Vector modulators and calibration thereof

专利名称：Vector modulators and calibration thereof发明人：Edwards, Allen P.,Gildea, David R.,Lau, Chung

Yiu

申请号：EP87309238.1申请日：19871020公开号：EP0265218B1公开日：19931215

摘要：Calibration of a vector modulator is done using a scalar detector (220) tomeasure the amplitude of the RF output signal, phase shifters (221, 223) to adjust therelative phases of the I and Q components of the RF carrier, and variable attentuators(225, 227) in the I and Q modulation signal input lines to adjust the relative amplitude ofthe modulation signals. DC signal sources provide reference signals for the I and Qmodulation inputs, carrier leak compensation signals, and calibration signals for balancingthe amplitude of the I and Q modulation signals. An iterative four step calibrationprocess is followed until no change in the results is observed. The quadrature phaseerror is minimized by adjusting the phase shifters (221, 223). The carrier leakage isminimized by adjusting the carrier leak compensation sources (229, 231) to minimize RFoutput with the modulation inputs grounded (247, 247). The amplitudes of the I and Qmodulation signals are balanced by adjusting the attenuators (225, 227) until the outputamplitudes are equal. Finally, the quadrature calibration signal sources (235, 237) areadjusted until the output amplitudes they produce are balanced.

申请人：HEWLETT PACKARD CO

地址：US

国籍：US

代理机构：Williams, John Francis

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