AN APPARATUS FOR AUTO-CALIBRATION OF FILTER CHARACTERISTIC

摘要

An apparatus for automatically calibrating filter characteristics is provided to perform calibration more accurately by sequentially correcting the central frequency and quality coefficient, and provide noise-resistance characteristics. A variable filter(200) is varied according to a control signal to set a passband, and makes a frequency signal from a frequency synthesizer pass therethrough. A power detecting unit(300) detects power of the signal which has passed through the variable filter(200). An AD converter(400) converts a detect signal of the power detecting unit(300) into a digital signal. A filter controller(500) calculates a filter characteristics parameter based on the digital signal and controls the passband of the variable filter(200) such that the filter parameter is included in a reference parameter area. A band adjusting unit(600) varies the passband of the variable filter(200) under control of the filter controller(500).