SOUND NOISE SUPPRESSING CIRCUIT

PURPOSE:To reduce an adjacent disturbance in a sound FM multiplex system sufficiently for its practical use, by prescribing a compression and expansion ratio of amplitude of a sound signal to be recorded, to an optimum value, in accordance with a level ratio of a desired FM sound signal and a distur...

Full description

Saved in:
Bibliographic Details
Main Authors ITOU SHIGEYUKI, WATAYA YOSHIZUMI
Format Patent
LanguageEnglish
Published 24.11.1982
Subjects
ELECTRIC COMMUNICATION TECHNIQUE
ELECTRICITY
INFORMATION STORAGE
INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORDCARRIER AND TRANSDUCER
PHYSICS
PICTORIAL COMMUNICATION, e.g. TELEVISION
TRANSMISSION
Online AccessGet full text

Cover

More Information
Summary:PURPOSE:To reduce an adjacent disturbance in a sound FM multiplex system sufficiently for its practical use, by prescribing a compression and expansion ratio of amplitude of a sound signal to be recorded, to an optimum value, in accordance with a level ratio of a desired FM sound signal and a disturbance FM sound signal. CONSTITUTION:A sound signal inputted from a terminal 1 passes through a preemphasizing circuit 2, and after that, is inputted to a 2/3 compressing circuit 6 through a switch 3 in case of an SP mode, and on the other hand, is inputted to a 1/2 compressing circuit 4 through a switch 5 in case of an LP mode. Subsequently, an output signal of the circuit 6 or 4 is FM-modulated 9 through a switch 8. Its output is added to an input video signal and is azimuth-recorded on a magnetic tape 12 by a magnetic head 11. Subsequently, a reproduced signal is FM-demodulated 14 through a BPF13, and as for its output, a noise caused by switching the head is processed by prevalue-holding by a holding circuit 16. After that, as for an output signal of the circuit 16, its dynamic range is restored by a 3/2 time expanding circuit 18 and a twice expanding circuit 20, in case of an SP mode and an LP mode, respectively.
Bibliography:Application Number: JP19810073556