US3636455A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tunable input circuit
Assignee: Telefunken Electronic GmbH
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Filing: 1969-09-29
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Granted: 1972-01-18
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Expires: 1989-09-29
Abstract
Abstract A tunable input circuit with high selectivity for feeding a signal to a variable-frequency band-pass filter with tuning elements identical to those of the input circuit. The high selectivity produced by the input circuit is a minimum in the range of the received frequency and a maximum in the range of the image frequency. The input circuit is a bridge having four arms with impedances in them and four points connecting the arms. The impedances are diagonally matched, and one set is variable. One set of diagonally opposite points connecting the arms is connected between an antenna lead and ground. A voltage-variable capacitance (such as a voltage-variable diode) is connected between the other pair of connecting points. A tuning voltage is fed back to the voltage-variable capacitance means. This voltage is preferably the same voltage used to tune the band-pass filter.
Inventors
- 👤 Willy Minner
- 👤 Gerhard Lindner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 12:40
CPC Classifications
H; H03; H03H; H03H7/00; H03H7/01; H03H7/0153; H03H7/0161
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
145 words
A tunable input circuit for producing an attenuation which is a minimum in the range of a received frequency and a maximum in the range of an image frequency, comprising, in combination: a. four arms connected as a bridge so that there are two pairs of opposite arms and two pairs of diagonally opposite connecting points, each arm of said bridge including inductance means, the inductance means of each arm being equal in value to the inductance means included in the opposite arm; b. voltage-variable capacitance means connected across one pair of said two pairs of connecting points for providing a synchronous attenuation peak; and c. an input lead and an output lead connected to one connecting point of the other of said two pairs of connecting points, the other connecting point of the other of said two pairs of connecting points connected to ground.
Claim 2
Dependent Claim
145 words
A tunable input circuit for producing an attenuation which is a minimum in the range of a received frequency and a maximum in the range of an image frequency, comprising, in combination: a. four arms connected as a bridge so that there are two pairs of opposite arms and two pairs of diagonally opposite connecting points, each arm of said bridge including inductance means, the inductance means of each arm being equal in value to the inductance means included in the opposite arm; b. voltage-variable capacitance means connected across one pair of said two pairs of connecting points for providing a synchronous attenuation peak; and c. an input lead and an output lead connected to one connecting point of the other of said two pairs of connecting points, the other connecting point of the other of said two pairs of connecting points connected to ground.
Claim 3
Dependent Claim
32 words
An input circuit as defined in claim 1 wherein a shifting capacitance means is connected in series with said voltage-variable capacitance means for setting the capacitance deviation of said voltage-variable capacitance means.
Claim 4
Dependent Claim
30 words
An input circuit as defined in claim 2 wherein a control voltage is applied between said voltage-variable capacitance means and said shifting capacitance means to bias said voltage-variable capacitance means.
Claim 5
Dependent Claim
45 words
An input circuit as defined in claim 3 wherein a trimmer capacitor is connected between a point between said voltage-dependent capacitance means and said shifting capacitance means and ground for fixing of the tuning deviation from said shifting capacitance means and a frequency range limit.
Claim 6
Dependent Claim
27 words
An input circuit as defined in claim 4 wherein two of said diagonally opposite inductance means are variable inductors for determining the position of the frequency deviation.
Claim 7
Dependent Claim
26 words
An input circuit as defined in claim 5 wherein said variable inductors are two parallel wire bows which can be bent with respect to each other.
Claim 8
Dependent Claim
17 words
An input circuit as defined in claim 6 wherein said voltage-variable capacitance means is a voltage-variable diode.
Claim 9
Dependent Claim
16 words
An input circuit as defined in claim 7 wherein said input lead is a 60-ohm wire.
Claim 10
Dependent Claim
28 words
An input circuit as defined in claim 1 wherein a control voltage is applied between said one of said pairs of points to bias said voltage-variable capacitance means.
Claim 11
Dependent Claim
41 words
An input circuit as defined in claim 1 wherein said input circuit is the input circuit for a tunable band-pass filter in a tuning assembly for a communications receiver, said filter having tuning elements identical to those of said input circuit.
Claim 12
Dependent Claim
25 words
An input circuit as defined in claim 10 wherein the input circuit is coupled with the tunable band-pass filter by means of an active element.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-01-17 | 1975-07-19 | 1976-01-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-17 | 1979-07-19 | 1980-01-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-17 | 1983-07-19 | 1984-01-18 | $7700.00 | Window Closed / Lapsed |