US3575662A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electronic search-tuning system
Assignee: Meritor Inc
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Filing: 1968-06-21
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Granted: 1971-04-20
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Expires: 1988-06-21
Abstract
Abstract A circuit for use in electronically sweeping the tuning capacitors of a radio receiver through their capacitance range for successively tuning in each station. The sweeping action stops automatically and the value of the tuning capacitors are held constant at each station which is picked up by the radio. The sweep function is restarted to drive the tuner toward the next higher frequency station by means of a manually operated switch. The tuning capacitors comprise voltage variable capacitance diodes which are varied by means of a ramp voltage supplied by a generator. The generator is formed by a PNP transistor which charges a capacitor to provide the ramp voltage, and by a first field effect transistor which controls the base current of the PNP transistor. A silicon controlled rectifier is connected in parallel with the capacitor at the output of the ramp generator to discharge the capacitor after it has reached the peak voltage level required to vary the diode''s capacitance. In the case of an FM radio, said first field effect transistor has its gate electrode coupled for bias control by a ratio detector in the IF strip of the FM receiver. The output of the ratio detector causes the ramp voltage to level off, when a station is tuned in, by establishing the currents in the transistors so that the charging current to the ramp generator capacitor ceases, thereby holding constant the voltage to the tuning diode. In the case of an AM radio, the IF frequency developed in the AM receiver is passed through a series circuit formed by a narrow band filter, an amplifier, and a rectifier, to provide a DC voltage which is applied to the base electrode of the PNP ramp generator transistor. The DC voltage at said base electrode becomes more positive as a station is tuned in, and the PNP transistor decreases its conduction so that the ramp function ceases and the output voltage to the tuning diodes remain constant.
Inventors
- 👤 Elden R Davisson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:52
CPC Classifications
H; H03; H03J; H03J7/00; H03J7/18; H03J7/20; H03J7/24; H03J7/26
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
68 words
An electronic search-tuning system for a receiver assembly comprising, a generator including a capacitor and a charge controlling transistor coupled in series for allowing current flow to charge the capacitor to produce a ramp function, tuning means for the receiving assembly, said tuning means being electrically connected to said generator and being sensitive to tune the receiver through a predetermined frequency range in response to said ramp function.
Claim 2
Dependent Claim
68 words
An electronic search-tuning system for a receiver assembly comprising, a generator including a capacitor and a charge controlling transistor coupled in series for allowing current flow to charge the capacitor to produce a ramp function, tuning means for the receiving assembly, said tuning means being electrically connected to said generator and being sensitive to tune the receiver through a predetermined frequency range in response to said ramp function.
Claim 3
Dependent Claim
61 words
The invention as set forth in claim 1 in which said receiving assembly comprises an FM receiver having an IF amplifier, a ratio detector forming a part of said IF amplifier, and a DC amplifying means connected between the ratio detector output and the ramp generator, said ratio detector output being a DC voltage for controlling current conduction in said generator.
Claim 4
Dependent Claim
37 words
The invention as set forth in claim 2 with the addition of a switch coupled between the DC amplifying means and a point of constant potential for actuation to cutoff the operation of said DC amplifying means.
Claim 5
Dependent Claim
139 words
An electronic search-tuning system for a receiver assembly comprising, a generator having a capacitor and a charge controlling transistor coupled in series for allowing current flow to charge the capacitor to produce a ramp function, reset means for said ramp function generator, said reset means having a potentiometer and a silicon controlled reCtifier connected in parallel with each other and in parallel with said capacitor, the movable arm of said potentiometer being connected to the gate electrode of said silicon controlled rectifier for causing conduction of said silicon controlled rectifier to discharge said capacitor when the voltage across the parallel combination reaches a predetermined level, and tuning means for the receiving assembly, said tuning means being electrically connected to said generator and being sensitive to tune the receiver through a predetermined frequency range in response to said ramp function.
Claim 6
Dependent Claim
139 words
An electronic search-tuning system for a receiver assembly comprising, a generator having a capacitor and a charge controlling transistor coupled in series for allowing current flow to charge the capacitor to produce a ramp function, reset means for said ramp function generator, said reset means having a potentiometer and a silicon controlled reCtifier connected in parallel with each other and in parallel with said capacitor, the movable arm of said potentiometer being connected to the gate electrode of said silicon controlled rectifier for causing conduction of said silicon controlled rectifier to discharge said capacitor when the voltage across the parallel combination reaches a predetermined level, and tuning means for the receiving assembly, said tuning means being electrically connected to said generator and being sensitive to tune the receiver through a predetermined frequency range in response to said ramp function.
Claim 7
Dependent Claim
57 words
The invention as set forth in claim 4 in which said tuning means comprises a voltage-variable capacitance-diode, said receiver assembly has a variable frequency oscillator for tuning said receiver from one station to another, and said voltage-variable capacitance-diode is connected within said oscillator to vary its frequency in response to the variation in voltage of said generator.
