| 摘要 |
PURPOSE:To realize a simple analog signal ciphering system without requiring any filter delay equalizer by superimposing plural frequency signals on an analog signal at each prescribed sampling period sequentially and transmitting the signal and allowing the receiving side to reproduce the original signal by sampling and filtering. CONSTITUTION:A start signal St is added to the head of the analog signal 5-1, the frequency signals f1, f2 and f3 are generated sequentially in synchronization with the start signal St and these frequency signals are superimposed on the analog signal 5-1 and transmitted. The receiving side detects the start signal St, samples a part where no frequency signal is superimposed based on the start signal St and the original signal 5'-1 is reproduced by passing the sampled signal through an LPF. |
