US3679990A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Variable frequency oscillator with substantially linear afc over tuning range
Assignee: Arris Technology Inc
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Filing: 1971-01-27
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Granted: 1972-07-25
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Expires: 1991-01-27
Abstract
Abstract A tuned transistor oscillator for use with an RF receiver includes a transistor amplifier having a tuned network coupled between the collector and base of the transistor. Feedback is provided by a capacitor coupled between the tuned network and the emitter of the transistor. The tuned network includes a transmission line, a variable capacitive reactance means in parallel therewith, a first variable capacitance diode in series with said reactance means, and a second variable capacitance diode serially connected to said line. The capacitance of said reactance means is varied to allow the oscillator to sweep the desired frequency range, and the first and second capacitance diodes are varied by a DC AFC (automatic frequency control) voltage provided by the discriminator of the RF receiver to prevent oscillator drift. Said first and second diode capacitances are arranged so that the first capacitance has its greatest effect at the lower end of the oscillator frequency range while the second capacitor has its greatest effect at the upper end of said range, thereby providing an AFC signal which varies the oscillator frequency by a substantially constant amount independently of the oscillator frequency.
Inventors
- 👤 David R Hiday
- 👤 Ralph L Mull Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 07:17
CPC Classifications
H; H03; H03J; H03J7/00; H03J7/02; H03J7/04; H03J7/08; H03J7/10
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
122 words
A variable frequency oscillator having AFC comprising an amplifier having an input terminal and an output terminal; a variable tuned network coupled to said output terminal; and feedback means coupled between said tuned network and said input terminal; said tuned network comprising: first variable capacitive reactance means for varying the frequency of said oscillator over its range; second variable capacitive reactance means serially coupled to said first reactance means for varying the frequency of said oscillator at the lower portion of its range; inductance means connected in parallel combination with said first and second reactance means; and third variable capacitive reactance means serially coupled to said parallel combination for varying the frequency of said oscillator at the upper portion of its range.
Claim 2
Dependent Claim
122 words
A variable frequency oscillator having AFC comprising an amplifier having an input terminal and an output terminal; a variable tuned network coupled to said output terminal; and feedback means coupled between said tuned network and said input terminal; said tuned network comprising: first variable capacitive reactance means for varying the frequency of said oscillator over its range; second variable capacitive reactance means serially coupled to said first reactance means for varying the frequency of said oscillator at the lower portion of its range; inductance means connected in parallel combination with said first and second reactance means; and third variable capacitive reactance means serially coupled to said parallel combination for varying the frequency of said oscillator at the upper portion of its range.
Claim 3
Dependent Claim
41 words
The variable frequency oscillator of claim 1, in which said second and third variable capacitance reactance means are voltage-variable, means for producing a first control voltage, and means for applying said first control voltage to said second and third reactance means.
Claim 4
Dependent Claim
38 words
The variable frequency oscillator of claim 2, in which said first variable capacitive reactance means is voltage-variable, means for for producing a second control voltage, and means for applying said second control voltage to said first reactance means.
Claim 5
Dependent Claim
35 words
The variable frequency oscillator of claim 1, in which said first variable capacitive reactance means is voltage-variable, means for producing a control voltage, and means for applying said control voltage to said first reactance means.
Claim 6
Dependent Claim
56 words
A variable frequency oscillator, according to claim 2, wherein said second voltage variable capacitive reactance means comprises: first capacitance means, the magnitude of which is controlled by said first control voltage; a first capacitor serially connected to said first capacitance means; and a second capacitor connected in parallel with said first capacitance means and first capacitor.
Claim 7
Dependent Claim
43 words
A variable frequency oscillator, according to claim 5, wherein said third voltage variable capacitive reactance means comprises: second capacitance means, the magnitude of which is controlled by said first control voltage; and a third capacitor connected in parallel with said second capacitance means.
Claim 8
Dependent Claim
57 words
A variable fRequency oscillator, according to claim 2, further comprising: a mixer circuit operatively connected to said output terminal of said oscillator; means for producing a second signal and for feeding it to said mixer circuit; and a discriminator circuit coupled to an output of said mixer circuit and having an output comprising said first control voltage.
Claim 9
Dependent Claim
37 words
The variable frequency oscillator of claim 7, in which said first variable capacitive reactance means is voltage-variable, means for producing a second control voltage, and means for applying said second control voltage to said first reactance means.
