Patent US3928548A successfully refreshed from Google Patents.
Patent US4914406A successfully refreshed from Google Patents.
US4914406A
Expired / Lapsed
US
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Voltage controlled oscillator free from free-run oscillating frequency adjustment
Assignee: NEC Electronics Corp
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Filing: 1989-04-19
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Granted: 1990-04-03
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Expires: 2009-04-19
Abstract
Abstract A voltage controlled oscillator free from free-run oscillating frequency adjustment is disclosed. This oscillator includes an amplifier having a positive feedback loop, a resonator connected to the output of the amplifier, and a variable reactance circuit connected to the output of the amplifier. The reactance circuit presents a reactance value variable by a control voltage to control an oscillation frequency of the oscillator. There is a further provided a low-pass filter which is connected in cascade to the variable reactance circuit. A high-pass filter is preferably inserted in the positive feedback loop.
Inventors
- 👤 Fumikazu Ohkubo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 22:24
CPC Classifications
H; H03; H03L; H03L5/00; H03B; H03B5/00; H03B5/08; H03B5/12; H03B5/1231; H03B5/1206; H03B5/1209; H03B5/1237; H03B5/124; H03B5/1243
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
84 words
A voltage controlled oscillator oscillating at a frequency which is variable by a control voltage, said oscillator comprising an amplifier having input and output terminals and a positive feedback circuit provided between the input and output terminals, a resonator coupled to the output terminal of said amplifier, circuit means supplied with said control voltage and having a controllable capacitance component which is controlled by said control voltage, a low-pass filter coupled to said circuit means in cascade to the output terminal of said amplifier.
Claim 2
Dependent Claim
84 words
A voltage controlled oscillator oscillating at a frequency which is variable by a control voltage, said oscillator comprising an amplifier having input and output terminals and a positive feedback circuit provided between the input and output terminals, a resonator coupled to the output terminal of said amplifier, circuit means supplied with said control voltage and having a controllable capacitance component which is controlled by said control voltage, a low-pass filter coupled to said circuit means in cascade to the output terminal of said amplifier.
Claim 3
Dependent Claim
41 words
The oscillator as claimed in claim 1, wherein said resonator has a first resonant frequency and a second resonant frequency different from said first resonant frequency and said low-pass filter has a cut-off frequency between said first and second resonant frequencies.
Claim 4
Dependent Claim
45 words
The oscillator as claimed in claim 1, wherein said circuit means includes first and second transistors connected in a differential form through a capacitor and said low-pass filter is connected between the output terminal of said amplifier and a control electrode of said first transistor.
Claim 5
Dependent Claim
109 words
A voltage controlled oscillator oscillating at a frequency which is varied by a control voltage, comprising an amplifier having input and output terminals and being formed with circuits elements including a capacitive element, a high-pass filter, means for coupling said high-pass filter to said amplifier to form a positive feedback circuit from the output terminal to an input terminal of said amplifier, a resonator, means for coupling said resonator to the output terminal of said amplifier, a variable reactance circuit supplied with said control voltage and presenting reactance controllable with a value of said control voltage, and a low-pass filter coupled between said amplifier and said variable reactance circuit.
Claim 6
Dependent Claim
109 words
A voltage controlled oscillator oscillating at a frequency which is varied by a control voltage, comprising an amplifier having input and output terminals and being formed with circuits elements including a capacitive element, a high-pass filter, means for coupling said high-pass filter to said amplifier to form a positive feedback circuit from the output terminal to an input terminal of said amplifier, a resonator, means for coupling said resonator to the output terminal of said amplifier, a variable reactance circuit supplied with said control voltage and presenting reactance controllable with a value of said control voltage, and a low-pass filter coupled between said amplifier and said variable reactance circuit.
Claim 7
Dependent Claim
54 words
The oscillator as claimed in claim 4, wherein said resonator has a first resonant frequency and a second resonant frequency higher than said first resonant frequency, said high-pass filter having a cut-off frequency lower than said first resonant frequency, and said low-pass filter having a cut-off frequency between said first and second resonant frequencies.
Claim 8
Dependent Claim
45 words
The oscillator as claimed in claim 4, wherein said amplifier has an inverting input terminal and a non-inverting input terminal and said high-pass filter is coupled between said output terminal and said non-inverting input terminal, said inverting input terminal being supplied with a bias voltage.
References Cited (Backward Citations)
US3986145A
Cited
US4745375A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-04-02 | 1993-10-02 | 1994-04-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-04-02 | 1997-10-02 | 1998-04-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-04-02 | 2001-10-02 | 2002-04-03 | $7700.00 | Window Closed / Lapsed |