Author Topic: The Siglent SDG2042X Thread  (Read 318051 times)

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Offline Performa01

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Re: The Siglent SDG2042X Thread
« Reply #1200 on: October 26, 2019, 10:30:24 am »
I did the test with the SDG6052X; it has indeed some continuous variable output level (probably by variable DAC reference), but only for a amplitude range of about 1:2.4. Everything else is accomplished by attenuators activated by relays.

Quite obviously, we cannot switch the relays very fast and even at slow burst periods the permanent relay operations would be annoying, cause glitches and vastly reduce the lifetime of the instrument. ;)

Finally, I've found that quite unsurprisingly the wideband output amplifier is not a high-end audio class A design, so it produces noticable crossover distortions at very low signal levels. You normally never see this, but you can force it with a sine amplitude modulated by a square and then watching the lower level with a high resolution DSO. Otherwise, the amplitude modulation as described could be a substitute for the dual level burst. Modulation depth can be set in 0.1% steps, so in theory up to 60dB ratio would be possible. But in practice, at -60dB there are only 6 bits left for the lower signal at best and the class B oputput amplifier isn't really up to the task either.

As stated before, I really think that my setup is the only option for quality dual signals and the fancy dual level burst of any generator would not be the solution for your problem either.
« Last Edit: October 26, 2019, 10:39:10 am by Performa01 »
 

Offline n3mmr

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Re: The Siglent SDG2042X Thread
« Reply #1201 on: October 26, 2019, 11:32:08 am »
I really think I should do this measurement using pcsoftware and a good sound card.

And not the 2042.

The output amp being class B with noticeable xover dist is really unacceptable in a serious function generator.
 

Offline Performa01

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Re: The Siglent SDG2042X Thread
« Reply #1202 on: October 26, 2019, 12:09:56 pm »

The output amp being class B with noticeable xover dist is really unacceptable in a serious function generator.
Well, blame Texas Instruments or Analog Devices - whoever make them.

And I haven't seen any integrated wideband OpAmp that is not class B in a long time.

If you need an ultra low distortion audio oscillator, there are dedicated devices for that, although with very limited frequency range.

We always had that distinction: Audio Oscillator vs. Function Generator.

Analog function generators had distortion figures up to 1% THD at any output level, so crossover distortions certainly have been a minor concern there.

Like any function (or signal) generator, modern digital AWGs operate at high output levels and use attenuators to get the signal down to the desired levels, so once again crossover distortions are a non-issue, even though the THD figures are much lower than on their analog counterparts.

For the setup I've described in my earlier posting, no crossover distortion will be noticable either, since both output amplifiers operate at reasonable levels. The THD for the SDG is specified as <-65dBc up to 1MHz, I've measured some -80dBc at 20kHz, not as good as a 16bit system could ideally be, but still very good for a function generator.

Of course a good soundcard in conjunction with an external step attenuator will be much better for high-end audio.
 

Offline n3mmr

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Re: The Siglent SDG2042X Thread
« Reply #1203 on: October 26, 2019, 12:27:25 pm »
You're possibly right about wideband amplifiers and class B, but in my experience, with discrete semiconductor wideband amps, class B xover can be designed with very little distortion but the added problem of adjustment in deployment.

120MHz is rather wider than what I worked with, I must admit.
 

Offline Performa01

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Re: The Siglent SDG2042X Thread
« Reply #1204 on: October 26, 2019, 01:04:53 pm »
Right, properly adjusted class B has the lowest distortion figure (if we exclude true class A). It is certainly lower than class C (= underbiased class B), but also lower than class AB (= overbiased class B), because of the gain doubling in the class A region.

Class AB is much more benign though, because the global feedback reduces the gain error (at lower frequencies at least), whereas global feedback cannot be effective in the class C region where there is no gain at all. But AB output stages usually operate with significant idle current.

The problem is that there is no solution for an automatic adjustment for the optimum bias, so this has to be trimmed manually. And the next challende is to make the adjustment temperature independent - even in an integrated circuit it might not be that easy to compensate the huge temperature differences between idle and full load for the output stage which has to drive 100 ohms from +/-15V supply rails, with 100mA peak current.

In case of my SDG6052X, which is a 500MHz device btw, the output amp is just slightly underbiased. Since idle current consumption is a major concern nowadays, this might be deliberate, but it might well be that the bias is correct for lowest distortion by design, but inevitable manufacturing tolerances throw it off a little.
 

Offline n3mmr

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Re: The Siglent SDG2042X Thread
« Reply #1205 on: October 26, 2019, 03:27:27 pm »
It ought to be quite simple to set up an automatic process to adjust biasing.

Never mind, I gjve up, I take it all back...
 

