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US 4,399,326 AGranted
Audio signal processing system
OwnerHarald E. W. Bodeinventor
Life of this patent
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OwnerHarald E. W. Bodeinventor
Estimating the term…
An audio signal processing system for producing a moving comb filter effect having an all pass phase filter or other suitable phase shifting device in a first input branch and a bypass circuit with an optional inverter in a second input branch. A frequency shifter is inserted either into the first or the second input branch. A first summing network is connected to the outputs of the first and second input branch. An optional second summing network is connected to the output of the first input branch and the inverted output of the second input branch. A feedback circuit may be connected between the output of one of the summing networks to the input of the system to enhance the moving comb filter effect. Also, at least one switching circuit may be used to obtain phase reversals in the frequency shifter thereby facilitating up or down detuning or successive up and down detunings of the comb filter frequencies.
An audio signal processing system for producing a moving comb filter effect upon an input audio signal, said system comprising frequency shifter means for shifting audio signals in frequency, such frequency shifts being over a range including frequencies equal and less than one Hz, all pass phase shifter means, at least one summing circuit means for providing at least one output signal, first and second parallel branches for applying said input signal to said summing circuit means, said first branch including said frequency shifter means, said all pass shifter means being connected in one of said first and second branches.
Dependencies are inferred from the claim text.