A phase shift characterizes the offset in time of the phase position of a signal between input and output of a two- or four-pole or the offset between the phases of two or more signals. It is the delay of a signal with respect to a reference signal.
Phase shifts occur in periodic signals, in sinusoidal signals, as well as in triangular signals or pulses. The reference point for phase shifts are reference points in time. The time offset of the phase-shifted signal to these reference times, for example the center of the rising edge of a pulse signal or the zero crossing of a sine wave, is set in relation to the period duration and thus to 360°. In the case of a sinusoidal signal, for example, the zero crossing is used as the reference time point to determine the phase shift, and the offset of the two sinusoidal signals is set in relation to time.
Phase shifts are not limited to electrical signals, but to all types of waves. They occur in frequency dependent circuits, in filters, high and low pass filters, RC gates or even in active circuits and can also be generated by phase shifters in steps or continuously.