The physical layer net bitrate, information rate, useful bit rate, payload rate, net data transfer rate, coded transmission rate, effective data rate or wire speed (informal language) of a digital communication channel is the capacity excluding the physical layer protocol overhead, for example time division multiplex (TDM) framing bits, redundant forward error correction (FEC) codes, equalizer training symbols and other channel coding. Where n is the number of parallel channels, M i is the number of symbols or levels of the modulation in the i-th channel, and T i is the symbol duration time, expressed in seconds, for the i-th channel.
In case of serial communications, the gross bit rate is related to the bit transmission time T b In digital communication systems, the physical layer gross bitrate, raw bitrate, data signaling rate, gross data transfer rate or uncoded transmission rate (sometimes written as a variable R b or f b ) is the total number of physically transferred bits per second over a communication link, including useful data as well as protocol overhead. The International Standard ( IEC 80000-13) specifies different abbreviations for binary and decimal (SI) prefixes (e.g. = 1 kbit/s (one thousand bits per second)īinary prefixes are sometimes used for bit rates. = 1 mbit/s (one bit per thousand seconds) When quantifying large or small bit rates, SI prefixes (also known as metric prefixes or decimal prefixes) are used, thus: 0.001 bit/s In most computing and digital communication environments, one byte per second (symbol: B/s) corresponds to 8 bit/s. The non-standard abbreviation bps is often used to replace the standard symbol bit/s, so that, for example, 1 Mbps is used to mean one million bits per second. The bit rate is expressed in the unit bit per second unit (symbol: bit/s), often in conjunction with an SI prefix such as kilo (1 kbit/s = 1,000 bit/s), mega (1 Mbit/s = 1,000 kbit/s), giga (1 Gbit/s = 1,000 Mbit/s) or tera (1 Tbit/s = 1,000 Gbit/s). In telecommunications and computing, bit rate ( bitrate or as a variable R) is the number of bits that are conveyed or processed per unit of time. For disk drives, see data transfer rate (disk drive).