Comb Filtering

[Xiao Z]

Hi Simon,

I’m still confused how comb filtering works. Does it automatically shift the interval of two notches to find the lowest total energy?

[Simon]

Yes, that’s basically right. The filter is ‘swept’ across a range of frequencies – i.e., hypothesised values for F0. The notches are at multiples of the hypothesised value of F0, and so when the filter is set for the correct value of F0, they will align with the harmonics and remove the maximum amount of energy.

This is an old-fashioned method, and was included in the video to illustrate that there are often several possible solutions to any problem in signal processing.

[Author]

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