FOURIER-ANALYSIS OF THE FULL-WAVE RECTIFIED MATCHED-FILTER OUTPUT OF A MODIFIED CHIRP-MATCHED FILTER SPECTRUM ANALYZER FOR ENVELOPE DETECTION

Chirp-matched filters are used for spectral analysis of signals. In a chirp-matched filter spectrum analyzer, the output of the matched filt er contains both the amplitude and phase information of the input sign al. To extract the amplitude information, an envelope detector, which is composed of a full-wave rectifier and a low-pass filter, is used at the matched filter output. However, a proper choice of bandwidth of t he lowpass filter is essential to extract the required amplitude spect rum from the matched filter output correctly. The approximate and the true outputs of the matched filter of a modified chirp-matched filter spectrum analyzer have been full-wave rectified and analyzed, to deter mine what bandwidth should be chosen for the lowpass filter for extrac ting the desired amplitude spectrum. (C) 1997 Elsevier Science B.V.