Cordless telephone with digital frequency adjustment

摘要

A digitally-controlled frequency synthesizer circuit is provided. The synthesizer circuit has a synthesizer that provides as an output a signal that is based on a reference frequency supplied from a resonator circuit. The reference frequency of the resonator circuit can be tuned by varying the control voltage applied to a voltage variable capacitor that is coupled to the resonator circuit. The voltage variable capacitor is located on the synthesizer. A digital-to-analog converter is also located on the synthesizer. The digital-to-analog converter provides the analog control voltage for the voltage variable capacitor based on digital voltage control data.