What is the use of local oscillator?

Answer 1

Trasmitting stations have their own transmitting frequency.

No one can construct an amplifier which amplifies signals over a wide range.

So every transmitting frequency has to be changed to one particular frequency. This is known as INTERMEDIATE frequency (IF)

This is quite possible by getting beats.

So a signal is to generated whose frequency is just more than the incoming frequency by IF

This signal is named as local singnal which is generated by the LOCAL oscillator.

Answer 2

A local oscillator generates a radio frequency signal that mixes with the incoming signal in a superheterodyne receiver to produce an intermediate frequency (IF) signal. This IF signal makes it easier to process and extract information from the incoming signal. The local oscillator helps in tuning and filtering the desired signal from the incoming radio frequency spectrum.