Patent US1799486A successfully refreshed from Google Patents.
Patent US5283653A successfully refreshed from Google Patents.
US5283653A
Expired / Lapsed
US
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Dual HDTV/NTSC receiver using sequentially synthesized HDTV and NTSC co-channel carrier frequencies
Assignee: Zenith Electronics LLC
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Filing: 1992-05-22
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Granted: 1994-02-01
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Expires: 2012-05-22
Abstract
Abstract A dual HDTV/NTSC receiver includes a microprocessor for controlling a tuner for synthesizing the carrier frequencies of HDTV signals and NTSC signals. The HDTV signals are inherently of much lower power than the NTSC signals. The tuner initially synthesizes the carrier frequency of a desired HDTV signal which is attempted to be detected in an narrow band synchronous detector. Detection of the HDTV signal produces a high lock detect signal which causes the microprocessor to enable an HDTV processing channel. If no HDTV signal is detected, the lock detect signal remains low and the microprocessor controls the tuner for synthesizing the carrier frequency of the NTSC co-channel television signal. A high lock detect signal from the narrow band synchronous detector, indicating detection of the NTSC co-channel causes the microprocessor to enable the NTSC processing channel. A system for automatically programming the receiver and memorizing which type signal is present on each television channel is also shown.
Inventors
- 👤 Richard W. Citta
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 15:23
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/44; H04N5/46; H04N11/00; H04N11/24
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
82 words
A method of operating a dual HDTV/NTSC television signal receiver, the HDTV television signals being inherently of lower power than the NTSC signals, comprising: synthesizing the carrier frequency of a desired one of said HDTV signals; and demodulating said one HDTV signal using said synthesized HDTV carrier frequency; if said one HDTV signal is not properly demodulated, then synthesizing the carrier frequency of the NTSC co-channel of said one HDTV signal; and demodulating said NTSC co-channel using the synthesized NTSC co-channel frequency.
Claim 2
Independent Claim
82 words
A method of operating a dual HDTV/NTSC television signal receiver, the HDTV television signals being inherently of lower power than the NTSC signals, comprising: synthesizing the carrier frequency of a desired one of said HDTV signals; and demodulating said one HDTV signal using said synthesized HDTV carrier frequency; if said one HDTV signal is not properly demodulated, then synthesizing the carrier frequency of the NTSC co-channel of said one HDTV signal; and demodulating said NTSC co-channel using the synthesized NTSC co-channel frequency.
Claim 3
Dependent Claim
21 words
The method of claim 1 wherein said demodulating of said one HDTV signal is accomplished with a narrow band synchronous detector.
Claim 4
Dependent Claim
31 words
The method of claim 2 wherein said receiver includes HDTV and NTSC processing channels, and wherein said demodulating of said NTSC co-channel si also accomplished with said narrow band synchronous detector.
Claim 5
Independent Claim
112 words
A method of comprising a dual HDTV/NTSC television receiver, the HDTV signals being inherently of lower power then the NTSC signals, comprising: initially processing a received television signal with a synthesized carrier corresponding to a desired one of said HDTV signals; developing an indicating signal denoting the presence or absence of said one HDTV signal; enabling further processing of said one HDTV signal responsive to said indicating signal denoting the presence of said one HDTV signal; and synthesizing a carrier corresponding to an NTSC co-channel signal of said one HDTV signal and enabling processing of said co-channel NTSC signal responsive to said indicating signal denoting the absence of said one HDTV signal.
Claim 6
Independent Claim
112 words
A method of comprising a dual HDTV/NTSC television receiver, the HDTV signals being inherently of lower power then the NTSC signals, comprising: initially processing a received television signal with a synthesized carrier corresponding to a desired one of said HDTV signals; developing an indicating signal denoting the presence or absence of said one HDTV signal; enabling further processing of said one HDTV signal responsive to said indicating signal denoting the presence of said one HDTV signal; and synthesizing a carrier corresponding to an NTSC co-channel signal of said one HDTV signal and enabling processing of said co-channel NTSC signal responsive to said indicating signal denoting the absence of said one HDTV signal.
Claim 7
Dependent Claim
20 words
The method of claim 4 wherein said indicating signal is produced by the lock-up of a narrow band synchronous detector.
Claim 8
Independent Claim
94 words
The method of automatically programming a receiver capable of receiving either HDTV or NTSX signals in the same television channel, with the HDTV signals being lower in power than the NTSC signals, comprising: for each television channel, initially attempting to detect an HDTV signal in said television channel and, if no HDTV signal is detected, subsequently attempting to detect and NTSC signal in said television channel, using synthesized carrier frequencies for said HDTV signals and said NTSC signals, respectively; and noting in a memory the type of signal detected for each said television channel.
Claim 9
Independent Claim
94 words
The method of automatically programming a receiver capable of receiving either HDTV or NTSX signals in the same television channel, with the HDTV signals being lower in power than the NTSC signals, comprising: for each television channel, initially attempting to detect an HDTV signal in said television channel and, if no HDTV signal is detected, subsequently attempting to detect and NTSC signal in said television channel, using synthesized carrier frequencies for said HDTV signals and said NTSC signals, respectively; and noting in a memory the type of signal detected for each said television channel.
Claim 10
Dependent Claim
157 words
A receiver for selectively receiving HDTV and NTSC television signals in a plurality of television channels, the HDTV signals being inherently lower in power than the NTSC signals, comprising: HDTV signal processing means; NTSC signal processing means; means operable for initially synthesizing the carrier frequency of a desired one of said HDTV signals; means subsequently operable for synthesizing the carrier frequency of an NTSC co-channel signal corresponding to said one HDTV signal; means including a narrow band synchronous detector for detecting said one HDTV signal and said NTSC co-channel signal in response to said initially and subsequently synthesized carrier frequencies, respectively; said narrow band synchronous detector developing a lock detect signal indicative of detection of said one HDTV signal or said NTSC co-channel signal by said narrow band detector; and means for selectively enabling a corresponding one of said HDTV signal processing means and said NTSC signal processing means responsive to development of said lock detect signal.
Claim 11
Dependent Claim
157 words
A receiver for selectively receiving HDTV and NTSC television signals in a plurality of television channels, the HDTV signals being inherently lower in power than the NTSC signals, comprising: HDTV signal processing means; NTSC signal processing means; means operable for initially synthesizing the carrier frequency of a desired one of said HDTV signals; means subsequently operable for synthesizing the carrier frequency of an NTSC co-channel signal corresponding to said one HDTV signal; means including a narrow band synchronous detector for detecting said one HDTV signal and said NTSC co-channel signal in response to said initially and subsequently synthesized carrier frequencies, respectively; said narrow band synchronous detector developing a lock detect signal indicative of detection of said one HDTV signal or said NTSC co-channel signal by said narrow band detector; and means for selectively enabling a corresponding one of said HDTV signal processing means and said NTSC signal processing means responsive to development of said lock detect signal.
Claim 12
Dependent Claim
50 words
The receiver of claim 7, further including microprocessor means for controlling said synthesizing of said carrier frequency signals, said microprocessor means also including said selectively enabling means for providing enable signals to selectively activate said HDTV and said NTSC signal processing means responsive to development of said lock detect signal.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-01-31 | 1997-08-02 | 1998-02-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-01-31 | 2001-08-02 | 2002-02-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-01-31 | 2005-08-02 | 2006-02-01 | $7700.00 | Window Closed / Lapsed |