| 摘要 |
A local oscillation circuit (622, 623) in a frequency converter circuit (1141, 1142) includes a resonant circuit (411), and a differential amplifier circuit (421) connected to the resonant circuit. The differential amplifier circuit includes two transistors (511, 521) constituting a differential stage. One end of the resonant circuit is connected to the base of one transistor (511) via a capacitive element (14), and to the collector of the other transistor (512) via a capacitive element (15). The other end of the resonant circuit is connected to only the base of the other transistor via a capacitive element (17). Accordingly, an unbalanced oscillate operation is performed in the local oscillation circuit, leading to reduction of the phase noise caused by decrease in an oscillation output due to the trap phenomenon, and an improvement in reception quality. <IMAGE> |
