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Control Loop Structure for Phase Correction

IP.com Disclosure Number: IPCOM000017936D
Original Publication Date: 2001-Oct-01
Included in the Prior Art Database: 2003-Jul-23
Document File: 2 page(s) / 151K

Publishing Venue

Siemens

Related People

Ralf Wendler: AUTHOR [+2]

Abstract

The principle of operation of the control loop struc- ture for phase correction is explained in the following text.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 89% of the total text.

Information / Kommunikation

einge-  Control Loop Structure for Phase

Correction

Idee: Ralf Wendler, Berlin;

Jörg Braune, Berlin

The principle of operation  of the control loop struc-ture for phase correction is explained in the followingtext.

The output signal of the   pre amplifier  (1) is undis-torted  because  pre  amplifier   (1)  works  as  class  Aamplifier. If  the final stage input power increases andthe output power approaches to the 1dB compressionpoint the output signal is distorted.

This distortion  causes  two  effects.  The  amplitudegain  becomes  smaller  and  the phase differencechanges between output and input of the final stage.

The amplitude problem is solved by an digital am-plitude predistortion,  which  uses  look  up  tables  inorder to correct the amplitude gain.

The phase difference problem is solved by the loopstructure,  which  is  displayed  in  the schematic (seepic.1). If the phase angle is changing at the outputthen the  power probe  (9) delivers the changed phaseto  the  phase  detector   (8).  The  undistorted  signalreaches  phase detector  (8) via  power probe  (2), thedelay line  (5) and an  limiter amplifier  (7). The  delayline  (5) compensates the additional delay caused bythe  signal  path  via  phase  shifter   (3),  final stages,power probe, additional line and limiter amplifier. Inresult the signal delay is equal in both pathes to thephase detector.

The principle operation is as follow. If an phase de-viation appears at the o...