Rigol DG1022Z or Siglent sdg1032x

[bd139]

Bode plot is neat but unnecessary. You only need to work out phase flips and 3dB / 6dB points mostly and you can do that sweeping by hand effectively. Actually takes less time than setting up a bode plot and you only need a 2 chan scope for it. NanoVNA is better past 5Mhz

[2N3055]

Bode plot is neat but unnecessary. You only need to work out phase flips and 3dB / 6dB points mostly and you can do that sweeping by hand effectively. Actually takes less time than setting up a bode plot and you only need a 2 chan scope for it. NanoVNA is better past 5Mhz

Operating word, mostly, that is if you only doing if for the stability reasons as a quick check... Than you can do it by hand. Agree.
If you want to get gain/phase response diagram doing it by hand is not really fun..
Especially if you're tweaking something that has multiple poles in response. And repeating measurements...
VNAs are usually only for 50Ω systems.
Truth is it really depends what you do. I use FRA (Frequency Response Analyser, that creates gain/phase plot) more than VNA.
The idea is that FRA is for non 50Ω systems and less than 10MHz systems...
Does somebody need that,  it is up to them, defined by what they do...

DG811 can be "unlocked" to DG992 but amplitude won't be calibrated above certain frequencies..
One thing that is great about my SDG6000X is that has VERY accurate level in full frequency range (even those "liberated", they calibrate them all full range, despite destination model speed). One thing to have in mind.

[tautech]

Yeah once you've used a decent FRA application who would want to do it the old way ?

[rf-loop]

Bode plot is neat but unnecessary. You only need to work out phase flips and 3dB / 6dB points mostly and you can do that sweeping by hand effectively. Actually takes less time than setting up a bode plot and you only need a 2 chan scope for it. NanoVNA is better past 5Mhz

Yep. you can try. Example this.


(and full dynamic range is not used even close)


Or just this very simple where -3dB bw is what it is but -60dBc points are very important (but my example is poor for this). Of course for these things are better tools but, also today these modern osccilloscopes give more and more...
(I do not have my old Rocwell-Collis filters or Racal filters BodePlots (made with other instruments) available (all gone when bunch of hard disks accidentally damaged time ago. These oscilloscopes can not go to -120dBc when ref level is 0dBm.  But, for many hobby grade things with these scopes can do lot. Lot of more than these old simple methods can even dream)


Or just simple 3 channel FRA
Again much more is is interesting than just -3dB points.




In all cases just SDG1032X used for test signal.

[bd139]

That is indeed neat

You can have some fun with even older equipment…



log-log plot on a TDS210.

Point is it is neat indeed but it depends on the application. 90% of what is bought is unused.

[mawyatt]

Personally we would never consider a modern DSO or AWG that's not directly compatible for Bode Plot capability.

Folks that downplay Bode Plots usefulness haven't spent the time with this built-in feature, and I count myself in that category a couple years ago!!

Before we acquired a SDS2102X+ (later a 2104X+) a FRA was employed for Bode Plots if available, usually not, or just the old hat input sweep, scope record, and then plot results which required having to convert in dB and getting the phase....real PITA!! Even recall using a Tek scope as a high Z input preamplifier as an input to a 50 ohm HP NA as a make shift FRA. Lots of work and such which now can be accomplished in just the DSO and no additional efforts other than a few setup parameters, and produces decent Dynamic Range (with input scaling) with nice graphics (will be interesting to see how well the new SDS2000X HD performs in Bode Mode)!! And for icing on the cake with a couple $ spent on an DIY Isolation Transformer, one can even do very respectable Closed Loop measurements!!

From an old retired analog guy I must say that these modern modest priced DSOs are amazing, not only doing anything and everything the old analog scopes could do, and generally even better, and incorporating a Logic Analyzer, very useful FFT feature, Bode Plots, waveform stats, remote access and on and on

So why would one consider an AWG that's not compatible with the DSO, is there a big price difference, or feature difference, or performance difference that's compelling enough to forgo the DSO compatibility?


Best,

[Martin72]

will be interesting to see how well the new SDS2000X HD performs in Bode Mode

Hmmm, could be one of the tasks when I got mine...

[mawyatt]

will be interesting to see how well the new SDS2000X HD performs in Bode Mode

Hmmm, could be one of the tasks when I got mine...

Was hoping some kind folks with these new HD models might pick up on the hint 

Envision the Bode Plot dynamic range will be quite good with the extra ADC bits and the low noise floor. What rf-loop has shown with the Two Tone IMD tests reenforces the wide DR expectations.

Best,

[bd139]

Personally we would never consider a modern DSO or AWG that's not directly compatible for Bode Plot capability.

Folks that downplay Bode Plots usefulness haven't spent the time with this built-in feature, and I count myself in that category a couple years ago!!

Before we acquired a SDS2102X+ (later a 2104X+) a FRA was employed for Bode Plots if available, usually not, or just the old hat input sweep, scope record, and then plot results which required having to convert in dB and getting the phase....real PITA!! Even recall using a Tek scope as a high Z input preamplifier as an input to a 50 ohm HP NA as a make shift FRA. Lots of work and such which now can be accomplished in just the DSO and no additional efforts other than a few setup parameters, and produces decent Dynamic Range (with input scaling) with nice graphics (will be interesting to see how well the new SDS2000X HD performs in Bode Mode)!! And for icing on the cake with a couple $ spent on an DIY Isolation Transformer, one can even do very respectable Closed Loop measurements!!

