phaseshifting

Phase shifting is the process of changing the phase of a periodic signal with respect to a reference, effectively rotating the signal’s cycle in time without necessarily altering its amplitude. The amount of phase shift is measured in degrees or radians and can depend on the signal frequency; for a time delay τ the phase shift is φ = -2π f τ.

Phase shifters are devices or circuits that implement this transformation. They can be passive or active, and can provide continuous or stepped phase changes. Common implementations include all-pass networks that modify phase across a band with near-constant amplitude, and transmission-line or lumped-element arrangements that adjust electrical length or reactance. Electronic implementations use varactors, PIN diodes, MEMS switches, or ferrite materials whose effective propagation constant is tunable by bias.

Applications include beam steering and shaping in phased-array antennas for radar and communications, rotation of signals in test equipment, and certain audio or signal-processing effects. In digital communications, phase shift keying uses discrete phase shifts to encode information, but a phase shifter device is not the same as a PSK modulation scheme.

Practical designs balance phase accuracy, bandwidth, insertion loss, and calibration. Limitations include dispersion, temperature sensitivity, and nonlinearity, which can distort multitone or broadband signals. The term phase shifting is often used in electronics and microwave engineering to describe any method that controls relative phase without necessarily altering amplitude.