Superheterodyne radio receiver, often known in short as a Superhet, was designed to overcome the shortcomings of a tuned radio frequency receiver. It uses a frequency mixer to convert the received radio frequency signal to a fixed and lower intermediate frequency (IF) signal. It is possible to process the fixed IF signal more easily than widely varying carrier frequencies received from the antenna. The superheterodyne process involves tuning the local oscillator to a frequency which is different from the received signal by as many kilohertz as the intermediate frequency. The process was called superheterodyne because the heterodyne signal or the difference between the two frequencies, was above the audible range. If the difference in frequencies is lower, you will have an audible 'beat' note. That was how we used to receive CW signals in our broadcast receivers by heterodyning with a beat frequency oscillator or BFO.
