一种新的MPPSK调制解调器实现结构

New scheme of MPPSK modem

为了简化多元位置相移键控(MPPSK)接收机的结构并提升其解调性能,给出了一种MPPSK调制器的实现结构,并提出了一种全新的基于冲击滤波多路判决的MPPSK解调器实现结构.该解调器结构先对冲击滤波器的输出信号取绝对值并进行低通滤波处理,再将得到的冲击包络通过由不同位同步信息控制的抽样判决器,将判决结果叠加,即可得到最终的符号序列.仿真结果表明,与基于锁相环的解调器结构相比,该解调器的结构更简单,解调性能更好.随着进制数的增大,MPPSK调制信号功率谱的边带线谱逐渐降低甚至消失,从而紧缩了信号功率谱,降低了邻道干扰,提高了频谱利用率.因此,在加性高斯白噪声信道条件下,该实现结构具有较强的应用优势.

In order to simplify the structure of the M-ary phase position shift keying （MPPSK） re- ceiver and enhance the demodulation performance, an implementation scheme of the MPPSK modu- lator is proposed, and a novel scheme of the MPPSK demodulator which uses the multi-path discrim- ination based on the output of impacting filter is put forward. Firstly, for the output of the impactingfilter, the absolute value is taken and the low-pass filtering is done. Secondly, the output envelope of the low-pass filter is put into sample discriminators controlled by different bit synchronization. Fi- nally, the discriminator results are added and the final symbol sequence is obtained. The simulation results indicate that this scheme is simpler and the demodulation performance is better than that basedon phase locked loop. With the increase of the hexadecimal number, the line spectrum components in the power spectrum of the MPPSK modulated signal become lower and even disappear, which tightens the power spectrum of the MPPSK modulated signal, reduces the adjacent-channel interfer- ence and improves the frequency spectrum utilization. Therefore, this implementation structure has astrong application advantage in the additive white Gaussian noise channel.