Method and apparatus for a finite impulse response filter

Abstract

A finite impulse response filter comprises an input formatter, a plurality of sample registers, a plurality of coefficient registers, an arithmetic unit, a multiply accumulate unit, a crosspoint switch, an interpolator, a control unit, and an output formatter. The input formatter separates the in-phase portion of a complex-number discrete-time sample from the quadrature portion. The sample registers store a plurality of discrete-time samples. The coefficient registers store a plurality of coefficients. The arithmetic unit adds two of the discrete-time samples to create a sum. The multiply accumulate unit includes a multiplier that multiplies the sum by a coefficient to create a product, an adder that adds the product to a sum of products, and a register that stores the sum of products. The crosspoint switch allows communication between the first and second plurality of registers and the arithmetic unit and the multiply accumulate unit. The interpolator inserts a desired number of zeros into the time-sampled data stream to adjust the time-sampled data stream to an increasing sampling rate. The control unit controls the settings of the crosspoint switch, the arithmetic unit, and the multiply accumulate unit. The output formatter combines the in-phase sum of products and the quadrature sum of products to create a filtered complex-number discrete-time sample.