Offline blurpy

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Re: The Siglent SDG2042X Thread
« Reply #1206 on: October 26, 2019, 05:09:29 pm »
I'm playing around with servos using the SDG2042X to generate PWM, and wondering if there is some way of sweeping the duty cycle? I'm trying to make the servo move back and forth automatically without having to change the duty cycle by turning the knob by hand.
« Last Edit: October 26, 2019, 05:27:05 pm by blurpy »
 

Offline JDubU

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Re: The Siglent SDG2042X Thread
« Reply #1207 on: October 26, 2019, 06:05:28 pm »
blurpy:

PWM Modulation.
« Last Edit: October 26, 2019, 06:10:55 pm by JDubU »
 
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Offline Performa01

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Re: The Siglent SDG2042X Thread
« Reply #1208 on: October 26, 2019, 06:24:51 pm »
I'm playing around with servos using the SDG2042X to generate PWM, and wondering if there is some way of sweeping the duty cycle? I'm trying to make the servo move back and forth automatically without having to change the duty cycle by turning the knob by hand.
That should be easy (my settings are in parenthesis):

Waveform: Pulse.
Pulse Frequency: as you like (100kHz)
Amplitude: as you like (500mVpp)
Rise and Fall times: reasonably fast (2ns)
Pulse Width: half the pulse period (5µs)

Modulation, type = PWM.
Waveform: internal (triangle)
PWM Frequency: slow (100mHz)
Width Deviation: maximum (4.996µs)

For the result see attachment (mp4 video in 7z archive).

« Last Edit: October 26, 2019, 06:34:26 pm by Performa01 »
 
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Offline blurpy

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Re: The Siglent SDG2042X Thread
« Reply #1209 on: October 26, 2019, 06:49:42 pm »
Thanks JDubU and Performa01!

I was able to get modulation setup so that the servo went back and forth all the way, and control the speed using PWM Freq.
The speed was linear, but I guess I can make it behave differently with the shape option? I'll continue experimenting tomorrow.
 

Offline Performa01

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Re: The Siglent SDG2042X Thread
« Reply #1210 on: October 26, 2019, 06:59:26 pm »
Thanks JDubU and Performa01!

I was able to get modulation setup so that the servo went back and forth all the way, and control the speed using PWM Freq.
The speed was linear, but I guess I can make it behave differently with the shape option? I'll continue experimenting tomorrow.
Yes, of course you can use whatever waveform you like, including an arbitrary one.
You could even select an external signal (Source/External) to modulate the pulse width.
 
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Offline blurpy

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Re: The Siglent SDG2042X Thread
« Reply #1211 on: October 26, 2019, 07:15:09 pm »
Ah, that sounds really nice!
 

Offline blurpy

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Re: The Siglent SDG2042X Thread
« Reply #1212 on: October 27, 2019, 02:36:41 pm »
Btw, Performa01, how did you make a video from your Siglent scope? I've got a SDS1204X-E and wondering if I can do the same.
 

Offline SteveRosenlund

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Re: The Siglent SDG2042X Thread
« Reply #1213 on: October 27, 2019, 11:02:18 pm »
Hey guys. My sdg2042 has a bit of an issue. There is a delayed response between when I press any button and the resultant action. Up to 5 seconds delay. For example, I press the output button or the utility button and have to wait up to 5 seconds for the machine to respond. I’m on a 2017 firmware 23r3 I believe. And I am hacked to 100mhz. Do I need to update firmware?

Steve
 

Online tautech

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Re: The Siglent SDG2042X Thread
« Reply #1214 on: October 27, 2019, 11:07:05 pm »
Hey guys. My sdg2042 has a bit of an issue. There is a delayed response between when I press any button and the resultant action. Up to 5 seconds delay. For example, I press the output button or the utility button and have to wait up to 5 seconds for the machine to respond. I’m on a 2017 firmware 23r3 I believe. And I am hacked to 100mhz. Do I need to update firmware?

Steve
Update it anyway as there's been a heap of improvements:
https://siglentna.com/service-and-support/firmware-software/waveform-generators/#sdg2000x-series

Study the release notes for any intermediate updates you must do before installing the latest version.
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Offline SteveRosenlund

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Re: The Siglent SDG2042X Thread
« Reply #1215 on: October 28, 2019, 03:02:27 am »
Weird sequence of events following my last post on this.  I updated firmware, one at a time, gradually getting to the latest version, and it wasn't until i upgraded to the latest version that the delay i was experiencing went away.  Now it's fine.  Weird to me.
 

Online tautech

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Re: The Siglent SDG2042X Thread
« Reply #1216 on: October 28, 2019, 05:10:54 am »
Weird sequence of events following my last post on this.  I updated firmware, one at a time, gradually getting to the latest version, and it wasn't until i upgraded to the latest version that the delay i was experiencing went away.  Now it's fine.  Weird to me.
Great.  :-+

Early on there were some issues with boot freezes (even Dave had his SDG2122X freeze) and some FW versions are to address this plus make it possible for USB boot freeze recovery so you didn't have to open the unit.
I suspect yours had a similar SW issue and updating to the latest firmware version has fixed it.

Anyways, you're now sorted it seems.  :-+
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Offline Performa01

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Re: The Siglent SDG2042X Thread
« Reply #1217 on: October 28, 2019, 12:29:23 pm »
Btw, Performa01, how did you make a video from your Siglent scope? I've got a SDS1204X-E and wondering if I can do the same.
I just used the integrated webserver of the DSO and a screen recorder program to capture the content of the browser window on the PC.

