Title:
SPEECH SIGNAL SUPPRESSING CIRCUIT FOR TELEPHONE SET
Document Type and Number:
Japanese Patent JPS59135961
Kind Code:
A
Abstract:
The invention relates to a circuit for a telephone set. In order to eliminate the mouthpiece signal between the receiver and the telephone set, there are provided a subtraction means receiving the mouthpiece signal and the composite signal present on the telephone line, one of the two being produced by different compensation impedances, and on the other hand a mixer controlled by a circuit as a function of the telephone line impedance. The two compensation impedances respectively correspond to the compensation of a long line and the compensation of a short line and the output of the mixer supplies a signal mixture, with variable proportions, which effectively suppresses the mouthpiece signal, no matter what the length of the telephone line.
Inventors:
JIYANNKUROODO KEERU
Application Number:
JP25224183A
Publication Date:
August 04, 1984
Filing Date:
December 28, 1983
Export Citation:
Assignee:
THOMSON CSF
International Classes:
H04M1/60; H04M1/58; H04M1/76; (IPC1-7): H04M1/60; H04M1/76
Domestic Patent References:
| JPS53105105A | 1978-09-13 | |||
| JPS5391509A | 1978-08-11 |
Attorney, Agent or Firm:
Takashi Koshiba