Claim 10
Dependent Claim
56 words
A variable frequency oscillator, according to claim 7, wherein said second voltage variable capacitive reactance means comprises: first capacitance means, the magnitude of which is controlled by said first control voltage; a first capacitor serially connected to said first capacitance means; and a second capacitor connected in parallel with said first capacitance means and first capacitor.
Claim 11
Dependent Claim
43 words
A variable frequency oscillator, according to claim 9, wherein said third voltage variable capacitive reactance means comprises: second capacitance means, the magnitude of which is controlled by said first control voltage; and a third capacitor connected in parallel with said second capacitance means.
Claim 12
Dependent Claim
107 words
A variable resonant frequency network comprising: first voltage variable capacitive reactance means controlled by a control voltage for varying said resonant frequency throughout a selected frequency range; second voltage variable capacitive reactance means controlled by another control voltage serially coupled to said first reactance means for varying said resonant frequency when said frequency is at the lower portion of its range; inductance means connected in parallel combination with said first and second reactance means; and third voltage variable capacitive reactance means controlled by said other control voltage serially coupled to said parallel combination for varying said frequency when it is at the upper portion of its range.
Claim 13
Dependent Claim
107 words
A variable resonant frequency network comprising: first voltage variable capacitive reactance means controlled by a control voltage for varying said resonant frequency throughout a selected frequency range; second voltage variable capacitive reactance means controlled by another control voltage serially coupled to said first reactance means for varying said resonant frequency when said frequency is at the lower portion of its range; inductance means connected in parallel combination with said first and second reactance means; and third voltage variable capacitive reactance means controlled by said other control voltage serially coupled to said parallel combination for varying said frequency when it is at the upper portion of its range.
Claim 14
Dependent Claim
64 words
A variable resonant frequency network, according to claim 11, wherein said second voltage variable capacitive reactance means comprises: a first variable capacitance diode, the magnitude of capacitance of which is controlled by said other control voltage; a first capacitor serially connected to said first variable capacitance diode; and a second capacitor connected in parallel with said first variable capacitance diode and said first capacitor.
Claim 15
Dependent Claim
49 words
A variable resonant frequency network, according to claim 12, wherein said third voltage variable capacitive reactance means comprise: a second variable capacitance diode, the magnitude of capacitance of which is controlled by said other control voltage; and a third capacitor connected in parallel with said second variable capacitance diode.
Claim 16
Dependent Claim
87 words
Variable resonant frequency network comprising: first variable capacitive reactance means for varying said resonant frequency throughout a selected frequency range; second variable capacitive reactance means serially coupled to said first reactance means for varying said resonant frequency when said frequency is at the lower portion of its range; inductance means connected in parallel combination with said first and second reactance means; and third variable capacitive reactance means serially coupled to said parallel combination for varying said frequency when it is at the upper portion of its range.
Claim 17
Dependent Claim
87 words
Variable resonant frequency network comprising: first variable capacitive reactance means for varying said resonant frequency throughout a selected frequency range; second variable capacitive reactance means serially coupled to said first reactance means for varying said resonant frequency when said frequency is at the lower portion of its range; inductance means connected in parallel combination with said first and second reactance means; and third variable capacitive reactance means serially coupled to said parallel combination for varying said frequency when it is at the upper portion of its range.
Claim 18
Dependent Claim
62 words
A variable resonant frequency network, according to claim 14, wherein said second variable capacitive reactance means comprises: a first variable capacitance diode, the magnitude of capacitance of which is controlled by a control voltage; a first capacitor serially connected to said first variable capacitance diode; and a second capacitor connected in parallel with said first variable capacitance diode and said first capacitor.
Claim 19
Dependent Claim
47 words
A variable resonant frequency network, according to claim 15, wherein said third variable capacitive reactaNce means comprises: a second variable capacitance diode, the magnitude of capacitance of which is controlled by said control voltage; and a third capacitor connected in parallel with said second variable capacitance diode.
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) | 1975-07-25 | 1976-01-24 | 1976-07-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-25 | 1980-01-24 | 1980-07-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-25 | 1984-01-24 | 1984-07-25 | $7700.00 | Window Closed / Lapsed |