Let's face it - most signals are periodic otherwise nobody would have ever bought an analog scope :)Let's face it - most interesting signals for hard to diagnose problems are one off transient events. That's why storage scopes were in demand, despite their eye watering prices; people used a lot of Polaroid film in their scope cameras, despite hating the stuff; and even the earliest very limited digital scopes were an instant hit for those with an adequate budget.
Taking the fairly common "4 analog plus 16 digital" model, doesn't that make a logic analyser largely redundant? I have a 16-channel IWATSU SL-4602 from the 1980s. It's pretty good for looking at slow logic signals but it doesn't even stuff like serial data decoding which some of these scopes offer as options. Maybe the devil is in the detail in that e.g. the IWATSU box came with some very nice probes which will always be expensive to make.
Could someone please give me a pointer on which digital scopes, starting from the bottom e.g. the RTB2000, have ETS?I'm not clear on why you insist on having ETS? It is only useful for repetitive signals. As long as the samplerate is at least 2.5 times the bandwidth then a single shot acquisition will give you the same information.
I have been in the analog sphere since the 1960s... up to a 400MHz Tek scope (long thread here about repairing that one, which I finally managed with some great help).Why wouldn't a SDS2304X do all you want ?
Now looking at a DSO...
OK; a good point.Look at the GW Instek MSO2000 series. No 50 Ohm inputs and 200MHz bandwidth but for the rest it ticks all your boxes at less than $2k. I have the version without digital channels of this oscilloscope (GDS2204E) and it works very well as a scope for daily use. I used to have an Agilent MSO7104A but the GW Instek GDS2204E is easier to drive for daily use and way less noisy (signal noise that is).
I used to use an active probe which had a 50 ohm output to a 50 ohm scope. Pricey...
However a 50 ohm input may not be quite mandatory. In a previous life I used to have some very pricey Tek passive probes which had a much lower capacitance than the standard "300MHz" ones. I remember taking a (broken) one apart. They used a very special cable, with a thinner than a hair single conductor. I have not seen such probes since. It was grey, quite fat, and came with a spring-loaded ground tip for use on PCBs with a ground plane. A google/images doesn't find it though.
EDIT: P6009 https://www.recycledgoods.com/tektronix-passive-probe-with-013-0071-00-screw-on-tip-p6009/ (https://www.recycledgoods.com/tektronix-passive-probe-with-013-0071-00-screw-on-tip-p6009/)
OTOH can't one use an active probe with a non-50-ohm scope input?
Maybe I should look at used scopes. This is taking the thread off topic however. I must have 4 channels, the ability to see lots of detail on 50MHz signals, and the 8 or 16 channel digital mode would be really nice, especially if one can read off serial data on a clock+data wire pair (e.g. SPI kind of thing). What is the best scope around the $3k-4k area, from a few years ago? Obviously active probes would be extra...
There is another problem with the RTB2000 you are overlooking: for 300MHz bandwidth to be usefull you will need 50 Ohm inputs and the RTB2000 doesn't have these. You'll need different probes / probing techniques like connecting signals directly as well. Regular high impedance probes will load signals over 100MHz too much due to the probe capacitance at the tip so you never get a good view of a signal even if the probe says it has a 500MHz bandwidth.
However a 50 ohm input may not be quite mandatory. In a previous life I used to have some very pricey Tek passive probes which had a much lower capacitance than the standard "300MHz" ones. I remember taking a (broken) one apart. They used a very special cable, with a thinner than a hair single conductor. I have not seen such probes since. It was grey, quite fat, and came with a spring-loaded ground tip for use on PCBs with a ground plane. A google/images doesn't find it though.
EDIT: P6009 https://www.recycledgoods.com/tektronix-passive-probe-with-013-0071-00-screw-on-tip-p6009/ (https://www.recycledgoods.com/tektronix-passive-probe-with-013-0071-00-screw-on-tip-p6009/)
OTOH can't one use an active probe with a non-50-ohm scope input?
Could someone please give me a pointer on which digital scopes, starting from the bottom e.g. the RTB2000, have ETS?
I looked at the SDS2304X.If you want to take a serious look at a frequency spectrum you need a spectrum analyser. Still this doesn't mean FFT on a DSO is useless as long as it is very deep (1Mpts) so you can have a very high frequency resolution. I have used FFT quite a lot for a recent project involving analog and digital signal processing.
Does anyone think that an 8 bit ADC is significantly worse compared to say the 10 bit one of the RTB2000?
I have a low-end DSO which is 8 bit (TDS2004B) and one can clearly see the steps on that. But more to the point I suspect it makes fourier analysis a lot worse because the dynamic range is poor. A spectrum displayed with a log y axis is a likely to be a bit of joke when the data came from an 8 bit ADC.
GDS-2000A CAN/LIN bus analysis software for DS2-08LA or DS2-16LA option
Are these Chinese scopes of reasonable quality, mechanically (quality of switches etc)?Encoders seem to be the most questioned but it's mostly if the manufacturer used detented ones or not. If the encoder algorithm has been poorly implemented then a detented version is the workaround that many resort to.
Unfortunately I really struggle to see the difference between these various Chinese scopes e.g. the above Rigol and the Siglent SDS2304X which is much cheaper.Then you need to keep looking, not take only just the opinions of a minority few that have some axe to grind.
