Jump to content
  • 0

Waveforms API relevant to oversampling


Yasuo

Question

Hi,

I have a question about Waveforms 3 API relevant to the oversampling functionality implemented in Analog Discovery 2.

Recently, I am trying to implement the oversampling functionality for my custom-coded software (written in C#) using Waveforms 3 APIs (3.12.2). Based on the reference manual in the SDK, I think that the relevant APIs are “FDwfAnalogInAcquisitionModeSet”, “FDwfAnalogInSamplingDelaySet”, and/or “FDwfAnalogInTriggerPositionSet”. I also found the (seemingly) relevant constants for the first function as follows: “acqmodeOvers = 4” or “acqmodeSingle1 = 5” in “dwf.cs” and “dwf.h”.

I am now wondering if acqmodeOvers = 4 should be used for the FDwfAnalogInAcquisitionModeSet function; and the FDwfAnalogInSamplingDelaySet is the function (not FDwfAnalogInTriggerPositionSet). I am afraid that I do not understand what the “sampling source” exactly does in the FDwfAnalogInSamplingDelaySet, DwfAnalogInSamplingSlopeSet, and FDwfAnalogInSamplingSourceSet functions. If anyone can tell me the detail (or indicate some documentation), I appreciate it!

Thank you in advance,
Yasuo

Link to comment
Share on other sites

2 answers to this question

Recommended Posts

Hi @Yasuo

For equivalent time oversampling you can perform multiple captures and combine these based on timing.
The WF application uses the following methods to identify the timing of the individual captures: FFT phase or FDwfAnalogInTriggerPositionStatus which returns the trigger position based on interpolation of the triggering and the previous sample.

For Analog Discovery the acqmodeOvers is the same as acqmodeSingle.

The FDwfAnalogInSamplingDelay/Slope/Source are for external clocking:

image.png.d0f3e8ca3f867874a8cea92bad32e056.png

Link to comment
Share on other sites

Hi Attila,

Thank you for the quick reply and sorry for the late my response.

According to your comment, I have tested FDwfAnalogInTriggerPositionStatus in my application. The function after a series of successive triggerings returned values as follows:

5.13393e-08
5.40841e-08
5.35999e-08
5.09805e-08
5.38568e-08
5.9583e-08
5.30252e-08
5.70766e-08
5.58465e-08
5.54824e-08
...

The unit is second so that these values indicate that I can sieve these waveforms into equally spaced time-intervals (e.g., 1 ns by 1 ns) and, eventually, acquire a waveform in systematic sampling, as long as the triggering is reliable enough.

Thank you,
Yasuo

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...