| 摘要 |
<p>PROBLEM TO BE SOLVED: To eliminate disturbance due to an image signal even when the device is used in a hand by providing an attenuating means which attenuates the image signal to a reception signal on the output side of a high-frequency amplifier. SOLUTION: An antenna common unit 1 which separates a transmit and a reception signal is connected to an antenna 1, and a transmitting circuit part 3 and a receiving circuit part 4 are connected to the antenna common unit 2. A signal received by the antenna 1 is amplified by the high-frequency amplifier 6 and converted by a mixer 8 into an intermediate-frequency signal. As the means which attenuates the image signal inputted to the antenna 1, an image trap circuit 10 consisting of an inductor 10a and a capacitor 10b connected to each other in series is provided between a band-pass filter 7 and a mixer 8 provided on the output side of the high-frequency amplifier 6. The high-frequency amplifier 6 functions as a buffer amplifier and variation in the impedance of the antenna 1 is not transmitted directly to the image trap circuit 10.</p> |
