Extension of time-bandwidth product in SAW spectrum analysers

Surface-acoustic-wave (SAW) spectrum analysers use the chirp transform algorithm for real time analysis over wide (MHz) signal bandwidths. This letter reports a new technique for the generation of the long-duration wideband linear frequency modulated (chirp) waveforms used in these analysers. It now permits the overall time bandwidth product of these spectrum analysers to exceed that of the constituent SAW filters, and has consequent application in analysis of communication signals. An externally programmable weighting technique, for optimising time sidelobe suppression is also demonstrated.