一种短时突发PSK信号的自适应解调方法

Demodulation Algorithm of Short-Term Sudden PSK Signal

短时突发相移键控(PSK)通信具有隐蔽性好、信道利用率高的特点,得到广泛应用。将已调信号非线性放大、限幅处理,使其幅度稳定在一定范围,基于锁相原理得到与已调信号同步的本地载波,是PSK信号解调相干载波恢复的常用方法。然而接收信号的非线性处理,会使PSK信号信噪比急剧下降,影响载波相位跟踪精度,给帧同步信号生成和码元抽取带来不确定性,导致误码率升高。针对常规方法存在的问题,提出了基于Hilbert变换的短时PSK信号自适应解调算法,通过信号归一化,在不降低解调信号信噪比情况下,确保载波恢复运算不受数据信号幅度的影响,具有恢复速度快、跟踪精度高、帧同步信号解调可靠、码元采样时间准确的特点。

Short-term sudden Phase Shift Keying(PSK)communication has the characteristics of good concealment and high channel utilization,which is widely used in military and civilian fields.By amplifying and limiting the modulation signal to stabilize its amplitude in a certain range,basing on the principle of phase-locked loop to obtain the local carrier synchronized with the PSK signal is the most commonly used carrier recovery method.However,nonlinear processing of the received PSK signal will cause a sharp decline in signal-to noise ratio of modulation signal,resulting in an increase in bit error rate.It affects the carrier phase tracking accuracy,brings uncertainty to frame synchronization signal generation and code element calculation uncertain.In response to the problems of this method,based Hilbert transformation,an adaptive PSK signal demodulation method is proposed to ensure that the carrier recovery operation is not affected by data signal amplitude.The method does not reduce signal-to-noise ratio of PSK signal.Compared with traditional method,the algorithm can adaptive adjust the signal amplitude and has the advantages of rapidly carrier wave tracking,reliable frame synchronization demodulation and accurate of code element sampling.