Patent US4700222A successfully refreshed from Google Patents.
US4700222A
Expired / Lapsed
US
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Apparatus and method of testing the frequency response of a cable television system
Assignee: Heritage Communications Inc
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Filing: 1985-05-30
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Granted: 1987-10-13
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Expires: 2005-05-30
Abstract
Abstract Apparatus and method for testing the frequency response of a cable television system by transmitting a test signal of varying frequency over the system. The test signal is transmitted during the blanking intervals between successive frames or lines of the television pictures and at a level comparable to the level of the video signals which carry the information for the pictures.
Inventors
- 👤 David J. Large
- 👤 William G. Kostka
- 👤 Richard A. Wayman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 05:19
CPC Classifications
H; H04; H04N; H04N7/00; H04N7/10; H04N7/102; H04N17/00
Claims Analysis
Total Claims: 37
Claim 1
Independent Claim
164 words
In apparatus for testing the frequency response of a cable television system in which program signals including video signals for different channels are transmitted in different frequency ranges and pictures for the different channels are displayed in segments with blanking intervals between successive ones of the segments: means for generating a test signal within the frequency range of one of the channels, means for applying the test signal to the cable television system for transmission over the system in one of the blanking intervals between the picture segments such that the test signal does not produce interference which is visible in the display of the picture, a receiver connected to the cable system and having means of limited bandwidth for selectively passing the test signal but not the video signals, and means for monitoring the signal passed by the receiver to determine the response of the cable television system to the test signal without interruption of the video signals for any of the channels.
Claim 2
Dependent Claim
164 words
In apparatus for testing the frequency response of a cable television system in which program signals including video signals for different channels are transmitted in different frequency ranges and pictures for the different channels are displayed in segments with blanking intervals between successive ones of the segments: means for generating a test signal within the frequency range of one of the channels, means for applying the test signal to the cable television system for transmission over the system in one of the blanking intervals between the picture segments such that the test signal does not produce interference which is visible in the display of the picture, a receiver connected to the cable system and having means of limited bandwidth for selectively passing the test signal but not the video signals, and means for monitoring the signal passed by the receiver to determine the response of the cable television system to the test signal without interruption of the video signals for any of the channels.
Claim 3
Dependent Claim
31 words
The apparatus of claim 1 wherein the test signal is applied to the system at a level on the order of the level of the video signals carried by the system.
Claim 4
Dependent Claim
15 words
The apparatus of claim 1 including means for varying the frequency of the test signal.
Claim 5
Dependent Claim
17 words
The apparatus of claim 3 wherein the frequency of the test signal is varied in discrete steps.
Claim 6
Dependent Claim
15 words
The apparatus of claim 3 wherein the frequency of the test signal is varied continuously.
Claim 7
Dependent Claim
38 words
The apparatus of claim 1 wherein the picture is displayed in discrete fields each comprising a plurality of discrete scan lines, and the test signal is transmitted during a blanking interval between successive ones of the picture fields.
Claim 8
Dependent Claim
38 words
The apparatus of claim 1 wherein the picture is displayed in discrete frames each comprising a plurality of discrete scan lines, and the test signal is transmitted during a blanking interval between successive ones of the scan lines.
Claim 9
Dependent Claim
43 words
The apparatus of claim 1 including means for varying the frequency of the test signal, means for tuning the receiver to selectively pass signals of different frequencies, and means for synchronizing the tuning of the receiver with the frequency of the test signal.
Claim 10
Dependent Claim
146 words
In a method for testing the frequency response of a cable television system in which program signals including video signals for different channels are transmitted at different frequencies and pictures for the different channels are displayed in segments with blanking intervals between successive ones of the segments, the steps of: generating a test signal within the frequency range of one of the channels, applying the test signal to the cable television system for transmission over the system in one of the blanking intervals between the picture segments such that the test signal does not produce interference which is visible in the display of the picture, and monitoring the response of the cable television system to the test signal without interruption of any of the video signals by means of a receiver having means of limited bandwidth which passes the test signal but not the video signals.
