Two sinusoidal signals have the same amplitude (A) and the same frequency (f). They differ in phase by 180 degrees. If these two signals are added together, the result is a sinusoidal signal having an amplitude of:
Two sinusoidal signals have the same amplitude (A) and the same frequency (f). They differ in phase by 180 degrees. If these two signals are added together, the result is a sinusoidal signal having an amplitude of:
When two sinusoidal signals with the same amplitude and frequency are 180 degrees out of phase and added together, their peaks and troughs cancel each other out. This results in a signal with zero amplitude.
If the phase difference is 1/2 of the period w/c means 180 degrees, two sinusoids is considered 180 degrees out of phase whose sum is ZERO ---TDMM page 139
TDMM page 1-23
TDMM page 139 (in the digital version)