| 摘要 |
PURPOSE:To achieve encryption of signal, by splitting an audio signal into a plurality of frequency bands and giving different delay to each band. CONSTITUTION:An audio signal from a microphone 1 is given to a tapped delay line 4 via a band pass filter 2 and an amplifier 3, and a split signal with different delay amount is prepared from each tap. The assignment of delay amount is determined to each input of each channel filter bank 6 succeeding to the next stage with a labyrinth (replacement) circuit 5 being a key. The output of the channel filter bank 6 is synthesized into one signal at an addition amplifier 7 and given on a signal carrier. To completely lose understanding, the delay time of frequency band occupied with consonants mainly and the delay time of the frequency band occupied mainly with vowels are separated by several hundred msec. |
