This section contains scenarios and debug hints. If you are facing the same problem, try the solutions here first.
Expected Results:
- Bode Plot shows enough suppression at noise signal frequency.
- Waveform shows clear HIGH and LOW signals, a good example is shown below. (Green: input noise signal, blue: output filtered signal)
- Successfully demodulated messages with a reasonable PSR at 1000 packet counts.
Scenario 1: When Bode Plot cutoff at designed frequency but no message can be demodulated.
Debug routine, possible causes and solutions:
- Check waveform, if signal is still noisy → Suppression level of noise signal is not enough. Consider shift cutoff frequency lower, change filter type, increase order of filter, etc.
- Check waveform, signal is not noisy. Pass clean signal without interference through the filter circuit, demodulate the recorded signal again, successfully demodulated with PSR. → Wanted signal is being suppressed/distorted. Consider shift the cutoff frequency higher and chec