A Novel Implementation of Digital Phase Shifters

A novel technique is presented for implementing a variable digital phase shifter which is capable of realizing noninteger delays. The theory behind the technique is based on the idea of first interpolating the signal to a high sampling rate, then using an integer delay, and finally decimating the signal back to the original sampling rate. Efficient methods for performing these processes are discussed in this paper. In particular, it is shown that the digital phase shifter can be implemented by means of a simple convolution at the sampling rate of the original signal.