Recommendation Request - NEW Rigol DS1054Z or USED Tektronix 2467BHD

[mtchastain]

Hi All!
I am in a quandary and I hope you can help enlighten me.

In the next month or so I will have enough funds for a scope purchase.  I don’t need anything particularly powerful and after a bunch of research, I believe a Rigol DS1054Z would work for me as it’s in my price range.
 
However, during my search I also found a used Tektronics 2467BHD (Analog - 400MHz) for sale that appears in good condition but has not been tested (but I have access to it and could test it on site). Last calibration was in the late 90’s from what I can remember, and it was listed at about 400.00 USD.

I have used Tektronics scopes in the past and was very impressed with the brand and the quality and so I am kind of torn now. I am willing to sacrifice the bells and whistles of a new digital scope if an older analog scope in this class is still viable.

Any suggestions would be greatly appreciated. Also, any ideas on the tests I should do to the used scope would be wonderful.

-Matt

[OldSchoolTechCorner]

As much as I love the Tektronix 2467 BHD, the Rigol DS1054Z is the best bang for the buck at that price.

[FlyingHacker]

The Tek is a much nicer instrument. It is like buying an older Mercedes va. a new Hyundai...

And just like that the Tek will likely take more maintenance. Typically the 2400 series scopes need new capacitors in their low voltage power supplies. This is pretty easy to do if you are decent with an iron, an ideally have a desoldering station (cheap Chinese one works fine). I did mine on a 2465. Sometimes there is damage to the boards from leaky caps, which can be easy or hard to cleanup, or repair (damaged traces). Mine had just two caps that had leaked, and cleanup was pretty easy.

The Rigol will give you more on screen displays and calculate things for you, like rise time, frequency, etc.

Personally, I use mainly analog scopes (2465 and a 2232, which is an analog hybrid DSO, whcich will behave as a purely analog scope, or a CRT based DSO). I have frequency counters for that purpose if I need a continuous update, or use the cursors on the scope of I just need a quick read.

So it is really a personal decision, a lot like the old Mercedes vs. Hyundai.

[OldSchoolTechCorner]

The Tek is a much nicer instrument. It is like buying an older Mercedes va. a new Hyundai...

And just like that the Tek will likely take more maintenance. Typically the 2400 series scopes need new capacitors in their low voltage power supplies. This is pretty easy to do if you are decent with an iron, an ideally have a desoldering station (cheap Chinese one works fine). I did mine on a 2465. Sometimes there is damage to the boards from leaky caps, which can be easy or hard to cleanup, or repair (damaged traces). Mine had just two caps that had leaked, and cleanup was pretty easy.

The Rigol will give you more on screen displays and calculate things for you, like rise time, frequency, etc.

Personally, I use mainly analog scopes (2465 and a 2232, which is an analog hybrid DSO, whcich will behave as a purely analog scope, or a CRT based DSO). I have frequency counters for that purpose if I need a continuous update, or use the cursors on the scope of I just need a quick read.

So it is really a personal decision, a lot like the old Mercedes vs. Hyundai.

The Tek 2467BHD is a great scope, consider one of the best analog scopes. Power supply will need to be rebuilt, as capacitor leak and high wattage resistors need to be changed out. It a personal favorite, but for someone starting in electronics get the DSO. 

[EEVblog]

Absolutely no contest, get the DS1054Z
An analog scope, no matter how good (and that Te is about about as good as it gets), is no match for a modern digital scope.
Digital scopes capture waveforms, that alone opens up a whole new world from analog scopes.

[EEVblog]

The Tek is a much nicer instrument. It is like buying an older Mercedes va. a new Hyundai...

No, it's nothing like that.
There is a huge fundamental difference between analog and digital scopes. One allows you to single shot capture waveforms, the other does not. One of them literally lets you work easily on any type of signal in any scenario, the other does not.
It's like comparing a car that only goes in a straight line and can't stop, to one that has steering and brakes.

[pickle9000]

The single button is what it's all about. I remember using my fist DSO the TDS-220, what a powerful tool compared to an analogue. If you have a choice a DSO is the smart one.

[coppice]

The Tek is a much nicer instrument. It is like buying an older Mercedes va. a new Hyundai...

No, it's nothing like that.
There is a huge fundamental difference between analog and digital scopes. One allows you to single shot capture waveforms, the other does not. One of them literally lets you work easily on any type of signal in any scenario, the other does not.
It's like comparing a car that only goes in a straight line and can't stop, to one that has steering and brakes.

What about a Tek that comes with a good old fashioned Polaroid scope camera? You could buy an awful lot of Polaroid film packs for the cost of an analogue storage tube. :-)

[EEVblog]

This 2467 is happy!
http://www.ebay.com/itm/Guaranteed-Tektronix-2467-4-channel-350-MHz-BrightEye-scope-Calibrated-NIST-/151876480197

[crispy_tofu]

Must have good working hours 

I would go with the DS1054Z.

[mtchastain]

The Tek is a much nicer instrument. It is like buying an older Mercedes va. a new Hyundai...

And just like that the Tek will likely take more maintenance. Typically the 2400 series scopes need new capacitors in their low voltage power supplies. This is pretty easy to do if you are decent with an iron, an ideally have a desoldering station (cheap Chinese one works fine). I did mine on a 2465. Sometimes there is damage to the boards from leaky caps, which can be easy or hard to cleanup, or repair (damaged traces). Mine had just two caps that had leaked, and cleanup was pretty easy.

The Rigol will give you more on screen displays and calculate things for you, like rise time, frequency, etc.

Personally, I use mainly analog scopes (2465 and a 2232, which is an analog hybrid DSO, whcich will behave as a purely analog scope, or a CRT based DSO). I have frequency counters for that purpose if I need a continuous update, or use the cursors on the scope of I just need a quick read.

So it is really a personal decision, a lot like the old Mercedes vs. Hyundai.

I like the car analogy, it kind of does feel like that especially when one has always owned Hyundais.

I think part of my reason for considering the used scope was that I go burned on a relatively cheap DSO a couple of years ago (not enough research on my part and a "too good to say no" price).

I would like to think that even a used scope of this class would be easier to trust to last at least another 5 to 10 years, though I now get the feeling I may be deluding myself.

I don’t think I would have any problems replacing most passive components if needed, but since here are a lot of other “not so easy to replace” parts, I still run a similar risk.

[EEVblog]

I like the car analogy, it kind of does feel like that especially when one has always owned Hyundais.

You don't get it, the car analogy is false.
Both of them are not cars that function the same. Both cannot get you from A to B.
To think it's about the quality is to miss the point.

I think part of my reason for considering the used scope was that I go burned on a relatively cheap DSO a couple of years ago (not enough research on my part and a "too good to say no" price).

I guarantee you will be bummed in few years if you get the analog scope and then figure out you can't capture a waveform with it!

I would like to think that even a used scope of this class would be easier to trust to last at least another 5 to 10 years, though I now get the feeling I may be deluding myself.

You are thinking about the wrong thing. You should be thinking about what the scope you are buying is capable of.
There are two types of scopes, those that can capture signals, and those that can't. The analog scope can't. The digital scope can, and do practically everything the analog scope can do.

[deadlylover]

I'd get the 1054Z, then camp out for a great deal on a 2467(or other analog scope) to satisfy your heart's desire. 

[mtchastain]

You don't get it, the car analogy is false.
Both of them are not cars that function the same. Both cannot get you from A to B.
To think it's about the quality is to miss the point.

Sorry, I do get what you are talking about. All the scopes I have ever owned did exactly what I wanted and expected from them, but I kinda wasted the extra functionality that came with the cheap DSO due to ignorance (only ever had one and it was very new to me).

After seeing the video on how they can really be used, did I start to understand what I was missing. I have to stop just thinking of scopes in an old-school analog way (old habits die hard).

You are thinking about the wrong thing. You should be thinking about what the scope you are buying is capable of.
There are two types of scopes, those that can capture signals, and those that can't. The analog scope can't. The digital scope can, and do practically everything the analog scope can do.

I think you are right…

Even if I can’t immediately use all the functionality of the DSO, I can at least learn to use it eventually rather than finding out I needed it and just not have it. I certainly don’t want to have to buy a second scope just to get something I could have had in the first place… Though a second higher bandwidth analog scope wouldn’t be a bad thing to have (that’s for the future)

[Howardlong]

No brainer, DS1054Z.

I had a similar quandary a few years back, I had a Tek TDS2024B and a 2465B, but had no room at the time and one of them had to go. It was the 2465B that went.

Later, once I had enough room, I bought a 2465B back again - and a 2467B for good measure. They are super scopes, but realistically, as others have said, single shot capability on its own trumps all the other benefits of the 2465B. Having both the TDS2024B and 2465B on the bench though, I'd almost always go for the 2465B first just because of its ease of use and responsiveness unless I needed single shot capabilities.

[EEVblog]

Even if I can’t immediately use all the functionality of the DSO, I can at least learn to use it eventually rather than finding out I needed it and just not have it.

You don't have to use all the functionality in a modern scope, but it's trivial to press the STOP button and have the waveform frozen on the screen for you to examine.
This alone will open a whole new world for you.