Then I read this forum and see so many reports of functions in all of these scopes which simply don't work. Plus reports of poor response (e.g. slow cursor movement) which the Tek and Keysight scopes do properly.Remember that yesterdays deficiencies that have made it into print have mostly been addressed in firmware revisions by most brands. Check a manufacturers firmware page for the history and frequency of FW updates to get some good idea how mature the product might be.
It would be easy for a nice digital scope user to buy one of these and after a year discover that some feature (e.g. SPI decoding) doesn't work and then it's out of warranty.All features on the SDS2304X work as expected. The warranty is 3 years.
Plenty of threads about most of these scopes being unable to decode serial data which is off-screen which I agree is almost totally useless.Manufacturers implement feature in different ways and not all implementations suit everybody. Does it mean you can't get in info/measurement you need...........no it doesn't.
That's really useful - many thanks.
Are there some "old" HP (Agilent/Keysight) scopes which tick these boxes and which are worth searching for on the used market? These would be very pricey today if you want logic inputs and serial data decoding. However I have used a lot of HP gear over the decades and it is really well built and mostly works very nicely.
A couple of years ago I bought a Marconi 2024 signal generator and an Anritsu 2661G for 2k the lot. This is perfectly usable stuff, if rather old now. OTOH if any of this stuff breaks it can easily be uneconomical or impossible to repair, so you need to get it cheap.
Thanks.All! It is much easier to capture a trace at a long time/div & high samplerate and zoom in to get more detail without needing to setup complicated trigger settings to catch part of a signal with a higher samplerate (let alone reproduce a rare event). Even better if the oscilloscope has a search function where you can search for anomalies.
One thing which is missing on older stuff is the amount of buffering - because memory used to be expensive and you need very fast RAM for a logic analyser / digital scope type of application (even if you interleave it). But does one need megabytes of memory in reality? What applications need it?
Thanks.
One thing which is missing on older stuff is the amount of buffering - because memory used to be expensive and you need very fast RAM for a logic analyser / digital scope type of application (even if you interleave it). But does one need megabytes of memory in reality? What applications need it?
All! It is much easier to capture a trace at a long time/div & high samplerate and zoom in to get more detail without needing to setup complicated trigger settings to catch part of a signal with a higher samplerate (let alone reproduce a rare event). Even better if the oscilloscope has a search function where you can search for anomalies.
DPO mode cannot catch an anomaly 100% because it has blind time (including the operator); only a properly set trigger condition can but that is a different discussion. Search works best in stop mode; it isn't a realtime tool so you can change the search parameters and examine the same data again. When combined with decoding or FFT you can also search for specific messages, data or frequency peaks.Thanks.
One thing which is missing on older stuff is the amount of buffering - because memory used to be expensive and you need very fast RAM for a logic analyser / digital scope type of application (even if you interleave it). But does one need megabytes of memory in reality? What applications need it?
All! It is much easier to capture a trace at a long time/div & high samplerate and zoom in to get more detail without needing to setup complicated trigger settings to catch part of a signal with a higher samplerate (let alone reproduce a rare event). Even better if the oscilloscope has a search function where you can search for anomalies.
I disagree with this in some respects. Delayed acquisition capability (delayed sweep) is just as good except where one needs to zoom into the pretrigger record (1) or where only a single acquisition is available. Searching for anomalies is a job for DPO mode rather than a search function; DPO operation will always catch it but how can you know what an automated search missed?
I have an opportunity to get an ex demo (half price) HP MSOX3034T. It is not clear if this has the 16ch MSO option (SPI etc decoding) but otherwise looks very good.Make sure it includes the MSO probe or expect to spend $300 to $400 on the probe. Also check for the options. Dunno if this model can be hacked and/or if you are willing to do that.
Are there any known gotchas?
Being able to decode NRZ (RS232/422/485) data would save a fair bit of time...
FWIW, I have a good selection of old HP and Tek kit (back to 1980s) and it is outstanding. I have the service manuals and have repaired some of it. It's clear to me that DSOs are however in a different category, with vastly more complexity and close to zero repairability once something nontrivial goes. That's why ex demo stuff is probably worth looking at. That MSOX3034T lists at about 8k GBP - not sure what the digital input situation is; they all seem to have the front panel header... would they just ship them without the probe??
QuoteSearching for anomalies is a job for DPO mode rather than a search function; DPO operation will always catch it but how can you know what an automated search missed?DPO mode cannot catch an anomaly 100% because it has blind time (including the operator);
only a properly set trigger condition can but that is a different discussion. Search works best in stop mode; it isn't a realtime tool
Unfortunately the used MSOX3034T which was on offer has gone, so I am in the market for one, with the digital inputs, and SPI and NRZ (RS232 etc) serial decoding. The ARINC429 decode option would be nice too... Upper limit GBP 4k which I believe is about right for an ex rental (good condition) scope - roughly 1/2 of the new price.
Rental companies do very well out of equipment sales because they buy the stuff at distributor prices and get a LOT of money on the rental. In a previous life I used to rent test equipment and you paid the new price in 1 year.
These are not so commonly seen so I wonder how buggy they are...?
Europe LeCroy has currently a some promos where you get all options or MSO for free:
http://teledynelecroy.com/europe/promotions/promotions.aspx (http://teledynelecroy.com/europe/promotions/promotions.aspx)
I'd also ask about ex-demo units which are regularly discounted by 40% or more.
