Use of the numerical phase-difference filter for the digital channel bank

The use of the numerical phase-difference filter in the single-sideband modulation scheme for frequency-division multiplexing is investigated and compared with the Weaver-modulator scheme proposed by Freeny et al. A simple algebraic solution to the approximation problem for arbitrary specifications in the stopband is given. The sensitivity of the stopband attenuation is the main problem that precludes the use of RC active structures; it is shown that the digital version can be implemented with a reasonable coefficients wordlength. The structure of the filter is optimised for round-off noise performance. Finally, the two modulation schemes are compared.