[TheSteve]

I don't even like Rigol but I still own a DS1054Z, as do many friends. I highly recommend it over the Tek scope.(and I love Tektronix!)

[Alex Nikitin]

I have both Tek 2465BCT and Agilent DSO3062A on my home bench, however the DSO is only used if I need it's specific abilities (to capture a single shot or a very slow process, to export a picture to my computer), for any live circuit work the analogue scope works much better for me due to the instantaneous beam response and WYSIWYG. That means I use the Tek 99% of the time. At work I have much fancier DSOs however it is a real pain if I have to work on a live HV/RF circuit with a DSO and I miss my Tek greatly. I may yet persuade my boss to get me a refurbished Tek 2465B/BCT  .

Cheers

Alex

[Fungus]

for any live circuit work the analogue scope works much better for me due to the instantaneous beam response and WYSIWYG.

If your DSO 'beam' isn't responding instantly then maybe you need to adjust a setting. The DS1054Z can grab 30,000 wavforms/sec if you let it.

[Solder_Junkie]

As most have said, the Rigol is the way to go. My own experience was 40+ years of analogue scopes as a servicing tech, I retired and "put up with" a dual beam 100 MHz Philips scope, it had a few minor faults (dirty switches, poor triggering, etc.) and then finally blew the power supply.

I had fancied a digital scope for some time but the early ones were pretty awful (at least in my price range). When the old scope failed, I bought a 1054Z based on Dave's video review and don't regret it at all. The saving in shelf space alone was worth it 

These days the scope is used for ham radio development and construction, the four channels are great to measure timing of control circuits, something that is tedious with a dual channel analogue scope and child's play with the 1054Z. I doubt the Rigol will last as long as the Philips did, but they are cheap enough and by then I probably won't care either.

[Howardlong]

I have both Tek 2465BCT and Agilent DSO3062A on my home bench, however the DSO is only used if I need it's specific abilities (to capture a single shot or a very slow process, to export a picture to my computer), for any live circuit work the analogue scope works much better for me due to the instantaneous beam response and WYSIWYG. That means I use the Tek 99% of the time. At work I have much fancier DSOs however it is a real pain if I have to work on a live HV/RF circuit with a DSO and I miss my Tek greatly. I may yet persuade my boss to get me a refurbished Tek 2465B/BCT  .

Who made the DSO3062A?It doesn't look very Agilent, is it an older rebadged Rigol? Id so I concur, I'd be reaching for the 2465B too.

[Alex Nikitin]

I have both Tek 2465BCT and Agilent DSO3062A on my home bench, however the DSO is only used if I need it's specific abilities (to capture a single shot or a very slow process, to export a picture to my computer), for any live circuit work the analogue scope works much better for me due to the instantaneous beam response and WYSIWYG. That means I use the Tek 99% of the time. At work I have much fancier DSOs however it is a real pain if I have to work on a live HV/RF circuit with a DSO and I miss my Tek greatly. I may yet persuade my boss to get me a refurbished Tek 2465B/BCT  .

Who made the DSO3062A?It doesn't look very Agilent, is it an older rebadged Rigol? Id so I concur, I'd be reaching for the 2465B too.

As I've said, I have some better DSOs at work - the Tek MSO2024 and Agilent DSO1014A and still I would prefer the 2465B. The Agilent scope at home is old but still adequate for it's capture capabilities when I need these, so I'm not upgrading it any time soon.

Cheers

Alex

[Wuerstchenhund]

As I've said, I have some better DSOs at work - the Tek MSO2024 and Agilent DSO1014A

Not sure I would call them better. The Agilent scope is very likely another rebadge of some Chinese scope.

[alsetalokin4017]

Anybody with a digital camera can capture a single-shot trace from an analog scope.

But no analog scope will do this:

[OldSchoolTechCorner]

I have both Tek 2465BCT and Agilent DSO3062A on my home bench, however the DSO is only used if I need it's specific abilities (to capture a single shot or a very slow process, to export a picture to my computer), for any live circuit work the analogue scope works much better for me due to the instantaneous beam response and WYSIWYG. That means I use the Tek 99% of the time. At work I have much fancier DSOs however it is a real pain if I have to work on a live HV/RF circuit with a DSO and I miss my Tek greatly. I may yet persuade my boss to get me a refurbished Tek 2465B/BCT  .

Who made the DSO3062A?It doesn't look very Agilent, is it an older rebadged Rigol? Id so I concur, I'd be reaching for the 2465B too.

As I've said, I have some better DSOs at work - the Tek MSO2024 and Agilent DSO1014A and still I would prefer the 2465B. The Agilent scope at home is old but still adequate for it's capture capabilities when I need these, so I'm not upgrading it any time soon.

Cheers

Alex

They are not a good DSO to based off of. The entry level Tek and Agilent are not that great, or competitive, huge gap in the market till you get to a decent one. Plus the FFT on most the Chinese scopes are not up to the task and only 10 kpts each channel and use interleaved analog-to-digital converters (ADCs), so poorer signal fidelity leads to more sampling errors. Some do it well, some don't. That Agilent DSO1014A is a modified Rigol 1000B, which is pretty dated technology. You want to get a Agilent X series 3000, or 4000 to get a reasonable scope, their budget lineup is not a good value, same with Tek.

For the price DS1054Z is a very good value.

[vk6zgo]

As most have said, the Rigol is the way to go. My own experience was 40+ years of analogue scopes as a servicing tech, I retired and "put up with" a dual beam 100 MHz Philips scope, it had a few minor faults (dirty switches, poor triggering, etc.) and then finally blew the power supply.

I had fancied a digital scope for some time but the early ones were pretty awful (at least in my price range). When the old scope failed, I bought a 1054Z based on Dave's video review and don't regret it at all. The saving in shelf space alone was worth it 

These days the scope is used for ham radio development and construction, the four channels are great to measure timing of control circuits, something that is tedious with a dual channel analogue scope and child's play with the 1054Z. I doubt the Rigol will last as long as the Philips did, but they are cheap enough and by then I probably won't care either.

Tedious with a 2 channel,maybe,but not with a 7000 series Tek with two vertical plugins!

[Rupunzell]

For those who do near zero work with digital this becomes a non-significnat feature... along with the data box.

The proper choice of DSO-MOS -vs- analog is a LOT more complex than a DSO's ability to store, retrieve, digitize and transmit converted data.

Those who are truly aware is likely going to choose the ideal instrument to fit a specific need. DSO-MSO domination of the time domain instrument market today appears to be due to the sheer-mass number of digital centric electronics folks along with software centric pre-packaged hardware offerings use to make the vast majority of techno widgets today.



Bernice

But no analog scope will do this:

[Alex Nikitin]

Well, just as a teaser - could somebody post a screen shot from the Rigol DS1054Z (or a similar DSO scope) of a 100Mhz signal with 50% AM modulation at 1kHz. A screen from the Tek 2465BCT is below.

Cheers

Alex

[EEVblog]

Who made the DSO3062A?It doesn't look very Agilent, is it an older rebadged Rigol?

Yep, just a rebaged early Rigol
Agilent helped Rigol set up and perfect their production and other stuff, and they now regret that deeply.

[Alex Nikitin]

Who made the DSO3062A?It doesn't look very Agilent, is it an older rebadged Rigol?

Yep, just a rebaged early Rigol
Agilent helped Rigol set up and perfect their production and other stuff, and they now regret that deeply.

Yes, and I knew that when I was buying it seven years ago. Still, not in a hurry to upgrade as it does what I need it for, for the rest of my work the analogue Tek is better anyway.

Cheers

Alex

[Howardlong]

Well, just as a teaser - could somebody post a screen shot from the Rigol DS1054Z (or a similar DSO scope) of a 100Mhz signal with 50% AM modulation at 1kHz. A screen from the Tek 2465BCT is below.

Source: HP 8656B, 50% 1kHz AM modulating 100MHz -10dBm carrier.

Rigol DS1054Z suffers beating and intensity gradient doesn't work at all well (24Mpts, 1GSa/s).


Tek MDO3054 has similar difficulties with intensity grtading (10Mpts, 1.25GSa/s).


Aglient/Keysight MSO7104B looks better, but by no means perfect. Looks better if the timebase time is reduced and therefore sampling rate increased (8Mpts, 400MSa/s).


So in short I think you're going to struggle to get an analogue style display on most DSOs with this particular test. Whether the test is a reasonable and regularly experienced scenario, I'll leave for others. Certainly it's not one I encounter in practice, although I'm aware it's a common test albeit usually with a much more relaxed carrier:modulation ratio. I'd be using a frequency domain instrument first and foremost for this myself!

[G0HZU]

So in short I think you're going to struggle to get an analogue style display on most DSOs with this particular test. Whether the test is a reasonable and regularly experienced scenario, I'll leave for others. Certainly it's not one I encounter in practice,

A classic two tone test waveform for an SSB transmitter is a good example for showing the relative strengths and weaknesses of analogue vs digital scopes.

