GB1271786A - Colour killer circuit for a pal colour-information-signal handling circuit - Google Patents

Colour killer circuit for a pal colour-information-signal handling circuit

Info

Publication number
GB1271786A
GB1271786A GB3973170A GB3973170A GB1271786A GB 1271786 A GB1271786 A GB 1271786A GB 3973170 A GB3973170 A GB 3973170A GB 3973170 A GB3973170 A GB 3973170A GB 1271786 A GB1271786 A GB 1271786A
Authority
GB
United Kingdom
Prior art keywords
signal
amplitude
detector
frequency
colour
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.)
Expired
Application number
GB3973170A
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.)
PHILLIPS ELECTRONIC AND ASSOCI
Original Assignee
PHILLIPS ELECTRONIC AND ASSOCI
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 PHILLIPS ELECTRONIC AND ASSOCI filed Critical PHILLIPS ELECTRONIC AND ASSOCI
Publication of GB1271786A publication Critical patent/GB1271786A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N9/00—Details of colour television systems
    • H04N9/64—Circuits for processing colour signals
    • H04N9/70—Circuits for processing colour signals for colour killing

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Processing Of Color Television Signals (AREA)
  • Color Television Systems (AREA)

Abstract

1,271,786. Colour television. PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd. 18 Aug., 1970 [21 Aug., 1969], No. 39731/70. Heading H4F. A colour killer circuit for a PAL receiver comprises a " swinging " burst signal synchronous detector 49 to which a reference-signal from an active chrominance subcarrier generator 43 is supplied, the output of the detector being fed via a filter 67 which passes a signal having a frequency equal to half the line frequency to a detector circuit 73 which includes a minimumsignal-amplitude detector. The colour killer signal is derived from the detector circuit 73 and supplied to chrominance signal amplifier 15. With monochrome reception harmonics of the line frequency which lie immediately on either side of the chrominance subcarrier generator frequency produce a signal of half line frequency at the output of burst detector 49, which signal is amplitude modulated at a frequency equal to the difference between the generator frequency and the mean frequency of the two harmonics. Thus its amplitude becomes zero twice per period of the amplitude modulation and detection of the minimum amplitude of this amplitude fluctuation indicates that the obtained signal of half line frequency does not originate from a received colour signal but from a monochrome signal, only the presence of a steady signal of half line frequency at the output of the burst detector causing operation of chrominance signal amplifier 15. The detector 73 is so arranged that when the amplitude fluctuations occur the minimum-signal-amplitude appearing at output 75 maintains the chrominance signal amplifier 15 cut off.
GB3973170A 1969-08-21 1970-08-18 Colour killer circuit for a pal colour-information-signal handling circuit Expired GB1271786A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL6912805A NL6912805A (en) 1969-08-21 1969-08-21

Publications (1)

Publication Number Publication Date
GB1271786A true GB1271786A (en) 1972-04-26

Family

ID=19807718

Family Applications (1)

Application Number Title Priority Date Filing Date
GB3973170A Expired GB1271786A (en) 1969-08-21 1970-08-18 Colour killer circuit for a pal colour-information-signal handling circuit

Country Status (3)

Country Link
DE (1) DE2040966A1 (en)
GB (1) GB1271786A (en)
NL (1) NL6912805A (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4936226A (en) * 1972-08-02 1974-04-04

Also Published As

Publication number Publication date
DE2040966A1 (en) 1971-03-04
NL6912805A (en) 1971-02-23

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Legal Events

Date Code Title Description
PS Patent sealed
PLNP Patent lapsed through nonpayment of renewal fees