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How can a module handle cases where the number of output samples differs from the number of input samples?

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Tue, 10/14/2025
4:56am
sone.yoshikatsu...
#1
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How can a module handle cases where the number of output samples differs from the number of input samples?

Hello DSPC Team,

I’m developing a custom module, and I’d like it to output twice as many samples as the number obtained from ClassWire_GetNumSamples().

For example, if ClassWire_GetNumSamples() returns 128, I want the output pin to produce 256 samples.

Is it possible to do this in a custom module?

Tue, 10/14/2025
6:42pm
DSPC_Gary
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Hi Sone-san,

Try something like this in your module's MATLAB file's prebuild function.  This is extracted from the BufferUp module.

    inBlockSize = SYS.inputPin{1}.type.blockSize;

    outBlockSize = inBlockSize * bufferUpFactor;

    SYS.(outName).outputPin{1}.type.blockSize = outBlockSize;

Let me know if this helps.

Thanks,

Gary 

 

 

Thu, 10/16/2025
4:16am
sone.yoshikatsu...
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Hello DSPC_Gary,

OK, thank you for showing me how to implement it. I really appreciate your help.

Fri, 10/31/2025
12:39am
sone.yoshikatsu...
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Hello DSPC Team,
I tried your suggestion, but it didn’t work as expected.

There seems to be a specific condition:

  • When an inputPin is configured, the outputPin’s blockSize always matches the inputPin’s blockSize.

  • When there is no inputPin (output only), it works correctly.

Is there any additional setting or step required to make it work when an input pin is present?

I’ve attached the MATLAB file I used for testing for your reference.

I would appreciate any further advice.

Binary Data test_output_sample_module.m
Fri, 10/31/2025
11:24am
DSPC_Gary
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Hi,

Please see "C:\DSP Concepts\AWE Designer 8.2025.2.A Pro\AWEModules\Source\Examples\matlab\downsampler_example_module.m" for an example.  You should have a prebuild function in your module's MATLAB script.

M.name=NAME;

M.preBuildFunc=@downsampler_example_prebuild_func;

and further down...

% ----------------------------------------------------------------------

% Prebuild function.  The main purpose is to determine the pin type

% of the output pin.  The function also checks that the output

% pin has an integer number of samples.

% ----------------------------------------------------------------------

 

function M=downsampler_example_prebuild_func(M)

 

blockSize=M.inputPin{1}.type.blockSize;

 

if (rem(blockSize, M.D) ~= 0)

    warning('The downsample factor D does not evenly divide the blockSize');

    newBlockSize=floor(blockSize/M.D);

else

    newBlockSize=blockSize/M.D;

end

Thanks,

Gary