METHOD FOR SIGNAL EXTRACTION WITH FREQUENCY SHIFT KEYING USING SQUARE COMPONENTS AND COMPENSATION OF COMBINATION COMPONENTS

摘要

This invention relates to radio engineering and may find application in communications. The technical result is an increase of the interference immunity of communications. This is achieved by generating a frequency-shift modulated signal (FSK), setting the signal frequency values so that the difference value of any pair of frequencies does not exceed the frequency value for which the difference in the amplitude-frequency characteristic (AFC) of the low-pass filter (LPF) and the bandpass filter (BF) becomes less than a certain value. After multiplying the signal and interference by reference signals (sine and cosine components) in each of the parallel bars (devices), the resulting signal is branched into two identical components. The first component is filtered by a low-pass filter, while the second component is filtered by a band-pass filter. The filter bands are matched with the signal band. Signals that have passed the low-pass filter and a band-pass filter are subtracted from one another. The received signals are converted to digital form. From the values of the quadratures, the spectral density (SP) for each subcarrier is determined proportional to the amplitude of the signals. Find the spectral density (SP) with the maximum value and the threshold value by multiplying this value of the spectral density of the spectral density (SP) by a certain coefficient. Based on the of spectral density values comparing results with a threshold, a conclusion is made about the presence of a signal with an appropriate frequency. The effectiveness of the proposed method in terms of signal / noise power ratio exceeds the efficiency of the prototype method by almost 6.7 times. The signal bandwidth ratio of the proposed method and of the prototype method is 0,1. 2 fig.