ABSTRACT
The output of the RF amplifier stage is applied
to the mixer stage. This stage combines the RF
signal with the signal derived from the local
oscillator (LO) stage in order to produce a signal
at the intermediate frequency (IF). It is worth
noting that the output signal produced by the
mixer actually contains a number of signal
components, including the sum and difference of
the signal and local oscillator frequencies as well
as the original signals plus harmonic components.
The wanted signal (i.e. that which corresponds to
the IF) is passed (usually by some form of filter-
see page 48) to the IF amplifier stage. This stage