In the time domain a decent analogue scope CRT (eg something a class above the Tek 2465 CRT) is really nice to look at provided the CRT is well set up. The 2465 really isn't a good choice here. Some of the older Tek scopes really are wonderful to use like this as they have a really sharp display. eg the Tek 453 series or even my old Tek 585.

But the DSO will be king in the frequency domain because the analogue scope can't compete here at all. Even my little TDS2012 can show the bandwidth of the signal using the FFT mode and it can display distortion terms of AM or SSB signals quickly and easily with decent refresh rate and reasonable dynamic range as well.

Partly why I keep my old Tek 465 is for (casually) looking at modulated RF waveforms in the time domain because it is so easy to use for stuff like this. I've not found a DSO at work that can compete (at a realistic price point) for time domain stuff like this. But pretty much everywhere else, even my old TDS2012 kills the 465 in terms of scope performance.

[Alex Nikitin]

So in short I think you're going to struggle to get an analogue style display on most DSOs with this particular test. Whether the test is a reasonable and regularly experienced scenario, I'll leave for others. Certainly it's not one I encounter in practice, although I'm aware it's a common test albeit usually with a much more relaxed carrier:modulation ratio. I'd be using a frequency domain instrument first and foremost for this myself!

This is just an easily repeatable example. And (importantly) you knew exactly what the signal contains and could play with setting on a DSO. Now imagine that you are looking at the output waveform of an audio power amplifier which has a mild oscillation about 20MHz frequency (say 200mV p-p) occurring near clipping on 1kHz 60V p-p sine wave . You don't know it is there. What chances are to see it with a DSO?

Cheers

Alex

[Wuerstchenhund]

Well, just as a teaser - could somebody post a screen shot from the Rigol DS1054Z (or a similar DSO scope) of a 100Mhz signal with 50% AM modulation at 1kHz. A screen from the Tek 2465BCT is below.

Just for fun, here's a screenshot from a LeCroy WavePro 7300A:






Here's also a screenshot from a Siglent SDS2204 when it doesn't suffer from any annoying bugs:



Source: R&S CRTU-RU
Signal: 100MHz -10dBm AM modulated @ 1kHz 50%

[Wuerstchenhund]

Now imagine that you are looking at the output waveform of an audio power amplifier which has a mild oscillation about 20MHz frequency (say 200mV p-p) occurring near clipping on 1kHz 60V p-p sine wave . You don't know it is there. What chances are to see it with a DSO?

With FFT, I'd say pretty much 100%.

[Alex Nikitin]

Now imagine that you are looking at the output waveform of an audio power amplifier which has a mild oscillation about 20MHz frequency (say 200mV p-p) occurring near clipping on 1kHz 60V p-p sine wave . You don't know it is there. What chances are to see it with a DSO?

With FFT, I'd say pretty much 100%.

You should try that  one time   - just imagine the required FFT parameters (and again, you should at least suspect what you are looking for).

Cheers

Alex

[OldSchoolTechCorner]

Who made the DSO3062A?It doesn't look very Agilent, is it an older rebadged Rigol?

Yep, just a rebaged early Rigol
Agilent helped Rigol set up and perfect their production and other stuff, and they now regret that deeply.

Yes, and I knew that when I was buying it seven years ago. Still, not in a hurry to upgrade as it does what I need it for, for the rest of my work the analogue Tek is better anyway.

Cheers

Alex

Anolog scopes is best at looking at mostly analog signals. Modulated signals also show up better on an analog scope. That why I had two 2465's and sold one to get a 2467B now. As do the same work you do. That being said I still won't recommend a newbie in getting into electronics a analog scope, unless they told me they are working on older radio gear, or tape decks, reel to reel's, or older audio/video gear.  Plus the fact the new DSOs are much better and have come a long ways, then the older DSO's and have improved quite a bit over the years, it depends if you can justify their sky-high prices.

[G0HZU]

Modulated signals also show up better on an analog scope.

That's my experience. However, I suppose you could argue that the difference is of limited benefit.

To me the images of the Lecroy scope showing a modulated carrier look pretty grim compared to the elegant image you see on a decent analogue scope. But I could live with the Lecroy if it was the only scope available. However, I'd expect to have to spend a fair bit of time setting it up to get something reasonable on the screen. By comparison, the analogue scope is much easier to set up for a measurement like this.

But the DSO can always swap across to the frequency domain and there is a lot of useful info to be gained doing this. I tend to use both analogue and digital scopes and swap between them as required

[G0HZU]

Anybody with a digital camera can capture a single-shot trace from an analog scope.

Been there and done that many times. I've even done it with an old school scope camera.

Struggling to use a digital camera with my 465 was the reason I dug deep and bought the little TDS2012 about 10-12 years ago

[Wuerstchenhund]

occurring near clipping on 1kHz 60V p-p sine wave . You don't know it is there. What chances are to see it with a DSO?

With FFT, I'd say pretty much 100%.
[/quote]

You should try that  one time   - just imagine the required FFT parameters (and again, you should at least suspect what you are looking for).[/quote]

I don't know but part of building stuff is to look for stuff that might be there could be missed. Just looking on a test instrument and assuming that's all there is is making things a bit too easy.

Just my 2 British Pence

[vk6zgo]

Well, just as a teaser - could somebody post a screen shot from the Rigol DS1054Z (or a similar DSO scope) of a 100Mhz signal with 50% AM modulation at 1kHz. A screen from the Tek 2465BCT is below.

Just for fun, here's a screenshot from a LeCroy WavePro 7300A:






Here's also a screenshot from a Siglent SDS2204 when it doesn't suffer from any annoying bugs:



Source: R&S CRTU-RU
Signal: 100MHz -10dBm AM modulated @ 1kHz 50%

Just as well you said "just for fun",as that display is about the most useless one you could show of an amplitude modulated RF waveform.
I am quite sure your LeCroy could show the classic style modulated RF envelope correctly,"standing on its head"!

[Wuerstchenhund]

To me the images of the Lecroy scope showing a modulated carrier look pretty grim compared to the elegant image you see on a decent analogue scope.

True, but then this is no analog scope but then this is a 7yr old 3Ghz scope based on a design that came out in 2001 and for that I think it's pretty reasonable in that mode (which isn't necessarily what I'd use in practice). But yes, if you want to look at modulated signals the way you do that on an analog scope then it's the wrong scope. But it's also not a scope that is really on-topic, and as stated I posted the screen shots for fun only anyways (and because I was shocked how terrible the "graded" MDO3000 screenshot looks).

Also, I guess my other scope (WaveRunner 64Xi, unfortunately out of order at the moment) would have been a better choice for that scenario, as it has a mode called WaveStream which much better reflects the behavior of an analog scope:



(the video shows a WaveRunner Xi)

But I could live with the Lecroy if it was the only scope available. However, I'd expect to have to spend a fair bit of time setting it up to get something reasonable on the screen.

Not necessarily, intensity grading is just one form to capture this information. Color grading might actually be a better option:



The color grading shows much better that it's modulated with a sine wave.

Or you could look at a 3D image:







The Wireframe isn't much use but the pits and grooves show clearly that this is an AM modulated waveform and that the modulation signal is sine-like.

[Howardlong]

Well, just as a teaser - could somebody post a screen shot from the Rigol DS1054Z (or a similar DSO scope) of a 100Mhz signal with 50% AM modulation at 1kHz. A screen from the Tek 2465BCT is below.

Just for fun, here's a screenshot from a LeCroy WavePro 7300A:






Here's also a screenshot from a Siglent SDS2204 when it doesn't suffer from any annoying bugs:



Source: R&S CRTU-RU
Signal: 100MHz -10dBm AM modulated @ 1kHz 50%

As a matter of interest do those look like at 1ms/div? I thought that's one of the points of the test, showing how well, or badly, the intensity gradient and deep memory work at around the modulation frequency given a carrier frequency within a decade or so of the sampling rate.

[vk6zgo]

Well, just as a teaser - could somebody post a screen shot from the Rigol DS1054Z (or a similar DSO scope) of a 100Mhz signal with 50% AM modulation at 1kHz. A screen from the Tek 2465BCT is below.

Source: HP 8656B, 50% 1kHz AM modulating 100MHz -10dBm carrier.

Rigol DS1054Z suffers beating and intensity gradient doesn't work at all well (24Mpts, 1GSa/s).


Tek MDO3054 has similar difficulties with intensity grtading (10Mpts, 1.25GSa/s).


Aglient/Keysight MSO7104B looks better, but by no means perfect. Looks better if the timebase time is reduced and therefore sampling rate increased (8Mpts, 400MSa/s).


So in short I think you're going to struggle to get an analogue style display on most DSOs with this particular test. Whether the test is a reasonable and regularly experienced scenario, I'll leave for others. Certainly it's not one I encounter in practice, although I'm aware it's a common test albeit usually with a much more relaxed carrier:modulation ratio. I'd be using a frequency domain instrument first and foremost for this myself!

In fairness to the DSOs,it would be very uncommon to display that many cycles of the modulation envelope for critical measurements.
Probably two to three cycles would be adequate,allowing the time/div to be reduced,with a resulting increase in sampling rate.