Claim 8
Dependent Claim
75 words
The invention as set forth in claim 4 in which said tuning means comprises first and second voltage-variable capacitance-diodes, said receiver assembly has a variable frequency oscillator and tunable RF amplifier for tuning said receiver from one station to another, and said voltage-variable capacitance-diodes are connected respectively within said oscillator and amplifier for varying the frequency of the oscillator and the selectivity of the amplifier in response to the variation in voltage of said generator.
Claim 9
Dependent Claim
128 words
An electronic search-tuning system for a receiver assembly comprising, a generator for producing a ramp function, tuning means for the receiving assembly, said tuning means being electrically connected to said generator and being sensitive to tune the receiver through a predetermined frequency range in response to said ramp function, said receiver assembly comprising an AM receiver having an IF amplifier, a narrow band filter is connected to the IF amplifier and is tuned to the IF frequency of the AM receiver, and a rectifier circuit is coupled between the filter and the generator for rectifying the IF signal to form a DC bias voltage at the generator, said DC bias voltage being applied to the generator for stopping the ramp function and holding constant the generator output voltage.
Claim 10
Dependent Claim
128 words
An electronic search-tuning system for a receiver assembly comprising, a generator for producing a ramp function, tuning means for the receiving assembly, said tuning means being electrically connected to said generator and being sensitive to tune the receiver through a predetermined frequency range in response to said ramp function, said receiver assembly comprising an AM receiver having an IF amplifier, a narrow band filter is connected to the IF amplifier and is tuned to the IF frequency of the AM receiver, and a rectifier circuit is coupled between the filter and the generator for rectifying the IF signal to form a DC bias voltage at the generator, said DC bias voltage being applied to the generator for stopping the ramp function and holding constant the generator output voltage.
Claim 11
Dependent Claim
62 words
The invention as set forth in claim 7 with the addition that a second IF amplifier is connected between said filter and said rectifier, and a switch is coupled between the second IF amplifier and a point of constant potential for actuation to cutoff the conduction of said second IF amplifier, thereby removing the generator from the control of the IF signal.
Claim 12
Dependent Claim
36 words
The invention as set forth in claim 7 in which said generator comprises a capacitor and a charge controlling transistor coupled in series for allowing current flow to charge the capacitor to produce said ramp function.
Claim 13
Dependent Claim
217 words
An electronic search-tuning system for a receiver assembly comprising, a generator having a capacitor and a charge controlling transistor coupled in series for allowing current flow to charge the capacitor to produce a ramp function, reset means for said ramp function generator, said reset means having a potentiometer and a silicon controlled rectifier connected in parallel with each other and in parallel with said capacitor, the movable arm of said potentiometer being connected to the gate electrode of said silicon controlled rectifier for causing conduction of said silicon controlled rectifier to discharge said capacitor when the voltage across the parallel combination reaches a predetermined level, said receiver assembly comprising an AM receiver having an IF amplifier, a narrow band filter is connected to the IF amplifier and is tuned to the IF frequency of the AM receiver, a rectifier circuit is coupled between the filter and the generator for rectifying the IF signal to form a DC bias voltage at the generator, said DC bias voltage being applied to the generator for stopping the raMp function and holding constant the generator output voltage, and tuning means for said receiving assembly, said tuning means being electrically connected to said generator and being sensitive to tune the receiver through a predetermined frequency range in response to said ramp function.
Claim 14
Dependent Claim
217 words
An electronic search-tuning system for a receiver assembly comprising, a generator having a capacitor and a charge controlling transistor coupled in series for allowing current flow to charge the capacitor to produce a ramp function, reset means for said ramp function generator, said reset means having a potentiometer and a silicon controlled rectifier connected in parallel with each other and in parallel with said capacitor, the movable arm of said potentiometer being connected to the gate electrode of said silicon controlled rectifier for causing conduction of said silicon controlled rectifier to discharge said capacitor when the voltage across the parallel combination reaches a predetermined level, said receiver assembly comprising an AM receiver having an IF amplifier, a narrow band filter is connected to the IF amplifier and is tuned to the IF frequency of the AM receiver, a rectifier circuit is coupled between the filter and the generator for rectifying the IF signal to form a DC bias voltage at the generator, said DC bias voltage being applied to the generator for stopping the raMp function and holding constant the generator output voltage, and tuning means for said receiving assembly, said tuning means being electrically connected to said generator and being sensitive to tune the receiver through a predetermined frequency range in response to said ramp function.
Claim 15
Dependent Claim
57 words
The invention as set forth in claim 10 in which said tuning means comprises a voltage-variable capacitance-diode, said receiver assembly has a variable frequency oscillator for tuning said receiver from one station to another, and said voltage-variable capacitance-diode is connected within said oscillator to vary its frequency in response to the variation in voltage of said generator.
Claim 16
Dependent Claim
75 words
The invention as set forth in claim 10 in which said tuning means comprises first and second voltage-variable capacitance-diodes, said receiver assembly has a variable frequency oscillator and tunable RF amplifier for tuning said receiver from one station to another, and said voltage-variable capacitance-diodes are connected respectively within said oscillator and amplifier for varying the frequency of the oscillator and the selectivity of the amplifier in response to the variation in voltage of said generator.
