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.
31 lines
800 B
C++
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;
|
|
}
|