Method of Weak Communication Signal Detection and Signal Quality Assessment at Low SNR

[Purpose] Aiming at the problem that the quality of weak communication signals with low SNR is challenging to be detected by spectrum analysis, the detection and evaluation methods of low SNR communication signals are studied. [Method] The receiving end amplifies and demodulates the low-frequency weak signal by transmitting a specific pseudo-random signal or a normal synchronous head. After demodulation of the communication signal, the correlation calculation with the restored pseudo-random coded signal is carried out, and the amplitude of the weak communication signal is detected. The amplitude of noise contained in the signal is calculated further, and the signal-to-noise ratio is obtained by comparing the signal and noise. Signal-to-noise ratio as the basis of communication signal evaluation. [Results] The signal detection and signal quality evaluation of -10dB signal-to-noise ratio were realized under 500Hz bandwidth. [Conclusion] It can realize the signal quality discrimination without affecting the communication and can grasp the communication signal quality in real-time.