ORTHOGONAL PHASE MODULATION CIRCUIT

摘要

PURPOSE:To perform the switching of a carrier frequency at high speed by partially taking charge of the switching of the carrier frequency with a frequency convert phase modulation part composed of a digital circuit for performing phase modulation and a synthesizer. CONSTITUTION:A frequency phase modulation part 110 composed of the digital circuit generates a modulated output signal for which frequency conversion and orthogonal phase modulation are performed by orthogonal sine waves at plural frequencies instructed to a base band signal 191 by the low-order digit of a carrier frequency instructing signal 192. This phase-modulated output signal is mixed with the output carrier signal of a synthesizer 107 for outputting a carrier signal based on the high-order digit of the carrier frequency instructing signal 192, and a phase-modulated ratio frequency signal is generated. In this case, the frequency convert phase modulation part 110 performs the frequency conversion and the orthogonal phase modulation by generating the orthogonal sine waves at the small number of low frequencies instructed by the low-order digit of the carrier frequency instructing signal 192 without necessity for performing the modulation corresponding to all the channels.