Final answer:
THD in square wave modulation is not higher than SPWM. Waves of different frequencies can superimpose to create complex wave patterns. Standing waves are formed by the superposition of identical waves traveling in opposite directions, not the same. The Doppler effect applies to all types of waves, including light, not just sound.
Step-by-step explanation:
The statement that THD in square wave modulation is higher than SPWM is false.
THD stands for Total Harmonic Distortion, which is a measure of the harmonics present in a signal. In square wave modulation, the signal is composed of multiple harmonics, resulting in a higher THD.
On the other hand, SPWM (Sinusoidal Pulse Width Modulation) uses a sinusoidal waveform to modulate the signal, which results in a cleaner and more sinusoidal output waveform with lower THD.