From an old retired analog guy I must say that these modern modest priced DSOs are amazing, not only doing anything and everything the old analog scopes could do, and generally even better, and incorporating a Logic Analyzer, very useful FFT feature, Bode Plots, waveform stats, remote access and on and on

So why would one consider an AWG that's not compatible with the DSO, is there a big price difference, or feature difference, or performance difference that's compelling enough to forgo the DSO compatibility?


Best,

You can do a bode plot on any 4 channel scope and any 1 channel AWG. The whole thing is just software and the devices have SCPI / LXI interfaces.

[2N3055]

That is indeed neat

You can have some fun with even older equipment…



log-log plot on a TDS210.

Point is it is neat indeed but it depends on the application. 90% of what is bought is unused.

As I said it depends of what you do.
You can improvise all kinds of contraptions, up to creating your own analyzer.
What you show is just a gain plot, without obvious frequency axis, and no phase information.
It is useful to a point but far from what FRA gives you...

But the point here is that you can have that (very powerful) tool for basically free if you chose one generator over the other.
Or loose it if you chose other AWG from other manufacturer for whatever reason.

[nctnico]

Personally we would never consider a modern DSO or AWG that's not directly compatible for Bode Plot capability.

Folks that downplay Bode Plots usefulness haven't spent the time with this built-in feature, and I count myself in that category a couple years ago!!

Before we acquired a SDS2102X+ (later a 2104X+) a FRA was employed for Bode Plots if available, usually not, or just the old hat input sweep, scope record, and then plot results which required having to convert in dB and getting the phase....real PITA!!

Network analysers have been around for a long time and these typically do the job quicker & better.

[mawyatt]

Network analysers have been around for a long time and these typically do the job quicker & better.

Yep and you pay a nice price for such

And the NA may not be a better choice always, regardless of price, since you now have another large expensive piece of equipment cluttering up the workbench!!

We've utilized many Network Analyzers, dating back well before the HP8510, so have considerable experience here, and can tell from first hand experience with the built-in Bode Plot capability for lower frequencies. This is quite useful and why now we wouldn't consider a DSO, nor AWG compatibility, without this built-in capability. Of course YMMV

Best,

[2N3055]

Personally we would never consider a modern DSO or AWG that's not directly compatible for Bode Plot capability.

Folks that downplay Bode Plots usefulness haven't spent the time with this built-in feature, and I count myself in that category a couple years ago!!

Before we acquired a SDS2102X+ (later a 2104X+) a FRA was employed for Bode Plots if available, usually not, or just the old hat input sweep, scope record, and then plot results which required having to convert in dB and getting the phase....real PITA!!

Network analysers have been around for a long time and these typically do the job quicker & better.

We had this discussion before. VNAs don't go to low frequencies and are not high impedance inputs.
Frankly, you need both FRA and VNA..

[nctnico]

Personally we would never consider a modern DSO or AWG that's not directly compatible for Bode Plot capability.

Folks that downplay Bode Plots usefulness haven't spent the time with this built-in feature, and I count myself in that category a couple years ago!!

Before we acquired a SDS2102X+ (later a 2104X+) a FRA was employed for Bode Plots if available, usually not, or just the old hat input sweep, scope record, and then plot results which required having to convert in dB and getting the phase....real PITA!!

Network analysers have been around for a long time and these typically do the job quicker & better.

We had this discussion before. VNAs don't go to low frequencies and are not high impedance inputs.

Appearantly you forgot that low frequency network analysers which have high impedance inputs do exist. The one I have is the Anritsu MS4630B

[2N3055]

Personally we would never consider a modern DSO or AWG that's not directly compatible for Bode Plot capability.

Folks that downplay Bode Plots usefulness haven't spent the time with this built-in feature, and I count myself in that category a couple years ago!!

Before we acquired a SDS2102X+ (later a 2104X+) a FRA was employed for Bode Plots if available, usually not, or just the old hat input sweep, scope record, and then plot results which required having to convert in dB and getting the phase....real PITA!!

Network analysers have been around for a long time and these typically do the job quicker & better.

We had this discussion before. VNAs don't go to low frequencies and are not high impedance inputs.

Appearantly you forgot that low frequency network analysers which have high impedance inputs do exist. The one I have is the Anritsu MS4630B

No I did not. It is discontinued product.. And new was very expensive.
Making a statement that a very expensive specialized instrument is better at something than a inexpensive FRA equipped scope is kinda obvious.. It should better be better...
The thesis here is going the other direction: FRA is good enough for most uses that you don't need to buy expensive specialized instrument for many tasks...
I would personally like to own a Bode100.. I just can't justify the investment..

And FRAforPico and Siglent's FRA running on 12 bit scope and even FRA on 8bit Keysight does a great job in general...
But lately it is mostly SDS6000/2000HD because it works great. I use external SDG6000/7000 generator if I need more signal, or 2000HD for all in one... Although integration with external AWG is seamless and just works...

Keysight implementation on 3000T is very easy to use and also very good. But Siglent's implementation is more  sophisticated and 12 bit and bigger screen wins.....