US3753172A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Varactor tuning system having means to maintain terminal voltage of varactor biasing capacitor within desired range
Assignee: Panasonic Holdings Corp
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Filing: 1972-09-11
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Granted: 1973-08-14
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Expires: 1992-09-11
Abstract
Abstract A tuning system in which a tuning voltage is applied from a voltage holding circuit including a capacitor to a tuning circuit using a variable capacitance diode. When the terminal voltage across the capacitor is reduced, the capacitor is charged from a power supply through a switch to compensate the reduction. When the frequency of the tuning circuit is changed to a predetermined extent, the switch is closed to recover the initial level of the voltage of the voltage holding circuit.
Inventors
- 👤 Y Sakamoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 13:53
CPC Classifications
H; H03; H03J; H03J7/00; H03J7/02; H03J7/04; H03J7/08; H03J7/10
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
108 words
A tuning system conprising a tuning circuit using a variable capacitance diode as a tuning element, a voltage holding circuit including a capacitor for giving a tuning voltage to said variable capacitance diode, a power supply to compensate reduction in the voltage of said voltage holding circuit, a switching means provided between said power supply and said voltage holding circuit, a control means for on-off controlling said switching means, and a drive means detecting the frequency change in said tuning circuit and adapted to drive said control means so as to render said switching means into the ''''on'''' state when a predetermined extent of frequency change is detected.
Claim 2
Dependent Claim
108 words
A tuning system conprising a tuning circuit using a variable capacitance diode as a tuning element, a voltage holding circuit including a capacitor for giving a tuning voltage to said variable capacitance diode, a power supply to compensate reduction in the voltage of said voltage holding circuit, a switching means provided between said power supply and said voltage holding circuit, a control means for on-off controlling said switching means, and a drive means detecting the frequency change in said tuning circuit and adapted to drive said control means so as to render said switching means into the ''''on'''' state when a predetermined extent of frequency change is detected.
Claim 3
Dependent Claim
128 words
The tuning system according to claim 1, wherein said voltage holding circuit further includes a field-effect transistor, said capacitor being connected between the gate of said field-effect transistor and ground, the source of said field-effect transistor being connected to said variable capacitance diode of said tuning circuit, the terminal of said capacitor on the field-effect transistor side being connected through said switching means to said power supply, said control means comprises a Schmitt circuit providing switching voltages for on-off controlling said switching means, and said drive means comprises a frequency deviation detecting circuit detecting the deviation of the frequency of said tuning circuit and generates a voltage corresponding to the detected deviation, the voltage corresponding to the detected frequency deviation being used to on-off control said Schmitt circuit.
Claim 4
Dependent Claim
146 words
The tuning system according to claim 1, wherein said voltage holding circuit further includes a field-effect transistor, said capacitor being connected between the gate and drain Of said field-effect transistor, the source of said field-effect transistor being connected to said variable capacitance diode of said tuning circuit, said switching means being inserted between the terminal of said capacitor on the field-effect transistor gate side and ground, said power supply being connected between the terminal of said capacitor on the field-effect transistor drain side and ground, said control means comprises a Schmitt circuit providing switching voltages for on-off controlling said switching means, and said drive means comprises a frequency deviation detecting circuit detecting the deviation of the frequency of said tuning circuit and generates a voltage corresponding to the detected deviation, the voltage corresponding to the detected frequency deviation being used to on-off control said Schmitt circuit.
Claim 5
Dependent Claim
63 words
The tuning system according to claim 1, wherein said drive means comprises a frequency deviation detecting circuit detecting the deviation of the frequency of said tuning circuit and generating a voltage corresponding to the detected deviation, the voltage corresponding to the detected frequency deviation being used to drive said control means while it is applied as AFC voltage to said variable capacitance diode.
Claim 6
Dependent Claim
57 words
The tuning system according to claim 1, wherein said voltage holding circuit further includes a field-effect transistor having the gate thereof connected to said capacitor, the terminal of said capacitor on the field-effect transistor side being a voltage impression terminal, the source of said field-effect transistor being connected to a voltage impression terminal of said tuning circuit.
Claim 7
Dependent Claim
37 words
The tuning system according to claim 5, wherein said switching means is connected to the terminal of said capacitor on the field-effect transistor gate side, said switching means having a high resistance element connected in series therewith.
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) | 1976-08-13 | 1977-02-12 | 1977-08-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-13 | 1981-02-12 | 1981-08-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-13 | 1985-02-12 | 1985-08-14 | $7700.00 | Window Closed / Lapsed |