Which stage of a receiver has its input and output circuits tuned to the received frequency?

The RF amplifier is the first active stage in a typical communications receiver, located right after the antenna and before the mixer. Its primary job is to amplify the weak, incoming radio signal at its original frequency before any conversion takes place. Because it processes the original over-the-air signal, both the input and output circuits of the RF amplifier must be tuned precisely to the received frequency. This helps provide initial filtering and prevents out-of-band signals from reaching the mixer. The local oscillator generates a completely different offset frequency, the detector operates on the intermediate frequency (IF), and the audio amplifier operates on baseband audio, meaning none of them are tuned to the actual received RF.