| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor device and a radio communication instrument which can reduce interference to a local oscillator caused by second harmonic of a transmission output.SOLUTION: A semiconductor device includes: first and second transmission paths including first and second transmission amplifiers, respectively; a local oscillator for outputting a carrier signal; a phase shifter for dividing a frequency of the carrier signal into halves to output a plurality of local signals having a phase difference of 90 degrees from one another; and first and second mixer circuits for multiplying the first and second baseband signals by the local signals having phases shifted by 90 degrees from each other. The semiconductor device comprises: a quadrature modulator for combining outputs from the first and second mixer circuits and outputting the resultant; and a 90 degree phase shifter to which the output from the quadrature modulator is input and which obtains 90 degree phase difference outputs each having a phase difference of 90 degrees from each other. The 90 degree phase difference outputs are input to first and second transmission amplifiers and transmission outputs from the first and second transmission paths have a phase difference of 90 degrees from each other and the transmission outputs are combined to generate a radio frequency signal. |
