METHOD FOR VOICE SIGNAL SECRECY AND SECRET COMMUNICATION SYSTEM

摘要

PROBLEM TO BE SOLVED: To realize an encoding method with a high compression rate which corresponds to the input and output of a digital signal and an analog signal and can sufficiently exhibit its function even to a low quality analog recording medium and transmitting medium in particular.;SOLUTION: A voice encoding processing part 3, a bit string reduction and mapping processing part 4, and a modulating part 5 uses a parameter for each secret key inputted by a secret key setting part 1 to make a voice signal quantized by an A/D converting part 2 of an encoding part secret. An analog signal made into secret outputted by a D/A converting part 6 does not have the original voice waveform any more. In the case of decoding the voice signal, an A/D converting part 8, a demodulating part 9, a voice decoding part 10, and a bit string restoration processing part 11 restore the voice signal in this order on the basis of the secret key inputted from a secret key setting part 7. In addition, when residual noise is present, a residual noise estimating and noise suppressing part 12 enhances voice, and an analog voice signal is outputted from a D/A converting part 13.;COPYRIGHT: (C)2006,JPO&NCIPI