Rigol Oscilloscopes With(out) Bode Plot Feature?

[tautech]

I'm not so sure Siglent copied Keysight. At least not after the Keysight 1000X scope was released. IIRC Siglent quickly came up with an FRA feature which performed significantly better compared to Keysight. Siglent must have been working on this for a long time.

But ... if they didn't release it then it was for marketing reasons.

When Keysight released theirs with the feature, Siglent followed, ie. they copied them.

Copied ?
Nah  improved !

Examples from forum screenshots at about the same time:

Notice the graticule on graticule implementation. 


Just 2 traces showing of a possible 3

[Mechatrommer]

it took me couple of days, 1 or 2 weeks at most for my bode plotter iirc, nothing too hard...

translated from mandarin

B: hey guys Keyslight do this...
<looking at bode plotter spec>
G: all wright we do it, we do it better!
<1 hour reading what is bode plot>
G: they do 10pts, we do 100pts!
<changing COUNT and INTERVAL value in if sweep loop>
G: but boss, we are a bit slowly.
B: nevermind this is marketing BS.
<1 week later>
G: we did it! now we have bode plot in our scope!
B: yes!!!

from autumn in my liver...

[rf-loop]

I ask because I know diddly about this feature:  Is the frequency scale logarithmic? 

User can select log or lin frequency scale.
Vertical scale also can select log or linear. 
  -Display mode can be Vin/Vout OR Vout.

Some random examples (test setup and scope settings are not optimal - lack of time)

[rstofer]

Thanks for the education!

That SDS1204X-E that I want is looking better all the time!  I'm assuming I can use my SDG2082X as the signal source, right?  The scope controls the generator?

I know, RTFM.  I'll get right on that as soon as I finish reading the comics.

[rf-loop]

Thanks for the education!

That SDS1204X-E that I want is looking better all the time!  I'm assuming I can use my SDG2082X as the signal source, right?  The scope controls the generator?

I know, RTFM.  I'll get right on that as soon as I finish reading the comics.

Yes,  just connect scope example with USB cable with generator. No need do anything but turn SDG power on. Scope BodePlot take full control.

But then note. BodePlot UI is not very user friendly. It need some exercises before user can get all out from it. I hope Siglent develop this UI for better usability. Of course after have some experience all can do and find optimal settings and can handle it quite easy.  Anyway, it's a little clumsy. UI could have made a lot more user friendly. Example some display runtime adjustments etc need some workout and experience how it can control when it is running. 

[Martin72]

(..)
Jump many years later and Rigol rolls out their new mso5000 series scopes. Hard to resist for the base price, can be loaded up to $5k+ for features (we all know ways around this though), and lacks this basic bode plot feature! Rigol what gives? Really they implement all these niche but appreciated features such as power analysis but cannot implement a simple bode plotter? A scope with 4 channels, 2 wave gens, and all the hardware necessary to get the job done yet they skip this feature? WHY?? It's not even an optional add on or anything. Is this feature buried in the menu somewhere? I cannot find any mention of it in the user manual. It must not exist. This can and should be implemented in a future firmware update.

Bode-Plot function will be implemented on the 5000 (I ask them for it)…..

[David Hess]

But almost as dumb is discarding the phase results of the FFT function because combined with differentiation or an impulse generator, a bode plot can be generated from the transient response of a system in one shot.

iirc i did play with this method while developing bode plotter, using square waves, we'll need few cycles for faithful FFT result. but the result was not as neat as classical sweep method. maybe the setup was poorly controlled.

The impulse method does not have the dynamic range of the swept sine method but many systems do not require greater dynamic range and it is faster which is convenient when making real time adjustments.  It can also work with a single shot measurement which is invaluable when dealing with slow systems like oven controllers.

[Mechatrommer]

But almost as dumb is discarding the phase results of the FFT function because combined with differentiation or an impulse generator, a bode plot can be generated from the transient response of a system in one shot.

iirc i did play with this method while developing bode plotter, using square waves, we'll need few cycles for faithful FFT result. but the result was not as neat as classical sweep method. maybe the setup was poorly controlled.

