US3728636A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Inverse logarithmic function generator
Assignee: United States Department of the Navy
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Filing: 1971-12-28
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Granted: 1973-04-17
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Expires: 1991-12-28
Abstract
Abstract An inverse or anti-logarithmic function generator wherein the systems input is one input of a differential amplifier whose output is integrated and fed into the input of a log generator, whose output is the other input to the differential amplifier. The integrated output of the differential amplifier is the inverse log of the systems input.
Inventors
- 👤 C Hill
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 19:26
CPC Classifications
H; H03; H03G; H03G3/00; H03G3/20; H03G3/30; H03G3/3005; G; G06; G06G; G06G7/00; G06G7/12; G06G7/24; H03G1/00; H03G1/0005
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
89 words
An inverse logarithmic function generator comprising: a differential amplifier having a first and second inputs, an output, and an integrator feedback; a logarithmic function generator whose input is connected to said output of said differential amplifier and whose output is connected to said first inputs of said differential amplifier; and a control voltage connected to said second input of said differential amplifier, whereby the voltage on said output of said differential amplifier is the inverse logarithm of said control voltage and is held at that value by said integrator.
Claim 2
Dependent Claim
89 words
An inverse logarithmic function generator comprising: a differential amplifier having a first and second inputs, an output, and an integrator feedback; a logarithmic function generator whose input is connected to said output of said differential amplifier and whose output is connected to said first inputs of said differential amplifier; and a control voltage connected to said second input of said differential amplifier, whereby the voltage on said output of said differential amplifier is the inverse logarithm of said control voltage and is held at that value by said integrator.
Claim 3
Dependent Claim
54 words
An inverse logarithmic function generator according to claim 1 further including a biasing means connected between the output of said log function generator and said first input of said differential amplifier so that for a given voltage out of said differential amplifier there is zero volts on said first input of said differential amplifier.
Claim 4
Dependent Claim
55 words
An inverse-logarithmic function generator according to claim 2, wherein said biasing means comprises: a transistor with its emitter connected to the output of said log generator and its base and collector shorted together at said first input of said differential amplifier; and a voltage supply connected through a resistor to said shorted base and collector.
Claim 5
Dependent Claim
116 words
An inverse-logarithmic function generator according to claim 1, wherein said log function generator comprises: an operational amplifier with a first end of a first resistor connected to its output; a transistor whose base is grounded, its collector connected to the input of said operational amplifier, and its emitter connected to the second end of said first resistor; and a first end of a second resistor connected to the junction of the input of said operational amplifier and said transistor''s collector, whereby the second end of said second resistor is the input of said log generator and the junction of said emitter and said second end of said first resistor is the output of said log generator.
Claim 6
Dependent Claim
155 words
An amplifier system with log linear AGC comprising: a first amplifier with a signal input, a control voltage input and an output; a second amplifier whose input is connected to the output of said first amplifier and which is of fixed gain; a third amplifier whose signal input is connected to the output of said second amplifier and which has a control voltage input and an output; a fourth amplifier whose input is connected to the output of said third amplifier and which is fixed gain; and an inverse log generator having an input and an output, said input connected to receive a signal feedback from the output of said fourth amplifier and said output connected to said control voltage inputs of said first and third amplifiers, whereby the input of said first amplifier is the input of said amplifier system and the output of said fourth amplifier is the output of said amplifier system.
Claim 7
Dependent Claim
155 words
An amplifier system with log linear AGC comprising: a first amplifier with a signal input, a control voltage input and an output; a second amplifier whose input is connected to the output of said first amplifier and which is of fixed gain; a third amplifier whose signal input is connected to the output of said second amplifier and which has a control voltage input and an output; a fourth amplifier whose input is connected to the output of said third amplifier and which is fixed gain; and an inverse log generator having an input and an output, said input connected to receive a signal feedback from the output of said fourth amplifier and said output connected to said control voltage inputs of said first and third amplifiers, whereby the input of said first amplifier is the input of said amplifier system and the output of said fourth amplifier is the output of said amplifier system.
Claim 8
Dependent Claim
29 words
An amplifier system with log linear AGC according to claim 5 wherein said first and third amplifiers are amplifiers whose gain are the linear function of its control voltage.
Claim 9
Dependent Claim
100 words
An amplifier system with log linear AGC according to claim 6 wherein said inverse log generator comprises: a differential amplifier having a first and second inputs, an output, and an integrator feedback; a logarithmic function generator whose input is connected to said output of said differential amplifier and whose output is connected to said first inputs of said differential amplifier; and a control voltage connected to said second input of said differential amplifier, whereby the voltage on said output of said differential amplifier is the inverse logarithm of said control voltage and is held at that value by said integrator.
Claim 10
Dependent Claim
119 words
An amplifier system with log linear AGC according to claim 7 wherein said log function generator comprises: an operational amplifier with a first end of a first resistor connected to its output; a transistor whose base is grounded, its collector connected to the input of said operational amplifier, and its emitter connected to the second end of said first resistor; and a first end of a second resistor connected to the junction of the input of said operational amplifier and said transistor''s collector, whereby the second end of said second resistor is The input of said log generator and the junction of said emitter and said second end of said first resistor is the output of said log generator.
References Cited (Backward Citations)
US3448289A
Cited
US3524074A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-04-16 | 1976-10-16 | 1977-04-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-16 | 1980-10-16 | 1981-04-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-16 | 1984-10-16 | 1985-04-17 | $7700.00 | Window Closed / Lapsed |