DIGITAL FILTER CIRCUIT, DIGITAL-FILTER APPLICATION METHOD, AND STORAGE MEDIUM CONTAINING DIGITAL-FILTER APPLICATION PROGRAM

摘要

The present invention reduces the circuit size and power consumption required to apply a digital filter in the frequency domain. This digital filter circuit is provided with the following: a complex-conjugate generation unit that generates a second complex signal containing the complex conjugate of each complex number constituting a first complex signal in the frequency domain, said first complex signal having been generated by performing a Fourier transform on a time-domain complex signal; a filter-coefficient generation unit that generates complex first and second frequency-domain filter coefficients from inputted complex first, second, and third input filter coefficients; a first filter unit that uses the first frequency-domain filter coefficients to apply a filter to the first complex signal, yielding a third complex signal; a second filter unit that uses the second frequency-domain filter coefficients to apply a filter to the second complex signal, yielding a fourth complex signal; and a complex-conjugate combination unit that combines the third and fourth complex signals, yielding a fifth complex signal.