| 摘要 |
PROBLEM TO BE SOLVED: To provide a circuit adjustment technology for highly accurately correcting the dissidence between the characteristics of a circuit through which an I signal passes and the characteristics of a circuit through which a Q signal passes. SOLUTION: A high frequency IC provided with: demodulation circuits (232a, 232b) for demodulating a received signal to produce I and Q signals; amplifier circuits (240a, 240b) with a variable gain for respectively amplifying the I and Q signals demodulated by the demodulation circuits to a desired level; low-pass filters (261a, 261b) for eliminating the spurious waves respectively from the I and Q signals at a transmission side; and modulation circuits (233a, 233b) for applying quadrature modulation to the I and Q signals at the transmission side passing through the low-pass filters, is characterized in that the high frequency IC includes signal selection means (271, 272) for selecting the output signals of the demodulation circuits or the signals at the transmission side passing through the low-pass filters and supplying the selected signals to the amplifier circuits and located between the demodulation circuits and the amplifier circuits. COPYRIGHT: (C)2005,JPO&NCIPI
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