The Scheme Of HF Digital Systems And Technical Innovation

The performance of HF data transmission systems is badly constrained by the HF channels what are characterized by the rapid time variation and dispersion. This thesis analyzed the error performance of MFSK and MPSK modulator in HF with optimal receiver, studied the shortcoming and strongpoint of several typical short-wave data transmission systems and their performance over fading and intersymbol interference channels. The theory and key technical of adaptive MODEM is discussed. In the last , an efficient modulation scheme - Block Coded Modulation is introduced into HF radio systems to improve the efficiency of HF data transmission, this paper also proposes a HF data transmission system scheme composed of a block coded modulator and a decision feedback type adaptive equalizer.