US4307422A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Receiver arrangement
Assignee: Plessey Semiconductors Ltd
•
Filing: 1979-09-13
•
Granted: 1981-12-22
•
Expires: 1999-09-13
Abstract
Abstract This application describes a receiver in which channel selection is controlled by a frequency synthesizer a sweep of available channels is made by a channel selecting arrangement and this sweep is arranged to be stopped when a signal is received. When the sweeping is stopped a fine tuning arrangement takes control to respond to the frequency of the received signal and to compensate for any drift of that signal.
Inventors
- 👤 Tapan K. Das
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 11:37
CPC Classifications
H; H03; H03J; H03J7/00; H03J7/18; H03J7/20; H03J7/22
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
146 words
A receiver comprising a frequency synthesizer controlled channel selection means which includes a controllable oscillator having a frequency and providing an output signal, dividing means including an adjustable divider for dividing the output signal to obtain a divided output signal, a reference signal source for providing a reference signal, a comparator for comparing the reference signal with the divided output signal and for providing a control signal to control the controllable oscillator, fine tuning means for fine tuning the frequency of the controllable oscillator, means for initiating a sweep of available channels by the channel selection means, means for stopping the sweep on reception of a signal by said receiver on one of the available channels, and control means operable on cessation of sweeping and responsive to the frequency of the signal for controlling the fine tuning means to compensate for frequency drift of the signal.
Claim 2
Dependent Claim
146 words
A receiver comprising a frequency synthesizer controlled channel selection means which includes a controllable oscillator having a frequency and providing an output signal, dividing means including an adjustable divider for dividing the output signal to obtain a divided output signal, a reference signal source for providing a reference signal, a comparator for comparing the reference signal with the divided output signal and for providing a control signal to control the controllable oscillator, fine tuning means for fine tuning the frequency of the controllable oscillator, means for initiating a sweep of available channels by the channel selection means, means for stopping the sweep on reception of a signal by said receiver on one of the available channels, and control means operable on cessation of sweeping and responsive to the frequency of the signal for controlling the fine tuning means to compensate for frequency drift of the signal.
Claim 3
Dependent Claim
14 words
A receiver as claimed in claim 1 wherein the receiver is a television receiver.
Claim 4
Dependent Claim
62 words
A receiver as claimed in any one of claims 1 or 2 wherein the control means comprises level detector means for receiving a frequency representative signal having a level which is representative of the frequency of the received signal so as to monitor frequency drift of said received signal, and for providing an output signal when a predetermined frequency drift is detected.
Claim 5
Dependent Claim
45 words
A receiver as claimed in claim 3 wherein two level comparators are provided, each of said two level comparators receiving the frequency representative signal and a respective reference level and providing an output representative of an upward and downward frequency drift, respectively, exceeding predetermined limits.
Claim 6
Dependent Claim
29 words
A receiver as claimed in claim 4 wherein the frequency representative signal is provided by automatic frequency control (A.F.C.) means for automatically controlling the frequency of the received signal.
Claim 7
Dependent Claim
17 words
A receiver as claimed in claim 5 wherein the automatic frequency control means comprises an A.F.C. discriminator.
Claim 8
Dependent Claim
29 words
A receiver as claimed in claim 3 wherein the frequency representative signal is provided by automatic frequency control (A.F.C.) means for automatically controlling the frequency of the received signal.
Claim 9
Dependent Claim
34 words
A receiver as claimed in claim 3 wherein the control means controls the fine tuning means via a signal path which includes blocking means for blocking said signal path until said signal is received.
Claim 10
Dependent Claim
60 words
A receiver as claimed in claim 3 wherein said channel selection means has a control input, and the means for initiating the sweep comprises an operator control coupled to the control input of the channel selection means, and the means for stopping the sweep is operative to isolate the operator control from the control input of the channel selection means.
Claim 11
Dependent Claim
24 words
A receiver as claimed in claim 3 wherein the means for stopping the sweep includes detecting means for detecting the reception of said signal.
Claim 12
Dependent Claim
40 words
A receiver as claimed in claim 10 wherein the detecting means comprises a synch comparator operative to compare video signals with line flyback signals and to provide an output signal having a level indicative of the reception of said signal.
Claim 13
Dependent Claim
34 words
A receiver as claimed in claim 1 wherein the control means controls the fine tuning means via a signal path which includes blocking means for blocking said signal path until said signal is received.
Claim 14
Dependent Claim
35 words
A receiver as claimed in claim 12 wherein the blocking means comprises gate means connected to said signal path and receiving, as a second input, a reception signal indicative of the reception of said signal.
Claim 15
Dependent Claim
60 words
A receiver as claimed in claim 1 wherein said channel selection means has a control input, and the means for initiating the sweep comprises an operator control coupled to the control input of the channel selection means, and the means for stopping the sweep is operative to isolate the operator control from the control input of the channel selector means.
Claim 16
Dependent Claim
30 words
A receiver as claimed in claim 14 wherein the operator control is coupled to the channel selection means via gating means operative for opening on operation of the operator control.
Claim 17
Dependent Claim
32 words
A receiver as claimed in claim 15 wherein the means for stopping the sweep is arranged to provide a blocking signal operative to block the gating means on receipt of said signal.
Claim 18
Dependent Claim
24 words
A receiver as claimed in claim 1 wherein the means for stopping the sweep includes detecting means for detecting the reception of said signal.
Claim 19
Dependent Claim
45 words
A receiver as claimed in any one of claims 2 or 17 wherein the detecting means comprises a synch comparator operative to compare video signals with line flyback signals and to provide an output signal having a level indicative of the reception of said signal.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-12-21 | 1985-06-22 | 1985-12-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-12-21 | 1989-06-22 | 1989-12-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-12-21 | 1993-06-22 | 1993-12-22 | $7700.00 | Window Closed / Lapsed |