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LOAD PULL- MEASUREMENT OF LOAD IMPEDANCE OF HIGH POWER DEVICES DENNIS POULIN NETWORK MEASUREMENTS DIVISION 1400 I=OUNTAIN GROVE PARKWAY SANTA ROSA, CALIFORNIA 95404 Flin- HEWLETT ~~ PACKARD www.HPARCHIVE.com INTRODUCTION Most microwave designers are familiar with the use of S parameters for design of small signal amplifiers. However, small signal S parameters are useless when a designer is concerned about designing or troubleshooting an oscillator, large signal amplifier or an amplifier operating REAL TIME in a mode other than Class A. In these circumstances, it is necessary to measure MANUAL LOAD PULL the load impedance required under the actual operating conditions. This type MEASUREMENT SYSTEM of measurement has classically been referred to as a "load pull" measurement. This paper describes a simple system to