Optimization and demodulation method of multiple offset carrier wave amplitude modulation signals

Abstract

The invention provides an optimization and demodulation method of multiple offset carrier wave amplitude modulation signals and aims at providing a method capable of selecting an amplitude modulation signal with a highest carrier-to-noise ratio from the multiple offset carrier wave amplitude modulation signals to carry out correct demodulation and simultaneously restraining other offset carrier wave signals. A technical scheme is characterized by in an offset carrier wave communication system, an analog-digital conversion chip carries out band-pass sampling on an intermediate frequency signal output by a receiver and the signal is converted into a baseband signal after digital down conversion; then, N point FFT and frequency spectrum correction are performed on the baseband signal, and through searching a maximum value of a frequency spectrum amplitude, a frequency offset amount of an optimum carrier wave is determined; and then through a frequency offset correction and low pass filtering method, other out-of-band offset carrier wave amplitude modulation signals are filtered so as to reduce an interference; and finally, amplitude modulation demodulation is performed and a voice signal is recovered. By using the method in the invention, the interference can be reduced and one voice signal with best quality can be correctly demodulated.

Description

technical field [0001] The invention belongs to the communication field, and mainly relates to a civil aviation ground-air very high frequency (VHF) communication system, in particular to a method for optimizing and demodulating multiple offset carrier amplitude modulation signals at a receiving end of an airborne station in the offset carrier communication system. Background technique [0002] In the civil aviation ground-air very high frequency (VHF) communication, the offset carrier communication system is often used to solve the problem of airspace coverage. The offset carrier communication system, also known as the same frequency and different location communication system, sets multiple ground stations with the same working frequency in different geographical locations. When the aircraft enters the covered airspace, the ground control center controls multiple ground stations to transmit signals simultaneously through the wired network, so as to ensure that at least one...

AI Technical Summary

Problems solved by technology

At present, the research on the signal optimization function mainly focuses on the optimization of multi-channel voice signals after demodulation by ground stations. For the optimization and demodulation of multiple offset carrier AM signals received by airborne stations, existing methods Mainly for the case of a single AM ​​signal, it cannot correctly demodulate multiple offset carrier AM signals

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