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词条 Data-rate units
释义

  1. Standards for unit symbols and prefixes

      Unit symbol    Unit prefixes    Variations  

  2. Decimal multiples of bits

      Kilobit per second    Megabit per second    Gigabit per second    Terabit per second  

  3. Decimal multiples of bytes

      Kilobyte per second    Megabyte per second    Gigabyte per second    Terabyte per second  

  4. Conversion table

  5. Examples of bit rates

  6. See also

  7. Notes

  8. References

  9. External links

{{bit rates}}

In telecommunications, data-transfer rate is the average number of bits (bitrate), characters or symbols (baudrate), or data blocks per unit time passing through a communication link in a data-transmission system. Common data rate units are multiples of bits per second (bit/s) and bytes per second (B/s). For example, the data rates of modern residential high-speed Internet connections are commonly expressed in megabits per second (Mbit/s).

Standards for unit symbols and prefixes

{{See also2|Bit rate for the differences between gross bitrate and net bitrate and between throughput and goodput.}}

Unit symbol

The ISQ symbols for the bit and byte are bit and B, respectively. In the context of data-rate units, one byte consists of 8 bits, and is synonymous with the unit octet. The abbreviation bps is often used to mean bit/s, so that when a 1 Mbps connection is advertised, it usually means that the maximum achievable bandwidth is 1 Mbit/s (one million bits per second), which is 0.125 MB/s (megabyte per second), or about 0.1192 MiB/s (mebibyte per second). The Institute of Electrical and Electronics Engineers (IEEE) uses the symbol b for bit.

Unit prefixes

In both the SI and ISQ, the prefix k stands for kilo, meaning 1,000, while Ki is the symbol for the binary prefix kibi-, meaning 1,024. The binary prefixes were introduced in 1998 by the International Electrotechnical Commission (IEC) and in IEEE 1541-2002 which was reaffirmed on 27 March 2008. The letter K is often used as a non-standard abbreviation for 1,024, especially in "KB" to mean KiB, the kilobyte in its binary sense. In the context of data rates, however, typically only decimal prefixes are used, and they have their standard SI interpretation.

Variations

In 1999, the IEC published Amendment 2 to "IEC 60027-2: Letter symbols to be used in electrical technology – Part 2: Telecommunications and electronics." This standard, approved in 1998, introduced the prefixes kibi-, mebi-, gibi-, tebi-, pebi-, and exbi- to be used in specifying binary multiples of a quantity. The name is derived from the first two letters of the original SI prefixes followed by bi (short for binary). It also clarifies that the SI prefixes be used only to mean powers of 10 and never powers of 2.

Decimal multiples of bits

These units are often used in a manner inconsistent with the IEC standard.

Kilobit per second

kilobit per second (symbol kbit/s or kb/s, often abbreviated "kbps") is a unit of data transfer rate equal to:

  • 1,000 bits per second
  • 125 bytes per second

Megabit per second

megabit per second (symbol Mbit/s or Mb/s, often abbreviated "Mbps") is a unit of data transfer rate equal to:

  • 1,000 kilobits per second
  • 1,000,000 bits per second
  • 125,000 bytes per second
  • 125 kilobytes per second

Gigabit per second

gigabit per second (symbol Gbit/s or Gb/s, often abbreviated "Gbps") is a unit of data transfer rate equal to:

  • 1,000 megabits per second
  • 1,000,000 kilobits per second
  • 1,000,000,000 bits per second
  • 125,000,000 bytes per second
  • 125 megabytes per second

Terabit per second

terabit per second (symbol Tbit/s or Tb/s, sometimes abbreviated "Tbps") is a unit of data transfer rate equal to:

  • 1,000 gigabits per second
  • 1,000,000 megabits per second
  • 1,000,000,000 kilobits per second
  • 1,000,000,000,000 bits per second
  • 125,000,000,000 bytes per second
  • 125 gigabytes per second

Decimal multiples of bytes

These units are often not used in the suggested ways; see above section titled "variations".

Kilobyte per second

kilobyte per second (kB/s) is a unit of data transfer rate equal to:

  • 8,000 bits per second
  • 1,000 bytes per second
  • 8 kilobits per second

Megabyte per second

megabyte per second (MB/s) is a unit of data transfer rate equal to:

  • 8,000,000 bits per second
  • 1,000,000 bytes per second
  • 1,000 kilobytes per second
  • 8 megabits per second

Gigabyte per second

gigabyte per second (GB/s) is a unit of data transfer rate equal to:

  • 8,000,000,000 bits per second
  • 1,000,000,000 bytes per second
  • 1,000,000 kilobytes per second
  • 1,000 megabytes per second
  • 8 gigabits per second

Terabyte per second

terabyte per second (TB/s) is a unit of data transfer rate equal to:

  • 8,000,000,000,000 bits per second
  • 1,000,000,000,000 bytes per second
  • 1,000,000,000 kilobytes per second
  • 1,000,000 megabytes per second
  • 1,000 gigabytes per second
  • 8 terabits per second

