I have an LTI filter that I want to treat like a black box. It has a latency of 24 samples.
This is what I'm doing (which works for a filter with no latency):
- Send unit impulse through my filter
- Capture first 16,384 samples output
- Perform FFT
- For each of first 8192 complex values, take phase
Doing the above gives the red line shown below.
If I replace step 2 with:
- Skip first 24 samples and then capture first 16,384 samples output
Then I get the blue line shown below.
The green line represents the actual phase of the signal.
Bode plot of phase vs log frequency (10Hz to 20kHz)