GB1271786A - Colour killer circuit for a pal colour-information-signal handling circuit - Google Patents
Colour killer circuit for a pal colour-information-signal handling circuitInfo
- 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
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.
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)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS4936226A (en) * | 1972-08-02 | 1974-04-04 |
-
1969
- 1969-08-21 NL NL6912805A patent/NL6912805A/xx unknown
-
1970
- 1970-08-18 GB GB3973170A patent/GB1271786A/en not_active Expired
- 1970-08-18 DE DE19702040966 patent/DE2040966A1/en active Pending
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 |