You should be able to get a WS3034 with options within your budget.
holy... why do they send me just marketing crap on emails?
thanks for pointing that out, tomorrow i'm definetly making the boss see that link. exactly one week ago we were talking about getting new equipment
old video but gives a hint at what wavescan is, on the WK3000
https://www.youtube.com/watch?v=cK6LwYyYWDo (https://www.youtube.com/watch?v=cK6LwYyYWDo)
A WS3034 does look nice; I have emailed them. These are not so commonly seen so I wonder how buggy they are...?These have been in the field for a few years now but only as LeCroy's in western markets where Siglent whom make them have an agreement that they can only sell the OEM in China as SDS3000 models.
A WS3034 does look nice; I have emailed them. These are not so commonly seen so I wonder how buggy they are...?These have been in the field for a few years now but only as LeCroy's in western markets where Siglent whom make them
have an agreement that they can only sell the OEM in China as SDS3000 models.
A search for SDS3000 in the forum gives plenty of hits for you to study up on.
I had ideas of getting one for myself but Siglent are bound by their agreement and can't even supply me. :(
The relatively small memory depth by todays standard is a small negative but otherwise they are a nice scope.
I have emailed all the LeCroy emails but they are not responding. The UK one came back saying "I am on maternity leave till September - please email xxxx" :) Their UK and German numbers here
http://teledynelecroy.com/europe/promotions/promotions.aspx (http://teledynelecroy.com/europe/promotions/promotions.aspx)
are dead.
I am still keeping an eye out for the Keysight one because it does ARINC429 decoding which is something I am starting to be involved it and having a protocol analyser for it is really handy. They do exist but then you get yet another expensive box which gets used maybe once a year...
These scopes all come with four standard probes.
It's interesting to look at stuff like active probes, especially what appears on Ebay. The $1000 HP one (< 1pF) pops up on Ebay for 1/2 price but this is a lot less likely on LeCroy.
Of course "HP" stuff is overpriced...
The WS3034 is rather outside my budget too, even after the discount, with the various options :)
(http://peter-ftp.co.uk/screenshots/2017-07-14_193858.jpg)
The Q is whether all these are worth getting.
The problem is that LeCroy apply these special discounts to an inflated price e.g. $5500 here for the basic box
http://www.tequipment.net/lecroy/oscilloscopes/digital-oscilloscopes/ (http://www.tequipment.net/lecroy/oscilloscopes/digital-oscilloscopes/)
$5500 = £4200
i.e. they inflated the price by 30% or so to start with.
I have told the Le Croy UK guy that he is just inflating the prices massively.Did you already take a close look at the GW Instek MSO2000 series?
In the meantime I have been told that the US disti is prohibited by Le Croy from shipping to the UK - to protect the distributors here... obviously this can be easily sorted via a contact in the USA, but then the warranty would be difficult. And any return to the USA is $200-300 for the round trip, anyway.
I will keep looking. £4k is the budget for 4+16 and serial analysis :)
I have told the Le Croy UK guy that he is just inflating the prices massively.Shame you might have burnt bridges. :-//
I will keep looking. £4k is the budget for 4+16 and serial analysis :)
I think that ETS is disappearing from a lot of scopes because the triggering has changed from analogue (with a time dilation circuit) to digital interpolation and the ETS principle doesn't really work on digital interpolation (the sample points don't move around in the same way to sample at different intermediate time values).
(http://peter-ftp.co.uk/screenshots/2017-07-14_193858.jpg)
http://www.tequipment.net/lecroy/oscilloscopes/digital-oscilloscopes/ (http://www.tequipment.net/lecroy/oscilloscopes/digital-oscilloscopes/)
WaveSurfer 3000 Series 200 - 750 MHz, 2 Ch and 4 Ch, up to 43.8%
Above models including: EMB Option, AUTO Option,Integrated Function Generator Option
Does anyone know anything about vendors not honouring warranty in Europe, on stuff bought in the USA? Keysight or LeCroy?You have to factor in shipping and import charges as well. Also some stuff just can't be bought because local dealers just don't bother to make sales happen. I'd look around in Europe to find a different dealer. Perhaps a good deal can be had from a used equipment dealer.
It must have come up, because US prices are so much lower.
If you buy a lot of equipment then there is some leverage for volume discounts. I couldn't get a single cent of a Wavesurfer 3000 and the local distributor offered a Rigol scope instead when I said the WS3000 was too expensive :palm: :wtf: Are they friggin' kidding me? I think the local distributor lost a potential customer for good!
I have told the Le Croy UK guy that he is just inflating the prices massively.Shame you might have burnt bridges. :-//
In the meantime I have been told that the US disti is prohibited by Le Croy from shipping to the UK - to protect the distributors here...
obviously this can be easily sorted via a contact in the USA, but then the warranty would be difficult. And any return to the USA is $200-300 for the round trip, anyway.
You have to realise that the WS3000 doesn't have peak detect which can be a serious problem when looking at signal where you can't use the maximum sampling frequency. Aliasing can cause all kinds of 'funny' signals to show up or narrow pulses to disapear. This is the sole reason I decided not to buy the WS3000.
