Secret speech equipment

Details Secret speech equipment Secret speech equipment

1988-06-02

1990-09-25

Cangialosi, Salvatore

Cryptography

Communication system using cryptography

Frequency shift or inversion

380 49, H04K 104

Patent

active

049598635

ABSTRACT:
Disclosed is a secret speech equipment for ensuring the secrecy of an analog voice signal, and used in voice communication systems such as an analog telephone and mobile radio. The equipment comprises a sub-band signal generating unit for treating input digital samples as frequency-multiplexed signals of voice spectra, to split the frequency-multiplexed signals into a plurality of frequency bands, and thus obtain sub-band signals of the frequency bands, a sub-band signal permutating unit for permuting the sequence of the sub-band signals, and a sub-band signal multiplexing unit for multiplexing the permutated sub-band signals.

REFERENCES:
patent: 3649915 (1972-03-01), Mildonian, Jr.
patent: 3970790 (1976-07-01), Guanella
patent: 3970791 (1976-07-01), Johnson
patent: 4221931 (1980-09-01), Seiler
patent: 4433211 (1984-02-01), McCalmont et al.
patent: 4443660 (1984-04-01), DeLong
patent: 4525844 (1985-06-01), Scheuermann
patent: 4551580 (1985-11-01), Cox et al.
patent: 4747137 (1988-05-01), Matsunaga
patent: 4792449 (1988-12-01), Virdee et al.
Vaidyanathan, "Quadrature Mirror Filter Banks, M-Band Extensions and Perfect-Reconstruction Techniques", IEEE ASSP Magazine, Jul. 1987.
Cox, "The Design of Uniformly and Nonuniformly Spaced Pseudo-Quadrature Mirror Filters", IEEE Transaction on Acoustics, Speech, and Signal Processing, vol. ASSP-34, No. 5, Oct., 1986.
Cox et al., "The Analog Voice Privacy System", AT&T Technical Journal, 1987.

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