Novel Linear Phase Condition for Digital Filter

This paper describes a linear phase digital filter with novel linear phase condition. A conventional linear phase digital filter is an FIR filter with coefficients of oddor even –symmetry and whose group delay NTs/2 where N is the number of the FIR filter taps and Ts is the sampling period; its group delay time resolution is Ts/2. We have generalized the linear phase condition, and with our novel linear phase condition, the group delay time resolution can be arbitrary small, and the coefficients are not necessarily oddor even-symmetric. However, ideally the number of the filter taps is infinite, and hence we have to truncate it using a window function for practical use. We present the theory of the new linear phase condition and effects of the truncation. We also compare our digital filter with the fractional delay digital filter.