Signal processing apparatus and method

A method of radar range processing in which the Fourier transform of the received signal is correlated with the complex conjugate of the transmitted signal divided by the power spectrum of the transmitted signal. This method avoids the generation of excessive range cell sidelobes while not requiring an increase in processing which is often necessary in the prior art eg using oversampling. The method utilises a matched filtering technique wherein received signal digitised samples are processed in a super-fast correlator 5 along with a computed version of a single period of the transmitted reference signal 3. Re-sampling at a rate commensurate with the digital input rate 6, which rate can be independent of that rate, allows a time or frequency domain representation of the processed signals to be output The invention may be used to investigate range information from the backscatter of an FMCW radar.