Hello WHThat is not peak-detect. Peak detect produces the minimum and maximum during a sample interval. This is especially usefull when the oscilloscope is working at a low samplerate. Without peak-detect you will miss narrow pulses or they turn up randomly. The same goes for aliasing when the input signal has a higher frequency than the samplerate. In short: with peak-detect you get more meaningfull data on your screen. I always have peak-detect switched on. Practical example: look at a slow process like charging a battery where you likely want to use a timebase of 100s/div or longer but you still want to see if there are problems like the current control circuit oscillating at a high frequency or the battery switching to a different charging mode. Here peak-detect will paint a full picture while normal sampling mode won't.
I have been doing a preliminary reading of the Lecroy MAUI interface manual, and they have a feature called Analog Compare which allows you to trigger on certain events occurring in the waveform
I get the impression that it can be setup to do peak detect type triggering. or am I not understanding something.
From what I understand the requirement of Peak Detect is pretty much down to your way of working.
I have been doing a preliminary reading of the Lecroy MAUI interface manual, and they have a feature called Analog Compare which allows you to trigger on certain events occurring in the waveform
I get the impression that it can be setup to do peak detect type triggering. or am I not understanding something.
Why can't one simply trigger from such a pin?[... a low duty cycle pin...]
//enter FSM state foo
output(foo, 1)
output(foo, 0)
...
//enter FSM state baz
output(baz, 1)
output(baz, 0)
...
//enter FSM state bar
output(bar, 1)
output(bar, 0)
//enter FSM state foo
output(baz, 0)
output(bar, 0)
output(foo, 1)
...
//enter FSM state baz
output(foo, 0)
output(bar, 0)
output(baz, 1)
...
//enter FSM state bar
output(foo, 0)
output(baz, 0)
output(bar, 1)
Why can't one simply trigger from such a pin?
As I said, I haven't used PD in nearly two decades, and before that only on a few occasions, simply because there were always better (to me) alternatives available like triggers and math, even on HPAK scopes. And that includes stuff like waiting for a fast low d.c. pulse on a FPGA output (tggzzz's example), all without PD. It's probably down to what you're used to, i.e. if you used PD often back in the old days of low memory scopes then you might be more likely to still use it. But it's no longer the only option.
Wavescan uses the CPU to do some kind of automated mask testing. It can be convenient but it has blind time and it seems you end up with a whole bunch of snapshots which may not paint a complete picture. Roll-mode + peak detect doesn't have blind time and you capture everything.Why can't one simply trigger from such a pin?seeing an event is only useful if you can see the context, context being what is happening in the surrounding pico/nano/micro/milli-seconds
then, imagine you had no peak detect (oh, this i see many times, esp. on rigol) and you trigger from pin.
you see that the waveform has updated. WTF? i see no glitches, but it's there. you can't see it because the screen data is an interpolated and decimated copy of sampled data so you see a flat line, but expand it and a sudden glitch appears!
as far as i understand you can implement peak detect on lecroy's wavescan, but since it operates on sampled data it may reduce wfm/s (someone correct me please) and will be pointless at lower samplerate
Why can't one simply trigger from such a pin?
seeing an event is only useful if you can see the context, context being what is happening in the surrounding pico/nano/micro/milli-seconds
then, imagine you had no peak detect (oh, this i see many times, esp. on rigol) and you trigger from pin.
you see that the waveform has updated. WTF? i see no glitches, but it's there. you can't see it because the screen data is an interpolated and decimated copy of sampled data so you see a flat line, but expand it and a sudden glitch appears!
as far as i understand you can implement peak detect on lecroy's wavescan, but since it operates on sampled data it may reduce wfm/s (someone correct me please) and will be pointless at lower samplerate
Wavescan uses the CPU to do some kind of automated mask testing. It can be convenient but it has blind time and it seems you end up with a whole bunch of snapshots which may not paint a complete picture.
There are indeed often ways around not having some form of peak detect. But it is very convenient when "randomly" probing to see what the hell is happening, and to warn you that you might be missing an important high frequency effect.
Certainly for cheap digitising scopes, "high frequency" means "shorter than one pixel width on the display" - whatever the timebase / memory depth / sampling rate. I don't know how modern high end scopes get around that.
Why can't one simply trigger from such a pin?
seeing an event is only useful if you can see the context, context being what is happening in the surrounding pico/nano/micro/milli-seconds
True. But pretty much any decent modern scopes can be setup to capture specific periods before and after a trigger occurs.
Quotethen, imagine you had no peak detect (oh, this i see many times, esp. on rigol) and you trigger from pin.
you see that the waveform has updated. WTF? i see no glitches, but it's there. you can't see it because the screen data is an interpolated and decimated copy of sampled data so you see a flat line, but expand it and a sudden glitch appears!
But that is because the primitive toolsets on a Rigol scope, not because it's difficult to setup.
Quoteas far as i understand you can implement peak detect on lecroy's wavescan, but since it operates on sampled data it may reduce wfm/s (someone correct me please) and will be pointless at lower samplerate
That's wrong. As stated above PD does not implement PD (i.e. reducing sample data to Extrema). It processes the raw sample data in realtime. The screen refresh rate will drop notably in WaveScan but because this isn't a 'user-staring-on-screen-to-wait-for-glitch-appearing' kind of mode this usually isn't a problem.
