RECEIVER WITH GAIN CALIBRATION FUNCTION

摘要

PROBLEM TO BE SOLVED: To obtain a constant gain over an entire range of received frequencies without being affected by a secular change or a replaced module. SOLUTION: A control section 5 controls a calibration signal generating section 6 to output a calibration signal with a prescribed level over the entire range of received frequencies to an RF reception section 2 in a gain calibration mode. An A/D converter section 4 A/D converts a level of a calibration signal outputted from the RF reception section 2 via an IF amplifier section 3 and the control section 5 receives the result. The control section 5 varies an attenuator 2b of the RF reception section so that a difference between the level of the calibration signal and a level after A/D conversion falls within a prescribed level range and stores its setting value into a storage section 5a as gain calibration data. In the case of a normal mode, the gain calibration data corresponding to a selected reception frequency are read from the storage section 5a to set an attenuation of the atennuator 2b of the RF reception section 2. Thus, the RF reception section 2 can obtain a constant gain for all the reception frequencies.