| 摘要 |
PURPOSE:To make the interpretation of the replacing method difficult, by changing the replacing method in the predetermined order at both reception and transmission sides, in a wiretap prevention where the amplitude of voice signals is replaced with time. CONSTITUTION:A voice signal at a voice signal input terminal 1 is sampled at an amplifier 2 and a low pass filter 3 at the transmission side for each prescribed time, a sampled voltage value is converted into a binary number at a converter 5, led to a common bus 8 via an output line group 6 and a peripheral device adaptor 7 and tentatively stored in a storage device 12. A read only memory 11 is written with instruction words to be sequentially executed with a binary number operation processor 9 and ''pass key'' for transmission and reception, and the binary number in the storage device 12 is read out accordingly through changing timing rate and inputted to a converter 16 via the bus 8 and devices 7, 15 and converted into a voltage value, then sampled at a sampling switch device 17, smoothed at a filter 18 and transmitted as voice signals. The signals are restored at the reception side through the inversion. |
