EP0392772A2
Expired / Lapsed
EP
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Sound signal processing system
Assignee: Technicolor USA Inc
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Filing: 1990-04-09
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Granted: —
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Expires: 2010-04-09
Abstract
Abstract In a television signal processing system, the picture signal is detected by a quasi-synchronous detector (60) wherein the picture carrier is amplitude limited (98) and video tank filtered (110) for insertion into the video mixer for deriving the composite video signal. The sound channel comprises a single parallel resonant tuned circuit (80) forming a bandpass filter with a passband centered at the sound carrier frequency. The modulated sound carrier is fed to a sound detector (84) which is also fed the same filtered picture carrier signal provided by the video tank (110) for providing the 4.5 MHz intercarrier sound signal.
Inventors
- 👤 Mark Francis Rumreich
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 03:56
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/14; H04N5/44; H04N5/60; H04N5/62
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
230 words
In a television receiver having a source of intermediate frequency (IF) signal including a picture carrier and a sound carrier modulated with video and audio information respectively, the picture carrier and the sound carrier having a predetermined frequency separation there between, apparatus for processing said signal comprising: IF bandpass filter means (74) for filtering said IF signal to produce a first filtered version of said picture carrier but still modulated by said video information, a video detector means (60) having an input coupled to the IF bandpass filter means (74) and including a video bandpass filter (110) for deriving a second filtered version of the picture carrier relatively free of said video modulation for producing in response to said first and second filtered versions of said picture carrier a detected video signal, a sound bandpass filter means (80) for bandpass filtering the IF signal and deriving the sound carrier modulated with audio information, and characterized by said sound bandpass filter comprising a single parallel resonant circuit, and sound detector means (84) coupled to both the video detector (60) and the sound bandpass filter means (80) for mixing the second filtered version of said picture carrier received from the video detector means (60) and the sound carrier modulated with audio information received from the sound bandpass filter (80), and having an output comprising a sound intercarrier modulated with the audio information.
Claim 2
Dependent Claim
230 words
In a television receiver having a source of intermediate frequency (IF) signal including a picture carrier and a sound carrier modulated with video and audio information respectively, the picture carrier and the sound carrier having a predetermined frequency separation there between, apparatus for processing said signal comprising: IF bandpass filter means (74) for filtering said IF signal to produce a first filtered version of said picture carrier but still modulated by said video information, a video detector means (60) having an input coupled to the IF bandpass filter means (74) and including a video bandpass filter (110) for deriving a second filtered version of the picture carrier relatively free of said video modulation for producing in response to said first and second filtered versions of said picture carrier a detected video signal, a sound bandpass filter means (80) for bandpass filtering the IF signal and deriving the sound carrier modulated with audio information, and characterized by said sound bandpass filter comprising a single parallel resonant circuit, and sound detector means (84) coupled to both the video detector (60) and the sound bandpass filter means (80) for mixing the second filtered version of said picture carrier received from the video detector means (60) and the sound carrier modulated with audio information received from the sound bandpass filter (80), and having an output comprising a sound intercarrier modulated with the audio information.
Claim 3
Dependent Claim
21 words
The television receiver of claim 1 wherein the single parallel resonant circuit of the sound bandpass filter (80) is single tuned.
Claim 4
Dependent Claim
25 words
The television receiver of claim 1 wherein the video bandpass filter (110) consists essentially of a parallel resonant circuit tuned to the picture carrier frequency.
Claim 5
Dependent Claim
27 words
The television receiver of claim 3 wherein the video bandpass filter (110) is common to both the video detector (60) means and the sound detector means (84).
Claim 6
Dependent Claim
17 words
The television receiver of claim 3 wherein the video detector means (60) further comprises a limiter (98).
Claim 7
Dependent Claim
17 words
The television receiver of claim 4 wherein the video detector means (60) further comprises a limiter (98).
Claim 8
Dependent Claim
80 words
The television receiver of claim 1 further comprising a picture gain controllable amplifier (94) for amplifying one of the IF signal and the first filtered version of the picture carrier, a sound gain controllable (82) amplifier for amplifying the sound carrier, and a picture AGC circuit (82) responsive to the detected video signal, the gain of the picture gain controllable amplifier and the gain of the sound gain controllable amplifier (82) both being adjustable by said picture AGC circuit (92).
Claim 9
Dependent Claim
27 words
The television receiver of claim 7 wherein the level of the IF signal fed to the sound bandpass filter is attenuated by a signal attenuation means (78).
Claim 10
Dependent Claim
16 words
The television receiver of claim 8 wherein the signal attenuation means (78) is a coupling capacitor.
References Cited (Backward Citations)
No citation records indexed.
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