The Boeing Company

Daniel H Koyama

Kurt William Loheit

Craig Schulz

Susan E Bach

Remy O Hiramoto

Suzanne E Kubasek

In a system for modulating an RF carrier, the RF carrier is fed through a lowpass filter and phase shifted approximately &#x2212;90 degrees. The RF carrier is also fed through a high pass filter and phase shifted approximately +90 degrees. A switch connected to the output of the lowpass filter and connected to the output of the highpass filter, selects and outputs either the &#x2212;90 degree phase shifted carrier output from the lowpass filter or the +90 degree phase shifted carrier output from the highpass filter depending on a switching state determined by data bit information received at a data port to produce a BPSK modulated RF carrier. Two such BPSK modulators may be combined using lowpass and highpass filters to form a QPSK modulator. Two such QPSK modulators may be combined with an attenuator to form a QAM modulator.

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Torrance, CA, United States of America

Daniel H Koyama