US3568065A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Signal seeking scanning communication receiver with lower gain during scanning
Assignee: Blaupunkt Werke GmbH
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Filing: 1968-07-15
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Granted: 1971-03-02
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Expires: 1988-07-15
Abstract
Abstract The threshold for signals to be selected during scanning is set such that signals will be selected which are just above the noise level of the receiver; during scanning, a gain control circuit regulates the overall gain of the receiver below its normal sensitivity, so that only stronger signals will be selected which, however, after having been selected will be amplified with a higher gain than during the scanning for selection.
Inventors
- 👤 Hubertus Pagany
- 👤 Hans Rasehorn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 07:45
CPC Classifications
H; H03; H03J; H03J7/00; H03J7/18; H03J7/20; H03J7/24; H03J7/26
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
273 words
In a scanning signal seeking communication receiver having: a signal amplifier (6, 7, 3); a tuned circuit including a variable capacity diode (4, 5) included in said amplifier; a sawtooth wave generator (10, 13) connected (16, 20, 21) to the variable capacity diode (4, 5) to supply a variable bias thereto, thereby to change the capacity thereof and thus cause said tuned circuit to scan; control voltage generating means (8) connected to the output of said amplifier to deliver a control voltage representative of signal strength of received signals, as amplified by said amplifier; means interconnecting said sawtooth wave generator and said control voltage generating means, said interconnecting means including means (22) to generate a control signal when said control voltage exceeds a predetermined threshold level and being connected (23, 27, 24) to said sawtooth wave generator to interrupt change in the bias supplied to said variable capacity diode (4, 5) upon generation of said control signal; means (9) connected to said control signal generating means (22) and to said amplifier, and delivering a gain control signal to said amplifier during scanning of said tuned circuit to reduce the gain of the amplifier during scanning only, wherein said amplifier has an amplifier section, switchable between levels of gain upon the application of an appropriate gain control signal to an amplifier control electrode; said means to generate said control signal includes a control transistor (22); and said means delivering a gain control signal includes a connection (9) from the collector of said control transistor (22) to the control electrode of an amplifier element in said amplifier section to supply a gain switching potential thereto.
Claim 2
Dependent Claim
273 words
In a scanning signal seeking communication receiver having: a signal amplifier (6, 7, 3); a tuned circuit including a variable capacity diode (4, 5) included in said amplifier; a sawtooth wave generator (10, 13) connected (16, 20, 21) to the variable capacity diode (4, 5) to supply a variable bias thereto, thereby to change the capacity thereof and thus cause said tuned circuit to scan; control voltage generating means (8) connected to the output of said amplifier to deliver a control voltage representative of signal strength of received signals, as amplified by said amplifier; means interconnecting said sawtooth wave generator and said control voltage generating means, said interconnecting means including means (22) to generate a control signal when said control voltage exceeds a predetermined threshold level and being connected (23, 27, 24) to said sawtooth wave generator to interrupt change in the bias supplied to said variable capacity diode (4, 5) upon generation of said control signal; means (9) connected to said control signal generating means (22) and to said amplifier, and delivering a gain control signal to said amplifier during scanning of said tuned circuit to reduce the gain of the amplifier during scanning only, wherein said amplifier has an amplifier section, switchable between levels of gain upon the application of an appropriate gain control signal to an amplifier control electrode; said means to generate said control signal includes a control transistor (22); and said means delivering a gain control signal includes a connection (9) from the collector of said control transistor (22) to the control electrode of an amplifier element in said amplifier section to supply a gain switching potential thereto.
Claim 3
Dependent Claim
50 words
Receiver according to claim 1, wherein the predetermined level is adjusted to be just above the noise level of the receiver and the control signal generating means are dimensioned to provide a control signal upon receipt of radiated signals by said receiver just exceeding the noise level of the receiver.
Claim 4
Dependent Claim
173 words
Receiver according to claim 1, wherein said control voltage generating means of said receiver is a ratio detector (8); and said interconnecting means includes an input transistor (24) having said control voltage applied thereto, the conduction of said input transistor (24) controlling said sawtooth wave generator (10, 13) and hence the bias applied to said variable-capacity diode (4, 5), said input transistor (24) being connected across the output of said sawtooth wave generator (10, 13) and forming a current bypass upon conduction thereof; a diode (40) biased in forward direction included in said ratio detector (8) to emphasize the output thereof applied to said input transistor (24) whereby change in conduction of said input transistor (24) controlling the sawtooth wave generator (10, 13) will cause change in the bias supplied to said variable-capacity diode (4, 5) and tend to regulate the variable-capacity diode to tune the receiver to the frequency at which said ratio detector will have a maximum control voltage output and whereby said circuit will function as an automatic frequency control.
Claim 5
Dependent Claim
61 words
Receiver according to claim 1, wherein said amplifier has a radio frequency tuned circuit (6) and an oscillator circuit (7) connected thereto: said variable-capacity diode (4, 5) includes a variable-capacity diode element in each of said radio frequency and oscillator circuits, respectively; and both of said diodes (4, 5) being connected in parallel and to said sawtooth wave generator (10, 13).
Claim 6
Dependent Claim
105 words
Receiver according to claim 1, wherein said control signal generating means includes a transistor (22) having a first voltage thereacross during scanning of said receiver and a second voltage thereacross during continued reception of a transmitted signal: the change of voltage level between said first and second voltages forming said gain control signal; and said means delivering said gain control signal comprises a connection (9) between said transistor (22) and said amplifier, and connected to said amplifier attenuating the gain thereof during persistence of said first voltage across said transistor, while permitting full amplification, without attenuation, during persistence of said second voltage across said transistor.
Claim 7
Dependent Claim
16 words
Receiver according to claim 1, wherein said amplifier section is the IF section of the receiver.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-03-01 | 1974-08-31 | 1975-03-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-01 | 1978-08-31 | 1979-03-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-01 | 1982-08-31 | 1983-03-02 | $7700.00 | Window Closed / Lapsed |