Analog Discovery 3 Waveform Sync

[diligent1]

Hello Digilent Forum!

We are experimenting with the Analog Discovery 3 board and trying to get multiple waveforms locked and synchronized together from a sync pulse however we are having jittering between the output pulses.

They look to be sequential?

Do you have any pointers/ common mistakes people make whilst doing this?

Many thanks!

 

Edited November 14, 2023 by diligent1

[attila]

Hi @diligent1

The VI package provides a limited set of features. FGen synchronization is not available in this but in the WF API/SDK.

 

[diligent1]

On 11/15/2023 at 10:08 AM, attila said:

Hi @diligent1

The VI package provides a limited set of features. FGen synchronization is not available in this but in the WF API/SDK.

 

Thank you @attila! Much appreciated. We will check out the SDK. Is this ok for Analog Discovery 3?

[attila]

Hi @diligent1

Yes, see the WF SDK manual and Python examples.

[diligent1]

On 11/16/2023 at 1:41 PM, attila said:

Hi @diligent1

Yes, see the WF SDK manual and Python examples.

Hi @attila, thanks for this info. We have been using the SDK to sync all channels of all devices. We are struggling to find an example which shows how to do both of these things.

Could you point me in the direction of a good strategy? We are looking to output 5 waveforms from 3 devices. Want to to output 3ms pulses and loop through to change the amplitude of 1 of them for 256 iterations from 1 to -1. 

Many thanks!

[attila]

Hi @diligent1

See the following: AnalogOut_Devices.pydwfconstants.py
Connect trigger IOs between devices for reference clock (supported by AD3, ADP2230, ADP3X50...) and trigger synchronization. First channel of first device will perform AM 256 steps. You change the device names to have an order or modify the (auto) connection. Run once if you want...

[diligent1]

1 hour ago, attila said:

Hi @diligent1

See the following: AnalogOut_Devices.pydwfconstants.py
Connect trigger IOs between devices for reference clock (supported by AD3, ADP2230, ADP3X50...) and trigger synchronization. First channel of first device will perform AM 256 steps. You change the device names to have an order or modify the (auto) connection. Run once if you want...

@attila This is amazing. Thank you so much! The only things are now that we need a custom function on each of these channels (including the scaled one and each of the functions is different). We have the functions in our python already. And we just want 1 pulse of each - not a continuous stream of pulses.

This is excellent. I really appreciate your help!

[diligent1]

@attila, I've been struggling working out how to output just one pulse of each waveform. There seems to be multiple pulses for each waveform. Is this an issue with my custom waveform? Do I need to fill the entire 32k buffer with the waveform otherwise it will repeat? How would I do this Or should I change the frequency somewhere?

Many thanks

[attila]

Hi @diligent1

Use FDwfAnalogOutRunSet and FDwfAnalogOutRepeatSet if you want to run for limited time

[diligent1]

6 minutes ago, attila said:

Hi @diligent1

Use FDwfAnalogOutRunSet and FDwfAnalogOutRepeatSet if you want to run for limited time

Thanks @attila. I already managed to do this to make it output just 1 pulse each by modifying your code - however when you just set it to run 1/hzfreq - the loop for the amplitude modulated pulse doesn't happen. You just get one pulse at the initial amplitude. I hope this makes sense!

[attila]

Hi @diligent1

Not only the carrier but also the AM/FM are restarted with each Run cycle.

[diligent1]

OK thank you. So how would you suggest we implement the functionality we are looking for?

 

[attila]

I'm not sure I have all the details you want to achieve.
Do you only need to run the pulse train once? If so, set the run to a burst length such as 2*256/hzFreq

[diligent1]

Hi @attila. Essentially -  I want to put out one pulse which changes amplitude over time betwen 1 and -1. In the example you kindly provided I have managed to get this working great however there are multiple pulses in a pulse train which all change in amplitude between 1 and -1. If I change the run time to 1/hzfreq - I just get 1 pulse which doesn't change in amplitude and if I change the burst length to 2*256/hzfreq then I get lots of pulses doing the same thing. We need a single pulse which varies over time.

I hope this clarifies things. Very grateful for all of your help.

 

[attila]

Do I understand correctly that you want for each software call to generate only one pulse on 5 channels synchronized ?
So the sequence of pulses does not need to have precise timing, just the phase between the channels ?