EP0630101A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Improvements in or relating to amplifiers

Assignee: Motorola Solutions Inc

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Filing: 1990-11-12

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Granted: —

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Expires: 2010-11-12

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Abstract

Abstract In order to improve the distortion performance of a feed forward corrected amplifier an amplifier arrangement includes a distortion generator 312, intermediate the input 15 and the main amplifier 1. The arrangement is such that the input signal passes to the distortion generator 312 via a coupler 307. The signal passes via a delay network 310 which compensates for the delay of distortion network 312 and is tapped by a coupler 308 to be combined by a coupler 313 with the distorted signal from the distortion generator 312. In this way the output of the distortion generator is subtracted from a sample of the input signal so that only the distortion remains to pass via phase and amplitude correction networks respectively 314 and 315 to be amplified by a gain element 316 before being coupled back into the main signal path by a coupler 309. The correction is active over a portion of the amplifier characteristic only,being the compression region of the amplifier Hence the amplifier compression point may be raised. Raising the compression point increases the overall power handling capability of the amplifier by increasing the level at which the overall arrangement will saturate to cause distortion.

Inventors

👤 Jack Powell

Bibliographic Details

Application Number —

Jurisdiction EP

Data Source google_patents

Last Synchronized 2026-11-08 07:48

CPC Classifications

H; H03; H03F; H03F1/00; H03F1/32; H03F1/3223; H03F1/3229; H03F1/3235; H03F1/3241; H03F1/3247; H03F2200/00; H03F2200/102; H03F2200/57; H03F2201/00; H03F2201/32; H03F2201/3212; H03F2201/3218; H03F2201/3233

Claims Analysis

Total Claims: 5

Claim 1

Independent Claim 237 words

An amplifier arrangement having an input (15) for receiving an input signal, an output (4) and a feed forward correction loop to provide the output (4), the arrangement including a main amplifier (1) and a distortion generator (312) coupled between the input (15) and the amplifier (1), the distortion generator (312) having a distortion characteristic which matches the distortion characteristic of the amplifier (1) over at least a portion thereof to produce a substantially linear overall transfer function, characterised in that said feed forward correction loop includes a comparison loop having comparison means (3) for comparing the output of the amplifier (1) with a delayed (5) input signal to provide an error signal, a cancellation loop including secondary amplifier means (2) for amplifying the error signal, and combining means (16) for combining the amplified error signal with the amplifier output to provide a combined output signal to the output (4), the arrangement further comprising a pilot generator (105) coupled to said amplifier input (13) to introduce a pilot tone therein, detector means (3) for detecting a level of pilot tone in said amplifier output and correction means (10, 11) for correcting the performance of said cancellation loop as a function of said detection, wherein said pilot generator (105) is further coupled to a multiplier (107) receiving said combined output signal, said multiplier (107) producing an output signal arranged to control a loop parameter to effect said correction.

Claim 2

Dependent Claim 20 words

An amplifier arrangement as claimed in claim 1, wherein said portion of said distortion characteristic is substantially the compression region.

Claim 3

Dependent Claim 23 words

An amplifier arrangement as claimed in either claim 1 or claim 2, wherein said distortion generator (312) comprises a model of said amplifier.

Claim 4

Dependent Claim 107 words

An amplifier arrangement as claimed in any preceding claim, wherein said feed forward correction loop further comprises a compensating network (8) coupled between the input (15) and the distortion generator (312), a first detector (17) coupled to said amplifier output to derive a parameter thereof, a second detector (18) coupled to said delayed input signal to derive a parameter thereof, means (14) for comparing respective outputs of said first (17) and second (18) detectors to derive a control signal which is applied to said compensating network (8), the response time of said control signal being less than the period of the highest frequency of said error signal.

Claim 5

Dependent Claim 89 words

An amplifier arrangement as claimed in any preceding claim, wherein said feed forward correction loop further comprises a second compensating network (9) coupled between the input (15) and the distortion generator (312), a third detector (19) coupled to said amplifier output to derive a parameter thereof, a fourth detector (100) coupled to said delayed input signal to derive a parameter thereof, means (12) for comparing respective outputs of said third (19) and fourth (100) detectors to derive a control signal which is applied to said second compensating network (9).

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