Use of the ultrawideband FMCW signal for HF communication radiochannel diagnostics

Ultrawideband frequency modulated continuous wave (FMCW) signals are using for ionospheric sounding by chirp sounders. We can use two techniques of digitizing. The first one is digitizing at intermediate frequency. The second one is digitizing at double maximum frequency of signal. Both of them use uniform sampling. In this paper we propose technique of non uniform sampling of FMCW signal. We describe the usage of FMCW signal in backscatter ionosphere sounding (BS) regimes. The results of BS give us possibility for direct diagnostics of HF radiochannel. We also present results of modeling and interpretation of BS ionograms which were obtained on the base of Institute of Solar-Terrestrial Physics chirpsounder.