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 Title: |
US4263612:
Comb filter equalization circuit
[ Derwent Title ]
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| Country: |
US United States of America
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| Inventor: |
Gibson, Walter G.; Princeton, NJ
Thompson, Roger D.; Lancaster, PA
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| Assignee: |
RCA Corporation, New York, NY
other patents from RCA CORPORATION (466175) (approx. 7,929)
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| Published / Filed: |
1981-04-21
/ 1979-08-01
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| Application Number: |
US1979000062787
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| IPC Code: |
Advanced:
H04N 9/78;
Core:
more...
IPC-7:
H04N 9/535;
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| ECLA Code: |
H04N9/78;
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| U.S. Class: |
Current:
348/665;
348/627;
348/E09.036;
Original:
358/031;
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| Field of Search: |
358/031,27
307/304
357/024
328/166
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| Priority Number: |
| 1979-08-01 |
US1979000062787 |
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| Abstract: |
A comb filter apparatus is provided with means for equalizing the delayed and undelayed signal levels at the inputs to the adding or subtracting matrix, whereby maximum cancellation and reinforcement of the undesired and desired signals is effected. An input signal is coupled to an additive or subtractive matrix by way of an undelayed signal path and a delayed signal path. The delayed and undelayed signals at the inputs to the matrix are each coupled to a detector by way of a bandpass filter, which pass frequencies at which the combing of the signal is most critical. The detectors detect the levels of the input signals and apply the detected levels as two inputs to a difference circuit. The two signal levels are compared in the difference circuit to develop a gain control signal. The gain control signal is utilized to control the gain of a gain controllable stage which is coupled in series with one of the signal paths thereby equalizing the levels of the input signals to the combining matrix.
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| Attorney, Agent or Firm: |
Whitacre, E. M. ;
Meagher, W. H. ;
Yorks, Jr., W. B. ;
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| Primary / Asst. Examiners: |
Murray, Richard;
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| INPADOC Legal Status: |
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| Family: |
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First Claim:
Show all 17 claims |
What is claimed is:
1. A comb filter for separating two frequency interleaved signal components of a television signal comprising:
- a source of video input signals, including two frequency interleaved signal components;
- means having two inputs for combining signals at said inputs to develop a combed output signal;
- first and second signal paths coupled from said input signal source to the inputs of said combining means;
- means, included in one of said signal paths, for delaying the signals in said one path by the scanning time of one horizontal television line;
- a first amplitude detector, having an input coupled to one of the inputs of said combining means, and an output and exhibiting a time constant which is long as compared to a television line scanning interval;
- a second amplitude detector, having an input coupled to the other input of said combining means, and an output and exhibiting a time constant which is long as compared to a television line scanning interval;
- means, having first and second inputs coupled to the outputs of said amplitude detectors, and an output for developing a control signal proportional to the long-term variation in signal amplitudes detected by said amplitude detectors; and
- means, included in one of said signal paths, and responsive to said control signal, for controlling the signal level on said path.
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| Background / Summary: |
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| Drawing Descriptions: |
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| Description: |
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| Forward References: |
Show 11 U.S. patent(s) that reference this one
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