is you can increase the memory 'bus width' between the two to crazy levels - many thousands of bits if you want - even for relatively small memory sizes. The means you don't need such a fast memory process, and it massively increases the memory bandwidth, which is generally the limiting factor in DSO applications. On the other hand, if you have an architecture with lots of fast RAM chips and FPGAs, like the typical higher end scope, then you get the increased memory bandwidth 'for free' as there are so many RAM chips each with their own data bus. Of course this costs more, and is much more power hungry, but these are acceptable in a high-end instrument. So the all-in-one ASIC design is better suited to lower tier designs (which are likely to sell in much larger volumes anyway)

Entry-level instruments using commodity DDR3 memory are limited by its 64-bit bus width. So you can easily & cheaply provide a lot of memory, but the waveform update rate is likely to be less than stellar, and if you aren't careful the UI will be sluggish as a result. or you can just offer a few thousand points of memory, sacrificing memory depth for waveform update rate & responsiveness. Current fashion in entry level scopes seems to be to cram as much memory in as possible for spec sheet bragging rights. I have no personal experience of using one of these scopes, but I expect if you wind the memory depth up to '11' the UI will get a bit treacly.

Comparing the two series, the 3000's offer a maximum of 4Mpts memory, while the 2000's offer only 1Mpt. But it seems there are actually two MZ4 ASICs in the 3000 and one in 2000, so you might expect a 2:1 ratio in maximum memory. That got me wondering if the 2000 was originally designed to be able to use part-good die, as well as lower speed bins (it has 2Gs/s compared to the 3000A's 4Gs/s)?

Nope, it's the exact same good die. The limited memory on the 2000 is purely a marketing spec decision. They always reserved the right to up the memory later via a software update to compete with competition.

Dave - you are right, IIRC the initial software only supported 100kPts, and no segmented memory either (and when segmented memory came out, it was originally limited to 25 segments). Who knows what goodies may still be in store for us, then?

[Wuerstchenhund]

They went with 4Mpts because that's what size memory is built onto the MZ4 die, that's what makes it crazy fast.
If the higher power scope use more and the same ASIC then they must be bypassing the internal memory and using external.

Yep, and looking at the specs of the higher end Keysight scopes with more memory it seems that their waveform update rate is quite a far cry away from the 1,000,000 wfms/s we see on those with only 4M memory points.

Yes, with Keysight Unfortunately while they do have the fastest entry-level scopes they don't when it comes to further up the ladder.

Their sampling rates are still pretty insane though.

Larger bandwidth requires higher sample rates. The current sample rate maximum are 240GSa/s but again, not from keysight

[Wuerstchenhund]

65nm was entering mainstream in 2011:
https://eda360insider.wordpress.com/2011/09/07/where-is-the-mainstream-ic-process-technology-today-28nm-40nm-65nm/

The article, which is from 2001 and mostly concerned with the 28nm process, says nothing of that kind. All it says that Gartner found that in 2011 65nm was considered mainstream. In fact, if you look at the graph, it shows that 65nm had a similar share in 2010 and 2009 (unfortunately the graph doesn't go further back than 2009), which makes the idea that it became "mainstream" in 2011 even more absurd.

And all this doesn't change the fact that 65nm is still a pretty old process:
https://en.wikipedia.org/wiki/65_nanometer

Besides, there are many designs still made in 90nm and 120nm but that doesn't make these processes less old. Even more so, quite often the fact that they are old is the reason a designer goes for them, as that makes them cheap (in regard to the process costs, not necessarily the material cost)  and well controlled.

[Wuerstchenhund]

The big advantage of putting the memory on the same die as the logic is you can increase the memory 'bus width' between the two to crazy levels - many thousands of bits if you want - even for relatively small memory sizes. The means you don't need such a fast memory process, and it massively increases the memory bandwidth, which is generally the limiting factor in DSO applications.

Yes, you could. Not sure if that is true for MZ4, though.

