US4584599A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Signal to noise ratio enhancement using baseband signals in an FM television system
Assignee: Scientific Atlanta LLC
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Filing: 1984-12-19
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Granted: 1986-04-22
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Expires: 2004-12-19
Abstract
Abstract In an FM television signal angle modulated with luminance and chrominance information, there exists a high degree of correlation between picture elements occurring one line period apart. In an effort to steer the pass band of a tunable bandpass filter to the instantaneous frequency of the incoming television signal, a steering signal is developed which utilizes this high degree of correlation. For NTSC systems, luminance information is delayed by one-line period (63.5 us in the U.S.A.) and combined with suitable delayed chrominance information to form the filter's steering signal. For MAC systems, one-line delayed luminance and two-line delayed chrominance information are alternately applied to the filter as its steering signal. By steering the pass band of the filter to the incoming signal, maximum signal will be captured with minimum noise, enhancing the signal-to-noise ratio of a color television system.
Inventors
- 👤 II Joseph G. Mobley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 06:15
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/64; H04N9/646; H04N11/00; H04N11/06; H04N11/08; H04N11/12; H04N11/14; H04N11/146; H04N7/00; H04N7/04; H04N7/045
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
101 words
An apparatus for improving the signal-to-noise ratio of a television signal angle modulated with line and field scanned luminance information, comprising: limiter means receiving the television signal, for limiting the amplitude of the television signal to a predetermined value; a voltage tuned bandpass filter, having a center frequency tunable by a tuning signal, to filter the limited signal from said limiter means; discriminator means for demodulating the filtered signal; feedback means for delivering the demodulated luminance information to said voltage tuned bandpass filter as the tuning signal, said feedback means comprising delay means for delaying the luminance information by one line.
Claim 2
Independent Claim
101 words
An apparatus for improving the signal-to-noise ratio of a television signal angle modulated with line and field scanned luminance information, comprising: limiter means receiving the television signal, for limiting the amplitude of the television signal to a predetermined value; a voltage tuned bandpass filter, having a center frequency tunable by a tuning signal, to filter the limited signal from said limiter means; discriminator means for demodulating the filtered signal; feedback means for delivering the demodulated luminance information to said voltage tuned bandpass filter as the tuning signal, said feedback means comprising delay means for delaying the luminance information by one line.
Claim 3
Dependent Claim
19 words
An apparatus as claimed in claim 1, wherein the tuning signal includes substantially all of the demodulated luminance information.
Claim 4
Dependent Claim
41 words
An apparatus as claimed in claim 1, wherein the television signal is further angle modulated with line and field scanned chrominance information, and wherein said feedback means further comprises means for combining the one-line delayed luminance information with the chrominance information.
Claim 5
Independent Claim
127 words
An apparatus for improving the signal-to-noise ratio of a television signal angle modulated with line and field scanned luminance and chrominance information, comprising: limiter means receiving the television signal, for limiting the amplitude of the television signal to a predetermined value; a voltage tuned bandpass filter, having a center frequency tunable by a tuning signal, to filter the limited signal from said limiter means; discriminator means for demodulating the filtered signal; feedback means, comprising: a first delay means for delaying the luminance information by one-line, a second delay means for delaying the chrominance information by two-lines, and controllable switching means for selectively applying either the one-line delayed luminance information signal or the two-line delayed chrominance information signal to said voltage tuned bandpass filter as the tuning signal.
Claim 6
Independent Claim
127 words
An apparatus for improving the signal-to-noise ratio of a television signal angle modulated with line and field scanned luminance and chrominance information, comprising: limiter means receiving the television signal, for limiting the amplitude of the television signal to a predetermined value; a voltage tuned bandpass filter, having a center frequency tunable by a tuning signal, to filter the limited signal from said limiter means; discriminator means for demodulating the filtered signal; feedback means, comprising: a first delay means for delaying the luminance information by one-line, a second delay means for delaying the chrominance information by two-lines, and controllable switching means for selectively applying either the one-line delayed luminance information signal or the two-line delayed chrominance information signal to said voltage tuned bandpass filter as the tuning signal.
Claim 7
Dependent Claim
23 words
An apparatus as claimed in claim 4, further comprising: means for generating a control signal to be applied to said controllable switching means.
Claim 8
Independent Claim
105 words
A method of tuning a tunable filter, to the instantaneous frequency band occupied by a previous incoming amplitude limited television signal angle modulated with line and field scanned luminance information, by a tuning signal, said method comprising: filtering the limited signal by said tunable filter about a center frequency controllable by the tuning signal; demodulating the filtered signal; delaying the demodulated signal by a period substantially corresponding to one-line period, producing a tuning signal; and applying the tuning signal to said tunable filter so as to adjust said filter's center frequency based on incoming signal's instantaneous center frequency which occurred one-line period prior in time.
