circuit breakers and fuses should be provided. When this protection is not provided, the excessive
voltages can cause arcing between transformer windings and between the plates of capacitors, which will
permanently destroy the dielectric material. Excessive currents can also cause overheating of tubes and
Ideally, you will want to operate a transmitter at 100-percent modulation so that you can provide the
maximum amount of energy in the sideband. However, because of the large and rapid fluctuations in
amplitude that these signals normally contain, this ideal condition is seldom possible. When the
modulator is properly adjusted, the loudest parts of the transmission will produce 100-percent modulation.
The quieter parts of the signal then produce lesser degrees of modulation.
To measure degrees of modulation less than 100 percent, you can use a MODULATION FACTOR
(M) to indicate the relative magnitudes of the rf carrier and the audio-modulating signal. Numerically, the
modulation factor is:
To illustrate this use of the equation, assume that a carrier wave with a peak amplitude of 400 volts is
modulated by a 3-kilohertz sine wave with a peak amplitude of 200 volts. The modulation factor is
figured as follows:
If the modulation factor were multiplied by 100, the resultant quantity would be the PERCENT OF