US4418317A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Logarithmic amplifier utilizing positive feedback
Assignee: Tektronix Inc
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Filing: 1981-05-18
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Granted: 1983-11-29
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Expires: 2001-05-18
Abstract
Abstract A non-linear amplifier circuit that may be used to provide a logarithmic amplification characteristic. The circuit includes an amplification stage employing positive non-linear feedback for low level input signals to reduce the input capacitance of the amplifier. For large level input signals the feedback is eliminated.
Inventors
- 👤 Glenn Bateman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 14:04
CPC Classifications
G; G06; G06G; G06G7/00; G06G7/12; G06G7/24
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
64 words
A non-linear amplifier, comprising: an amplifier stage having an input and an output; a non-linear element coupled between said input and a reference potential level; a constant current source coupled to said input; and a feedback network coupled from said output to said input for providing positive feedback from said output to said input when the input signal is less than a predetermined value.
Claim 2
Dependent Claim
64 words
A non-linear amplifier, comprising: an amplifier stage having an input and an output; a non-linear element coupled between said input and a reference potential level; a constant current source coupled to said input; and a feedback network coupled from said output to said input for providing positive feedback from said output to said input when the input signal is less than a predetermined value.
Claim 3
Dependent Claim
86 words
An amplifier according to claim 1, wherein the feedback network comprises a diode having a cathode which is connected to said output and also having an anode, and a capacitor connected between the anode of said diode and said input, and the amplifier further comprising voltage source means connected to the anode of the diode whereby the diode is forward biased when the amplifier input signal is less than said predetermined value and reverse biased when the amplifier input signal is greater than said predetermined value.
Claim 4
Dependent Claim
35 words
An amplifier according to claim 2, wherein the potential of said voltage source means is such that said predetermined value is substantially equal to the value of the output current from said constant current source.
Claim 5
Dependent Claim
23 words
An amplifier according to claim 1, further comprising a circuit element connected to the feedback network for providing temperature compensation to said amplifier.
Claim 6
Dependent Claim
81 words
An amplifier according to claim 4, further comprising a voltage source, and wherein the feedback network comprises a diode having a cathode which is connected to said output and also having an anode, and a capacitor connected between the anode of said diode and said input, and wherein the temperature compensation circuit element comprises a second diode having an anode which is connected to the anode of the first diode and having a cathode which is connected to said voltage source.
Claim 7
Dependent Claim
46 words
An amplifier according to claim 5, further comprising a second voltage source connected to the anodes of the first and second diodes, the relative potentials of the voltage sources establishing equal current flow through the two diodes when no input signal is applied to said amplifier.
References Cited (Backward Citations)
US3254304A
Cited
US3562550A
Cited
US3992622A
Cited
US4259641A
Cited
US4236126A
Cited
US4323798A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-11-28 | 1987-05-30 | 1987-11-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-11-28 | 1991-05-30 | 1991-11-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-11-28 | 1995-05-30 | 1995-11-29 | $7700.00 | Window Closed / Lapsed |