New Realization of DFT Applied to CCITT No. 5 Telephone Signaling System

This paper describes a digital multifrequency signal receiver based on the discrete Fourier transform (DFT) principle. The new lookup table implementation for fast multiplication of an input PCM sample and a kernel sample leads to simple hardware for the operation of 128 time-multiplexed channels of the CCIT No. 5 line signal receiver. Overlap operation and guard logics are also employed to meet the signaling system requirements.