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US4370673A
Expired / Lapsed
US
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Signal generator for a color television transmitting system
Assignee: Panasonic Holdings Corp
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Filing: 1980-12-18
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Granted: 1983-01-25
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Expires: 2000-12-18
Abstract
Abstract A signal generator for a color television transmitting system improves the picture quality when color encoded signals are reproduced in the picture displayed by a conventional color television receiver. The system utilizes a primary color level detector, a color-difference level detector, and a luminance signal producer which outputs a luminance signal in response to the difference between the primary color level signal output from the primary color level detector and a color-difference level signal output from the color-difference level detector. The output luminance signal is then utilized in the transmission of a color television signal so that a conventional color television receiver may display a color picture having an improved quality.
Inventors
- 👤 Tetsuo Tomimoto
- 👤 Yoshitomi Nagaoka
- 👤 Reiichi Sasaki
- 👤 Hiroshi Oyama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 10:19
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/64; H04N9/641
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
182 words
A signal generator for a color television transmitting system which has a narrower bandwidth color-difference signal channel than a luminance signal channel, said signal generator comprising: a primary color level detector, which is supplied with primary color signals representative of red, green and blue levels of a picture, for substantially respectively squaring said primary color signals, and for adding said squared signals together, and for outputting a primary color level signal representative of a luminance of a picture; a color-difference level detector, which is supplied with wideband color-difference signals representative of red, green and blue chrominance levels of a picture, for extracting low frequency components of said color-difference signals, and for respectively squaring said low frequency components, and for adding said squared low frequency components together, and for outputting a color-difference level signal representative of a luminance component conveyed by said color-difference signal; a luminance signal producer, which is supplied with said primary color level signal and said color-difference level signal, for outputting a luminance signal in response to the difference between said primary color level signal and said color-difference level signal.
Claim 2
Dependent Claim
182 words
A signal generator for a color television transmitting system which has a narrower bandwidth color-difference signal channel than a luminance signal channel, said signal generator comprising: a primary color level detector, which is supplied with primary color signals representative of red, green and blue levels of a picture, for substantially respectively squaring said primary color signals, and for adding said squared signals together, and for outputting a primary color level signal representative of a luminance of a picture; a color-difference level detector, which is supplied with wideband color-difference signals representative of red, green and blue chrominance levels of a picture, for extracting low frequency components of said color-difference signals, and for respectively squaring said low frequency components, and for adding said squared low frequency components together, and for outputting a color-difference level signal representative of a luminance component conveyed by said color-difference signal; a luminance signal producer, which is supplied with said primary color level signal and said color-difference level signal, for outputting a luminance signal in response to the difference between said primary color level signal and said color-difference level signal.
Claim 3
Dependent Claim
81 words
A signal generator for a color television transmitting system according to claim 1, wherein said luminance signal producer comprises a subtractor which subtracts said color-difference level signal from said primary color level signal to detect a difference signal, and a non-linear circuit which is supplied with said difference signal, said non-linear circuit producing a signal having a level which is substantially equal to a square root of said difference signal level to thereby output said produced signal as said luminance signal.
Claim 4
Dependent Claim
41 words
A signal generator for a color television transmitting system according to claim 1, wherein said luminance signal producer includes a subtractor for outputting as said luminance signal a difference signal between said primary color level signal and said color-difference level signal.
Claim 5
Dependent Claim
57 words
A signal generator for a color television transmitting system according to claim 1, wherein said primary color level detector includes at least one multiplier for generating a squared signal substantially equal to the square of said primary color signal, and a matrix circuit which adds each of said squared signals to generate said primary color level signal.
Claim 6
Dependent Claim
41 words
A signal generator for a color television transmitting system, according to claim 1, wherein said primary color level detector is arranged such that said primary color signals are added in a certain proportion to thereby produce said primary color level signal.
Claim 7
Dependent Claim
57 words
A signal generator for a color television transmitting system according to claim 1, wherein said color-difference level detector includes a low pass filter for removing low frequency components from said wideband color-difference signals, and a square sum circuit for producing a signal substantially equal to the squared sum of the low frequency components of said color-difference signals.
Claim 8
Dependent Claim
66 words
A signal generator for a color television transmitting system according to claim 6, wherein said low pass filter includes a modulator for outputting a phase and amplitude modulated signal by said wideband color-difference signal, a bandpass filter for limiting the bandwidth of said phase and amplitude modulated signal, and a demodulator which demodulates said bandlimited signal to extract the low frequency components from said color-difference signals.
References Cited (Backward Citations)
US3002050A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-01-24 | 1986-07-26 | 1987-01-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-01-24 | 1990-07-26 | 1991-01-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-01-24 | 1994-07-26 | 1995-01-25 | $7700.00 | Window Closed / Lapsed |