| 摘要 |
PROBLEM TO BE SOLVED: To prevent occurrence of an unnecessary wave and abnormal oscillation in a frequency conversion section in the case of realizing radio communication where carrier frequencies have a relating of 1:2 with a radio communication equipment having a single local oscillation circuit. SOLUTION: The frequency multiplying circuit configuring a frequency conversion section is provided with an input section 37 of an oscillation signal from a local oscillation circuit, an amplifier element 40 whose linear/nonlinear operation is selected by a control signal 54 to amplify an oscillation signal, and an output circuit where switches 41, 48 connect/disconnect filter circuits 42, 50 blocking a prescribed multiplied wave to/from an output of the amplifier element 40 so as to selectively output a fundamental wave and multiplied waves to an output terminal 53 of a mixer. Since the amplifier element 40 that makes linear or nonlinear operation and the output circuit whose frequency pass characteristic can be changed are connected in series, production of an unnecessary wave and abnormal oscillation can be prevented. |
