Title:
SECRET-SPEECH DEVICE
Document Type and Number:
WIPO Patent Application WO/1983/004151
Kind Code:
A1
Abstract:
This secret-speech device inserts a secret-speech signal into a main signal as a dummy for a predetermined period of time (a period sufficient that the main signal is not affected). This device comprises a circuit (36) for detecting when the level of a main signal (fd) drops below a predetermined value, and an adding circuit (25) for adding the main signal (fd) and a secret-speech signal (fc), thereby preventing any leakage of the secret-speech signal (fc) by stopping the input of the secret-speech signal (fc) to the adding circuit (25) depending on the output of the detection circuit (36).
Inventors:
HAREYAMA NOBUO (JP)
OHSAWA MITSUO (JP)
OHSAWA MITSUO (JP)
Application Number:
PCT/JP1983/000132
Publication Date:
November 24, 1983
Filing Date:
April 28, 1983
Export Citation:
Assignee:
SONY CORP (JP)
International Classes:
H04K1/02; H04K1/10; (IPC1-7): H04K1/02; H04K1/10
Foreign References:
| JPH017687C2 | ||||
| JPH0118767C1 | ||||
| JPS5526741A | 1980-02-26 |
Other References:
See also references of EP 0108151A4
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