| 摘要 |
PROBLEM TO BE SOLVED: To provide a transmitter dealing with two radio frequencies that prevents transmission spurious radiation, prevents malfunction of its synthesizer section and reduces its size and cost. SOLUTION: The synthesizer section of a PLL circuit configuration, that is provided in two radio sections different in transmission frequency and from which a local signal floa for converting the frequency of QPSK modulation wave by a mixer is obtained, is provided with a variable phase shifter 17 that varies an impedance of a frequency control terminal of a VCO 13. The variable phase shifter 17 is controlled so as to cause a high impedance against an interference wave from the other radio section by a phase control signal. |