On the other hand, if you have an architecture with lots of fast RAM chips and FPGAs, like the typical higher end scope, then you get the increased memory bandwidth 'for free' as there are so many RAM chips each with their own data bus. Of course this costs more, and is much more power hungry, but these are acceptable in a high-end instrument. So the all-in-one ASIC design is better suited to lower tier designs (which are likely to sell in much larger volumes anyway)

That depends on the design. Most high-end scopes are pretty slow when it comes to update rates, which don't really matter that much in that class as they do in the low-end segment. Especially designs that do their processing in ASICs are generally relatively slow in processing the large amounts of data a modern high-end scope produces (other manufacturers use standard x86/x64 intel processors to get better performance).

Entry-level instruments using commodity DDR3 memory are limited by its 64-bit bus width. So you can easily & cheaply provide a lot of memory, but the waveform update rate is likely to be less than stellar, and if you aren't careful the UI will be sluggish as a result.

Yes, but at least it is cheap. Which is the prime objective for pretty much any B-brand.

or you can just offer a few thousand points of memory, sacrificing memory depth for waveform update rate & responsiveness.

As explained further up, there is a fixed limit to how often a scope can update when using large memory. Even MegaZoom can't change that, it pretty much just cheats itself out of it by using a small sample size during operation.

Responsiveness is an UI issue. Tek is a good example how not to do it as on its scopes the UI locks up during longer operations. Other manufacturers maintain a responsive UI at all operations.

Current fashion in entry level scopes seems to be to cram as much memory in as possible for spec sheet bragging rights. I have no personal experience of using one of these scopes, but I expect if you wind the memory depth up to '11' the UI will get a bit treacly.

Yes but again that is because especially the B-brand scopes are targeted at the lowest possible price point. They also can't make a lot of use of their large memories, i.e. due to the lack of proper analysis tools. And despite the large memory, FFT is often poor as well (i.e. some 4kpts on Rigol DS2000 Series scopes if I remember right).

[nfmax]

There is probably a distinction to be made between the 'B brand' entry level scopes like the DS 1054Z and the 'A brand' entry level scopes like the Keysight 2000 & 3000 scopes. The former are targeted at hobbyists (& Shenzhen backstreet workshops) while the latter are aimed at general-purpose lab hack scopes - the sort of scope that spends weeks hooked up to a prototype repeating the same measurement, or even as part of manufacturing test. Overlapping both are the educational scopes, where Tektonix still rules because of their name and 'flexible' pricing. The Keysight 1000 range is aimed there too, but without much traction.

As you move up the ladder then scopes become much more specialised: a 100GHz LeCroy would be a poor choice when troubleshooting a DDR4 interface, while a Keysight S series can't achieve the bandwidth needed for fast opto-electronics. Though you might be able to use either, it would be a compromise.

[Wuerstchenhund]

There is probably a distinction to be made between the 'B brand' entry level scopes like the DS 1054Z and the 'A brand' entry level scopes like the Keysight 2000 & 3000 scopes. The former are targeted at hobbyists (& Shenzhen backstreet workshops) while the latter are aimed at general-purpose lab hack scopes - the sort of scope that spends weeks hooked up to a prototype repeating the same measurement, or even as part of manufacturing test.

It's not just entry-level B-brand scopes, though. Just look at Rigols DS6000, a $9k scope that by its price would be solidly placed in the mid-range. However, it is neither in performance, feature or maturity (apparently basic things like ETS sampling are still broken).

Overlapping both are the educational scopes, where Tektonix still rules because of their name and 'flexible' pricing.

And to some extend to the fact that many educators don't get out very often and from their youth pretty much only know Tek (analog) scopes.

The Keysight 1000 range is aimed there too, but without much traction.

Well, the DSOX2k isn't a complete stranger to the edu market, I believe Keysight has even some bundles (with special pricing) for them.

As you move up the ladder then scopes become much more specialised: a 100GHz LeCroy would be a poor choice when troubleshooting a DDR4 interface, while a Keysight S series can't achieve the bandwidth needed for fast opto-electronics. Though you might be able to use either, it would be a compromise.

