Ternary signal
In telecommunication, a ternary signal is a signal that can assume, at any given instant, one of three states or significant conditions, such as power level, phase position, pulse duration, or frequency.
Examples of ternary signals are a pulse that can have a positive, zero, or negative voltage value at any given instant, a sine wave that can assume phases of 0°, 120°, or 240° relative to a clock pulse, and a carrier signal that can assume any one of three different frequencies depending on three different modulation signal significant conditions.
Some examples of PAM-3 line codes that use ternary signals are:
3-PSK can be seen as falling between "binary phase-shift keying", which uses two phases, and "quadrature phase-shift keying", which uses four phases.