QuoteBut that is because the primitive toolsets on a Rigol scope, not because it's difficult to setup.
the same happens in my lecroy mainframe, which is understandable given its > 20 years old
i found out while troubleshooting a faulty plugin, i would get unexplainable triggers but if i expanded the waveform i would see a literal drop to bottom screen (a failed memory chip) that wasn't there while seeing the full acquisition
thanks for the corrections, but may i ask: what if the event happens during the blind time? (pros and cons of everything of course. no system is perfect)
A WS3034 does look nice; I have emailed them. These are not so commonly seen so I wonder how buggy they are...?I'm only aware of a few trivial bugs in the current firmware. One is that even if you don't have a mouse plugged in it sometimes leaves a cursor on the screen (which goes away at the next touch).
and they can use the same ProBus active probesAnd if you're not made of money it's nice that a lot of the older active probes available inexpensively on eBay will work fine. The ONLY gotcha I've found is with the AP020 (1GHz, 1Mohm, 1.6pF, 10V range) and AP022 (2.5GHz, 100kohm, 0.6pF, 10V range) where if measurements or the DVM are enabled the trace will flicker once during the blind time or when it
Hello XXX,
I don't think that the statement in the manual is untrue, because it says 'rated for the oscilloscopes bandwidth', and these older probes are 1GHz and 2.5 GHz respectively, but I do see how this could be misleading.
We do track compatibility between most of our much older probes and newer products. It may be the case that these probes will function to some extent, but we either never verified that the probe/scope system meets specifications, or it doesn't meet specifications.
I would suggest to check the oscilloscope datasheet (http://cdn.teledynelecroy.com/files/pdf/wavesurfer-3000-datasheet.pdf (http://cdn.teledynelecroy.com/files/pdf/wavesurfer-3000-datasheet.pdf)), and if the probe is not on the datasheet, you can contact us and we can check compatibility.
Best,
Carl Damm
Applications Engineer
1-800-553-2769 x6018
carl.damm@teledynelecroy.com
By the way - again thanks for the assistance - but I’m curious how you'd determine compatibility?
The WS3000 manual I have says, "WaveSurfer3000 oscilloscopes are compatible with the
included passive probes and all Teledyne LeCroy ProBus active probes that are rated
for the oscilloscope’s bandwidth.” Maybe I misunderstood this and it only refers to ProBus
active probes currently in production?
Just trying to avoid future misunderstandings. I realize these probes are pretty vintage!
and they can use the same ProBus active probesAnd if you're not made of money it's nice that a lot of the older active probes available inexpensively on eBay will work fine. The ONLY gotcha I've found is with the AP020 (1GHz, 1Mohm, 1.6pF, 10V range) and AP022 (2.5GHz, 100kohm, 0.6pF, 10V range) where if measurements or the DVM are enabled the trace will flicker once during the blind time or when itretriggersrearms the trigger. But they're recognized and otherwise work perfectly. The differential AP034 (1GHz, 1.5pF, with 10:1 +/-4V, 1:1 +/-0.4V, and AC coupling) works fine, as does of course the current ZS1000 active probe. (I have all those four.) With the ADPPS power supply (50ohm BNC out) they can all be used with other instruments like counters, VNAs, and SAs. Want to see the see the spectrum of a differential 250MHz signal? No problem! (I'd also recommend a really good AC coupler since they won't be auto-zeroed without a ProBus scope.)
I asked LeCroy about the flicker and was told the WS3000 is only compatible with probes rated for its bandwidth, which according to them excludes 1GHz and 2.5GHz probes. (But then they sell the ZS1000 as being compatible.) This is a little specious to me, but not worth fussing over - basically they work but are unsupported with no compatibility guarantee.
Why isn't one active probe same as any other?
I realise they need to be powered somehow, via contacts next to the BNC or whatever coaxial connector, but if you are feeding a 50 ohm scope input why is there a compatibility issue?
But what about single ended probes?Single-ended active probes can have the same problem. Obviously passive probes should work apart from mechanical issues (I am not aware of any passive probes that use DSP for correction). As will older passive probes from before they started using DSP and identification EEPROMs. One thing that may still be controlled from the scope, even for older probes, is offset voltage.
Can the Keysight MSOX3034 or LeCroy WS3034 work with simple passive probes like the one above?
Whoops I meant ACTIVE :)
I see the connectors on the more recent ones are not BNC... they can't be BNC because there is no way to access the bayonet on the "fat-box" probes whose body goes right up to the scope front panel. But if the scope is not BNC, that's a case of getting the right adaptors.
What I am getting at is that the scope can't be insisting on EEPROM identification (like inkjet cartridges etc) IF it accepts PASSIVE probes with its 50 ohm input mode. An old style active probe will look just like a passive probe.
but a basic one like this
(http://peter-ftp.co.uk/screenshots/2017-07-17_110739.jpg)
should be usable so long as you work out how to connect the external power to it (looks like a Lemo connector on that one).
I have got a better price now for the WS3024 from Le Croy here in the UK, after I told him the USA is a lot cheaper. Still inflated though.
I wonder if the function gen is truly worthless... you can get one of these https://www.rigol-uk.co.uk/Rigol-DG1032Z-Waveform-Generator-p/dg1032z.htm (https://www.rigol-uk.co.uk/Rigol-DG1032Z-Waveform-Generator-p/dg1032z.htm) for less!
with the increasing EU regulation like the ROHS, ROHS2, REACH, etc nonsense.Sidenote: I don't see how preventing toxic materials from entering the food supply chain is a bad thing. There is more to doing business than making money. Unfortunately companies will only do the morally right thing when they really have to. Also if your business' profitability strongly depends on the value of the currency then there is something fundamentally wrong with it because it can go any direction.
