US5789984A
Expired / Lapsed
US
⏱️ 0.0 years remaining
RF power amplifiers
Assignee: Roke Manor Research Ltd
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Filing: 1996-11-01
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Granted: 1998-08-04
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Expires: 2016-11-01
Abstract
Abstract A radio frequency (r.f.) amplifier power control system comprises an r.f. power amplifier for supplying r.f. transmission power to an antenna, a current sensing resistor via which operating current is fed to the power amplifier, a differential amplifier having a first input terminal to which a feed-back voltage derived from the sensing resistor indicative of r.f. transmission power is fed and a second input terminal to which a reference voltage is fed thereby to produce, in the presence of a voltage difference between the feed-back voltage and the reference voltage, a control voltage for the power amplifier, whereby the transmission power is controllable in dependence upon the reference voltage, and a shunt which is fed with current from the sensing resistor. The impedance of the shunt is arranged to vary responsively to the control voltage.
Inventors
- 👤 Michael Colin Davis
- 👤 Martin Victor Whittle
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 16:04
CPC Classifications
H; H03; H03G; H03G3/00; H03G3/20; H03G3/30; H03G3/3036; H03G3/3042; H03F; H03F2200/00; H03F2200/504
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
109 words
An r.f. amplifier power control system, comprising: an r.f. power amplifier for supplying r.f. transmission power to an antenna; a current sensing impedance having an output which feeds operating current to the power amplifier; a differential amplifier having a first input terminal connected to a feed-back voltage derived from the sensing impedance and a second input terminal to which a reference voltage is connected; the differential amplifier having an output control voltage connected to the input of the power amplifier; and a shunt connected to the output of the sensing impedance, the impedance of the shunt is arranged to vary in response to a value of the control voltage.
Claim 2
Dependent Claim
109 words
An r.f. amplifier power control system, comprising: an r.f. power amplifier for supplying r.f. transmission power to an antenna; a current sensing impedance having an output which feeds operating current to the power amplifier; a differential amplifier having a first input terminal connected to a feed-back voltage derived from the sensing impedance and a second input terminal to which a reference voltage is connected; the differential amplifier having an output control voltage connected to the input of the power amplifier; and a shunt connected to the output of the sensing impedance, the impedance of the shunt is arranged to vary in response to a value of the control voltage.
Claim 3
Dependent Claim
16 words
The r.f. amplifier power control system of claim 1, wherein the sensing impedance is a resistor.
Claim 4
Dependent Claim
27 words
The r.f. amplifier power control system of claim 1, wherein the shunt comprises a transistor and the control voltage is applied to a base of the transistor.
Claim 5
Dependent Claim
55 words
The r.f. amplifier control system as claimed in claim 3, wherein a collector of the transistor is connected to the sensing impedance and an emitter of the transistor is coupled via a further resistor to ground, the base of the transistor being coupled via a series resistor to an output terminal of the differential amplifier.
Claim 6
Dependent Claim
21 words
The r.f. amplifier control system of claim 1, further comprising: a transmitter antenna connected to an output from the power amplifier.
Claim 7
Dependent Claim
25 words
The r.f. amplifier control system of claim 1, wherein the power amplifier is a part of a mobile unit transmitter for a mobile radio system.
Claim 8
Dependent Claim
19 words
The r.f. amplifier control system of claim 6, wherein the mobile radio system is a GSM mobile radio system.
Claim 9
Independent Claim
68 words
A method of controlling an r.f. amplifier comprising the steps of: applying an operating current to a power amplifier; generating a feedback signal indicative of the operating current; generating a control signal based on a comparison of the feedback signal with a reference; applying the control signal to the power amplifier; and controlling a shunt connected to the operating current based on a value of the control signal.
Claim 10
Independent Claim
68 words
A method of controlling an r.f. amplifier comprising the steps of: applying an operating current to a power amplifier; generating a feedback signal indicative of the operating current; generating a control signal based on a comparison of the feedback signal with a reference; applying the control signal to the power amplifier; and controlling a shunt connected to the operating current based on a value of the control signal.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-08-03 | 2002-02-02 | 2002-08-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-08-03 | 2006-02-02 | 2006-08-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-08-03 | 2010-02-02 | 2010-08-04 | $7700.00 | Window Closed / Lapsed |