US3573683A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Varactor diode tuned circuit having substantially constant loaded q-factor
Assignee: Plessey Overseas Ltd
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Filing: 1968-05-29
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Granted: 1971-04-06
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Expires: 1988-05-29
Abstract
Abstract A tuned circuit arrangement comprising a tuned circuit having varactor diode means for the tuning thereof over a band of frequencies, and compensation means operative for providing selective damping to said tuned circuit so that the loaded Qfactor of the tuned circuit arrangement remains substantially constant over the frequency band.
Inventors
- 👤 Richard S Marshall
- 👤 Allan S Summers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 16:24
CPC Classifications
H; H03; H03J; H03J3/00; H03J3/02; H03J3/06; H03J3/16; H03J3/18; H03J3/185
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
97 words
A tuned circuit arrangement comprising a single tuned circuit having varactor diode means for the tuning thereof over a band of frequencies in dependence upon an applied tuning voltage, a tapped inductance forming part of the tuned circuit, and compensation means including a PIN diode interposed between the inductance tap and the applied tuning voltage so that it operates on that part of its admittance/forward current characteristic that is substantially linear, the compensation means being effective for providing selective damping to said tuned circuit so that the loaded Q-factor of the tuned circuit arrangement remains substantially constant.
Claim 2
Dependent Claim
97 words
A tuned circuit arrangement comprising a single tuned circuit having varactor diode means for the tuning thereof over a band of frequencies in dependence upon an applied tuning voltage, a tapped inductance forming part of the tuned circuit, and compensation means including a PIN diode interposed between the inductance tap and the applied tuning voltage so that it operates on that part of its admittance/forward current characteristic that is substantially linear, the compensation means being effective for providing selective damping to said tuned circuit so that the loaded Q-factor of the tuned circuit arrangement remains substantially constant.
Claim 3
Dependent Claim
36 words
A tuned circuit arrangement as claimed in claim 1, in which the PIN diode is connected in series with an electrical resistance so that the PIN diode current is substantially proportional to the applied tuning voltage.
Claim 4
Dependent Claim
57 words
A tuned circuit arrangement as claimed in claim 1, in which the PIN diode is connected between the tap of the inductance and the junction of a potential divider network connected effectively between the applied tuning voltage and a voltage of opposite polarity so that the PIN diode is reverse biassed at low applied tuning voltage levels.
Claim 5
Dependent Claim
40 words
A tuned circuit arrangement as claimed in claim 3, in which the potential divider network has associated wiTh it further diode means which ensures that the PIN diode current is substantially proportional to the logarithm of the applied tuning voltage.
Claim 6
Dependent Claim
21 words
A tuned circuit arrangement as claimed in claim 4, in which the further diode means are shunted by an electrical resistance.
Claim 7
Dependent Claim
93 words
A tuned circuit arrangement comprising a single tuned circuit having varactor diode means for the tuning thereof over a band of frequencies in dependence upon an applied tuning voltage and compensation means for providing selective damping to said tuned circuit so that the loaded Q-factor of the tuned circuit arrangement remains substantially constant, the compensation means comprising a transmission line, which is effectively short circuited, connected in series with a resistance, the length of the transmission line corresponding effectively to between a quarter and half wavelength of the frequency of the tuned circuit.
Claim 8
Dependent Claim
93 words
A tuned circuit arrangement comprising a single tuned circuit having varactor diode means for the tuning thereof over a band of frequencies in dependence upon an applied tuning voltage and compensation means for providing selective damping to said tuned circuit so that the loaded Q-factor of the tuned circuit arrangement remains substantially constant, the compensation means comprising a transmission line, which is effectively short circuited, connected in series with a resistance, the length of the transmission line corresponding effectively to between a quarter and half wavelength of the frequency of the tuned circuit.
Claim 9
Dependent Claim
26 words
A tuned circuit as claimed in claim 6, in which the transmission line takes the form of a helical coil positioned coaxially inside a conducting tube.
Claim 10
Dependent Claim
43 words
A tuned circuit arrangement as claimed in claim 6, in which the transmission line is connected in series with the collector circuit of a transistor and is arranged to shunt at least part of the tuned circuit by means of a coupling capacitor.
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) | 1974-04-05 | 1974-10-05 | 1975-04-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-04-05 | 1978-10-05 | 1979-04-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-04-05 | 1982-10-05 | 1983-04-06 | $7700.00 | Window Closed / Lapsed |