I agree with your example, but that is pretty much only because that 100Ghz LabMaster is a very special and unique scope. In general, with a modern high-end scope you can do pretty much most things you can do with your entry-level scope. As mentioned in another thread my daily work horses are highend scopes, and I use them even for basic measurement because going to fetch some smaller scope is combersome and modern high-end scopes do simple jobs more than good enough.

[nfmax]

I agree with your example, but that is pretty much only because that 100Ghz LabMaster is a very special and unique scope. In general, with a modern high-end scope you can do pretty much most things you can do with your entry-level scope. As mentioned in another thread my daily work horses are highend scopes, and I use them even for basic measurement because going to fetch some smaller scope is combersome and modern high-end scopes do simple jobs more than good enough.

You are lucky! In many situations, the high-end scope is a shared resource, so a hack scope that doesn't have 'legs' has a lot of advantages!

[EEVblog]

I think the original concern was why the 2000A was more severely limited in memory than the 3000A. And while binning could have been a reason, marketing is more likely as yields should've been really good by then and especially now.

I can guarantee you it's entirely marketing driven, I've heard this direct from head people at Agilent at the time. It is no secret.
And IIRC they increases the memory in the 2000 series as per their plan last year or so I think it was?
The waveform update rate is also limited by marketing decision, the 2000x is capable of the same update rate as the 3000x. Same thing with serial decoding, they even left the unused button on the front panel "just in case".

[EEVblog]

Overlapping both are the educational scopes, where Tektonix still rules because of their name and 'flexible' pricing.

And to some extend to the fact that many educators don't get out very often and from their youth pretty much only know Tek (analog) scopes.

Educational scopes are driven by the educational course materials that come with them.
Look at the news Tek TBS2000 series just released, it is chock full of education stuff built in that tie into the course lessons available, directly on the scope display.

The Keysight 1000 range is aimed there too, but without much traction.

Well, the DSOX2k isn't a complete stranger to the edu market, I believe Keysight has even some bundles (with special pricing) for them.

Keysight offer educational course material and educational modes on the scope much like Tek does.

[EEVblog]

Responsiveness is an UI issue. Tek is a good example how not to do it as on its scopes the UI locks up during longer operations. Other manufacturers maintain a responsive UI at all operations.

This is where the MZ4 ASIC shines.
It's not just acquisition but it does the display processing too, along with FFT and serial decoding in hardware, everything on the one chip. That's why the Keysight X-series never slows down when you enable serial decode, FFT, or use the controls or anything else.

This is also a downside as seen on the 4000X series when they used the larger screen, the resolution was crippled because of the fixed display resolution inside the MZ4 ASIC. They could not increase the display window size without ditching the entire MZ4 ASIC. Any newer Keysight scopes will have to use a new MZ ASIC to overcome the display limitation and the memory size limitation. Although you can bet your bottom dollar they will continue to milk the MZ4 ASIC because the investment has been made and recouped there, they have the potential to churn out a high-ish performance hardware cheaply.

MZ1 was 1996
MZ4 was 2011
So 3 new ASIC's in 15 years. We are almost overdue for another one one.

[nfmax]

This is also a downside as seen on the 4000X series when they used the larger screen, the resolution was crippled because of the fixed display resolution inside the MZ4 ASIC. They could not increase the display window size without ditching the entire MZ4 ASIC. Any newer Keysight scopes will have to use a new MZ ASIC to overcome the display limitation and the memory size limitation. Although you can bet your bottom dollar they will continue to milk the MZ4 ASIC because the investment has been made and recouped there, they have the potential to churn out a high-ish performance hardware cheaply.

MZ1 was 1996
MZ4 was 2011
So 3 new ASIC's in 15 years. We are almost overdue for another one one.

Because of the ever-growing acquisition memory size, and the increasing capability of FPGAs, the ASIC sweet spot has been moving toward entry-level scopes over the period. It will be interesting to see where MZ5 first appears! 

