| 摘要 |
A tuner includes a low noise amplifier (LNA), a first received signal strength indicator (RSSI), a mixer, an intermediate frequency (IF) filter, a second RSSI and an adjustment unit. The LNA amplifies a radio frequency (RF) signal. The first RSSI detects received signal strength indication of the RF signal and obtains a first signal strength voltage. The mixer is coupled to the LNA and down-converts the RF signal into a first IF signal according to a local oscillation frequency. The IF filter is coupled to the mixer and filters the first IF signal to obtain a second IF signal. The second RSSI detects received signal strength indication of the second IF signal and obtains a second signal strength voltage. The adjustment unit adjusts a gain of the LNA according to the first signal strength voltage and the second signal strength voltage. |