The impulse method does not have the dynamic range of the swept sine method but many systems do not require greater dynamic range and it is faster which is convenient when making real time adjustments.

i'm not sure my result is something dynamic range related. i dig back my bode plotter and i still have result comparing sweep and square + fft (single capture) method. in fact, the feature is included in the software all this long i've already forgotten (3rd picture). the test was on a simple 4.7uF capacitor, 1st picture is sweep method, 2nd picture is fft method. but i'm not sure if you are talking about the same thing, but i cant think of any other method for single impulse capture other than it has to go through FFT to extract all frequencies component for analysis/plot.

since you mentioned real time, i've forgotten how many points i used in the FFT implementation, but bigger points/bins count means slower operation hence not real time. real time needs smaller bins and that means greater spectral leakage in FFT. i think my problem was leakage or/in FFT implementation throwing harmonics/frequencies element's phase and magnitude out , this certainly needs more time for R&D or a paid paper somewhere. maybe some sort of averaging can fix that, but then again, averaging is not real time, for an affordable grade hardwares. fwiw ymmv..

[Mechatrommer]

or maybe i was just talking about a different thing... or maybe square wave is not an ideal signal for this...

[jackbob]

Bode-Plot function will be implemented on the 5000 (I ask them for it)…..

I sure hope so. I have a new MSO5000 on my bench waiting for the update 

[EEVblog]

This makes me wonder now who got it first, Keysight or Siglent? This budget end scope market has really become quite competitive and when one rolls out a scope with specific features and specs for X dollars, it's not too much later before other brands start to follow with a similar product. In this case I wonder if Keysight was putting their 1000x series together and saw Siglents bode plot feature and thought they should include it as well.

I'm pretty sure Siglent copied Keysight.
The Keysight was released in Feb 2017, but I was given the prototype by a guy in a trench coat in the back alley at the Electronex show in Sep 2016

Copy what? Quite a hard accusation or suspicion.

No it's not, there is nothing wrong with copying/matching a feature that competitor brings out, that's normal business practice.

BTW, Siglent have copied the UI of Keysight gear completely in previous products, down to every menu option and screen layout.

Perhaps Keysight copied some others idea that also oscilloscope may have SFRA.

Of course they did, SFA in a scope is not new, Keysight didn't invent it. But what they did do was to introduce it into an entry level bench scope.
Siglent have been working on the same thign at the same time, but I believe Keysight beat them to market, and first to market wins innovation bragging rights, and everyone else "copied"/"followed".

Perhaps also Siglent think same, independently of each others.  If only copy idea that oscilloscope may have SFRA is it copying. Perhaps like Nissan or Lamborghini copy Ford.
Why I think this?
IF Siglent have copied  Keysight this model perhaps then they release something total junk crap.
But because they did not copy they make something what is even some amount useful and not only for tell students that  in the world there is also "BodePlot" and studets roll they eyes.

Chill out, you seem to be caught up on the word "copy", it's no big deal to copy a feature, in fact it's expected that a competitor do so.
Ford puts airbags as standard in entry level cars, Nissan copies, etc etc.

[EEVblog]

I'm pretty sure Siglent copied Keysight.
The Keysight was released in Feb 2017, but I was given the prototype by a guy in a trench coat in the back alley at the Electronex show in Sep 2016

Or this might simply mean that you don't know any trenchcoat guys at Siglent. 
How would you know when Siglent started prototyping this feature? It's kind of an obvious idea, once you have combined a scope and function generator in one device and look for "what's next" after you are done with FFT...

I don't know.
As I said in a previous post, it doesn't matter, first to market gets bragging rights and everyone else "copied", that's how it works.

[nctnico]

Bode-Plot function will be implemented on the 5000 (I ask them for it)…..

I sure hope so. I have a new MSO5000 on my bench waiting for the update 

I hope you have time...

[Martin72]

Always negative, hm? 
If everything comes in a right way, it won´t be soo long waiting for it.
But I don´t have a problem to wait a little bit longer, if their priorities lies more to the bugs as to additional features ( like bode-plot is one).

[nctnico]

Not negative. Just being realistic... look at the threads about the DS1000, DS2000 and DS4000 series. It has taken Rigol literally years to make these scope relatively bug free and deliver on the promised features.

[2N3055]

Not negative. Just being realistic... look at the threads about the DS1000, DS2000 and DS4000 series. It has taken Rigol literally years to make these scope relatively bug free and deliver on the promised features.

So did R&S for RTB2000.......

[Fungus]

Not negative. Just being realistic... look at the threads about the DS1000, DS2000 and DS4000 series. It has taken Rigol literally years to make these scope relatively bug free and deliver on the promised features.

a) Not true. My DS1054Z has been relatively bug free and had all features since three months after launch date (unless you count spelling mistakes in the menus as major bugs)
b) Why do you even go into "Rigol" threads? It seems to distress you.

[dkggpeters]

Thanks for the education!

That SDS1204X-E that I want is looking better all the time!  I'm assuming I can use my SDG2082X as the signal source, right?  The scope controls the generator?

I know, RTFM.  I'll get right on that as soon as I finish reading the comics.

