Noise immunity of receiving signals with amplitude and phase-shift keying in the presence of phase-shift keying interference
The development of television technologies and the need to transmit high-quality video information requires that modern digital television and broadcasting systems can transmit large amounts of information. The use of signals with multi-position amplitude and phase-shift keying 16-APSK and 32-APSK in DVB-S2 generation satellite television systems made it possible to transmit 30% more data in the same frequency bands compared to the previous DVB-S standard. The latest DVB-S2X digital satellite TV standard is an extension of the DVB-S2 standard and supports modulations of 64,128,256-APSK. It is known that increasing the positionality of signals reduces the noise immunity of their reception and the system as a whole. In addition, the presence of non-fluctuation interference in the radio channel that falls into the frequency band of the useful signal has a strong influence on noise immunity. The article uses statistical radio engineering methods to calculate the probability of a bit error when receiving M-APSK signals against the background of phase-shift keying interference at different parameters of the latter. It is shown that of phase-shift keying interference of even low intensity (µ < 0.3) falling into the main lobe of the signal spectrum significantly reduces the noise immunity of receiving 16-APSK and 32-APSK signals. High-intensity interference (µ ≥ 0.5) practically destroys reception. The influence of phase-shift keying interference decreases with an increase in its detuning relative to the carrier frequency of the useful signal and an increase in the relative transmission rate of the interference. A comparison of the reception quality when using M-PSK, M-QAM and M-APSK signals is carried out and it is shown that the noise immunity of receiving M-QAM and M-APSK against the background of phase-shift keying interference is approximately the same. M-PSK signals are significantly inferior to them in terms of reception noise immunity.