Claim 9
Independent Claim
105 words
A method of tuning a tunable filter, to the instantaneous frequency band occupied by a previous incoming amplitude limited television signal angle modulated with line and field scanned luminance information, by a tuning signal, said method comprising: filtering the limited signal by said tunable filter about a center frequency controllable by the tuning signal; demodulating the filtered signal; delaying the demodulated signal by a period substantially corresponding to one-line period, producing a tuning signal; and applying the tuning signal to said tunable filter so as to adjust said filter's center frequency based on incoming signal's instantaneous center frequency which occurred one-line period prior in time.
Claim 10
Independent Claim
137 words
A method of tuning a tunable filter, to the instantaneous frequency band occupied by a previous incoming amplitude limited television signal and demodulated with line and field scanned luminance and chrominance information, by a tuning signal, said method comprising: filtering the limited signal by said tunable filter about a center frequency controllable by the tuning signal; demodulating the filtered signal; delaying the demodulated signal by a period substantially corresponding to one-line period, producing a one-line delayed signal; delaying the one-line delayed signal by a period substantially corresponding to one-line period, producing a two-line delayed signal; alternately applying the one-line delayed signal and the two-line delayed signal to said tunable filter so as to adjust said filter's center frequency based on the incoming signal's instantaneous center frequency which occurred alternately one-line period and two-line periods prior in time.
Claim 11
Independent Claim
137 words
A method of tuning a tunable filter, to the instantaneous frequency band occupied by a previous incoming amplitude limited television signal and demodulated with line and field scanned luminance and chrominance information, by a tuning signal, said method comprising: filtering the limited signal by said tunable filter about a center frequency controllable by the tuning signal; demodulating the filtered signal; delaying the demodulated signal by a period substantially corresponding to one-line period, producing a one-line delayed signal; delaying the one-line delayed signal by a period substantially corresponding to one-line period, producing a two-line delayed signal; alternately applying the one-line delayed signal and the two-line delayed signal to said tunable filter so as to adjust said filter's center frequency based on the incoming signal's instantaneous center frequency which occurred alternately one-line period and two-line periods prior in time.
Claim 12
Independent Claim
80 words
An apparatus for improving the signal-to-noise ratio of a television signal angle modulated with line and field scanned luminance information, comprising: a voltage tuned bandpass filter, having a center frequency tunable by a tuning signal, to filter an amplitude limited signal; discriminator means for demodulating the filtered signal; feedback means for delivering the demodulated luminance information to said voltage tuned bandpass filter as the tuning signal, said feedback means comprising delay means for delaying the luminance information by one line.
Claim 13
Independent Claim
80 words
An apparatus for improving the signal-to-noise ratio of a television signal angle modulated with line and field scanned luminance information, comprising: a voltage tuned bandpass filter, having a center frequency tunable by a tuning signal, to filter an amplitude limited signal; discriminator means for demodulating the filtered signal; feedback means for delivering the demodulated luminance information to said voltage tuned bandpass filter as the tuning signal, said feedback means comprising delay means for delaying the luminance information by one line.
Claim 14
Dependent Claim
19 words
An apparatus as claimed in claim 8, wherein the tuning signal includes substantially all of the demodulated luminance information.
Claim 15
Dependent Claim
41 words
An apparatus as claimed in claim 8, wherein the television signal is further angle modulated with line and field scanned chrominance information, and wherein said feedback means further comprises means for combining the one-line delayed luminance information with the chrominance information.
Claim 16
Independent Claim
106 words
An apparatus for improving the signal-to-noise ratio of a television signal angle modulated with line and field scanned luminance and chrominane information, comprising: a voltage tuned bandpass filter, having a center frequency tunable by a tuning signal, to filter an amplitude limited signal; discriminator means for demodulating the filtered signal; feedback means, comprising: a first delay means for delaying the luminance information by one-line, a second delay means for delaying the chrominance information by two-lines, and controllable switching means for selectively applying either the one-line delayed luminance information signal or the two-line delayed chrominance information signal to said voltage tuned bandpass filter as the tuning signal.
Claim 17
Independent Claim
106 words
An apparatus for improving the signal-to-noise ratio of a television signal angle modulated with line and field scanned luminance and chrominane information, comprising: a voltage tuned bandpass filter, having a center frequency tunable by a tuning signal, to filter an amplitude limited signal; discriminator means for demodulating the filtered signal; feedback means, comprising: a first delay means for delaying the luminance information by one-line, a second delay means for delaying the chrominance information by two-lines, and controllable switching means for selectively applying either the one-line delayed luminance information signal or the two-line delayed chrominance information signal to said voltage tuned bandpass filter as the tuning signal.
Claim 18
Dependent Claim
23 words
An apparatus as claimed in claim 11, further comprising: means for generating a control signal to be applied to said controllable switching means.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1989-04-21 | 1989-10-21 | 1990-04-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-04-21 | 1993-10-21 | 1994-04-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-04-21 | 1997-10-21 | 1998-04-22 | $7700.00 | Window Closed / Lapsed |