FREQUENCY SYNTHESIZER, WIRELESS COMMUNICATION SYSTEM, AND SEMICONDUCTOR DEVICE

摘要

A transmission frequency modulation of wireless communication is made to be possible to correspond to a multiple-value frequency modulation with transmission data of a plurality of bits while a circuit area is suppressed to increase. When a transmission frequency of wireless communication is modulated, responding data by a digital filter is calculated by a logic circuit provided in a transmission modulator. Thus, since a changing volume of divided data are calculated by the logic circuit, no ROM is needed to store the responding data, and the circuit area can be suppressed to increase even in the case of a frequency change of a reference signal or in compliance with a multiple-value frequency modulation with transmission data of a plurality of bits. Further, a modulation process of the transmission frequency can be carried out in a plurality of steps divided by using timing in synchronization with a clock signal, so that it is possible to make a transmission frequency spectrum narrow in band.