AFAIK there was never any evidence that metals from scrapped electronic equipment enter the food chain. Most of the toxic stuff gets there from other sources.It is not just about the electronics scrap but also about manufacturing of goods using toxic substances. Google 'China lead poisoning' for example and you'll see the problem. If there is no market for products with toxic materials then the toxic materials won't be used. But these things don't always happen far from your own front door. Over here in the NL we currently have a problem with a factory producing Teflon which has been dumping toxic waste in the surface water. This has lead to contamination of the drinking water.
What I am getting at is that the scope can't be insisting on EEPROM identification (like inkjet cartridges etc) IF it accepts PASSIVE probes with its 50 ohm input mode. An old style active probe will look just like a passive probe.Not entirely true, manufacturers can and do lock out probes they don't want used:
The offset adjustment can't be a big issue. One has to move traces up and down when using a scope anyway...
Is the LeCroy WS3024 (200MHz) with the 350MHz software key applied *exactly* the same as the 3034, including all accessories?
I know this is a bit silly but presumably the front label says "200MHz", or does the upgrade come with a sticker? :)
Also, since this seems to be the 500MHz model anyway, how are the bandwidth degradations implemented?
Also this scope supports ETS and does that work with a 200MHz or 500MHz analog input amp? I would be amazed if they have analog switches which switch in some capacitors to slow down the front end amp!
The exact way that ETS works (or doesn't) will be dependent on the front end, before the ADC.
Let's say for example that the bandwidth crippling is implemented with a lowpass filter on the waveform displayed on the LCD i.e. wholly in software. That would be the easiest (and the most cynical) way to do it. It would be very easy to do because it doesn't matter whether it takes 10ms or 50ms to draw the picture on the LCD.
But if they actually modify the BW of the input amp that will affect ETS too because the waveform is already BW-crippled.
What I am getting at is that a 70MHz scope which is actually 500MHz might be giving you 500MHz with ETS i.e. when looking at any repetitive waveform. Only with single shot signals it will be BW limited to 70MHz.
But if they actually modify the BW of the input amp that will affect ETS too because the waveform is already BW-crippled.
What I am getting at is that a 70MHz scope which is actually 500MHz might be giving you 500MHz with ETS i.e. when looking at any repetitive waveform. Only with single shot signals it will be BW limited to 70MHz.
It wouldn't be very easy, it would require a real-time fourier transformation, stepped removal of the excess frequency components, and then a real-time inverse FT to get the waveform back. Even on a high end scope with powerful processing this won't result in very good update rates. And it would be a silly way to do this as limiting BW in hardware is much easier, especially when considering that better DSOs already use DSPs to get the required linearity from their front ends.
It appears that some of HP's old Infiniium 54800 Series scopes show a slightly increased BW in ETS mode than in normal sampling mode, probably caused through different parameters feed into the scope's DSPs. But these are exceptions.
It just requires a FIR filter so a bunch of multiply-accumulate operations. Many DSOs implement this in real time and any digital equalization is done the same way.
QuoteIt appears that some of HP's old Infiniium 54800 Series scopes show a slightly increased BW in ETS mode than in normal sampling mode, probably caused through different parameters feed into the scope's DSPs. But these are exceptions.
I have seen this on high bandwidth DSOs. I think it comes about because the processing used to minimize aliasing is not required or even desired in ETS mode where the sample rate is much higher. Switching to ETS mode removes the Gibb's phenomena for the same reason.
So is the 3024 + 350MHz exactly identical to the 3034, and does anyone know how the BW limit is implemented?
Pre-amplifiers with adjustable bandwidth have been available for decades (for example: the Tektronix TDS500/700 series used this). Often the bandwidth limits (like 20MHz) are implemented the same way.So is the 3024 + 350MHz exactly identical to the 3034, and does anyone know how the BW limit is implemented?
Considering that this is just a SW code it's very likely done via a DSP in the front end.
QuoteIt appears that some of HP's old Infiniium 54800 Series scopes show a slightly increased BW in ETS mode than in normal sampling mode, probably caused through different parameters feed into the scope's DSPs. But these are exceptions.
I have seen this on high bandwidth DSOs. I think it comes about because the processing used to minimize aliasing is not required or even desired in ETS mode where the sample rate is much higher. Switching to ETS mode removes the Gibb's phenomena for the same reason.
I've never seen this on any scope I had an opportunity to test its BW limit in real-time and ETS/RIS mode, which were quite a few including my own 3Ghz LeCroy WavePro 7300A, my trusty old 13Ghz DSO90k at work, a few models of the Keysight DSO9k, LeCroy HDO4k/6k, WP7zi-A, WM 8zi-A and a few other scopes including a 65Ghz LabMaster 9zi-A (where RIS works only for signals <25GHz).
It also wouldn't make a lot of sense to change the front end's BW envelope because while, as you said, aliasing might not be an issue in ETS mode because of the high sample rate, increasing the BW also means increasing the noise floor, i.e. potentially introducing non-repetitive artefacts which would degrade the waveform integrity.
But then, ETS is pretty pointless these days because as long as all frequency components of a signal to measure are within Nyquist-Shannon (fsignal < 2 * fsampling) then using sin(x)/x interpolation will always present a true waveform.
