Patent EP0385641A2 successfully refreshed from Google Patents.
EP0385641A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
A high efficiency UHF linear power amplifier
Assignee: AT&T Inc
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Filing: 1990-02-21
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Granted: —
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Expires: 2010-02-21
Abstract
Abstract An RF amplifier for a phase and envelope varying signal employs a class C operated device (110) for high efficiency. In order to improve the linearity of the class C operated device (110), a signal (s₂(t)) corresponding to the envelope of the amplifier output is formed and a portion thereof is fedback to an envelope modulation element such as a pulse width modulator (140) connected to the class C operated device (110) to reduce distortion at the amplifier output.
Inventors
- 👤 Reed Edward Fisher
- 👤 Michael Joseph Koch
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 14:43
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/20; H03F3/21; H03F3/217; H03F1/00; H03F1/02; H03F1/0205; H03F1/0211; H03F1/0216; H03F1/0222; H03F1/32; H03F2200/00; H03F2200/15; H03F2200/192; H03F2200/204; H03F2200/222; H03F2200/228; H03F2200/267; H03F2200/351; H03F2200/387; H03F2200/393; H03F2200/75; H03F2200/99
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
241 words
A circuit for amplifylng a radio frequency signal having a varying envelope, comprising an amplifying device having first, second and control electrodes, a supply voltage source, a loading device, means for coupling the radio frequency signal to the amplifying device, means for coupling the first electrode of the amplifying device to the loading device, and characterized by means (101, 105, 120) for separating the envelope variations in the radio frequency signal to form an envelope variation signal and a constant magnitude radio frequency signal, means (105) for coupling the constant magnitude radio frequency signal to the control electrode of the amplifying device, modulating means (140, 145) comprising an input terminal and a pair of output terminals coupled between the supply voltage source and the first electrode of the amplifying device and responsive to the separated envelope variation signal for modulating the signal on the first electrode of the amplifying device, means (125) responsive to the radio frequency signal coupled to the loading device for forming a signal corresponding to the envelope variations of the radio frequency signal at the load device, means (130) responsive to the separated envelope varying signal and the signal corresponding to the envelope variations of the radio frequency signal at the load device for producing a signal representative of the difference therebetween, and means (135) for applying the difference signal to the modulating means input terminal to reduce distortion in the envelope variations at the loading device.
Claim 2
Dependent Claim
241 words
A circuit for amplifylng a radio frequency signal having a varying envelope, comprising an amplifying device having first, second and control electrodes, a supply voltage source, a loading device, means for coupling the radio frequency signal to the amplifying device, means for coupling the first electrode of the amplifying device to the loading device, and characterized by means (101, 105, 120) for separating the envelope variations in the radio frequency signal to form an envelope variation signal and a constant magnitude radio frequency signal, means (105) for coupling the constant magnitude radio frequency signal to the control electrode of the amplifying device, modulating means (140, 145) comprising an input terminal and a pair of output terminals coupled between the supply voltage source and the first electrode of the amplifying device and responsive to the separated envelope variation signal for modulating the signal on the first electrode of the amplifying device, means (125) responsive to the radio frequency signal coupled to the loading device for forming a signal corresponding to the envelope variations of the radio frequency signal at the load device, means (130) responsive to the separated envelope varying signal and the signal corresponding to the envelope variations of the radio frequency signal at the load device for producing a signal representative of the difference therebetween, and means (135) for applying the difference signal to the modulating means input terminal to reduce distortion in the envelope variations at the loading device.
Claim 3
Dependent Claim
23 words
A circuit as claimed in claim 1 wherein the amplifying device (110) is a non-linear amplifying device having first, second and control electrodes.
Claim 4
Dependent Claim
28 words
A circuit as claimed In claim 2 wherein the non-linear amplifying device (110) is a class C operated amplifier device having a base, an emitter and a collector.
Claim 5
Dependent Claim
19 words
A circuit as claimed in claim 3 wherein the modulating means (140, 145) comprises a pulse width modulator (340).
Claim 6
Dependent Claim
55 words
A circuit as claimed in any preceding claim wherein the radio frequency signal has an angle varying carrier, the separating means (301, 305, 320) serves to separate the envelope variations from the angle varying carrier, and the coupling means serves to couple the angle varying carrier to the control electrode of the amplifying device (310).
Claim 7
Dependent Claim
17 words
A circuit as claimed in claim 5 wheirein the angle varying carrier is a frequency varying carrier.
Claim 8
Dependent Claim
19 words
A circuit as claimed in claim 6 wherein the frequency varying carrier comprises a plurality of frequency varying signals.
Claim 9
Dependent Claim
15 words
A circuit as claimed in claim 5 wherein the carrier angle variations are phase variations.
Claim 10
Dependent Claim
39 words
A circuit as claimed in claim 8 wherein the phase variations comprise an M-ary differential phase shift keying modulation having predefined phase shifts and the envelope variations are envelope variations between the predefined phase shifts of the MDPSK modulation.
Claim 11
Dependent Claim
44 words
A circuit as claimed in claim 1 wherein the modulating means (140, 145) comprises a pulse width modulator (140) and filter means (145) coupled between the pulse width modulator and the first electrode for removing high frequency portions of the pulse width modulator output.
Claim 12
Dependent Claim
97 words
A circuit as claimed in any preceding claim wherein the means (120) for forming the separated envelope varying signal means comprises a first diode (570) and means (574, 576) for biasing the first diode, the means (125) for forming the signal corresponding to the envelope variations of the radio frequency signal at the load device comprises a second diode (560) and means (564,567) for biasing the second diode, and the means (564,567,574,576) for biasing the first and second diodes (560, 570) are set to maintain the first and second diodes (560, 570) at substantially similar operating characteristics.
References Cited (Backward Citations)
No citation records indexed.
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