甚低频MSK灵敏解调器的设计与实现

Design and Implementation of VLF MSK Sensitive Demodulator

利用单片集成锁相环LM565实现了MSK甚低频信号的灵敏解调,针对用于水下通信信号源MSK信号带宽窄、频偏小的特点,相较于传统的锁相环-电压比较器的解调方法,在传统解调电路上添加直流再生部分,通过峰值保持电路使频偏较小的MSK甚低频信号也能被完整地解调出来;分别设计实现了利用传统与优化解调方法的电路并通过调试得出符合甚低频通信要求的结果;优化后电路将解调灵敏度提高了约300 Hz。

A sensitive demodulation of the VLF MSK signal was achieved by the use of monolithic phase- locked loop LM565. Aimed at the narrow signal bandwidth and small frequency offset of the underwater communication source-MSK, compared with the traditional use of demodulation method of PLL-vohage comparator, a direct regeneration was added on the traditional demodulation circuit, which made the small offset VLF MSK signal completely demodulated into reality by using peak holding circuit. Traditional and optimal demodulation circuit was designed and realized and a result which is conform with the requirement of the VLF communication was obtained by debugging. After optimization, the demodulation circuit sensi- tivity was increased by about 300Hz.