analog outputs

nick arran

Posted on 23.11.2017 15:32

We are trying to play back a signal we recorded at 200kS/s (on a dewe-43) using the analogue output of a sirius slice.

We can play back the signals that were created using MATH (which are down sampled to 200S/s) but the original 200kS/s signal just won't come out the output.

Is there something limiting the sample rate applied to the sirius' analog output? Do we have to set up the analog outputs to the correct sample rate?

The help files are little help here because they all relate to earlier versions of dewesoft!

nick arran

Posted on 23.11.2017 18:20

Following the above, we recorded signals from 5kHz to 20kHz at 200kS/s. The sirius plays back the signals up to about 10kHz but will not play back higher frequency signals. Ie is this a bandwidth limitation of the playback system rather than a sample rate limitation? Surely the playback hardware should have the same bandwidth as the acquisition hardware.

DEWESoft Support
Technical support
Posted on 24.11.2017 09:33


we have recorded 4 different data files with DEWE-43 with different sample rates (5kHz, 10kHz, 20kHz and 200kHz). The data files were opened on a Sirius slice with firmware version in DEWEsoft X3 release but the analog out worked normally also with 200kHz data file.

Can I ask which version of DEWESoft were you using and what is the firmware version of the Sirius slice?
Could you send us one of the data files which is not replayed correctly on your system so we can check if the problem is in the data file?

nick arran

Posted on 24.11.2017 11:26

I have now set up the complete system on my own desk. Here is the configuration:

Sirius (DO9A7055) with firmware PC running dewesoft X2 SP10 (build 20).

I have tried using dewesoft X3 but it will not let me access the function generator (no license!)

Dewesoft X2 allows the function generator to work, but the sample rate is limited to 20kS/s and the output frequency limited to 7.812kHz ... so it isn't possible to check the bandwidth of the output using the internal signal generator.

So, using real data.

The sirius is attempting to play back data, a section of which is in the attached data file (VAntenna) which contains a pulse of noise at around 65kHz recorded at 200kS/s. note that VAntenna has a -4V DC offset, but we have the same issues trying to playback VAntenna/IIRfilter which is the same signal band-passed filtered to the 64kHz to 67kHz band.

I am monitoring the output of the sirius using a dewe-43A (DB17005773) hardware 2.3, firmware

The dewe-43 is running the same setup as I used to collect the original data, except a) the 20:1 voltage sensor is not between the source and the dewe-43, b) the dewe-43 has a MSI-BR-V-200 module (40V range) instead of the "direct" input used in the original tests. The scale factor for the input is set to 1V/V instead of 20V/V to compensate.

The output of the sirius does contain the 65kHz signal pulse, but it is greatly attenuated. The DC offset is accurately produced (proving the scale factors) but the high frequency data is attenuated from 132mV to 7mV.

This looks like some kind of analogue bandwidth limitation.

Attached files:
nick arran

Posted on 24.11.2017 12:36

... and more. I recorded a frequency sweep from 3kHz to 80kHz, generated by a lab sig gen, on the sirius, then played it back into the dewe-43 (running at 200kS/s).

There is a very steep roll off for frequencies above 32kHz, so for our 60-70kHz application it just won't do! Is there any way to get at the full bandwidth?

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