Patent US3668535A successfully refreshed from Google Patents.
US3668535A
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Logarithmic rf amplifier employing successive detection
Assignee: Varian Medical Systems Inc
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Filing: 1970-01-15
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Granted: 1972-06-06
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Expires: 1990-01-15
Abstract
Abstract A logarithmic radio frequency amplifier is disclosed which employs a series of cascaded RF amplifier stages. Each amplifier stage includes a detector for demodulating the output of each amplifier to produce a video signal. A limiter is provided for each detector for limiting the video signal output of each of the detectors. The limited video output from each successive stage is applied to a summing delay line to produce the logarithmic video output at the end of the delay line.
Inventors
- 👤 Kenneth H Lansdowne
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 17:29
CPC Classifications
H; H03; H03G; H03G7/00; H03G7/06; G; G06; G06G; G06G7/00; G06G7/12; G06G7/24; H03G7/001
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
195 words
In a logarithmic radio frequency amplifier for amplifying an input RF signal and producing an amplified detected envelope output which is a function of the logarithm of the amplitude of the RF input signal, a succession of series RF amplifier means for cascade amplifying the RF input signal, a succession of detector means each being disposed for detection of the envelope of the RF output signal derived from each RF amplifier to produce a succession of demodulated output signals, a succession of limiter means each being disposed for limiting the maximum amplitude of a signal derived from each of said amplifiers, means for summing the succession of demodulated output signals derived from each of said amplifiers to produce the amplified logarithmic detected envelope output signal, THE IMPROVEMENT WHEREIN, each of said limiter means is connected to receive and operate on the demodulated output signal derived from each of said detector means, whereby said limiter means are operable at the lower frequency of the modulation, if any, on the RF input. CM,2Pparatus of claim 1 wherein each of said limiter means is connected in series between said detector means and the output of said summing means.
Claim 2
Dependent Claim
29 words
The apparatus of claim 1 wherein each of said limiter means is connected in parallel with a respective one of said detectors and the output of said summing means.
Claim 3
Dependent Claim
85 words
The apparatus of claim 1 wherein said summing means include a delay line to which the outputs of said seParate limiter means are connected at successive intervals along said delay line with the signal delay between each successive connection on said delay line being approximately equal to the delay experienced by the signal being amplified in passing through each successive cascaded amplifier, and the respective detector and limiter such that the demodulated output signals from successive amplification stages add in phase on said delay line.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-06-06 | 1975-12-06 | 1976-06-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-06 | 1979-12-06 | 1980-06-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-06 | 1983-12-06 | 1984-06-06 | $7700.00 | Window Closed / Lapsed |