JPS57131175A - Video signal clamping circuit - Google Patents

Video signal clamping circuit

Info

Publication number
JPS57131175A
JPS57131175A JP56017333A JP1733381A JPS57131175A JP S57131175 A JPS57131175 A JP S57131175A JP 56017333 A JP56017333 A JP 56017333A JP 1733381 A JP1733381 A JP 1733381A JP S57131175 A JPS57131175 A JP S57131175A
Authority
JP
Japan
Prior art keywords
clamping circuit
clamping
strength
variation
video signal
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
JP56017333A
Other languages
Japanese (ja)
Other versions
JPH021425B2 (en
Inventor
Shunichi Yamamoto
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NEC Corp
Original Assignee
NEC Corp
Nippon Electric Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by NEC Corp, Nippon Electric Co Ltd filed Critical NEC Corp
Priority to JP56017333A priority Critical patent/JPS57131175A/en
Publication of JPS57131175A publication Critical patent/JPS57131175A/en
Publication of JPH021425B2 publication Critical patent/JPH021425B2/ja
Granted legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/14—Picture signal circuitry for video frequency region
    • H04N5/16—Circuitry for reinsertion of dc and slowly varying components of signal; Circuitry for preservation of black or white level
    • H04N5/18—Circuitry for reinsertion of dc and slowly varying components of signal; Circuitry for preservation of black or white level by means of "clamp" circuit operated by switching circuit
    • H04N5/185—Circuitry for reinsertion of dc and slowly varying components of signal; Circuitry for preservation of black or white level by means of "clamp" circuit operated by switching circuit for the black level

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Picture Signal Circuits (AREA)

Abstract

PURPOSE:To obtain a clamping circuit which responds quickly, by removing a variation of a pedestral by a sink chip clamping circuit whose clamping strength is strong, and after that, clamping the burst part by a clamping circuit whose strength is weak. CONSTITUTION:An input video signal (a) clamps a sink chip part a-1 by the timing of its pulse (b) through the first keying and clamping circuit 3 whose strength is strong, consisting of a clamping potential setting electric power source 4 and an electronic switch 11, etc. Subsequently, a burst part (a-2) is clamped by the timing of a pulse (c) of the second keying and clamping circuit 5 which is weak in its clamping strength and small in its response speed, consisting of a DC reproducing capacitor 10, a resistance 9, etc. In this way, a variation of a pedestal at every 1H is suppressed by the first clamping circuit 3, a hum component is removed, and after that, a pedestal variation due to a sink level difference is removed without damaging the burst part by the second clamping circuit, and a clamping circuit which responds quickly is obtained.
JP56017333A 1981-02-06 1981-02-06 Video signal clamping circuit Granted JPS57131175A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP56017333A JPS57131175A (en) 1981-02-06 1981-02-06 Video signal clamping circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP56017333A JPS57131175A (en) 1981-02-06 1981-02-06 Video signal clamping circuit

Publications (2)

Publication Number Publication Date
JPS57131175A true JPS57131175A (en) 1982-08-13
JPH021425B2 JPH021425B2 (en) 1990-01-11

Family

ID=11941123

Family Applications (1)

Application Number Title Priority Date Filing Date
JP56017333A Granted JPS57131175A (en) 1981-02-06 1981-02-06 Video signal clamping circuit

Country Status (1)

Country Link
JP (1) JPS57131175A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60210070A (en) * 1984-04-03 1985-10-22 Hitachi Ltd Video camera
EP0255274A2 (en) * 1986-07-19 1988-02-03 Sony Corporation Gain control circuits
DE4032724A1 (en) * 1989-10-27 1991-05-02 Siemens Ag CIRCUIT ARRANGEMENT BY WHICH A VIDEO SIGNAL CAN BE SWITCHED TO A REFERENCE LEVEL
EP0651565A1 (en) * 1993-11-02 1995-05-03 Nec Corporation Circuit for compensating the drift of the level of the direct current of a video signal

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS579189A (en) * 1980-06-19 1982-01-18 Sanyo Electric Co Ltd Clamp circuit

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS579189A (en) * 1980-06-19 1982-01-18 Sanyo Electric Co Ltd Clamp circuit

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60210070A (en) * 1984-04-03 1985-10-22 Hitachi Ltd Video camera
JPH0553107B2 (en) * 1984-04-03 1993-08-09 Hitachi Ltd
EP0255274A2 (en) * 1986-07-19 1988-02-03 Sony Corporation Gain control circuits
DE4032724A1 (en) * 1989-10-27 1991-05-02 Siemens Ag CIRCUIT ARRANGEMENT BY WHICH A VIDEO SIGNAL CAN BE SWITCHED TO A REFERENCE LEVEL
US5128764A (en) * 1989-10-27 1992-07-07 Siemens Aktiengesellschaft Level correcting circuit having switched stages of differing time constants
EP0651565A1 (en) * 1993-11-02 1995-05-03 Nec Corporation Circuit for compensating the drift of the level of the direct current of a video signal
US5508749A (en) * 1993-11-02 1996-04-16 Nec Corporation Sag compensation circuit for a video signal

Also Published As

Publication number Publication date
JPH021425B2 (en) 1990-01-11

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