IEEE Std C37.118.1-2011 pdf download – IEEE Standard for Synchrophasor Measurements for Power Systems.
2. Normative references The following referenced documents are indispensable for the application of this document (i.e., they must be understood and used, so each referenced document is cited in text and its relationship to this document is explained). For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments or corrigenda) applies. IEEE Std 754™-1985, IEEE Standard for Binary Floating-Point Arithmetic. 2, 3 3. Definitions, acronyms, and abbreviations For the purposes of this document, the following terms and definitions apply. The IEEE Standards Dictionary: Glossary of Terms & Definitions [B2] should be consulted for terms not defined in this clause. 4 3.1 Definitions anti-aliasing: The process of filtering a signal before sampling to remove components of that signal whose frequency is equal to or greater than the Nyquist frequency (one-half the sample rate). If not removed, these signal components would appear as a lower frequency component (an alias). Coordinated Universal Time (UTC): (Initials are ordered based on French language.) The time of day at the Earth’s prime meridian (0° longitude). It is distributed by various media, including the Global Positioning System (GPS) system.
data concentrator (DC): A device that combines data from several measurement devices. frequency error (FE): The measure of error between the theoretical frequency and the measured frequency for the given instant of time. Global Positioning System (GPS): A U.S. Department of Defense (DoD) navigation system that uses a constellation of 24 satellites broadcasting a precision signal for location and time synchronization. Basic time synchronization accuracy is ± 0.2 microseconds (μs). IEEE floating point: A 32-bit representation of a real number. NOTE—This definition is in accordance with IEEE Std 754-1985. 5 leap second: A positive or negative one-second adjustment to the Coordinated Universal Time (UTC) that keeps it close to mean solar time. Nyquist frequency: A frequency that is one-half the sampling frequency of a discrete signal processing system. Nyquist rate: A sampling rate that is twice the bandwidth of a band-limited signal. It is the minimum sample rate that will result in an alias-free representation of a signal. It must therefore be greater than twice the highest frequency component in the signal.