| 摘要 |
PROBLEM TO BE SOLVED: To improve linearity in a transmission signal by correcting the delay difference between two signal paths composited after passing through the path having a different amount of delay for demodulation, such as I and Q signals in a quadrature modulation system and r andθsignals in an EER system, in radio communication equipment. SOLUTION: There are provided a DA conversion circuit for converting two signals separated from an inputted digital signal or two digital signals inputted after the separation, a composite circuit for composing the analog signal converted by the DA conversion circuit, a distribution circuit for taking out one portion of the composited signal as a feedback signal, an AD conversion circuit for converting the feedback signal to the digital signal, an oscillation circuit for supplying an operating clock signal to each DA conversion circuit and the AD conversion circuit, a first separation circuit for separating the feedback signal converted by the AD conversion circuit into two signals, and a comparison circuit for comparing the separated input signal with the feedback signal separated by the first separation circuit. The oscillation circuit controls the output, based on the comparison result by the comparison circuit. COPYRIGHT: (C)2005,JPO&NCIPI
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