Interestingly,% modulation checks of AM signals using an analog 'scope are usually done in X-Y mode,with the modulating signal being applied to the
 X amp & the RF envelope to the Y amp.
This gives a "trapezoid" pattern with which it is easier to determine the modulation percentage.
This is how we used to calibrate AM Modulation Monitors.

With a DSO,it should be easier to determine the required levels from an envelope pattern,plus there would be less possibility of error due to vertical amp non-linearity.

[vk6zgo]

As a matter of interest do those look like at 1ms/div? I thought that's one of the points of the test, showing how well, or badly, the intensity gradient and deep memory work at around the modulation frequency given a carrier frequency within a decade or so of the sampling rate.

Of course that's the point of the test,
As long as people have been able to look at amplitude modulated RF signals on Oscilloscopes,they have displayed them with the 'scope displaying one or more cycles at the modulating frequency.

Nobody looks at it at carrier rate,as it is a fairly meaningless waveform.
You can see it is modulated,but it doesn't give any indication of the modulating frequency,or modulation percentage.

Wuerstchenhund knows this perfectly well-------he's just "pulling your leg"!

[Howardlong]

As a matter of interest do those look like at 1ms/div? I thought that's one of the points of the test, showing how well, or badly, the intensity gradient and deep memory work at around the modulation frequency given a carrier frequency within a decade or so of the sampling rate.

Of course that's the point of the test,

Wuerstchenhund knows this perfectly well-------he's just "pulling your leg"!

Let's hope so! I guess I missed that...

[Rupunzell]

Here is another.. Previously posted here and re-post as easier to do example.

Symmetrical display over drive to reveal specific details. How much symmetrical display over drive can a modern DSO-MSO accept? Using DC offset is not possible due to waveform symmetry and what the important information is near zero.

Precise waveform numeric values are of less value as much of this analog stuff works over a broad range and absolute precise numeric metric is not always what matters most, how the circuit behaves under specific conditions matters a LOT more as it is more telling of actual circuit behavior.

Under these conditions, a tube O'scope like the Tek 500 series does really well due to the high internal voltages that allow LOTs of amplifier dynamic range. Tek 7000 is not as good, Tek portables are ok for this.



The Tek P6042 has enough dynamic range to allow significant over drive without distortion. With the power line variac set to the where the voltage regulator is just going in and out of regulation, the regulator behavior at transition between in and out of regulation can be observed in real time with no updating time gaps.


Bernice

[Wuerstchenhund]

As a matter of interest do those look like at 1ms/div? I thought that's one of the points of the test, showing how well, or badly, the intensity gradient and deep memory work at around the modulation frequency given a carrier frequency within a decade or so of the sampling rate.

You're right of course, but as I said, the shots were merely just for fun (and frankly I didn't really pay much attention to the details when I should have), and also because I some of the other DSO's intensity grading looked astonishingly poor. Plus I was fiddling with the SDS2000 and Siglent's "new" firmware, and glad I could get the scope to display a waveform without a strange shift downwards (another bug).

If I don't forget then I'll see if I can take some proper shots tomorrow. Overall I doubt the WavePro will perform very well in that test, though.

[G0HZU]

Just as well you said "just for fun",as that display is about the most useless one you could show of an amplitude modulated RF waveform.
I am quite sure your LeCroy could show the classic style modulated RF envelope correctly,"standing on its head"!

The second set of plots from Wuerstchenhund look even more bizarre.

I suspect that many people on here don't have a classic comms background so maybe it's the first time they tried to look at an AM test waveform on a scope.

Taking it a step further, an analogue scope really shines when looking at the AMC setting/performance on something like an AM ham/CB radio when using human speech into the microphone. I've not tried this with many DSOs but the one's I have tried it on have been very poor compared to an analogue scope. But I guess a modern DSO (or even a downmixer+PC soundcard) could be used to capture the signal and play it back in slow motion on a PC.  The analogue scope can't do this...

[alsetalokin4017]

Just for fun?  Well, one _could_ use scope settings that give the scope a chance to perform, I suppose. But that might be cheating.....   

Source: HP8640B
Scope: DS1054z "unlocked" to 100MHz bw

[Howardlong]

Just for fun?  Well, one _could_ use scope settings that give the scope a chance to perform, I suppose. But that might be cheating.....   

Source: HP8640B
Scope: DS1054z "unlocked" to 100MHz bw

In fact, I tried a number of settings over the period of about fifteen minutes to get a reasonable display but failed, including number of points, intensity, hold off etc etc. What was your magic sauce?

[alsetalokin4017]

Just for fun?  Well, one _could_ use scope settings that give the scope a chance to perform, I suppose. But that might be cheating.....   

Source: HP8640B
Scope: DS1054z "unlocked" to 100MHz bw

In fact, I tried a number of settings over the period of about fifteen minutes to get a reasonable display but failed, including number of points, intensity, hold off etc etc. What was your magic sauce?

Dots, anti-aliasing, intensity and persistence, mostly.

And I'm even (mostly) in the "analog" camp, too!

[G0HZU]

Just for fun?  Well, one _could_ use scope settings that give the scope a chance to perform, I suppose. But that might be cheating.....   

Source: HP8640B
Scope: DS1054z "unlocked" to 100MHz bw

In fact, I tried a number of settings over the period of about fifteen minutes to get a reasonable display but failed, including number of points, intensity, hold off etc etc. What was your magic sauce?

I can remember that Dave managed to get a pretty reasonable 'graded' display from the 1054 in his youtube review. Even my old TDS2012 looks better on an AM waveform than your previous attempt with the 1054 and my TDS2012 doesn't have intensity grading 

I suspect that the Tek MDO 3000 is capable of a lot better too. At work we have a lot of the big old Tek MSO/DPO 4000 scopes and with a fair bit of menu bashing you can get a fairly acceptable graded display. Not as nice as an old school analogue scope but I suspect that the difference is of limited benefit in terms of extra information anyway. But to someone of my generation the graded display does look a bit lame compared to a decent CRO.

[vk6zgo]

Also, I guess my other scope (WaveRunner 64Xi, unfortunately out of order at the moment) would have been a better choice for that scenario, as it has a mode called WaveStream which much better reflects the behavior of an analog scope:



(the video shows a WaveRunner Xi)

Either the Waverunner is "making heavy weather"  resolving the burst & horizontal sync pulse,or the originator of this video picked a particularly poor example of a video signal.
A clean burst should have a well defined envelope shape,& there shouldn't be that much sync tip noise,to say nothing of the rounding of the sync pulse leading edge & the overshoot preceding the falling edge.

In any case,a reasonably modern DSO should not have problems resolving a signal with a maximum frequency component of 5MHz,at a setting of 10 us/div.
Where many of them had problems was when the user attempted to display the same signal at field rate.or as is the more common test,tried to look at both the odd & even fields,requiring an overall time of 40ms.

My feeling about "intensity grading" is that it arose from a fundamental misunderstanding of people's objections to earlier DSOs---something along the lines of:-
"The silly old b----s won't be happy till we make it look like an analog 'scope"

What they didn't (or didn't want to) understand was that  we would have been happy with a "leaky fountain pen" display  attached to an instrument that wouldn't "fail at every hurdle" during.everyday tests.

[TheSteve]

100 MHz AM 1 kHz @ 50 %, then hit the auto button on my "unlocked" 1054Z.

Second pic with the intensity turned down.

[vk6zgo]

100 MHz AM 1 kHz @ 50 %, then hit the auto button on my "unlocked" 1054Z.

Second pic with the intensity turned down.

As I have already pointed out,this display is not a lot of use in determining any important information about the characteristics of the AM signal.
Neither does it say anything useful about the performance of the DSO.

[TheSteve]

100 MHz AM 1 kHz @ 50 %, then hit the auto button on my "unlocked" 1054Z.

Second pic with the intensity turned down.

As I have already pointed out,this display is not a lot of use in determining any important information about the characteristics of the AM signal.
Neither does it say anything useful about the performance of the DSO.

Fair enough - you can see AM depth and amplitude but that is about it. Adjusting the time base will let you see the modulation frequency easy enough. If I really need details of an AM signal I generally use my spectrum analyzer which has a modulation analyzer built in.

[vk6zgo]

"you can see AM depth and amplitude "---can you,though?

I'd have to play around with it to see how viable a method it is.

The conventional modulation rate triggered display has well established formulas,enabling quick determination of modulation percentage.
Even it gives way to the "trapezoid" pattern method for precision,however.

[Fungus]

Just for fun?  Well, one _could_ use scope settings that give the scope a chance to perform, I suppose. But that might be cheating.....   

Heresy! You'll burn in Analog hell for posting those blasphemous images.

[mtchastain]

Hi All,
Not to interrupt this lively discussion (definitely a bit over my head now) but I wanted to thank everyone for the recommendations regarding my question. Based on all the feedback, I will be planning on purchasing the Rigol scope.

Thanks again everyone!

-Matt

[SteveLy]

Well, just as a teaser - could somebody post a screen shot from the Rigol DS1054Z (or a similar DSO scope) of a 100Mhz signal with 50% AM modulation at 1kHz.

