US4066976A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Amplifier with variable gain
Assignee: Deutsche Thomson OHG
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Filing: 1976-07-06
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Granted: 1978-01-03
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Expires: 1996-07-06
Abstract
Abstract An amplifier circuit having a variable transmission factor and an effective transmission frequency band delimited by a lower limit frequency is arranged to enable the value of the lower limit frequency to be varied as a function of a control voltage, by including in the circuit an amplifier member and circuit components defining a feedback path connected between the output of the amplifier and an input thereof which is inverting with respect to the output signals of the amplifier, the components defining the feedback path including an electronically voltage-controllable resistor having a control voltage input and a first frequency dependent impedance connected in parallel with the resistor, and the circuit further including a second frequency dependent impedance connected between the inverting input of the amplifier and a point at the circuit reference potential, and a line for supplying the control voltage to the control voltage input of the controllable resistor.
Inventors
- 👤 Gerhard Dickopp
- 👤 Ernst Schroder
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 19:09
CPC Classifications
H; H03; H03G; H03G9/00; H03G9/02; H03G9/025
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
154 words
In an amplifier circuit arranged to be connected in a useful signal path and having a variable transmission factor and an effective transmission frequency band delimited by a lower limit frequency which can be varied as a function of a control voltage, the circuit including an amplifier member and circuit components defining a feedback path connected between the output of the amplifier member and an input thereof which is inverting with respect to the output signals of the amplifier member, the improvement wherein the components defining said feedback path comprise an electronically voltage-controllable resistor having a control voltage input and a first frequency dependent impedance connected in parallel with said resistor, and said circuit further comprises a second frequency dependent impedance connected between the inverting input of said amplifier member and a point at the circuit reference potential, and means for supplying the control voltage to the control voltage input of said controllable resistor.
Claim 2
Dependent Claim
154 words
In an amplifier circuit arranged to be connected in a useful signal path and having a variable transmission factor and an effective transmission frequency band delimited by a lower limit frequency which can be varied as a function of a control voltage, the circuit including an amplifier member and circuit components defining a feedback path connected between the output of the amplifier member and an input thereof which is inverting with respect to the output signals of the amplifier member, the improvement wherein the components defining said feedback path comprise an electronically voltage-controllable resistor having a control voltage input and a first frequency dependent impedance connected in parallel with said resistor, and said circuit further comprises a second frequency dependent impedance connected between the inverting input of said amplifier member and a point at the circuit reference potential, and means for supplying the control voltage to the control voltage input of said controllable resistor.
Claim 3
Dependent Claim
75 words
An arrangement as defined in claim 1 wherein said circuit is provided to produce a dynamic compression or expansion of useful signals, and said circuit further comprises a control voltage generator connected for deriving a control voltage from the information signal to be processed and having an output connected to the control voltage input of said controllable resistor for causing the lower limit frequency to be shifted toward higher values with increasing information signal amplitudes.
Claim 4
Dependent Claim
27 words
An arrangement as defined in claim 2 wherein said control voltage generator includes a circuit connected for rectifying the alternating voltage signals in the useful signal path.
Claim 5
Dependent Claim
24 words
An arrangement as defined in claim 1 wherein said controllable resistor is a field effect transistor whose control electrode constitutes said control voltage input.
Claim 6
Dependent Claim
15 words
An arrangement as defined in claim 1 wherein said amplifier member is a differential amplifier.
Claim 7
Dependent Claim
31 words
An arrangement as defined in claim 1 further comprising a further frequency dependent impedance, and switch means for selectively connecting said further impedance in parallel with said first frequency dependent impedance.
Claim 8
Dependent Claim
27 words
An arrangement as defined in claim 1 further comprising a further resistor, and switch means for selectively connecting said further resistor in parallel with said controllable resistor.
Claim 9
Dependent Claim
16 words
An arrangement as defined in claim 1 wherein said frequency dependent impedances are constituted by capacitors.
Claim 10
Dependent Claim
189 words
In an amplifier circuit arranged to be connected in a useful signal path and having a variable transmission factor and an effective transmission frequency band delimited by a lower limit frequency which can be varied as a function of a control voltage, the circuit including an amplifier member and circuit components defining a feedback path connected between the output of the amplifier member and an input thereof which is inverting with respect to the output signal of the amplifier member, the improvement wherein the components defining said feedback path comprise a first electronically voltage-controllable resistor having a control voltage input, and a first frequency dependent impedance connected in parallel with said first resistor, and said circuit further comprises a second electronically voltage-controllable resistor having a control input, said second resistor being connected in the useful signal path and to an input of said amplifier member which is inverting with respect to the output signals of said amplifier member, a second frequency dependent impedance connected in parallel with said second resistor, and means for supplying the control voltage to the control voltage inputs of said first and second controllable resistors.
Claim 11
Dependent Claim
189 words
In an amplifier circuit arranged to be connected in a useful signal path and having a variable transmission factor and an effective transmission frequency band delimited by a lower limit frequency which can be varied as a function of a control voltage, the circuit including an amplifier member and circuit components defining a feedback path connected between the output of the amplifier member and an input thereof which is inverting with respect to the output signal of the amplifier member, the improvement wherein the components defining said feedback path comprise a first electronically voltage-controllable resistor having a control voltage input, and a first frequency dependent impedance connected in parallel with said first resistor, and said circuit further comprises a second electronically voltage-controllable resistor having a control input, said second resistor being connected in the useful signal path and to an input of said amplifier member which is inverting with respect to the output signals of said amplifier member, a second frequency dependent impedance connected in parallel with said second resistor, and means for supplying the control voltage to the control voltage inputs of said first and second controllable resistors.
Claim 12
Dependent Claim
16 words
An arrangement as defined in claim 9 wherein said frequency dependent impedances are constituted by capacitors.
Claim 13
Dependent Claim
31 words
An arrangement as defined in claim 9 wherein, at any given control voltage value, the resistance values of said first and second controllable resistors have a fixed relationship to one another.
Claim 14
Dependent Claim
32 words
An arrangement as defined in claim 11 wherein said first and second controllable resistors are constructed to exhibit resistance variation in response to the control voltage applied to their control voltage inputs.
Claim 15
Dependent Claim
44 words
An arrangement as defined in claim 9 further comprising a third frequency dependent impedance, switch means connecting said third impedance in parallel with said first resistor, a fourth frequency dependent impedance, and switch means connecting said fourth impedance in parallel with said second resistor.
Claim 16
Dependent Claim
44 words
An arrangement as defined in claim 9 further comprising a first additional resistor, switch means connecting said first additional resistor in parallel with said first resistor, a second additional resistor, and switch means connecting said second additional resistor in parallel with said second resistor.
Claim 17
Dependent Claim
60 words
An arrangement as defined in claim 14 wherein at any given control voltage value, the resistance values of said first and second controllable resistors have a fixed relationship to one another and the resistance values of said first and second additional resistors have the same relationship to one another as the resistance values of said first and second controllable resistors.
References Cited (Backward Citations)
US3433937A
Cited
US3667055A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-01-02 | 1981-07-04 | 1982-01-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-01-02 | 1985-07-04 | 1986-01-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-01-02 | 1989-07-04 | 1990-01-03 | $7700.00 | Window Closed / Lapsed |