Yes,  just connect scope example with USB cable with generator. No need do anything but turn SDG power on. Scope BodePlot take full control.

But then note. BodePlot UI is not very user friendly. It need some exercises before user can get all out from it. I hope Siglent develop this UI for better usability. Of course after have some experience all can do and find optimal settings and can handle it quite easy.  Anyway, it's a little clumsy. UI could have made a lot more user friendly. Example some display runtime adjustments etc need some workout and experience how it can control when it is running.

Or you can connect using a network.  All my Siglent test gear is on the network.

[dkggpeters]

BTW, Siglent have copied the UI of Keysight gear completely in previous products, down to every menu option and screen layout.

The buttons are different colors.  We all know that button color is where it is at.

[Martin72]

So did R&S for RTB2000.......
[/quote]

And so did Lecroy for WS3000......and still it isn´t bug-free.

[Mechatrommer]

Not negative. Just being realistic... look at the threads about the DS1000, DS2000 and DS4000 series. It has taken Rigol literally years to make these scope relatively bug free and deliver on the promised features.

a) Not true. My DS1054Z has been relatively bug free and had all features since three months after launch date (unless you count spelling mistakes in the menus as major bugs)

maybe you have not into great depth usage of the scope other than normal usage like we did in CRO age. i for one found few bugs on ni-visa usb communication, others figured in linux usbmtc what? others reported others bugs that i may find minor issues, its true Rigol did fix some of them, fixing major issues obviously normal usage like CRO day usage should be fixed quickly, but for minor delusive features bell and whistle things, it can take months or years of time (not sure if ni-visa usb stuffs is fixed to the date i havent checked). but try asking Rigol to add "new feature" like Bode plot into DS1000Z series, or even ask to show serial data of whole captured in memory (not whats displayed on lcd alone). the same case with this 5000 series is a suspect same situation. asking new feature not originally speced to come in is like an hopelessly eternal wait, if not they try to sell you license at a fortune. not specifically to Rigol, it can be any brand. ymmv.

[JPortici]

[..] beat them to market, and first to market wins innovation bragging rights, and everyone else "copied"/"followed".

true dat oh, how many thimes this have happened..

[IDEngineer]

But almost as dumb is discarding the phase results of the FFT function....

Which leads me to the question I've been researching a bit lately. There are few scopes that have integrated Bode plot features, and apparently even fewer than include frequency-phase - most seem to just do frequency-amplitude. Proper FFT's yield phase data too, so why not display that?

For that matter, it appears even dedicated spectrum analyzers (at least the lower end ones) don't offer to display phase. A quick scan of (for example) Rigol SA's doesn't reveal any way to select phase as a displayed parameter.

What am I missing here? Phase response is not exactly a new concept.

[David Hess]

But almost as dumb is discarding the phase results of the FFT function....

Which leads me to the question I've been researching a bit lately. There are few scopes that have integrated Bode plot features, and apparently even fewer than include frequency-phase - most seem to just do frequency-amplitude. Proper FFT's yield phase data too, so why not display that?

Because DSO designs are dumb.  I suspect it is the marketers who are responsible.

For that matter, it appears even dedicated spectrum analyzers (at least the lower end ones) don't offer to display phase. A quick scan of (for example) Rigol SA's doesn't reveal any way to select phase as a displayed parameter.

Common spectrum analyzers are scalar instruments so the phase information is not available.

For the phase information, something more along the lines of a network analyzer is required.  But a network analyzer lacks the selectivity of a spectrum analyzer so that by itself is not enough.  There are some instruments however which combine the capabilities of both.

[2N3055]

But almost as dumb is discarding the phase results of the FFT function....

Which leads me to the question I've been researching a bit lately. There are few scopes that have integrated Bode plot features, and apparently even fewer than include frequency-phase - most seem to just do frequency-amplitude. Proper FFT's yield phase data too, so why not display that?

For that matter, it appears even dedicated spectrum analyzers (at least the lower end ones) don't offer to display phase. A quick scan of (for example) Rigol SA's doesn't reveal any way to select phase as a displayed parameter.

What am I missing here? Phase response is not exactly a new concept.

Picoscope FRA shows both phase and gain. Keysight 3000T also has it, together with variable signal/frequency.. As far as I know Siglent 1000X-E has it too, it also have phase, variable level, and also something no other can which is multiple channels simultaneously... I presume Siglent 5000X will have the same (when it's available, if not already).

And SA+TG is not a VNA. That is why TG+SA makes SNA (scalar vector analyser, only gain), while VNA (vector network analyser) has gain and phase.