| 摘要 |
PURPOSE:To simplify the circuit constitution of reception, by providing the filter passing through the frequency of each area parallelly adding signal to the input terminal selectively, and picking up it at the output terminal with synthesis. CONSTITUTION:The RF signal is received at the antenna 7, it passes through the filters 10, 11 corresponding to the area frequency receiving the service and it is inputted to the RF synthesis circuit 12. The output of the synthesis circuit 12 is the IF signal at the mixer 14 and it is fed to the terminal section 6 via the IF filter 15. The frequency of the local oscillator 13 is made to (f1+f2)/2, taking two area frequencies as f1, f2. |
