US3980957A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Circuit arrangement for tuning and range or band switching of an RF resonant circuit
Assignee: US Philips Corp
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Filing: 1975-03-14
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Granted: 1976-09-14
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Expires: 1995-03-14
Abstract
Abstract A television tuner features a switching voltage generator that resets the voltage across the varicap tuning diodes to about zero voltage when a new tuning range is switched on. This allows the full steepness of the capacitance-voltage characteristics of the diodes to be used in each range. This in turn allows more ranges to be tuned and reduces the effects of stray capacitances.
Inventors
- 👤 Walter Putzer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 01:24
CPC Classifications
H; H03; H03J; H03J3/00; H03J3/02; H03J3/16; H03J3/18; H03J3/185; H03J5/00; H03J5/24; H03J5/242; H03J5/244
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
117 words
A circuit arrangement for tuning and range for band switching of an RF resonant circuit, comprising a variable capacity diode which can be controlled by a tuning voltage for tuning the resonant circuit, a switching diode controlled by a switching voltage for short-circuiting part of the resonant circuit inductor for range switching and a switching voltage generator controlled by the tuning voltage for generating the switching voltage for the switching diode, characterized in that a reset voltage derived from the switching voltage is applied in addition to the tuning voltage to the variable capacity diode, which reset voltage resets the voltage across the variable capacity diode to approximately 0 V when a new range is switched on.
Claim 2
Dependent Claim
117 words
A circuit arrangement for tuning and range for band switching of an RF resonant circuit, comprising a variable capacity diode which can be controlled by a tuning voltage for tuning the resonant circuit, a switching diode controlled by a switching voltage for short-circuiting part of the resonant circuit inductor for range switching and a switching voltage generator controlled by the tuning voltage for generating the switching voltage for the switching diode, characterized in that a reset voltage derived from the switching voltage is applied in addition to the tuning voltage to the variable capacity diode, which reset voltage resets the voltage across the variable capacity diode to approximately 0 V when a new range is switched on.
Claim 3
Dependent Claim
115 words
A circuit arrangement as claimed in claim 1 in which the variable capacity diode and the switching diode each have a first electrode and a second electrode and the tuning voltage is applied to the first electrode of the variable capacity diode and the switching voltage to the first electrode of the switching diode, characterized by a resistor connected with respect to direct current to the second electrode of the switching diode through which electrode the reset voltage is adjusted and by a connection connected with respect to direct current between said resistor and the second electrode of the variable capacity diode through which connection the reset voltage is applied to the variable capacity diode.
Claim 4
Dependent Claim
136 words
A circuit arrangement as claimed in claim 1 for tuning and switching over an RF resonant circuit over at least three frequency ranges, characterized by a switching voltage generator for generating a first switching voltage for a first switching diode switching the RF resonant circuit from a first into a second frequency range and for generating a second switching voltage for a second switching diode switching the RF resonant circuit from a second into a third frequency range, characterized in that a reset voltage derived from the two switching voltages is applied to the variable capacity diode which reset voltage reduces the voltage across the variable capacity diode to substantially 0 V both when changing over from the first to the second frequency range and when changing over from the second to the third frequency range.
Claim 5
Dependent Claim
37 words
A circuit arrangement as claimed in claim 1, for use in a tuner with an oscillator controlled by the tuning voltage, characterized by a switching voltage generator controlled by said oscillator and comprising one or more rectifiers.
Claim 6
Dependent Claim
111 words
A circuit arrangement for tuning and range switching of an RF resonant circuit, comprising a variable capacity diode means which can be controlled by a tuning voltage for tuning the resonant circuit, a switching diode means controlled by a switching voltage for short-circuiting part of the resonant circuit inductor for range switching, a switching voltage generator means controlled by the tuning voltage for generating the switching voltage for the switching diode, and means for deriving a reset voltage from the switching voltage and for applying said reset voltage to the variable capacity diode for resetting the voltage across the variable capacity diode to approximately zero volts when the range is switched.
Claim 7
Dependent Claim
111 words
A circuit arrangement for tuning and range switching of an RF resonant circuit, comprising a variable capacity diode means which can be controlled by a tuning voltage for tuning the resonant circuit, a switching diode means controlled by a switching voltage for short-circuiting part of the resonant circuit inductor for range switching, a switching voltage generator means controlled by the tuning voltage for generating the switching voltage for the switching diode, and means for deriving a reset voltage from the switching voltage and for applying said reset voltage to the variable capacity diode for resetting the voltage across the variable capacity diode to approximately zero volts when the range is switched.
References Cited (Backward Citations)
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US3646450A
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US3813615A
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US3889210A
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US3825858A
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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) | 1979-09-14 | 1980-03-15 | 1980-09-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-09-14 | 1984-03-15 | 1984-09-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-09-14 | 1988-03-15 | 1988-09-14 | $7700.00 | Window Closed / Lapsed |