Physics, mathematics, and technology

2021 Issue №2

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Generalized model of a satellite information transmission channel using Nyquist shaping filters



The results of generalized satellite channel model constructing in MathCAD, including the synthesis of a discrete information signal, the im­plementation of a convolutional encoder, a forming Nyquist filter and a BPSK modulator, the synthesis of a discrete additive narrow-band Gaussian noise, the implementation of a BPSK demodulator and a decoder based on the Wit­terby algorithm are presented in this article. As a result of verification of the model, it is shown that in the absence of additive noise, the Nyquist filter eliminates intersymbol interference. The gain in the signal-to-noise ratio (SNR), at which the set value of the bit error rate (BER) is achieved, can be up to 9 dB when the rounding factor of the Nyquist filter is reduced from 0.9 to 0.3.