Single sampler heterodyne method for wideband frequency measurement

摘要

An input signal of unknown frequency is applied to a sampler which is driven by a sampling signal of frequency fO to produce an intermediate signal of frequency fIF. The sampling frequency fO varies in response to a randomly, or pseudo-randomly varying signal which in turn causes the signal of frequency fIF to also vary. fIF will vary in the same way as fO, but with a scale factor of +/- N, where N is the harmonic number. Correlation techniques are used to determine the harmonic number and the sideband to enable calculation of the input frequency. Errors in the determination of the harmonic number and sideband due to frequency modulation of the input signal are reduced, due to the variation imposed on the sampling frequency fO.