| According to practical project requirement, the modulation and demodulation modules of twelve kinds of signals are introduced in this paper in virtue of a new idea of Software Radio, for example, AM~. 55W. FM5 ASKS FSK.. MSK-. P5K.. DPSK..QPSKS QDPSK.. OQPSK and 8PSK.Based on these modules, the interference effects of various signals are presented by a great deal of emulation experiments. A method of correlation coefficients is proposed for estimating the interference effect of analog signals. It is an effective method for measuring signal energy in the case of high noise-to-signal.These demodulation schemes and interference effects have proved to be correct by these experiments on modulated speech signals carrying additive AM modulated noise, such as SSB FM~ BPSK~ DPSK. A kind of estimate function is provided for estimating interference effects and comparing objective intelligibility parameter with subjective intelligibility parameter. At the same time, the research on interference effect about different kinds of modulated noise to the same demodulation method has been done in order to provide reference for the selection of optimal interference mode.
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