Figure 3.
Harmonic generating circuit.
Another common method is to
apply the
fundamental signal to a
specially
designed
coil
called
a
saturable
reactor. The symbol of this
component
is shown in figure 3.
b. When a signal is applied to
these non-linear devices, the output
is rich in harmonics.
Each of the
harmonics is separated from each other
by the value of the original signal.
For example, the harmonics of a 4 kHz
signal are; 8 kHz, 12 kHz, 16 kHz, and
so on.
The desired signals are
selected by filter circuits as shown
in figure 3. The selected signals, in
turn, can develop additional signals
if they are applied to a modulating
circuit as shown in figure 4.
c. Another
method
of
generating
harmonics is to generate rectangular
(square) waves because they are rich
in odd harmonics. One technique is to
make a signal source control the
operation of a multivibrator so that
the
output
is
a
predetermined
Figure 4.
One source can produce
The
output
of
the
many signals.
multivibrator is then filtered to get
the various desired output signals, as
shown in figure 5.
327 L1
5
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