Filtering coded waveforms - the effect and correction

Abstract

This paper examines the effect of filtering a coded waveform, and develops methods for correction of errors that the filter introduces. The spectral response of coded waveforms have significant spectral components outside the half power bandwidth, these components are corrupted when filtered by a typical radar receiver. Radar receiver digitisers generally sample such coded waveforms at the same rate as the code, which creates ambiguities in the spectral response and hence complicates correction. This paper analyses the effect that a filter has on coded CW radar waveforms with perfect periodic correlation functions by examination of the resultant sampled response and the correlation function. Techniques to derive simple spectral correction masks are then examined and results are produced for measured and theoretical filter responses.