A frequency conversion circuit having a plurality of N signal channels, each being fed an input signal and a train of pluses having a period T and a duty cycle T/N. Each channel includes: a sampler coupled the input signal and being responsive to sampling signals; and a controllable time delay for producing the train of sampling signals in response to the train of pulses, the time delay imparting a time delay to the pulses in accordance with a time delay command signal fed to the time delay. Each one of the sampling signals is produced by the time delay in each one of the channels with the period T and the duty cycle T/N with the sampling signals in one of the trains of the sampling signals being delayed with respect to the sampling signals in another one of the trains the sampling signals a time T/N.