of the two original frequencies.
The remaining frequency that is present in the
output is a frequency equal to the
difference of the two original frequencies. In
most receivers only the difference
frequency is of interest, and all of the other
frequencies must be filtered out.
The difference frequency used in a receiver is
referred to as the IF.
c. Mixer Output. The input and output waveforms of a mixer stage are shown in A
of figure 2-1.
The input radio frequency is represented by F1, and the input
oscillator frequency is represented by F2.
The two input frequencies applied to
the mixer stage produce four prominent output frequencies.
The original radio
The original oscillator
frequencies is represented by F11 plus F2.
The difference of the two original
frequencies is represented by F1 minus F2.
Figure 2-1.
Input and output waveforms of a mixer and a converter.
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