| 摘要 |
PROBLEM TO BE SOLVED: To provide a receiving circuit for obtaining stable reception characteristics against environmental change due to the change of use configurations. SOLUTION: A local signal whose frequency is the same as reception frequency is oscillated from a local oscillator 11 of a direct conversion receiver, and the local signal is output through a high frequency switch 13, an impedance equalizer 8, a high frequency switch 4, and a directional coupler 3 to an antenna 1. The reflection quantity of a reflected wave from the antenna 1 is measured by a reflection quantity detector 7, and the impedance of an impedance matching circuit 2 is adjusted to a direction where reflection is reduced based on the measurement result. COPYRIGHT: (C)2007,JPO&INPIT
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