Most unfair since the DS1054Z is a 50MHz scope. And yours is not a screenshot. Analog scopes don't do screenshots. I bet with the right settings on the scope and on the camera taking the photo you could get something very similar out of a DS1054Z (or DS1104Z that's actually 100MHz capable).

@mtchastain Great choice! 

[Howardlong]

Just for fun?  Well, one _could_ use scope settings that give the scope a chance to perform, I suppose. But that might be cheating.....   

Source: HP8640B
Scope: DS1054z "unlocked" to 100MHz bw

In fact, I tried a number of settings over the period of about fifteen minutes to get a reasonable display but failed, including number of points, intensity, hold off etc etc. What was your magic sauce?

I can remember that Dave managed to get a pretty reasonable 'graded' display from the 1054 in his youtube review. Even my old TDS2012 looks better on an AM waveform than your previous attempt with the 1054 and my TDS2012 doesn't have intensity grading 

I suspect that the Tek MDO 3000 is capable of a lot better too. At work we have a lot of the big old Tek MSO/DPO 4000 scopes and with a fair bit of menu bashing you can get a fairly acceptable graded display. Not as nice as an old school analogue scope but I suspect that the difference is of limited benefit in terms of extra information anyway. But to someone of my generation the graded display does look a bit lame compared to a decent CRO.

The typical Dave method is with 1MHz carrier and 1kHz modulation, so is far less "stressful": there is little problem getting a reasonable display with this on a DSO with intensity gradient and reasonable deep memory, pretty much the only thing you need to fiddle with is the hold off just as you would in an analogue scope.

Using 100MHz carrier means the scope will have to be able to trigger accurately at nanosecond or less resolution while still being able to display at 1ms/div.

[vk6zgo]

Well, just as a teaser - could somebody post a screen shot from the Rigol DS1054Z (or a similar DSO scope) of a 100Mhz signal with 50% AM modulation at 1kHz.

Most unfair since the DS1054Z is a 50MHz scope. And yours is not a screenshot. Analog scopes don't do screenshots. I bet with the right settings on the scope and on the camera taking the photo you could get something very similar out of a DS1054Z (or DS1104Z that's actually 100MHz capable).

@mtchastain Great choice! 

Quite apart from the fact that he never claimed it as such,it is in fact a screenshot.
The term predated devices which could save their displays to another device by many decades.

Are you implying that the artifacts present on the display are from the transfer process,& were not visible on the original DSO screen?

That "puts the cat amongst the pigeons" for all such postings of a DSO display,unless they are produced photographically.

What is a bit unfair is the high carrier frequency chosen,plus the number of modulation cycles displayed.
That is certainly a savage test for a 50MHz,or even a 100MHz DSO.

A 50MHz analog would just need the signal level increased to compensate for being some dBs down on the response slope.

[BravoV]

I own a comparable Tek 2465B and 2 sub 100Mhz DSOs, my POV is simple ...

Rigol DS1054Z -> Cover by warranty.

Tek 2467BHD -> Full of risk, and if you're running of of luck, it may be dead at the 2nd times you powering it up. And pray really hard that its not those unobtainium hybrid IC that is toasted. 

Also you will need "another" scope to aid the troubleshooting of that dead Tek analog scope if that happened.

Maybe its just me, its so obvious and clear, and no, it is not even about analog vs dso, its a decision to choose on a working and worry free scope that you need it to help your work 1st.

[Howardlong]

Just for fun?  Well, one _could_ use scope settings that give the scope a chance to perform, I suppose. But that might be cheating.....   

Source: HP8640B
Scope: DS1054z "unlocked" to 100MHz bw

In fact, I tried a number of settings over the period of about fifteen minutes to get a reasonable display but failed, including number of points, intensity, hold off etc etc. What was your magic sauce?

Dots, anti-aliasing, intensity and persistence, mostly.

And I'm even (mostly) in the "analog" camp, too!

Hmm, not much luck I'm afraid at 100MHz, lots of beating, but at 101MHz, I got this though (dots definitely at these high carrier frequencies BTW)...



A bit more old school, but one of my favourite scopes, an Agilent 54642D made it easy, no fiddling other than hold off and setting to dots:

[G0HZU]

The typical Dave method is with 1MHz carrier and 1kHz modulation, so is far less "stressful": there is little problem getting a reasonable display with this on a DSO with intensity gradient and reasonable deep memory, pretty much the only thing you need to fiddle with is the hold off just as you would in an analogue scope.

Using 100MHz carrier means the scope will have to be able to trigger accurately at nanosecond or less resolution while still being able to display at 1ms/div.

Traditionally, you are supposed to trigger the scope using the baseband modulation signal rather than try and trigger from the modulated waveform. I can feed >200MHz into my 100MHz TDS2012 and instantly get a stable display by using external trigger from the 1kHz modulation signal. Most sig gens have a modulation out connector. Use this to trigger the scope

[G0HZU]

Maybe its just me, its so obvious and clear, and no, it is not even about analog vs dso, its a decision to choose on a working and worry free scope that you need it to help your work 1st.

I wouldn't have a Tek 2465 here anyway. I would buy the 1054 and then buy something cheap like my old Tek 465 to use for certain traditional tests.
I'm one of the few that doesn't rate the Tek 2465 as a good choice for a basic analogue scope. To me it is too big, the trace quality is fairly poor, the UI is fiddly and it has too many distracting lamp indicators on the front panel. So I can't tolerate having one of these things in my face. I don't like the look of these scopes at all.

[Wuerstchenhund]

Just for fun?  Well, one _could_ use scope settings that give the scope a chance to perform, I suppose. But that might be cheating.....   

Yes, I know  I should really have paid more attention  Me culpa!

Anyways, I have provisionally assembled my LeCroy WaveRunner 64Xi and found a chance to give it a try there, this time with the scope set a 1ms/div 

I'll post the pictures later.

[Howardlong]

The typical Dave method is with 1MHz carrier and 1kHz modulation, so is far less "stressful": there is little problem getting a reasonable display with this on a DSO with intensity gradient and reasonable deep memory, pretty much the only thing you need to fiddle with is the hold off just as you would in an analogue scope.

Using 100MHz carrier means the scope will have to be able to trigger accurately at nanosecond or less resolution while still being able to display at 1ms/div.

Traditionally, you are supposed to trigger the scope using the baseband modulation signal rather than try and trigger from the modulated waveform. I can feed >200MHz into my 100MHz TDS2012 and instantly get a stable display by using external trigger from the 1kHz modulation signal. Most sig gens have a modulation out connector. Use this to trigger the scope

That was indeed one of the tests I tried yesterday, it didn't make much difference, and, as it halved the sample rate on the Rigol by using a second channel (no ext trigger, so needed to use a spare channel and even if switched off, if you use the channel for triggering the ADC appeared to be used) I went back to single channel.

[Wuerstchenhund]

Either the Waverunner is "making heavy weather"  resolving the burst & horizontal sync pulse,or the originator of this video picked a particularly poor example of a video signal.

I think the idea was to present looking at a poor video signal, but yes the video isn't great.

There's another one:




At the end of the day the idea of WaveStream was to provide a mode that looks and feels "analog" like. Nothing more. I can't say I've ever felt the need to use it, though.

[EV]

Rigol DS2202

[Rupunzell]

Gigatronics 1018 generator, Tektronix 7104, 7A29, 7A24, 7B10, 7B15, Krohn Hite 1000 FG, hp 3326A synthesizer, Vari-L mixer.
Have a Tek 2467B, it is used only when a portable is required. Sits in storage most of the time. Tek 7000 simply has better performance, ergonomics and MUCH better configurability due to plug-ins.


Balanced mixer, 1.5Ghz carrier, 1Khz sine modulation, trigger on modulated signal.


Balanced mixer, 1.5Ghz carrier, 1.25Mhz triangle modulation, trigger on modulated signal.


Gigatronics 1018 set to AM, 1.5Ghz carrier, 30Khz modulation. Trigger on modulated signal:


Tek 7104 has zero problems triggering on a modulated signal at 1.5 Ghz carrier.


Using both time bases, top is the 1.5Ghz carrier, bottom is the 1Khz sine wave carrier:


2 Ghz sine wave:


Another way to measure this:
Gigatronics 1018 to 1.5Ghz carrier, 30Khz sine AM mod, hp 8566B:


Gigatronics 1018 to 18Ghz carrier, 30Khz sine AM mod, hp 8566B:





Bernice

[Rupunzell]

There is also Mr. Gibbs to consider:
https://www.eevblog.com/forum/testgear/my-first-oscilloscope/75/

Really comes down to knowing test gear limitations, how to get the best of them and their limitations. While there are user preferences, that is a matter of individual choice in the same way as food preferences. Still, technical limitations apply.


Bernice

[Wuerstchenhund]

Most unfair since the DS1054Z is a 50MHz scope. And yours is not a screenshot. Analog scopes don't do screenshots.

Actually, that is exactly where the term 'screenshot' comes from - taking a picture of the image on an analog scope's CRT with a special photographic camera.

