| 摘要 |
<p>PURPOSE:To reduce the size of the device by inputting the fundamental frequency of the output of a local oscillation circuit for transmission or its multiplied frequency to a mixer and converting a common IF signal into an RF signal of a 1st or 2nd band. CONSTITUTION:For transmission using the 1st band, a switch 6 is set to a terminal (a), the fundamental wave of a frequency synthesizer 4 is inputted as a local oscillation signal to the mixer 3, and the IF signal is converted up to the transmission frequency of the 1st band. Then a 1st RF circuit 7 removes an image frequency component and the signal is sent. For transmission using the 2nd band, the switch 6 is set to a terminal (b), the output of the synthesizer 4 is inputted to a doubler circuit 5, and a generated 2nd higher harmonic is used as the local oscillation signal to convert an IF signal up to the transmission frequency of the 2nd band by the mixer 3, thereby transmitting the signal. Thus, circuits shared for communication in the 1st and 2nd bands are increased to reduce the size of the device.</p> |
