| 摘要 |
PROBLEM TO BE SOLVED: To provide the radio relay amplifier installed at a dead band that satisfies tight requirements for out-band attenuation at a transmission reception frequency band. SOLUTION: An outgoing amplifier section 3 (incoming amplifier section 4) is provided with an intermediate frequency stage 32(46) to convert a high frequency RF (900 MHz) into an intermediate frequency IF (90 MHz) to increase an attenuation gradient of a filter. In the intermediate frequency stage 32, a non-polar BPF 37, a polar LPF 39 and a polar HPF 40 are connected in cascade, the intermediate frequency component is selectively amplified, the increase in loss is suppressed and a low noise amplifier section 31 and a high power amplifier section 33 maintain a noise figure and a high output. |
