A digital mixer, part 2

A study was made to determine the characteristic response of D flip-flop digital logic units used as mixing devices for telemetry applications. The D flip-flop is shown to perform the mixing operation under a variety of input frequency conditions. The output signal is a rectangular wave whose long term average frequency is the desired difference frequency. The output signal contains frequency jitter which is a function of the relationship between the two input frequencies. The seriousness of the jitter depends on the application.