BTW, what modern scopes like the DS1054z do is not a 'screenshot', it's actually a 'screen dump' because they don't take a 'shot  of the screen but dump the content of the video memory into a file. It's just because people were more familiar with the term 'screenshot' so they still use the term for DSOs.

[Wuerstchenhund]

Next try, this time I did even pay attention to the timebase settings 

Again, source is a R&S CRTU-RU at 100MHz modulated at 1kHz AM 50%. The scope is a provisionally assembled LeCroy WaveRunner 64Xi, and since the CRTU-RU has no Mod out it's triggered from the input signal.

These screenshots show the signal in Persistence (intensity graded) mode at 500MS/s and 1GS/s:



https://www.eevblog.com/forum/testgear/recommendation-request-new-rigol-ds1054z-or-used-tektronix-2467bhd/?action=dlattach;attach=180776;image


And this is what it looks like in Normal mode:

At 2GSa/s:




And at 500MSa/s:




Anyways, as it was said above that's a pretty synthetic test for a digital scope which is unlikely to matter in a practical sense.

[vk6zgo]

Either the Waverunner is "making heavy weather"  resolving the burst & horizontal sync pulse,or the originator of this video picked a particularly poor example of a video signal.

I think the idea was to present looking at a poor video signal, but yes the video isn't great.

There's another one:



At the end of the day the idea of WaveStream was to provide a mode that looks and feels "analog" like. Nothing more. I can't say I've ever felt the need to use it, though.

Yes,I guess they were in a "no win" situation.
If they used a "copybook" waveform out of a TV Studio,people would blame the LeCroy when the signal out of their 30 year old VCR didn't look the same!
After years in TV Broadcasting,I'm just hypercritical!

The "jitter" test looks good,though I agree with you that the "Wavestream" feature doesn't really add much functionality.

[xrunner]

Can you still hack the DS1054 to 100 MHz? I wasn't sure if they had blocked that or not. The DS1074 is only about $66 more, but if the 1054 can still be hacked I'll buy that one. Thanks. 

[c4757p]

Yeah, I just did my brand new one a couple days ago. Nothing blocked.

[vk6zgo]

Next try, this time I did even pay attention to the timebase settings 

Again, source is a R&S CRTU-RU at 100MHz modulated at 1kHz AM 50%. The scope is a provisionally assembled LeCroy WaveRunner 64Xi, and since the CRTU-RU has no Mod out it's triggered from the input signal.

These screenshots show the signal in Persistence (intensity graded) mode at 500MS/s and 1GS/s:



https://www.eevblog.com/forum/testgear/recommendation-request-new-rigol-ds1054z-or-used-tektronix-2467bhd/?action=dlattach;attach=180776;image


And this is what it looks like in Normal mode:

At 2GSa/s:




And at 500MSa/s:




Anyways, as it was said above that's a pretty synthetic test for a digital scope which is unlikely to matter in a practical sense.

Yes,you are very unlikely to come across an Amplitude Modulated 100MHz signal "in the wild",except in the Aeronautical service,which is a pretty specialised & highly regulated area,where "just looking at the envelope" would only be a rough check.

I have looked at TV modulation envelopes at VHF,but it is again,hardly a definitive test.

In any case,the only thing you are likely to be interested in is the envelope amplitude  & to a lesser extent, shape,to determine modulation percentage,& fairly roughly,distortion.

How the RF is "drawn in" doesn't really matter for these applications--a little featheriness of the envelope "line" can be worked around.

For AM MF Broadcasting,around 1MHz or so,where this test is more likely to be used,the DSO display would show no such artifacts.

 On HF,"plain old AM" pretty much tops out around 30MHz--SSB is far more common for other than Short Wave Broadcasting,even in the lower range.

[Wuerstchenhund]

Yes,I guess they were in a "no win" situation.
If they used a "copybook" waveform out of a TV Studio,people would blame the LeCroy when the signal out of their 30 year old VCR didn't look the same!

Actually, I wouldn't be surprised if someone at LeCroy just said "hey, on the way to work I found that old VCR at the curb. Lets do some a video". They didn't really seem to have any strategy for doing these videos at that time.

After years in TV Broadcasting,I'm just hypercritical!

Well, I can imagine that spec compliance is a big think in public broadcasting. Also nothing wrong with being a bit hypercritical (better than a "good enough" attitude).

The "jitter" test looks good,though I agree with you that the "Wavestream" feature doesn't really add much functionality.

Yes, I see it mostly as a nod to the "analog forever" crowd. When I did the tests at 1ms/div WaveStream didn't even produce anything useful.

It also seems to be gone from their current scopes so I guess it didn't really catch on.

[Rupunzell]

Signals with close in side bands such as AM does matter for more than a few analog folks. It is one of the reasons why some old analog geezers stick with a crt based time domain instrument over any DSO. This most basic example also points to how different some analog folks use a time domain instrument compared to digital-data centric folks do.

Common test signal types such as sine. triangle, square, pulse and such are not always the case for analog stuff. If the instrument display is full of test signal related artifacts, more often than not, it would render the data displayed mostly useless due to questions of what is real and what is not.

Absolute precision of measured data might not matter nearly as much as that digital stuff (timing measurement accuracy, instant rise-fall time, frequency, amplitude and...) as what cam matter more in analog systems or circuit behavior over a broad range of test parameters since one is dealing with a lot more states than on or off.

As for that LeCroy real time "Jitter" test, there are better ways to achieve this. Active real time information display such as this can reveal rate information relative to a fixed wave form transition edge giving clues as to what could be the cause of the displayed jitter.  This could be the reason why the LeCroy folks offered it as a feature, except the majority of users had not idea of how to get useful information from this feature.


Bernice

Anyways, as it was said above that's a pretty synthetic test for a digital scope which is unlikely to matter in a practical sense.

Yes,you are very unlikely to come across an Amplitude Modulated 100MHz signal "in the wild",except in the Aeronautical service,which is a pretty specialised & highly regulated area,where "just looking at the envelope" would only be a rough check.

I have looked at TV modulation envelopes at VHF,but it is again,hardly a definitive test.

In any case,the only thing you are likely to be interested in is the envelope amplitude  & to a lesser extent, shape,to determine modulation percentage,& fairly roughly,distortion.

How the RF is "drawn in" doesn't really matter for these applications--a little featheriness of the envelope "line" can be worked around.

For AM MF Broadcasting,around 1MHz or so,where this test is more likely to be used,the DSO display would show no such artifacts.

 On HF,"plain old AM" pretty much tops out around 30MHz--SSB is far more common for other than Short Wave Broadcasting,even in the lower range.
[/quote]

[Howardlong]

Yes,you are very unlikely to come across an Amplitude Modulated 100MHz signal "in the wild",except in the Aeronautical service,which is a pretty specialised & highly regulated area,where "just looking at the envelope" would only be a rough check.

When ever I've looked at civilian NAV/COM equipment (from 108MHz to 137MHz) it has never occurred to me to even attempt to look at the RF with a scope, I use a comms test set and spectrum analyser, plus a VOR/ILS baseband generator with an RF signal generator. I'm not sure what the point is of looking at the RF on a scope would be, but I'm happy to be educated! At AF/baseband and IF a scope is certainly of value.

[vk6zgo]

Yes,you are very unlikely to come across an Amplitude Modulated 100MHz signal "in the wild",except in the Aeronautical service,which is a pretty specialised & highly regulated area,where "just looking at the envelope" would only be a rough check.

When ever I've looked at civilian NAV/COM equipment (from 108MHz to 137MHz) it has never occurred to me to even attempt to look at the RF with a scope, I use a comms test set and spectrum analyser, plus a VOR/ILS baseband generator with an RF signal generator. I'm not sure what the point is of looking at the RF on a scope would be, but I'm happy to be educated! At AF/baseband and IF a scope is certainly of value.

Sometimes,you have to "just run what you brung".
We had a strange problem with an NEC FM broadcast Transmitter.

This Tx had a FET PA driving a big tetrode in common cathode configuration.
There was an output meter on the FET PA,to show the drive to the tetrode control grid tuned circuit.

Using the time honoured "peak the grid & dip the anode" tuning method,we found a seemingly ridiculous situation where more grid drive on the meter caused lower output power.

The FET PA had an adjacent monitor point,so,as it was to hand,I grabbed the 200MHz Iwatsu 'scope & looked at that point.
The problem was immediately obvious----a horrible,peaky waveform,with a high second harmonic component.
The FET PA output meter was a "peak & hold " type----higher peaks from the distorted waveform looked like more grid drive.

All that second harmonic power was suppressed in the anode tuned circuit--hence less transmitter output power!
From then on,we tuned "for maximum smoke"instead!

We had a 7L12 in a Tek 7000 mainframe,so  could have used that,but it was hard to get to the monitor point,& I wasn't quite as familiar with the 7L12 as I later became.

In any case,the time domain display gave an immediate insight into the problem.

Apart from that,I had very little occasion to look at VHF RF signals in the time domain.

If your 'scope will do it,it is a very quick way of checking modulation percentage of AM transmitters,but this is mostly done in the MF & HF case.

