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31 lines
800 B
C++
31 lines
800 B
C++
1 year ago
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/**
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* 7_iir_echo.cpp
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* Written by Clyne Sullivan.
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*
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* This filter produces an echo of the given input. There are two parameters:
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* alpha controls the feedback gain, and D controls the echo/delay length.
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*/
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Sample* process_data(Samples samples)
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{
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constexpr float alpha = 0.75;
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constexpr unsigned int D = 100;
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static Samples output;
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static Sample prev[D]; // prev[0] = output[0 - D]
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// Do calculations with previous output
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for (unsigned int i = 0; i < D; i++)
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output[i] = samples[i] + alpha * (prev[i] - 2048);
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// Do calculations with current samples
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for (unsigned int i = D; i < SIZE; i++)
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output[i] = samples[i] + alpha * (output[i - D] - 2048);
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// Save outputs for next computation
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for (unsigned int i = 0; i < D; i++)
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prev[i] = output[SIZE - (D - i)];
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return output;
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}
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