How to filter a signal that have the same frequency with the noise?

Hi, I add a 8kHz audio wav signal with a 8kHz noise wav signal. Is it possible for me to filter the output by using low-pass, high-pass, or any other FIR filter? How to do it? Thank you.

Answer 1

[Star Strider]

No. You can only filter out signals that are separated in frequency with FIR or IIR filters. So if you have broadband noise, you can filter out some of it but not all of it.

[arina octave]

Thank you, Star Strider. I've fixed the input signal, so I have a 16kHz audio signal with a 22050 Hz white noise. What about filtering this wav file? I guess I can filter this signal by using fdesign.lowpass(SPEC) function. But the problem is I don't really understand about determining the SPEC. Could you help me?

[Star Strider]

My pleasure.

If your audio signal has an upper bandwidth of 16 KHz and you want to filter out everything above that, use a lowpass filter with a cutoff of 16-18 KHz. If you have a narrowband signal centred about 16 KHz, then do a fft of it, and design a bandpass filter that will pass your signal. You have to decide the passband frequencies depending on what information the fft gives you.

The documentation on the fdesign function will tell you more about how to use that function than I ever could. I leave that to you.