EP0212839A1
Expired / Lapsed
EP
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Ghost cancelling reference signal transmission/reception system
Assignee: Panasonic Holdings Corp
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Filing: 1986-07-14
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Granted: —
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Expires: 2006-07-14
Abstract
Abstract A ghost cancelling reference signal transmission/reception system allows a built-in ghost cancelling device to totally eliminate group-delay distortion, frequency-amplitude characteristic distortion, ghost components and the like generated in a television signal transmission path. A digital signal generated in a digital signal generation circuit (15) is superposed on a television signal by a signal superposition circuit (12) in a vertical blanking period of the television signal as a ghost cancelling reference signal. On reception, a ghost cancelling device (14) responsive to the superposed digital signal cancels group delay distortion, frequency-amplitude characteristic distortion, and ghost distortion resulting from the television signal transmission path (13).
Inventors
- 👤 Kazuo Kobo
- 👤 Kiyotake Fukui
- 👤 Toshiro Nozoe
- 👤 Noriaki Morotomi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 16:14
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/14; H04N5/21; H04N5/211; H04N7/00; H04N7/025; H04N7/035
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
89 words
A ghost cancelling reference signal transmission/reception system comprising: means for generating a digital signal; means for superposing said digital signal on a television signal in a vertical blanking interval of the television signal; transmission means for transmitting said television signal containing said superposed digital signal; and ghost cancelling means that eliminates group-delay distortion, frequency-amplitude characteristic distortion and ghost generated in said transmission means from the television signal transmitted through said transmission means, said ghost cancelling means using said digital signal superposed on said television signal as a reference signal.
Claim 2
Dependent Claim
89 words
A ghost cancelling reference signal transmission/reception system comprising: means for generating a digital signal; means for superposing said digital signal on a television signal in a vertical blanking interval of the television signal; transmission means for transmitting said television signal containing said superposed digital signal; and ghost cancelling means that eliminates group-delay distortion, frequency-amplitude characteristic distortion and ghost generated in said transmission means from the television signal transmitted through said transmission means, said ghost cancelling means using said digital signal superposed on said television signal as a reference signal.
Claim 3
Dependent Claim
18 words
The system as claimed in claim 1, wherein said digital signal contains an information needed for transmitting data.
Claim 4
Dependent Claim
20 words
The system as claimed in claim 1, wherein said digital signal is a random signal or a pseudo random signal.
Claim 5
Dependent Claim
26 words
The system as claimed in claim 1, wherein said digital signal is a combined signal of a random or pseudo random signal and a data signal.
Claim 6
Dependent Claim
23 words
The system as claimed in claim 1, wherein said digital signal is composed of frame synchronizing signals, clock synchronizing signals, and data signals.
Claim 7
Dependent Claim
26 words
The system as claimed in claim 1, wherein transmission bit rate of said digital signal is at least twice the video band of the television signal.
Claim 8
Dependent Claim
26 words
The system as claimed in claim 1, wherein transmission bit rate of said digital is at least twice the color subcarrier frequency of the television signal.
Claim 9
Dependent Claim
37 words
The system as claimed in claim 1, wherein said digital signal is composed of first and second digital signals which are alternately superposed on the television signal every n fields (n: interger) in the vertical blanking period.
Claim 10
Dependent Claim
38 words
The system as claimed in claim 1, wherein said digital signal is composed of first and second digital signals which are alternately superposed on the television signal every n horizontal periods (n: interger) in the vertical blanking period.
Claim 11
Dependent Claim
35 words
The system as claimed in claim 1, wherein said digital signal is composed of first and second digital signals which are superposed on the television signal in each horizontal period in the vertical blanking period.
Claim 12
Dependent Claim
42 words
The system as claimed in claim 1, wherein said digital signal is composed of a first signal which is an arbitrary digital signal and a second signal which is a fixed signal which will become a bar signal when modulated for transmission.
Claim 13
Dependent Claim
60 words
The system as claimed in claim 1, wherein said ghost cancelling means comprises: delay means for delaying an input television signal; waveform equalizing means for equalizing the waveform of the delayed television signal; memory means for storing the input and output signals of said waveform equalizing means; and means for controlling said delay means, waveform equalizing means and memory means.
References Cited (Backward Citations)
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