Symbol Rate - Significant Condition

In telecommunication, concerning the modulation of a carrier, a significant condition is one of the signal's parameters chosen to represent information.

A significant condition could be an electrical current (voltage, or power level), an optical power level, a phase value, or a particular frequency or wavelength. The duration of a significant condition is the time interval between successive significant instants. A change from one significant condition to another is called a signal transition. Information can be transmitted either during the given time interval, or encoded as the presence or absence of a change in the received signal.

Significant conditions are recognized by an appropriate device called a receiver, demodulator, or decoder. The decoder translates the actual signal received into its intended logical value such as a binary digit (0 or 1), an alphabetic character, a mark, or a space. Each significant instant is determined when the appropriate device assumes a condition or state usable for performing a specific function, such as recording, processing, or gating.