[Someone]

65nm was entering mainstream in 2011:
https://eda360insider.wordpress.com/2011/09/07/where-is-the-mainstream-ic-process-technology-today-28nm-40nm-65nm/

The article, which is from 2001 and mostly concerned with the 28nm process, says nothing of that kind. All it says that Gartner found that in 2011 65nm was considered mainstream. In fact, if you look at the graph, it shows that 65nm had a similar share in 2010 and 2009 (unfortunately the graph doesn't go further back than 2009), which makes the idea that it became "mainstream" in 2011 even more absurd.

And all this doesn't change the fact that 65nm is still a pretty old process:
https://en.wikipedia.org/wiki/65_nanometer

Besides, there are many designs still made in 90nm and 120nm but that doesn't make these processes less old. Even more so, quite often the fact that they are old is the reason a designer goes for them, as that makes them cheap (in regard to the process costs, not necessarily the material cost)  and well controlled.

The article is from 2011, the year in question and shows a single graph with an estimated breakdown of the node shares. For 2011 just 25% of chip fabrication was on smaller nodes than 90nm, that puts 90nm right in mainstream despite its share declining. Very few low-mid volume ASIC customers use new nodes until the libraries are mature and proven which makes 90nm a typical choice for an ASIC publicly released/presented in 2011, considering the long development time involved for these test and measurement products.

[nfmax]

It's not just entry-level B-brand scopes, though. Just look at Rigols DS6000, a $9k scope that by its price would be solidly placed in the mid-range. However, it is neither in performance, feature or maturity (apparently basic things like ETS sampling are still broken).

Well that's just an uncompetitive scope that no one is likely to be considering, unless forced to. An exit-level design, maybe?

[Keysight DanielBogdanoff]

I doubt it's the exactly same ASIC, but yes I'd guess the memory is external.

Not the same ASIC. We actually use a combo of in-house ASICs for the acquisition systems on various scopes. The "MegaZoom" sticker basically means it's using an in-house processing ASIC.

I can guarantee you it's entirely marketing driven, I've heard this direct from head people at Agilent at the time. It is no secret.

Yup. We knew going in that the MZ4 would be overkill for the 2000X, but it made more sense to use one ASIC across the family instead of designing multiple.

Comparing the two series, the 3000's offer a maximum of 4Mpts memory, while the 2000's offer only 1Mpt. But it seems there are actually two MZ4 ASICs in the 3000 and one in 2000, so you might expect a 2:1 ratio in maximum memory. That got me wondering if the 2000 was originally designed to be able to use part-good die, as well as lower speed bins (it has 2Gs/s compared to the 3000A's 4Gs/s)?

Having two MZ4 is not about memory depth, it's more that we're using certain functions from each MZ4. For example, on the 2000 you can't do protocol decoding and use digital channels at the same time. Why? A single ASIC can only do one of those two things at a time. Having two MZ4s in the 3000+ gives us the ability to do digital channels on one ASIC, decoding on the other.

Also, AFAIK our yields are pretty much standard for their given geometries and chip sizes.

[TheSteve]

I can guarantee you it's entirely marketing driven, I've heard this direct from head people at Agilent at the time. It is no secret.
And IIRC they increases the memory in the 2000 series as per their plan last year or so I think it was?
The waveform update rate is also limited by marketing decision, the 2000x is capable of the same update rate as the 3000x. Same thing with serial decoding, they even left the unused button on the front panel "just in case".

I believe this to be true but keep in mind these are the same people who told you the 350/500 MHz model used a much more expensive front end then the 100/200 MHz model.

I always wondered why my DSOX3K didn't give any indication of the sample memory on screen - guess they figure you don't need to know, and maybe they don't want you to know.
Either way I think it is an amazing scope and am very happy with it.

[Wuerstchenhund]

It's not just entry-level B-brand scopes, though. Just look at Rigols DS6000, a $9k scope that by its price would be solidly placed in the mid-range. However, it is neither in performance, feature or maturity (apparently basic things like ETS sampling are still broken).

Well that's just an uncompetitive scope that no one is likely to be considering, unless forced to.

You say this but there was a forum member who bought one after asking here and getting mostly negative feedback regarding that scope, only to return it later because it was so poor

I believe in the animal world this is called "learning through pain"