Patent US 4,125,764

A correlator error detector generates a first repeating digital pseudo noise code signal which is compared in a correlator to a second signal generated by the error detector with the second signal having the same pseudo noise code but with a noise signal intentionally added. The error detector measures the capability of the correlator to correlate the first signal with the second signal under varying noise conditions. Errors produced by the correlator are counted, and classified as being either missed correlation outputs or false correlation outputs.