Low-power CSD linear phase FIR filter structure using vertical common sub-expression

A high-speed/low-power canonic signed digit (CSD) linear phase finite impulse response (FIR) filter structure using vertical common sub-expression is proposed. In the conventional linear phase CSD filter, the horizontal common sub-expression method (see Hartley, 1996) has been widely utilised due to the inherent symmetrical filter coefficients. However, use has been made of the fact that the most significant bits of adjacent filter coefficients in the linear phase filter are also equal since they have mostly similar values. Through the example, it is shown that the proposed structure is more efficient in the case where bit precision of implementation is lower