ADC and DAC at different sampling frequency

ADC and DAC at different sampling frequency

Postby RJA4000 » Fri Sep 20, 2019 5:15 am

Hello

I have separate ADC and DAC.
Both use the same driver, but display as different ASIO pairs.

I'd like to analyze high-frequency response of DUT using a lower frequency excitation.
(Ex: 44.1kHz sine, 192kHz FFT)
So far, every time I change it, both ADC and DAC are changed.

Is there a way to set different DAC and ADC sampling frequencies ?
RJA4000
 
Posts: 32
Joined: Sun Jul 28, 2019 2:28 am

Re: ADC and DAC at different sampling frequency

Postby VirtinsTech » Sat Sep 21, 2019 1:39 am

The software will interlock the selection of ADC and DAC sampling rates ONLY WHEN both ADC and DAC uses Sound Card ASIO drivers and the ASIO drivers used have the same sequential number in the Device No. selection box (see figure below). In your case, do the two have the same sequential number there? If yes, do they have a different textual description? Basically the software needs a way to know that the ASIO drivers used are for different hardware devices in order to disable the interlocking.

ASIO-SamplingRateInterlocking.png
ASIO-SamplingRateInterlocking.png (50.35 KiB) Viewed 3152 times
VirtinsTech
Site Admin
 
Posts: 149
Joined: Tue Oct 01, 2013 3:06 pm

Re: ADC and DAC at different sampling frequency

Postby RJA4000 » Sat Sep 21, 2019 5:44 am

Hi

That's the issue indeed.
I use 2 RME ADI-2 Pro fs, which, obviously, are using the same driver.
I'll give ASIO4ALL a try for one of them.

Thanks for the answer :-)
RJA4000
 
Posts: 32
Joined: Sun Jul 28, 2019 2:28 am

Re: ADC and DAC at different sampling frequency

Postby VirtinsTech » Sun Sep 22, 2019 3:53 am

You mentioned in your first Post that "...I have separate ADC and DAC. Both use the same driver, but display as different ASIO pairs...." It seems that there is a difference either in textual description of the two driver instances, or different positions in the ADC and DAC Device No. selection boxes?
VirtinsTech
Site Admin
 
Posts: 149
Joined: Tue Oct 01, 2013 3:06 pm

Re: ADC and DAC at different sampling frequency

Postby RJA4000 » Sun Sep 29, 2019 9:14 pm

Hi
Thanks for your answer

As they are the same Brand/Model, they share the same driver.

When selecting the ADC, as an example, it looks like this:
Both have same Device No, but device channel names are followed by (1) for first device and (2) for second.

ADC_Select_RME.PNG
ADC_Select_RME.PNG (118.03 KiB) Viewed 2986 times


In "RME settings", both devices appear, and one may set the Sampling frequency independently... as long as the software doesn't force it :-(

2019-09-29 15_17_59-MADIface Series Settings.png
2019-09-29 15_17_59-MADIface Series Settings.png (72.06 KiB) Viewed 2986 times

2019-09-29 15_18_02-MADIface Series Settings.png
2019-09-29 15_18_02-MADIface Series Settings.png (70.6 KiB) Viewed 2986 times


It would be handy to have a checkbox to allow setting different Sampling frequencies in that case.
Of course, that won't work if that's the same physical device.
But in my case, that would make my life much easier...
RJA4000
 
Posts: 32
Joined: Sun Jul 28, 2019 2:28 am

Re: ADC and DAC at different sampling frequency

Postby VirtinsTech » Tue Oct 01, 2019 10:42 pm

Thanks for the information. Using two MI instances, with each instance pointing to a different sound card (for this particular case, it is done through Device Channel Selection), should allow you to change the sampling rate independently even if the two sound cards uses the same ASIO driver.

If only one MI instance is used, then your method - ADC using the original ASIO driver, DAC using ASIO4ALl, or the other way should also work.
VirtinsTech
Site Admin
 
Posts: 149
Joined: Tue Oct 01, 2013 3:06 pm

Re: ADC and DAC at different sampling frequency

Postby RJA4000 » Wed Oct 02, 2019 4:56 pm

Thanks
ASIO4ALL is also not very "stable" in its behaviour.
That's not a Multi Instrument issue there, though.
Best option will probably be 2 instances... with automation :-)
RJA4000
 
Posts: 32
Joined: Sun Jul 28, 2019 2:28 am


Return to Questions

Who is online

Users browsing this forum: No registered users and 1 guest

cron