Tuned amplifier

They are widely used in a variety of wireless applications.

There are several tuning schemes in use, The RF amplifier stages of radio receivers require variable tuning to select the station, usually achieved by using variable capacitors in the resonant circuits.

The tuning of all stages of the RF amplifier have to be kept in step along with the frequency of the local oscillator.

Since linked tuning becomes more difficult as the number of stages increase, the number of RF stages is kept to a minimum with most of the tuning happening in the IF stages.

The IF amplifier operates at a fixed frequency making tuning much easier.