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.
stmdsp/gui/templates/5_fir_differentiator.cpp

31 lines
939 B
C++

/**
* 5_fir_differentiator.cpp
* Written by Clyne Sullivan.
*
* Does an FIR differentiation on the incoming signal, so that the output is representative of the
* rate of change of the input.
* A scaling factor is applied so that the output's form is more clearly visible.
*/
adcsample_t *process_data(adcsample_t *samples, unsigned int size)
{
constexpr int scaling_factor = 4;
static adcsample_t output[SIZE];
static adcsample_t prev = 2048;
// Compute the first output value using the saved sample.
output[0] = 2048 + ((samples[0] - prev) * scaling_factor);
for (unsigned int i = 1; i < size; i++) {
// Take the rate of change and scale it.
// 2048 is added as the output should be centered in the voltage range.
output[i] = 2048 + ((samples[i] - samples[i - 1]) * scaling_factor);
}
// Save the last sample for the next iteration.
prev = samples[size - 1];
return output;
}