If you measure a fast edge, then sin(x)/x interpolation will cause distortion do to signal components close to the Nyquist frequency. A good example of this occurs when you view a fast edge on a 100 MHz Rigol DS1074Z is while it is in 4 channel mode limiting it to 250 MS/s. Any RTS DSO under these conditions will produce the same result which are *not* as accurate as the result produced by ETS.Signal components close to the Nyquist frequency, or beyond the Nyquist frequency? It is not hard to imagine a 100 MHz scope's input filter (which is most likely Gaussian) letting through frequencies beyond 125 MHz. You would need a bandwidth-limited edge to be sure. An input filter of fsample/2.5 is very aggressive for a Gaussian filter.
If you measure a fast edge, then sin(x)/x interpolation will cause distortion do to signal components close to the Nyquist frequency. A good example of this occurs when you view a fast edge on a 100 MHz Rigol DS1074Z is while it is in 4 channel mode limiting it to 250 MS/s. Any RTS DSO under these conditions will produce the same result which are *not* as accurate as the result produced by ETS.
Signal components close to the Nyquist frequency, or beyond the Nyquist frequency? It is not hard to imagine a 100 MHz scope's input filter (which is most likely Gaussian) letting through frequencies beyond 125 MHz. You would need a bandwidth-limited edge to be sure. An input filter of fsample/2.5 is very aggressive for a Gaussian filter.
The limit of sin x/x reconstruction is around 0.4fs and beyond that you'll get odd behavior. ETS doesn't have this issue so it could be usefull in some cases at the expense of being slower and needing a repetitive signal. Either way it is not a good idea to blindly trust what is on the screen of an oscilloscope. You always have to take it's limits into account.
Is the LeCroy WS3024 (200MHz) with the 350MHz software key applied *exactly* the same as the 3034, including all accessories?I wouldn't be sure that the probe BW was the same.
I have seen this on high bandwidth DSOs. I think it comes about because the processing used to minimize aliasing is not required or even desired in ETS mode where the sample rate is much higher. Switching to ETS mode removes the Gibb's phenomena for the same reason.
I've never seen this on any scope I had an opportunity to test its BW limit in real-time and ETS/RIS mode, which were quite a few including my own 3Ghz LeCroy WavePro 7300A, my trusty old 13Ghz DSO90k at work, a few models of the Keysight DSO9k, LeCroy HDO4k/6k, WP7zi-A, WM 8zi-A and a few other scopes including a 65Ghz LabMaster 9zi-A (where RIS works only for signals <25GHz).
I am referring to the sin(x)/x interpolation filter and the bandwidth enhancement filter. I saw it on an Agilent multi-GHz DSO which supported selectable RTS and ETS
but it actually applies to any DSO where you can manually select modes.
QuoteBut then, ETS is pretty pointless these days because as long as all frequency components of a signal to measure are within Nyquist-Shannon (fsignal < 2 * fsampling) then using sin(x)/x interpolation will always present a true waveform.
If you measure a fast edge, then sin(x)/x interpolation will cause distortion do to signal components close to the Nyquist frequency.
A good example of this occurs when you view a fast edge on a 100 MHz Rigol DS1074Z is while it is in 4 channel mode limiting it to 250 MS/s.
The limit of sin x/x reconstruction is around 0.4fs and beyond that you'll get odd behaviour.
ETS doesn't have this issue so it could be usefull in some cases at the expense of being slower and needing a repetitive signal
Either way it is not a good idea to blindly trust what is on the screen of an oscilloscope. You always have to take it's limits into account.
the datasheets mentions 250 and 500 MHz passive probes but doesn't tell which gets what...
i would think 250 MHz for the 200 MHz version, 500 MHz for 350,500,750 MHz versions?
No, that's not a good example. The DS1074Z, while being cheap, isn't really a good representation of a modern decent DSO, not just because Rigol's demonstrated inability to design a proper oscillator.
I had a long post about ETS and sin(x)/x but the Gateway 502 error with something about maintenance in March ate it.
I am now looking at the 200MHz version as it is much cheaper and with the MSO and EMB options it should be within the budget.
And maybe one day there will be a special offer going on the 350MHz or even 500MHz software key (or I might be able to pick it up somewhere...). This scope is bound to get hacked one day,
because this pricing policy is really cynical.
Unlikely, considering how aggressive LeCroy is when it comes engaging all attempts of hacking their key system. Which is somewhat understandable, as they use the same key system for all of their non-entry-level scopes since the old WaveRunner LT from 1998 right up to the >$1M 100GHz LabMaster 10zi. Unlike other vendors, LeCroy also still sells keys for all these scopes going back to that 1998 WaveRunner LT, so they are very motivated to fight against any hacking attempts.Even if it means losing sales... nowadays hackability means sales because nobody is going to pay for common options like decoding.
nowadays hackability means sales because nobody is going to pay for common options like decoding.
The cheaper brands are getting much better so they must be eating into the A-brand's market share pretty bad.nowadays hackability means sales because nobody is going to pay for common options like decoding.Depends on who your target market is.
Currently Le Croy are sticking to the $500 FG being bundled and won't let you drop that one out to save the $500.There's all sorts of politics come into play with rebrands and maybe it's a good time to take a step back and have a rethink about what you must have in a scope and better value for money options.
They also always want $1500 for the logic input option. Don't they populate the PCB anyway, like Keysight do, so the only extra cost to them is just the logic probe?
Which scope was it that required the logic option in order to do serial decoding? I think it was the Instek one... but Instek make the Le Croy scopes.