Claim 11
Dependent Claim
146 words
In a method for testing the frequency response of a cable television system in which program signals including video signals for different channels are transmitted at different frequencies and pictures for the different channels are displayed in segments with blanking intervals between successive ones of the segments, the steps of: generating a test signal within the frequency range of one of the channels, applying the test signal to the cable television system for transmission over the system in one of the blanking intervals between the picture segments such that the test signal does not produce interference which is visible in the display of the picture, and monitoring the response of the cable television system to the test signal without interruption of any of the video signals by means of a receiver having means of limited bandwidth which passes the test signal but not the video signals.
Claim 12
Dependent Claim
31 words
The method of claim 9 wherein the test signal is applied to the system at a level on the order of the level of the video signals carried by the system.
Claim 13
Dependent Claim
16 words
The method of claim 9 including the step of varying the frequency of the test signal.
Claim 14
Dependent Claim
17 words
The method of claim 11 wherein the frequency of the test signal is varied in discrete steps.
Claim 15
Dependent Claim
15 words
The method of claim 11 wherein the frequency of the test signal is varied continuously.
Claim 16
Dependent Claim
38 words
The method of claim 9 wherein the picture is displayed in discrete fields each comprising a plurality of discrete scan lines, and the test signal is transmitted during a blanking interval between successive ones of the picture fields.
Claim 17
Dependent Claim
38 words
The method of claim 9 wherein the picture is displayed in discrete frames each comprising a plurality of discrete scan lines, and the test signal is transmitted during a blanking interval between successive ones of the scan lines.
Claim 18
Dependent Claim
40 words
The method of claim 9 including the steps of varying the frequency of the test signal, tuning the receiver to selectively pass signals of different frequencies, and synchronizing the tuning of the receiver with the frequency of the test signal.
Claim 19
Dependent Claim
102 words
In apparatus for testing the frequency response of a cable television system which carries video signals for pictures displayed in discrete fields each comprising a plurality of discrete scan lines with blanking intervals between successive ones of the scan lines: means for applying a test signal to the cable television system for transmission over the system in one of the blanking intervals between successive ones of the scan lines so that the test signal does not produce interference which is visible in the display of the picture, and means for monitoring the response of the cable television system to the test signal.
Claim 20
Dependent Claim
102 words
In apparatus for testing the frequency response of a cable television system which carries video signals for pictures displayed in discrete fields each comprising a plurality of discrete scan lines with blanking intervals between successive ones of the scan lines: means for applying a test signal to the cable television system for transmission over the system in one of the blanking intervals between successive ones of the scan lines so that the test signal does not produce interference which is visible in the display of the picture, and means for monitoring the response of the cable television system to the test signal.
Claim 21
Dependent Claim
102 words
In a method for testing the frequency response of a cable television system which carries video signals for pictures displayed in discrete frames each comprising a plurality of discrete scan lines with blanking intervals between successive ones of the scan lines, the steps of: applying a test signal to the cable television system for transmission over the system in one of the blanking intervals between successive ones of the scan lines such that the test signal does not produce interference which is visible in the display of the picture, and monitoring the response of the cable television system to the test signal.
Claim 22
Dependent Claim
102 words
In a method for testing the frequency response of a cable television system which carries video signals for pictures displayed in discrete frames each comprising a plurality of discrete scan lines with blanking intervals between successive ones of the scan lines, the steps of: applying a test signal to the cable television system for transmission over the system in one of the blanking intervals between successive ones of the scan lines such that the test signal does not produce interference which is visible in the display of the picture, and monitoring the response of the cable television system to the test signal.
Claim 23
Dependent Claim
149 words
In apparatus for testing the frequency response of a cable television system in which video signals for different channels are transmitted in different frequency bands and pictures for the different channels are displayed in segments with blanking intervals between successive ones of the segments: means for generating a test signal at a frequency which can be varied over the frequency bands for the different channels, means active when the test signal is at a predetermined frequency in one of the bands for monitoring the video signal for the next channel to be tested to obtain a synchronization signal which defines a blanking interval for the next channel, means responsive to the synchronization signal for applying the test signal for the next channel to the cable system only during the blanking interval for the next channel, and means for monitoring the reaction of the cable system to the test signal.
