US3684977A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Adjustable frequency generator equipments
Assignee: Marconi Instruments Ltd
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Filing: 1970-10-19
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Granted: 1972-08-15
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Expires: 1990-10-19
Abstract
Abstract An adjustable frequency generator equipment having automatically controlled output level and low harmonic distortion comprises an adjustable R.F. oscillator, a variable bandwidth low pass filter, a detector and a comparator. The detector, at the output of the filter, provides a D.C. output proportional to the R.F. input thereto. This D.C. voltage is fed to one terminal of the comparator, and the output from the comparator controls varactor diodes in the filter, thereby automatically adjusting the upper cut-off frequency of the filter to a value close to the fundamental frequency of the oscillator. The output level of the equipment is adjusted by varying the reference voltage applied to a second terminal of the comparator.
Inventors
- 👤 Roger Stanley Viles
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 09:56
CPC Classifications
H; H03; H03B; H03B23/00
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
155 words
An adjustable generator equipment comprising a source of oscillations of adjustable frequency, a low pass filter of adjustable upper cut-off frequency fed with oscillations from said source, a rectifier circuit connected to the output of the filter which provides a D.C. output that is substantially proportional to the level of the R.F. input thereto; a comparator and a reference D.C. voltage source wherein said comparator is adapted to compare said D.C. output from the rectifier circuit with D.C. voltage from the reference D.C. voltage source to derive a D.C. control voltage which is applied as adjustment controlling voltage to the filter for automatically adjusting said upper cut-off frequency of the filter to a value lower than the fundamental input frequency supplied to the filter and for maintaining the level of the filter output at a substantially constant level, said constant level being determined by the value of the voltage from said reference D.C. voltage source.
Claim 2
Dependent Claim
155 words
An adjustable generator equipment comprising a source of oscillations of adjustable frequency, a low pass filter of adjustable upper cut-off frequency fed with oscillations from said source, a rectifier circuit connected to the output of the filter which provides a D.C. output that is substantially proportional to the level of the R.F. input thereto; a comparator and a reference D.C. voltage source wherein said comparator is adapted to compare said D.C. output from the rectifier circuit with D.C. voltage from the reference D.C. voltage source to derive a D.C. control voltage which is applied as adjustment controlling voltage to the filter for automatically adjusting said upper cut-off frequency of the filter to a value lower than the fundamental input frequency supplied to the filter and for maintaining the level of the filter output at a substantially constant level, said constant level being determined by the value of the voltage from said reference D.C. voltage source.
Claim 3
Dependent Claim
158 words
An adaptor, suitable for connection in cascade with an adjustable frequency generator, said adaptor comprising a low pass filTer of adjustable upper cut-off frequency fed with oscillations from said source; a rectifier circuit connected to the output of the filter which provides a D.C. output that is substantially proportional to the level of the R.F. input thereto; a comparator and a reference D.C. voltage source wherein said comparator is adapted to compare said D.C. output from the rectifier circuit with D.C. voltage from the reference D.C. voltage source to derive a D.C. control voltage which is applied as adjustment controlling voltage to the filter for automatically adjusting said upper cut-off frequency of the filter to a value lower than the fundamental input frequency supplied to the filter and for maintaining the level of the filter output at a substantially constant level, said constant level being determined by the value of the voltage from said reference D.C. voltage source.
Claim 4
Dependent Claim
158 words
An adaptor, suitable for connection in cascade with an adjustable frequency generator, said adaptor comprising a low pass filTer of adjustable upper cut-off frequency fed with oscillations from said source; a rectifier circuit connected to the output of the filter which provides a D.C. output that is substantially proportional to the level of the R.F. input thereto; a comparator and a reference D.C. voltage source wherein said comparator is adapted to compare said D.C. output from the rectifier circuit with D.C. voltage from the reference D.C. voltage source to derive a D.C. control voltage which is applied as adjustment controlling voltage to the filter for automatically adjusting said upper cut-off frequency of the filter to a value lower than the fundamental input frequency supplied to the filter and for maintaining the level of the filter output at a substantially constant level, said constant level being determined by the value of the voltage from said reference D.C. voltage source.
Claim 5
Dependent Claim
43 words
Apparatus as claimed in claim 2 wherein the low pass filter includes at least one reactance constituted by a varactor diode so connected therein that the upper cut-off frequency thereof is adjustable by an adjustable control D.C. bias voltage applied to said diode.
Claim 6
Dependent Claim
24 words
Apparatus as claimed in claim 3 wherein the filter includes at least one capacitative shunt arm containing two voltage-controlled varactor diodes back to back.
Claim 7
Dependent Claim
13 words
Apparatus as claimed in claim 2 wherein the comparator is a differential amplifier.
Claim 8
Dependent Claim
14 words
Apparatus as claimed in claim 2 wherein the reference D.C. voltage source is adjustable.
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) | 1975-08-15 | 1976-02-14 | 1976-08-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-15 | 1980-02-14 | 1980-08-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-15 | 1984-02-14 | 1984-08-15 | $7700.00 | Window Closed / Lapsed |