I feel it is a very savage test of a DSO,asking it to display frequency components with a ratio of 100,000:1.

Looking back,though,we condemned early DSOs because they aliased their hearts out when trying to display
2 fields of PAL video ---that was a ratio of 200,000:1!

[AF6LJ]

The Tek is a much nicer instrument. It is like buying an older Mercedes va. a new Hyundai...

No, it's nothing like that.
There is a huge fundamental difference between analog and digital scopes. One allows you to single shot capture waveforms, the other does not. One of them literally lets you work easily on any type of signal in any scenario, the other does not.
It's like comparing a car that only goes in a straight line and can't stop, to one that has steering and brakes.

So tell me;
What do you do when the Rigol fails and needs fixed.
Do they provide service information?
Do they provide a way for it to be calibrated without sending it back to China?
Do they sell replacement parts to people who (like myself) have the skill to repair it?

Now for the final question; why would I buy a scope I couldn't fix myself or send it out locally for calibration??

[Rupunzell]

Sine wave modulated AM does not reveal all that could be happening.

Gigatronics 1018 synthesizer at 1Ghz, hp 3326A synthesizer at 9Khz square wave driving the Gigatronics 1018 AM mod input.

Tek 7104, 7A26, 7B15, 7B10.

Square wave driving the AM modulator reveals the step response of this synthesizer:



Switching over to pulse modulation (1Ghz carrier), Tek 2102 Pulse generator driving the Gigatronics Pulse mod input also reveals the step response of the pulse modulator. The cable reflections can be seen on the monitoring trace on top.


Frequency domain of the same, 75Mhz span:


At 17.5 Mhz span:


At 4.26 Mhz span:


Step response of the pulse modulator not so easy to interpret from frequency domain.
Precise shape of the modulation envelop shape provides good information of modulator step response. If there are artifacts due to the data conversion process (DSO) what would the results be, how much resolution and can the presented information be trusted?


Bernice









 

[AF6LJ]

Sine wave modulated AM does not reveal all that could be happening.

Gigatronics 1018 synthesizer at 1Ghz, hp 3326A synthesizer at 9Khz square wave driving the Gigatronics 1018 AM mod input.

Tek 7104, 7A26, 7B15, 7B10.

Square wave driving the AM modulator reveals the step response of this synthesizer:



Switching over to pulse modulation (1Ghz carrier), Tek 2102 Pulse generator driving the Gigatronics Pulse mod input also reveals the step response of the pulse modulator. The cable reflections can be seen on the monitoring trace on top.


Frequency domain of the same, 75Mhz span:


At 17.5 Mhz span:


At 4.26 Mhz span:


Step response of the pulse modulator not so easy to interpret from frequency domain.
Precise shape of the modulation envelop shape provides good information of modulator step response. If there are artifacts due to the data conversion process (DSO) what would the results be, how much resolution and can the presented information be trusted?


Bernice

Well done; I am not convinced that the lower end DSOs are the be-all and End-all.
Perhaps it is just me, but I think not. One RF lab I visit on a regular basis has a number of analogue Tek 400 and 7000 series scopes and a couple of Tek DSOs collecting dust except for the times when they are used for digital troubleshooting tasks.

[xrunner]

Yeah, I just did my brand new one a couple days ago. Nothing blocked.

Well I got it ordered and should be here this Friday. This will be a real treat for me 'cause I've had a Hitachi V-212 since 1985. I plan to spend the weekend in Nirvana. 

[vk6zgo]

Sine wave modulated AM does not reveal all that could be happening.

Gigatronics 1018 synthesizer at 1Ghz, hp 3326A synthesizer at 9Khz square wave driving the Gigatronics 1018 AM mod input.

Tek 7104, 7A26, 7B15, 7B10.

Square wave driving the AM modulator reveals the step response of this synthesizer:



Switching over to pulse modulation (1Ghz carrier), Tek 2102 Pulse generator driving the Gigatronics Pulse mod input also reveals the step response of the pulse modulator. The cable reflections can be seen on the monitoring trace on top.


Frequency domain of the same, 75Mhz span:


At 17.5 Mhz span:


At 4.26 Mhz span:


Step response of the pulse modulator not so easy to interpret from frequency domain.
Precise shape of the modulation envelop shape provides good information of modulator step response. If there are artifacts due to the data conversion process (DSO) what would the results be, how much resolution and can the presented information be trusted?


Bernice

I agree,Bernice.

The time domain display is more immediately intuitive than the frequency domain.
(This was definitely the case with  the FM Tx problem I referred to in reply #82)

Having seen the former,you have a reasonable idea what is happening in the latter,& can select the correct settings on the SA.

Most of us don't have 'scopes with the capabilities of yours,so if we want to get an idea of the modulator step response have to use a "Precision detector" of some kind to look at the baseband demodulated signal,(introducing another device into the test,with it's own possible errors).

In analog TV,we formerly used a DSB detector,or more recently,a precision receiver to look at such things,but obviously not quite as high in frequency.

For higher frequencies we are usually pretty much stuck with the frequency domain.

[smbaker]

What do you do when the Rigol fails and needs fixed.

It's a sub-$400 piece of equipment. In the unlikely event that mine fails before it becomes obsolete and I'm unable to repair it, then it would get recycled and replaced. In that respect it's no different than my dvd player or my computer monitor.

As a practical matter, if I can't fix my Rigol myself and it's out of warranty, I'd probably ship it to Dave. It'd be worth the shipping cost to see what he does with it.

[AF6LJ]

What do you do when the Rigol fails and needs fixed.

It's a sub-$400 piece of equipment. In the unlikely event that mine fails before it becomes obsolete and I'm unable to repair it, then it would get recycled and replaced. In that respect it's no different than my dvd player or my computer monitor.

As a practical matter, if I can't fix my Rigol myself and it's out of warranty, I'd probably ship it to Dave. It'd be worth the shipping cost to see what he does with it.

Seems wasteful to me to build something that a company has no intention of providing a means to repair it.
But...
That is just me. 

[Rupunzell]

Point of all this is to illustrate digitizing artifacts can and do happen and might be of significance to measurements required. Knowing what can happen due to instrumentation is very relevant to the measurement required.

Back in a time when video was analog, some video systems did push slightly past the Nyquist limit to achieve a recovered BW slight more than the Nyquist limit using double pulse type discriminators and fancy dancy filters. There was a price to pay for doing this, but the overall results remained acceptable.

The more common way and technique to measure microwave pulse modulator rise-fall time and shape is to use a biased detector. These can produce accurate pulse response time of less than 10nS. The common RF detector has a baked in filter network and detector diode response that is impedance dependent far more than a biased detector.

While the Tek 7104 performed admirably in these examples, It would be a total and utter failure at measurements involving many modern data systems as it is simply not design for that requirement.

There are DSOs today that perform well into the 30Ghz range allowing more possibilities of using time domain instruments well into the microwave region of the EM spectrum. Yet, for the vast majority of RF and microwave work, a frequency domain instrument is often more useful in many ways.

This is all very much an issue of knowing what to use, when to use and how to get the very most from instrumentation.

There are so many excellent choices for instrumentation on the used market today. Many absolutely state of the art items of instrumentation from the past can be had for a tiny fraction of their original cost-value. Current market value for many of these classic instrumentation creations is driven by market demand and the needs of current-modern technology. Items like NTSC-PAL-SECAM signal generators, monitors, vectorscopes and such are now a low demand item. Items such as precision power supplies appear to have an on-going demand due to the basic nature of how power supplies are used.



Bernice

I agree,Bernice.

The time domain display is more immediately intuitive than the frequency domain.
(This was definitely the case with  the FM Tx problem I referred to in reply #82)

Having seen the former,you have a reasonable idea what is happening in the latter,& can select the correct settings on the SA.

Most of us don't have 'scopes with the capabilities of yours,so if we want to get an idea of the modulator step response have to use a "Precision detector" of some kind to look at the baseband demodulated signal,(introducing another device into the test,with it's own possible errors).

In analog TV,we formerly used a DSB detector,or more recently,a precision receiver to look at such things,but obviously not quite as high in frequency.

For higher frequencies we are usually pretty much stuck with the frequency domain.

[smbaker]

Seems wasteful to me to build something that a company has no intention of providing a means to repair it.

That's true of consumer electronics in general though. They're often intended to be thrown away rather than repaired. It's a shame, but I've come to expect it, especially with lower price equipment.

Unless I abuse my DS1054Z, I don't really expect anything to go wrong with it during the time period where it's not obsolete.

[nfmax]

Seems wasteful to me to build something that a company has no intention of providing a means to repair it.

Unless I abuse my DS1054Z, I don't really expect anything to go wrong with it during the time period where it's not obsolete.

I didn't expect anything to go wrong with my Agilent DSO1014A during the time period when it wasn't obsolete, either. That didn't stop the PSU failing less than one year out of warranty, which is 'beyond economic repair'. I'm working on it when I get time https://www.eevblog.com/forum/repair/only-just-out-of-warranty-agilent-dso1014a/ - there is no service information whatsoever available.
I guess you might be lucky, you might not. Is it possible to insure against failure (at a reasonable cost)? Do Rigol offer extended warranties?

