US3745374A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Logarithmic amplifier and limiter
Assignee: United States Department of the Navy
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Filing: 1972-01-26
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Granted: 1973-07-10
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Expires: 1992-01-26
Abstract
Abstract A solid state logarithmic amplifier and limiter device using seven logarithmic stages to achieve a 70 db logarithmic range. Without the use of vacuum tubes or diodes, the input voltage is attenuated and amplified in separate channels to produce seven logarithmic currents which are summed to produce the log amplified and limited output.
Inventors
- 👤 J Hecker
- 👤 R Zinke
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 22:54
CPC Classifications
G; G06; G06G; G06G7/00; G06G7/12; G06G7/24
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
168 words
A logarithmic amplifier and limiter device for providing an output signal representative of the logarithm of an input signal comprising: a plurality of amplifier stages, each stage including a voltage amplifier and a logarithmic current amplifier, both amplifiers in each stage being connected to a common input; means for connecting the output of each voltage amplifier to the input of another voltage amplifier, whereby said voltage amplifiers are connected in cascade; a plurality of attenuators connected in cascade; means for connecting said input signal to the inputs of the first of said cascaded voltage amplifiers and the first of said cascaded attenuators; a plurality of logarithmic current amplifiers, the number being the same as the number of attenuators, each one connected to the output of one said attenuators; and, a first output means connected to the outputs of all of said logarithmic current amplifiers including those in said amplifier stages, for summing the logarithmic currents and generating at its output a logarithmic representation of the device''s input signal.
Claim 2
Dependent Claim
168 words
A logarithmic amplifier and limiter device for providing an output signal representative of the logarithm of an input signal comprising: a plurality of amplifier stages, each stage including a voltage amplifier and a logarithmic current amplifier, both amplifiers in each stage being connected to a common input; means for connecting the output of each voltage amplifier to the input of another voltage amplifier, whereby said voltage amplifiers are connected in cascade; a plurality of attenuators connected in cascade; means for connecting said input signal to the inputs of the first of said cascaded voltage amplifiers and the first of said cascaded attenuators; a plurality of logarithmic current amplifiers, the number being the same as the number of attenuators, each one connected to the output of one said attenuators; and, a first output means connected to the outputs of all of said logarithmic current amplifiers including those in said amplifier stages, for summing the logarithmic currents and generating at its output a logarithmic representation of the device''s input signal.
Claim 3
Dependent Claim
43 words
A logarithmic amplifier and limiter device as in claim 1 wherein: said first output means also provides a modulated output signal; and a second output means is connected to the output of the last cascaded voltage amplifier for providing a voltage limited output.
Claim 4
Dependent Claim
54 words
A logarithmic amplifier and limiter device as in claim 2 wherein: said voltage amplifier connecting means includes a plurality of filters connected one to each voltage amplifier output; and said second output means comprises a differential amplifier whose input is connected to the last of said filters and which produces a limited IF signal.
Claim 5
Dependent Claim
67 words
A logarithmic amplifier and limiter device of claim 2 wherein said first output means includes: a peak detector and first filter; an emitter follower connected to said peak detector and first filter for providing said modulated output signal; an attenuator and second filter connected to said peak detector and first filter; and an operational amplifier connected to said attenuator and second filter for providing said logarithmic output.
Claim 6
Dependent Claim
31 words
A logarithmic amplifier and limiter device of claim 4 wherein: the attenuator of said attenuator and second filter is manually adjustable; and said operational amplifier has a manually adjustable D.C. offset.
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) | 1976-07-09 | 1977-01-08 | 1977-07-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-09 | 1981-01-08 | 1981-07-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-09 | 1985-01-08 | 1985-07-10 | $7700.00 | Window Closed / Lapsed |