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Article Example for FIR Decimation and Interpolation Sampling using ADSP-21569

Multi-rate filters change the sampling rate of a signal—they convert the input samples of a signal to a different set of
data that represents the same signal sampled at a different rate.

Decimation:
A decimation filter provides a single output result for every M input samples, where M is the decimation ratio. The
output rate is 1/M’th of the input rate. The filter implementation exploits the low output sample rate by not starting a computation until a new set of M input samples is available.

Interpolation:
An interpolator filter provides L output results for each new input sample,
where L is the interpolation ratio. Note that the output rate is L times the
input rate.

Attached example demonstrates how to use FIR Accelerator Driver in Legacy Mode. One FIR task is created with two channels.
First channel has taps/window of 256/1024 with Interpolation sampling.
Second channel have taps/window of 1024/128 with Decimation sampling.

The Outputs obtained are compared with the MATLAB generated output .dat files : - decimatedoutput128.dat, expectedinterpoutput2048.datFIR_Inter_Deci_21569.zip

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