Abstract: A signal detection system, which consists of a Frequency-Stepping signal generator and a corresponding Post-Detdcted-Matching-Processor, was studied both theoretically and experimentally. The characteristic function determining the detection performance of FS-PDMP system was derived and analysed, and a set of equipment, which can generate and process an 8-unit long signal with various FS modes n （T = 8τ = 200ms, f_n=1360 + nx40 Hz）, was made for the experimental studies. Some results are as follow: 1) The output waveforms of PDMP matched with many FS modes were recorded. It has been shown that the output with narrow mainlobe (the duration =τ) and a few sidelobes (the level ﹤p/8, p is the peak of mainlobe) can be obtained from PDMP with the FS modes composed of 8 different frequencies and that if there are two or more same frequencies in the FS modes, either the mainlobe will widen or the sidelobe level will increase, or even both.
2) The response of the FS-PDMP system to Doppler frequency β was investigated. For mode 01234567, the output of PDMP gradually reduces from p to p/8 with the variation of β from 0 to ±280 Hz, and the time of output appearance correspondingly changes from 0 to ±7τ. For both modes 75310246 and 05274163, when β varies from 0 to ±40 Hz, the reduction of the mainlobe of PDMP output is very fast, and no notable sidelobe appears for the former while there are two remarkable ones for the latter.
3) The detection threshold of the FS-PDMP system is about -8dB lower than that of a single unit envelope detector. The above results are in conformity with the theoretical analysis.