Frequency generator and communication system using the same

摘要

A frequency generator which can perform stable frequency oscillation unaffected by temperature variation. A frequency generator having a differential amplifier (1) having an LC resonance circuit (10) as a load and buffer circuits (21, 22) feeding back an output of the differential amplifier to its input, wherein a temperature coefficient converter (5) converting an output voltage of a reference voltage generator (4) and its temperature dependence to a voltage having a predetermined voltage and temperature coefficient and outputting it is provided to control bias currents IEF of emitter follower circuits to be in proportion to temperature variation. There are a characteristic in which delay time of the emitter follower circuits constructing the buffer circuits is in inverse proportion to a transconductance of transistors and a characteristic in which the transconductance is in inverse proportion to temperature and is in proportion to the bias currents IEF. An oscillation frequency stable to temperature variation can be obtained.