| 摘要 |
The invention describes an intermediate frequency input circuit (1), which is coupled between output nodes of a frequency mixing circuit (2) and input nodes of an intermediate frequency amplifier circuit (3). The intermediate frequency circuit (1) comprises a first inductor (4), a first capacitor (6) and a third capacitor (8), which are in resonance with a lower intermediate frequency and a second inductor (5), a second capacitor (7), a fourth capacitor (8), which are in resonance with an upper intermediate frequency. These resonant frequencies are coupled by a fifth capacitor (10) in order to obtain a flat graph of a frequency characteristic of the intermediate frequency input circuit 1. |
