Ternary signal
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In telecommunication, a ternary signal is a signal that can assume, at any given instant, one of three significant conditions, such as power level, phase position, pulse duration, or frequency.
Note: Examples of ternary signals are (a) a pulse that can have a positive, zero, or negative voltage value at any given instant (PAM-3), (b) a sine wave that can assume phases of 0°, 120°, or 240° relative to a clock pulse (3-PSK), and (c) a carrier wave that can assume any one of three different frequencies depending on three different modulation signal significant conditions (3-FM).
| Modulation techniques |
|---|
| Analog modulation |
| AM · SSB · FM · PM · QAM · SM |
| Digital modulation |
| OOK · FSK · ASK · PSK · QAM MSK · CPM · PPM · TCM · OFDM |
| Spread spectrum |
| FHSS · DSSS |
Some examples of PAM-3 line codes that use ternary signals are:
- hybrid ternary code
- bipolar encoding
- MLT-3 encoding used in 100BASE-TX Ethernet
- B3ZS
- 4B3T used in some ISDN basic rate interface
- 8B6T used in 100BASE-T4 Ethernet
- return-to-zero
- SOQPSK-TG uses ternary continuous phase modulation[1]
3-PSK can be seen as falling between "binary phase-shift keying" (BPSK) which uses two phases, and "quadrature phase-shift keying" (QPSK) which uses four phases.
Source: Portions of this article were taken from Federal Standard 1037C
[edit] See also
- balanced ternary
- digital signal
- Fast Ethernet#100BASE-T2 uses PAM-5, which, like ternary, is one of the few modulation schemes that does not use a power-of-two number of symbols.
- three-phase electric power, like 3-PSK, uses 3 phases at a single frequency and amplitude.
