Another type of modulation is PULSE MODULATION. Pulse modulation has many uses, including
telegraphy, radar, telemetry, and multiplexing. Far too many applications of pulse modulation exist to
elaborate on any one of them, but in this section we will cover the basic principles of pulse modulation.
Amplitude modulating a simple rf carrier to a point where it becomes drastically overmodulated
could produce a waveform similar to that required in pulse modulation. A modulating signal [view (A) of
figure 2-27] that is much larger than the carrier results in the modulation envelope shown in view (B).
The modulation envelope would be the same if the modulating wave shape were not sinusoidal; that is,
like the one shown in view (C).
Figure 2-27A.Overmodulation of a carrier. MODULATING WAVE.
Figure 2-27B.Overmodulation of a carrier. MODULATION ENVELOPE.