You cannot select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
dsp-paw/gui/examples/7_iir_echo.cpp

31 lines
800 B
C++

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