AnX-band evenharmonic typedirect converter forCDMA satellite communications
Hiroshi Ikematsu, Kenji Kawakami, Kenji Itoh · 1998
This paper describes anX-band evenharmonic type direct converter(EH-DC) usedinearth stations for CDMAsatellite communications. Technicalfeatures ofthis EH-DCareasfollows: (a)Carrier leakage ofamodulator isextremely lowbyemploying anevenharmonic mixer(EH-MIX). (b) Highaccuracy ofademodulator(low amplitude error andphase error) isachieved byemploying anevenharmonic quadrature mixer(EH-QMIX). (c) Automatic frequency control(AFC) function isrealized byemploying aPLLfrequency synthesizer driven byadirect digital synthesizer(DDS) with Hz-order tuning. Experimental results inX-band indicate that theproposed EH-DChasnodegradation ofBERcharacteristics compared with aheterodyne type transceiver