The frame rate is limited to some 10fps with an SDS1004X-E, so it's not as smooth as on the real device, but certainly acceptable for many applications.

 
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Offline blurpy

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Re: The Siglent SDG2042X Thread
« Reply #1218 on: October 28, 2019, 06:09:29 pm »
Btw, Performa01, how did you make a video from your Siglent scope? I've got a SDS1204X-E and wondering if I can do the same.
I just used the integrated webserver of the DSO and a screen recorder program to capture the content of the browser window on the PC.

The frame rate is limited to some 10fps with an SDS1004X-E, so it's not as smooth as on the real device, but certainly acceptable for many applications.

Thanks, that's clever!
 

Offline trojanrabbit

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Re: The Siglent SDG2042X Thread
« Reply #1219 on: November 03, 2019, 08:43:54 pm »
Good afternoon everyone.

Have had an SDG2042X for a while, combining new technology with old.  I use it primarily when I'm restoring an antique radio or TV as an IF / RF generator, checking IF strips by sweeping the appropriate range (around 455kHz for AM, 10.7MHz for FM and 21MHz for very early TVs) and use the trigger output to trigger my scope.  For that it works great.

Wanted to play with LabVIEW and noticed that Siglent's VI for setting sweep frequencies doesn't work that well, most of the time it doesn't program the "Start" frequency.

Since I'm still running the original 2.01.01.12R1 firmware, I decided to try to upgrade to the latest 2.01.01.35R3B1

For the last 3 hours the display has remained at 0% progress.  Yeah, I can keep the power on in the hope that something happens, but I've seen nothing in this 40 something page thread that suggests I should wait that long.

For the moment, I sent a message to Siglent to see if they have anything to try.

Just a little bummed out.  In the middle of restoring a 1953 Revere reel-to-reel tape recorder and trying to align the AM receiver section, it's a bit off.
 

Online tautech

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Re: The Siglent SDG2042X Thread
« Reply #1220 on: November 03, 2019, 09:15:01 pm »
Turn it OFF.
Any issues, I have the recovery files to help you.
Reboot and check the Sys info to see if the update was successful.

I just checked the FW release notes and there's no mention of intermediate FW versions to install before installing the latest.  :-//
https://siglentna.com/wp-content/uploads/dlm_uploads/2019/09/SDG2000X-Firmware-Revise-History-Update-Instructions.pdf
There's a note for 2.01.01.17R5 so that's the version I would upgrade to first before installing the latest.

Come back and report how things went.  :popcorn:

Edit
SDG2000X last four FW versions:
https://siglentna.com/service-and-support/firmware-software/waveform-generators/#sdg2000x-series

« Last Edit: November 03, 2019, 09:16:33 pm by tautech »
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Offline trojanrabbit

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Re: The Siglent SDG2042X Thread
« Reply #1221 on: November 03, 2019, 09:42:04 pm »
Turn it OFF.
Any issues, I have the recovery files to help you.
Reboot and check the Sys info to see if the update was successful.

I just checked the FW release notes and there's no mention of intermediate FW versions to install before installing the latest.  :-//
https://siglentna.com/wp-content/uploads/dlm_uploads/2019/09/SDG2000X-Firmware-Revise-History-Update-Instructions.pdf
There's a note for 2.01.01.17R5 so that's the version I would upgrade to first before installing the latest.

Come back and report how things went.  :popcorn:

Edit
SDG2000X last four FW versions:
https://siglentna.com/service-and-support/firmware-software/waveform-generators/#sdg2000x-series

Turned it off, waited a few seconds and turned back on.  Still at 2.01.01.12R1

I'll take your advice and try 2.01.01.17R5

Thanks
 

Offline trojanrabbit

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Re: The Siglent SDG2042X Thread
« Reply #1222 on: November 03, 2019, 10:11:07 pm »
Two step process got me to 2.01.0135R3B1

Interesting that the hardware version stayed at 01-07-00-40-00. I thought I had seen some responses where the Hardware version tracked the Software version

Thanks again!  Now to see if it behaves better in LabVIEW
 
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Offline trojanrabbit

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Re: The Siglent SDG2042X Thread
« Reply #1223 on: November 04, 2019, 03:26:11 pm »
Which it does not.  Actually it’s pretty non-responsive to LabVIEW, at least the sweep-setting commands.  The Siglent-supplied VI just sends a massively long string setting all the parameters at once.  Maybe that’s too much for the generator to handle.  Not the first time I’ve had to fix manufacturer-supplied VIs.

One thing I did like to see added is a “TV signal” as part of the internal arbitrary waveform library.  I dreaded having to define one myself.
 

Offline ahope

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Re: The Siglent SDG2042X Thread
« Reply #1224 on: November 09, 2019, 10:51:04 am »
I jsut got the 2042X, and discovered the Labview drivers that are available for download are too new for my labview 2014 home edition.
Anyone got labview 2014 drivers for 2042X? I see I have the same problem with my siglent  3045s and 1202X-e, those labview drivers are also too new for 2014.
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