Claim 17
Dependent Claim
170 words
An electronic search tuning system for a receiver assembly comprising, a generator for producing a ramp function, tuning means for the receiving assembly, said tuning means being electrically connected to said generator and being sensitive to tune the receiver through a predetermined frequency range in response to said ramp function, said receiving assembly comprising an FM receiver having an IF amplifier, a ratio detector forming a part of said IF amplifier, and a DC amplifying means connected between the ratio detector output and the ramp generator, said ratio detector output being a DC voltage for controlling current conduction in said generator, and an AM receiver having a second IF amplifier, a narrow band filter is connected to said second IF amplifier and is tuned to the IF frequency of the AM receiver, and a rectifier circuit is coupled between the filter and the generator for rectifying the IF signal to form a DC bias voltage at the generator for stopping the ramp function and holding constant the generator output voltage.
Claim 18
Dependent Claim
170 words
An electronic search tuning system for a receiver assembly comprising, a generator for producing a ramp function, tuning means for the receiving assembly, said tuning means being electrically connected to said generator and being sensitive to tune the receiver through a predetermined frequency range in response to said ramp function, said receiving assembly comprising an FM receiver having an IF amplifier, a ratio detector forming a part of said IF amplifier, and a DC amplifying means connected between the ratio detector output and the ramp generator, said ratio detector output being a DC voltage for controlling current conduction in said generator, and an AM receiver having a second IF amplifier, a narrow band filter is connected to said second IF amplifier and is tuned to the IF frequency of the AM receiver, and a rectifier circuit is coupled between the filter and the generator for rectifying the IF signal to form a DC bias voltage at the generator for stopping the ramp function and holding constant the generator output voltage.
Claim 19
Dependent Claim
197 words
An electronic search-tuning system for a receiver assembly comprising, a generator for producing a ramp function, said receiving assembly comprising an FM receiver having an IF amplifier, a ratio detector forming a part of said IF amplifier and a DC amplifying means connected between the ratio detector output and the ramp generator, said ratio detector output being a DC voltage for controlling current conduction in said generator, said generator having a capacitor and a charge controlling transistor coupled in series for allowing current flow to charge the capacitor to produce said ramp function, a first field effect transistor coupled to the base of the change controlling transistor for causing it to conduct in proportion to the amount of conduction of said first field effect transistor, a second field effect transistor connected between the first field effect transistor and the ratio detector, said second field effect transistor being connected to conduct to cause an inversely proportional current flow in the first field effect transistor, and tuning means for said receiving assembly, said tuning means being electrically connected to said generator and being sensitive to tune the receiver through a predetermined frequency range in response to said ramp function.
Claim 20
Dependent Claim
197 words
An electronic search-tuning system for a receiver assembly comprising, a generator for producing a ramp function, said receiving assembly comprising an FM receiver having an IF amplifier, a ratio detector forming a part of said IF amplifier and a DC amplifying means connected between the ratio detector output and the ramp generator, said ratio detector output being a DC voltage for controlling current conduction in said generator, said generator having a capacitor and a charge controlling transistor coupled in series for allowing current flow to charge the capacitor to produce said ramp function, a first field effect transistor coupled to the base of the change controlling transistor for causing it to conduct in proportion to the amount of conduction of said first field effect transistor, a second field effect transistor connected between the first field effect transistor and the ratio detector, said second field effect transistor being connected to conduct to cause an inversely proportional current flow in the first field effect transistor, and tuning means for said receiving assembly, said tuning means being electrically connected to said generator and being sensitive to tune the receiver through a predetermined frequency range in response to said ramp function.
Claim 21
Dependent Claim
84 words
The invention as set forth in claim 14 in which said generator further comprises reset means for said ramp function generator, said reset means having a potentiometer and a silicon controlled rectifier connected in parallel with each other and in parallel with said capacitor, the movable arm of said potentiometer being connected to the gate electrode of said silicon controlled rectifier for causing conduction of said silicon controlled rectifier To discharge said capacitor when the voltage across the parallel combination reaches a predetermined level.
Claim 22
Dependent Claim
57 words
The invention as set forth in claim 15 in which said tuning means comprises a voltage-variable capacitance-diode, said receiver assembly having a variable frequency oscillator for tuning said receiver from one station to another, and said voltage-variable capacitance-diode is connected within said oscillator to vary its frequency in response to the variation in voltage of said generator.
Claim 23
Dependent Claim
75 words
The invention as set forth in claim 15 in which said tuning means comprises first and second voltage-variable capacitance-diodes, said receiver assembly has a variable frequency oscillator and tunable RF amplifier for tuning said receiver from one station to another, and said voltage-variable capacitance-diodes are connected respectively within said oscillator and amplifier for varying the frequency of the oscillator and the selectivity of the amplifier in response to the variation in voltage of said generator.
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) | 1974-04-19 | 1974-10-19 | 1975-04-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-04-19 | 1978-10-19 | 1979-04-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-04-19 | 1982-10-19 | 1983-04-20 | $7700.00 | Window Closed / Lapsed |