A Microwave Correlator

A method is presented for the measurement of auto- or cross-correlation functions of wide-band uhf signals. A novel method of frequency translation is used to obtain a transformation of the spectrum into a more convenient form for computation. This method involves the generation of a line spectrum of local oscillator frequencies throughout the bandwidth of the signal, and subsequent summing of the frequency differences into a narrower band of video signals containing all the coffelative characteristics of the original signal. A theoretical analysis of the operation is presented along with experimental results obtained with this correlator on a 200-mc bandwidth noise signal centered at 1.1 kmc.