Frequency translation using variable delay

It is shown how, using clocked delay systems, it is possible to translate the frequency of an applied periodic voltage. The translation can represent an increase or a decrease in frequency. Moreover, the amount of the translation can itself be made to change with time. A clocked delay system is constructed in a straight-forward manner using shift registers. The theory is tested using clock rates that change linearly with time and using clock rates that provide a linear time variation of delay. The resulting frequency translation is measured for sinusoidal, triangular and square wave inputs. The results are in good agreement with the theory