| 摘要 |
PROBLEM TO BE SOLVED: To maintain high precision even when widening a frequency band of a frequency conversion circuit. SOLUTION: A band hardly deteriorated by a secular change or the like within the frequency band of the frequency conversion circuit is used as a reference band, and an ideal characteristic thereof is stored preliminarily. A calibration signal is supplied from a calibration signal source built in the frequency conversion circuit to the frequency conversion circuit, a characteristic of the reference band is measured to store a difference with respect to the ideal characteristic. Then, the calibration signal is supplied to acquire a characteristic data of the frequency band other than the reference band, and a correction factor is calculated to correct the characteristic data corrected in response to the difference to the ideal characteristic. When using the frequency conversion circuit, a frequency area data is corrected using the correction factor to keep the high precision even in the widened frequency band. COPYRIGHT: (C)2005,JPO&NCIPI
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