Claim 24
Dependent Claim
149 words
In apparatus for testing the frequency response of a cable television system in which video signals for different channels are transmitted in different frequency bands and pictures for the different channels are displayed in segments with blanking intervals between successive ones of the segments: means for generating a test signal at a frequency which can be varied over the frequency bands for the different channels, means active when the test signal is at a predetermined frequency in one of the bands for monitoring the video signal for the next channel to be tested to obtain a synchronization signal which defines a blanking interval for the next channel, means responsive to the synchronization signal for applying the test signal for the next channel to the cable system only during the blanking interval for the next channel, and means for monitoring the reaction of the cable system to the test signal.
Claim 25
Dependent Claim
18 words
The apparatus of claim 19 including means for varying the frequency of the test signal in discrete steps.
Claim 26
Dependent Claim
16 words
The apparatus of claim 19 including means for varying the frequency of the test signal continuously.
Claim 27
Dependent Claim
33 words
The apparatus of claim 19 wherein the predetermined test signal frequency during which the video signal for the next channel is monitored is the last frequency to be tested in the preceding channel.
Claim 28
Dependent Claim
24 words
The apparatus of claim 19 wherein the test signal is applied to the system at a level on the order of the video signals.
Claim 29
Dependent Claim
41 words
The apparatus of claim 19 wherein the picture for each channel is displayed in discrete fields each comprising a plurality of discrete scan lines, and the test signal is transmitted during a blanking interval between successive ones of the picture fields.
Claim 30
Dependent Claim
41 words
The apparatus of claim 19 wherein the picture for each channel is displayed in discrete frames each comprising a plurality of discrete scan lines, and the test signal is transmitted during a blanking interval between successive ones of the scan lines.
Claim 31
Dependent Claim
135 words
In a method for testing the frequency response of a cable television system in which video signals for different channels are transmitted in different frequency bands and pictures for the different channels are displayed in segments with blanking intervals between successive ones of the segments: generating a test signal at a frequency which can be varied over the frequency bands of the different channels, monitoring the video signal for the next channel to be tested while the test signal is at a predetermined frequency in the preceding channel to obtain a synchronization signal which defines a blanking interval for the next channel, applying the test signal for the next channel to the cable system only during the blanking interval for the next channel, and monitoring the reaction of the cable system to the test signal.
Claim 32
Dependent Claim
135 words
In a method for testing the frequency response of a cable television system in which video signals for different channels are transmitted in different frequency bands and pictures for the different channels are displayed in segments with blanking intervals between successive ones of the segments: generating a test signal at a frequency which can be varied over the frequency bands of the different channels, monitoring the video signal for the next channel to be tested while the test signal is at a predetermined frequency in the preceding channel to obtain a synchronization signal which defines a blanking interval for the next channel, applying the test signal for the next channel to the cable system only during the blanking interval for the next channel, and monitoring the reaction of the cable system to the test signal.
Claim 33
Dependent Claim
31 words
The method of claim 26 wherein the test signal is applied to the system at a level on the order of the level of the video signals carried by the system.
Claim 34
Dependent Claim
17 words
The method of claim 26 wherein the frequency of the test signal is varied in discrete steps.
Claim 35
Dependent Claim
15 words
The method of claim 26 wherein the frequency of the test signal is varied continuously.
Claim 36
Dependent Claim
41 words
The method of claim 26 wherein the picture for each channel is displayed in discrete fields each comprising a plurality of discrete scan lines, and the test signal is transmitted during a blanking interval between successive ones of the picture fields.
Claim 37
Dependent Claim
41 words
The method of claim 26 wherein the picture for each channel is displayed in discrete frames each comprising a plurality of discrete scan lines, and the test signal is transmitted during a blanking interval between successive ones of the scan lines.
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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) | 1990-10-12 | 1991-04-13 | 1991-10-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-10-12 | 1995-04-13 | 1995-10-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-10-12 | 1999-04-13 | 1999-10-13 | $7700.00 | Window Closed / Lapsed |