What I want are the logic input and SPI etc decoding.Buy the GW Instek MSO2000 and be done with it.
What I want are the logic input and SPI etc decoding.Yeah but you want the large display too so that cuts down choice some.
It clearly looks like LC are working hard to prevent the box going for too little, by always bundling the FG option at $500.
It would be pretty weird if the EMB option (frequently bundled in the USA right now) required the MSO option ($1500 always) :)
I am now looking at the 200MHz version as it is much cheaper and with the MSO and EMB options it should be within the budget.
And maybe one day there will be a special offer going on the 350MHz or even 500MHz software key (or I might be able to pick it up somewhere...). This scope is bound to get hacked one day, because this pricing policy is really cynical.
No, it isn't. It's exactly the same for all big test & measurement manufacturers. Just for fun, go and ask how much Keysight charges for the serial decode options, mask testing or the N8900A InfiniiView PC software. And then, if you think these are expensive, go and check the list price for similar option for Rohde & Schwarz RTM, RTE and RTO scopes.
That's why negotiating is so important.
It is curious that there were no used DSOX scopes of that spec; it was my #1 choice. They do come up but at nearly-new prices. Perhaps if one waited a year... but clearly people keep this stuff because it is good. You don't get used ones coming up except at bankrupcy auctions etc.There are always several on Ebay including from Keysight's own Ebay store. The latter would be a wise choice if you care about warranty.
Unlikely, considering how aggressive LeCroy is when it comes engaging all attempts of hacking their key system. Which is somewhat understandable, as they use the same key system for all of their non-entry-level scopes since the old WaveRunner LT from 1998 right up to the >$1M 100GHz LabMaster 10zi. Unlike other vendors, LeCroy also still sells keys for all these scopes going back to that 1998 WaveRunner LT, so they are very motivated to fight against any hacking attempts.
Even if it means losing sales... nowadays hackability means sales because nobody is going to pay for common options like decoding.
There are always several on Ebay including from Keysight's own Ebay store. The latter would be a wise choice if you care about warranty.
AFAIK you can always get repair agreements on Keysight equipment as long as it is supported.There are always several on Ebay including from Keysight's own Ebay store. The latter would be a wise choice if you care about warranty.The only instruments that have full warranty are Keysight's CertiPrime instruments, used gear usually only comes with 60 days or so of warranty.
Pretty much all my Agilent/Keysight gear aside from my HP GPSDO and my DSO8064A (both too old) has got Repair Agreements on it.
Is there a list of active probes which will work with the WS3034?
LeCroy list only the ZS1000 which sure enough is on Ebay too, at about $1000 for a new one. One can buy them from distis for less...
There are several others with the same "box" style which look like they have the same connector.
Ebay # 272663607402 is an HPF-1000 which again looks similar style. There is an AP-020, likewise
Ebay item 172796394593 lists as "Agilent/Lecroy AP020 Active FET Probe, 1GHz". Did these two really share the same probe interface?
There is also a ZS1500, going for a lot less than the ZS1000.
Are the differential probes usable as a normal probe? There doesn't seem to be much difference in the way they look. Both types of "1GHz" active probes need the ground pin really close to the signal pin (usually to touch a ground plane).
Are the differential probes usable as a normal probe? There doesn't seem to be much difference in the way they look. Both types of "1GHz" active probes need the ground pin really close to the signal pin (usually to touch a ground plane).Usually there is a restrictive voltage range compared to passive probes, so active probes can't be used for everything. But even comparing active probes to each other the differential probes tend to have more noise when used single ended. Once you have a few probes you realise you could do with many many more.
Obviously the answer should be "yes" but I wonder if there is some gotcha...
I have a sweet commercial Tek scope with ~30kS/s which is used to see 140ps risetimes. Occasionally you see them on fleabay at high prices; currently one is (claimed to be) available for ~£1000!
I have a sweet commercial Tek scope with ~30kS/s which is used to see 140ps risetimes. Occasionally you see them on fleabay at high prices; currently one is (claimed to be) available for ~£1000!
Sorry for being late to this thread. What Tek model is this? Thx
The AP-034 seems to have a max diff voltage range of 0.4V which makes is unsuitable for logic probingIts the same Preamble probe as branded the Agilent 1159A, they're designed to be used with matched attenuators:
One thing we could not find today was decoding data on RS422/485 i.e. the difference between two signals. There is one option called RS232, and one called UART which I assume is the TTL level at a microcontroller i.e. inverted version of RS232.According to this datasheet (http://cdn.teledynelecroy.com/files/pdf/tdme-datasheet.pdf), the UART is a bit more configurable.
Oh, the "whys" of the datasheets... The information is there not to be an axiomatic truth, but instead each speck of data must be slowly inhaled while carefully performing a deep search inside oneself to find the true metaphysical sense...... and to grok what isn't being said and what isn't being specified.
Good one!Oh, the "whys" of the datasheets... The information is there not to be an axiomatic truth, but instead each speck of data must be slowly inhaled while carefully performing a deep search inside oneself to find the true metaphysical sense...... and to grok what isn't being said and what isn't being specified.
Can you use a maths function to find the difference between the two signals, then run the decode on that result?I would guess it's possible to use "MATH" as a source on a LeCroy. I was surprised by the ancient 9400 and how it allows you to stack operations using "MATH" as a source.