[smbaker]

Do Rigol offer extended warranties?

Maybe this is just me, but I'm not the type of person who buys extended warranties. Whenever the guy at the Best Buy tells me I need an extended warranty for my new TV, I figure he's just trying to make extra money insuring against a very unlikely occurrence. Is it a gamble? Yes.

[Rupunzell]

This is what the world of tech has become after the profit driven CEO's, MBA's, share holders and more have done after their take-over of the T&M industry. Turned it into a universe of disposable, non serviceable, feature driven consumable.

This is not the way it once was, but today has become a requirement due to the easy availability of low cost manufacturing in China-Asia and else where. Add to this, the marketing of older is never desirable or worthy to keep permeates the majority of user ideology.

Instrumentation once were designed, built and intended to be completely serviceable, have long life times, designed to the very limits of technology and be well supported by it's manufacture and produce a reasonable profit for the organization company that produced them.

This business model and user mind-set is mostly gone today. This is the same way MBAs, CEO's share holders and all treat their employees, equally disposable once aged beyond their best by date.

It is curious to note some vintage technology items have become collectable which has driven their market value up significantly.



Bernice

Do Rigol offer extended warranties?

Maybe this is just me, but I'm not the type of person who buys extended warranties. Whenever the guy at the Best Buy tells me I need an extended warranty for my new TV, I figure he's just trying to make extra money insuring against a very unlikely occurrence. Is it a gamble? Yes.

[AF6LJ]

Seems wasteful to me to build something that a company has no intention of providing a means to repair it.

That's true of consumer electronics in general though. They're often intended to be thrown away rather than repaired. It's a shame, but I've come to expect it, especially with lower price equipment.

Unless I abuse my DS1054Z, I don't really expect anything to go wrong with it during the time period where it's not obsolete.

I have had a lot of experience with electronics of all types and things fail, it doesn't matter if it is a Sony Walkman or a 1,000,000 ion implanter. Someone must fix it or throw it out. I've seen brand new HP spectrum analyzers fail within a month after their warranty period expired. Modern test equipment is built not to be repaired, toss it out and buy another one... This is a waste of resources as much as waging war over stupid political ideas is.

[smbaker]

Instrumentation once were designed, built and intended to be completely serviceable, have long life times, designed to the very limits of technology and be well supported by it's manufacture and produce a reasonable profit for the organization company that produced them.

Ultimately, I think it comes down to what consumers want. If our goals are Serviceable, Featureful, and Cheap, we can get at most two of those.

It is curious to note some vintage technology items have become collectable which has driven their market value up significantly.

I love vintage equipment. It's fun. It's nostalgic. It's usually well built. Just turning the knobs you can feel the quality.

When it comes down to it though, the measurement capability of a modern DSO is just too advantageous to me not to prefer that equipment. I have an analog scope, but it hasn't been taken out of the box since I bought my first DSO (an 1052E).

If I could justify a more expensive more quality scope than the 1054Z (preferably something where the damn selector knob doesn't skip), then I would. I made a practical decision to optimize for the most bang for the buck, and assume the risk that it may not be practical to repair it if there's a failure.

This is a waste of resources as much as waging war over stupid political ideas is.

Sure it's a waste of resources, but who do we blame? Consumers are buying DS1054Z scopes, myself included. We've made the decision to optimize for price and features, rather than optimize for serviceability.

[AF6LJ]

Sure it's a waste of resources, but who do we blame? Consumers are buying DS1054Z scopes, myself included. We've made the decision to optimize for price and features, rather than optimize for serviceability.

Do what you have to do; I am not here to change your mind simply to shed light on the problem. I suppose if you use all the features that is good.

[Wuerstchenhund]

I have had a lot of experience with electronics of all types and things fail, it doesn't matter if it is a Sony Walkman or a 1,000,000 ion implanter. Someone must fix it or throw it out. I've seen brand new HP spectrum analyzers fail within a month after their warranty period expired.

This. I've also seen my fair share of very expensive instruments dying shortly after or even when still in warranty. Every complex product can fail. The questions is what happens then.

Modern test equipment is built not to be repaired

That is probably true for cheap Chinese B-brand kit like the gear from Rigol and Siglent but most big brand gear (aside from the cheap bottom-of-the-barrel stuff) definitely is designed for repair. What has changed however is how the repair is performed. In the old days, components were replaced in the field, but due to the much higher integration these days it's mostly module/board swaps where at the customer site the defective module/board is replaced, and the defective board goes back to the manufacturer for repair and thorough testing, and afterwards ends up in storage waiting to be used as a spare in another customer's instrument. Alternatively, in many cases the defective board can be sent in for repair, which might be cheaper but takes longer than the onsite replacement (often a defective instrument can be brought up again in less than an hour).

[AF6LJ]

Agreed.
    

[SteveLy]

Most unfair since the DS1054Z is a 50MHz scope. And yours is not a screenshot. Analog scopes don't do screenshots.

Actually, that is exactly where the term 'screenshot' comes from - taking a picture of the image on an analog scope's CRT with a special photographic camera.

Thanks (to you and to the previous poster too who made similar comment). It makes sense. One learns something new most days. Regular sampling is what stuffs up digital displays, even ones with good graded intensity. When the frequencies of the signals being displayed and the sampling rate are irrational ratios (or near-enough-to, like Howardlong's 101MHz AM signal a couple of pages ago), the sampling artefacts tend to go away. Some randomness in the sampling rate could also get rid of the artefacts that but it would also greatly complicate a DSO's design and operation.

[SoundTech-LG]

Modern test equipment is built not to be repaired

That is probably true for cheap Chinese B-brand kit like the gear from Rigol and Siglent but most big brand gear (aside from the cheap bottom-of-the-barrel stuff) definitely is designed for repair. What has changed however is how the repair is performed. In the old days, components were replaced in the field, but due to the much higher integration these days it's mostly module/board swaps where at the customer site the defective module/board is replaced, and the defective board goes back to the manufacturer for repair and thorough testing, and afterwards ends up in storage waiting to be used as a spare in another customer's instrument. Alternatively, in many cases the defective board can be sent in for repair, which might be cheaper but takes longer than the onsite replacement (often a defective instrument can be brought up again in less than an hour).
[/quote]

Just guessing he meant "Modern test equipment is built not to be repaired" BY THE END USER. The module is replaced by a Factory Authorized Servicer. No Service Manuals, No Schematics, No Component Level information. No modules for sale either, at least for the customers...
Unless you are under warranty, you'll be paying for "Authorized" servicing only.

[Wuerstchenhund]

Just guessing he meant "Modern test equipment is built not to be repaired" BY THE END USER. The module is replaced by a Factory Authorized Servicer. No Service Manuals, No Schematics, No Component Level information. No modules for sale either, at least for the customers...

But that would be incorrect as well. Every big brand sells you individual parts, boards, modules, you name it. You can usually also get service/maintenance manuals, too (although often without schematics, but for replacing modules that's not really an issue), either for free or paid.

Some big brands (i.e. LeCroy) also accept you sending in a board for repair, which can be noticably cheaper than sending in the whole instrument.

Unless you are under warranty, you'll be paying for "Authorized" servicing only.

Not really. I lost count of the newer out-of-warranty test equipment I have repaired over the years, and had little problems getting spares and documentation for it.

As I said before, the way repairs are done has changed, but in general modern big brand kit is still repairable.

[electrongeek]

I have both a Tek 2465A and a DS1054Z. I bought the 2465A cheap because it had an intermittent triggering problem. After extensive trouble shooting and empiric parts replacement, and help from the TekScopes Yahoo group, I narrowed it down to a failed trigger hybrid IC. That was cured . by buying a dead 2445 to be a donor. After that I recapped the LV power supply for good measure. So what I'm saying is that I love that scope and it has a lot of my sweat in it - albeit fun sweat. It works FB too and I doubt I will ever let it go.

However, the DS1054Z gets the most use on my bench. Its just too convenient and useful. I do still use the 2465A on occasion - usually just for the heck of it. It is extremely rare that I will find it is needed instead of the DS1054Z.

So I would say that you should buy the DS1054Z with your $400. Then, just for fun at a later date, buy one of those older Tek scopes - a broken one for a song - and make it good again. I really enjoyed diving into mine. You will also be able to use your newer scope to troubleshoot the older scope. Double bonus!

[Alfons]

What are we talking about? Such a device such as the Rigol 1054Z has so far at such a price never existed for the hobby area. Not so long ago would have been very, very much money paid for a device of this performance class. And of course also fascinate me the old equipment from Tek or HP, as I previously would never have to buy. These are two worlds: high-tech from China today (incidentally, no B-Ware, but good equipment) and the old guard of devices, that could only afford laboratories and industry. Realistically consider, we talk about emotions. The concern, that quality disappears. We will see...

[mtchastain]

Hi All,
Wanted to send along an update to my last email, seems the jolly fat man made am early appearance today at my house. Guess I was good this year....



-Matt