The all phase DFT filter

This paper proposes a concept of all phase data space, and, based on the DFT/IDFT filtering a new type of zero-phase filter, called the all phase DFT (APDFT) filter is proposed. The APDFT is a new FIR filter design scheme possessing concurrently the merits of the conventional windowing and the frequency sampling. This paper gives the custom design method of the APDFT filter and demonstrates some of it's good properties. Theoretical analysis and simulation experiment showed that it has the advantage of frequency sampling in the overall filter performance, and can be used to realize strictly and power complementary, sub-band filtering. The APDFT filter can be implemented with common convolution structure, and a direct network in frequency domain as well. This paper gives the architecture of the network and an associate simplified algorithm. This network is not sensitive to the finite word length effect. It can constitute a time-varying system, and be easily integrated into a universal zero-phase digital filter with programmable length and frequency response. The APDFT digital filter can be extensively adopted in digital signal processing applications.