Title:
NOISE SUPPRESSING CIRCUIT
Document Type and Number:
Japanese Patent JPS62137976
Kind Code:
A
Abstract:
PURPOSE:To make the switching operation visually inconspicuous by providing a time constant circuit and changing the quantity of suppression of picture noise divisionally several times by switching due to a control signal. CONSTITUTION:A time constant circuit 9 outputs a noise suppression characteristic control address E to a fixed storage device 6 in accordance with the control signal inputted from an input terminal 7 and a vertical synchronizing pulse inputted from an input terminal 8. In this case, when the control signal is switched from the high level to the low level or from the low level to the high level, the output control address E is switched stepwise by the circuit 9. Then, the noise suppression characteristic is changed stepwise. That is, two upper bits of a differential signal D from a subtracting circuit 4 are substituted with the address E, and the noise suppression characteristic is switched to a maximum of 4 stages. Thus, the noise suppression characteristic is switched at a slow gradient to make the switching operation of the noise suppression characteristic visually inconspicuous.
Inventors:
SASAI AKIO
Application Number:
JP28009085A
Publication Date:
June 20, 1987
Filing Date:
December 12, 1985
Export Citation:
Assignee:
MITSUBISHI ELECTRIC CORP
International Classes:
H04N5/21; (IPC1-7): H04N5/21
Attorney, Agent or Firm:
Kenichi Hayase