Conversion table

NameSymbolbit per secondbyte per secondbit per second (formula)byte per second (formula)
bit per secondbit/s10.1251{{sfrac|1|8}}
byte per secondB/s8181
kilobit per secondkbit/s1,000125103{{sfrac|1|8}} × 103
kibibit per secondKibit/s1,02412821027
kilobyte per secondkB/s8,0001,0008 × 103103
kibibyte per secondKiB/s8,1921,024213210
megabit per secondMbit/s1,000,000125,000106{{sfrac|1|8}} × 106
mebibit per secondMibit/s1,048,576131,072220217
megabyte per secondMB/s8,000,0001,000,0008 × 106106
mebibyte per secondMiB/s8,388,6081,048,576223220
gigabit per secondGbit/s1,000,000,000125,000,000109{{sfrac|1|8}} × 109
gibibit per secondGibit/s1,073,741,824134,217,728230227
gigabyte per secondGB/s8,000,000,0001,000,000,0008 × 109109
gibibyte per secondGiB/s8,589,934,5921,073,741,824233230
terabit per secondTbit/s1,000,000,000,000125,000,000,0001012{{sfrac|1|8}} × 1012
tebibit per secondTibit/s1,099,511,627,776137,438,953,472240237
terabyte per secondTB/s8,000,000,000,0001,000,000,000,0008 × 10121012
tebibyte per secondTiB/s8,796,093,022,2081,099,511,627,776243240

Examples of bit rates

{{Main|List of interface bit rates}}
QuantityUnitbits per secondbytes per secondFieldDescription
56kbit/s56,0007,000Networking56kbit modem – 56 kbit/s – 56,000 bit/s
64kbit/s64,0008,000Networking64 kbit/s in an ISDN B channel or best quality, uncompressed telephone line.
1,536kbit/s1,536,000192,000Networking24 channels of telephone in the US, or a good VTC T1.
10Mbit/s10,000,0001,250,000Networking107 bit/s is the speed of classic Ethernet: 10BASE2, 10BASE5, 10BASE-T
10Mbit/s10,000,0001,250,000Biology7 bit/s[1] [2]{{Dubious>date=June 2015}}
54Mbit/s54,000,0006,750,000Networking802.11g, Wireless G LAN
100Mbit/s100,000,00012,500,000NetworkingFast Ethernet
600Mbit/s600,000,00075,000,000Networking802.11n, Wireless N LAN
1Gbit/s1,000,000,000125,000,000Networking1 Gigabit Ethernet
10Gbit/s10,000,000,0001,250,000,000Networking10 Gigabit Ethernet
100Gbit/s100,000,000,00012,500,000,000Networking100 Gigabit Ethernet
1Tbit/s1,000,000,000,000125,000,000,000NetworkingSEA-ME-WE 4 submarine communications cable – 1.28 terabits per second[3]
4kbit/s4,000500Audio dataminimum achieved for encoding recognizable speech (using special-purpose speech codecs)
8kbit/s8,0001,000Audio datalow bit rate telephone quality
32kbit/s32,0004,000Audio dataMW quality and ADPCM voice in telephony, doubling the capacity of a 30 chan link to 60 ch.
128kbit/s128,00016,000Audio data128 kbit/s MP3 – 128,000 bit/s
192kbit/s192,00024,000Audio data192 kbit/s MP3 – 192,000 bit/s
1,411.2kbit/s1,411,200176,400Audio dataCD audio (uncompressed, 16 bit samples × 44.1 kHz × 2 channels)
2Mbit/s2,000,000250,000Video data30 channels of telephone audio or a Video Tele-Conference at VHS quality
8Mbit/s8,000,0001,000,000Video dataDVD quality
27Mbit/s27,000,0003,375,000Video dataHDTV quality
1.244Gbit/s1,244,000,000155,500,000NetworkingOC-24, a 1.244 Gbit/s SONET data channel
9.953Gbit/s9,953,000,0001,244,125,000NetworkingOC-192, a 9.953 Gbit/s SONET data channel
39.813Gbit/s39,813,000,0004,976,625,000NetworkingOC-768, a 39.813 Gbit/s SONET data channel, the fastest in current use
60MB/s480,000,00060,000,000Computer data interfacesUSB 2.0 High-Speed
98.3MB/s786,432,00098,304,000Computer data interfacesFireWire IEEE 1394b-2002 S800
120MB/s960,000,000120,000,000Computer data interfacesHarddrive read, Samsung SpinPoint F1 HD103Uj[4]
133MB/s1,064,000,000133,000,000Computer data interfacesParallel ATA UDMA 6
133MB/s1,064,000,000133,000,000Computer data interfacesPCI 32-bit at 33 MHz (standard configuration)
188MB/s1,504,000,000188,000,000Computer data interfacesSATA I 1.5 Gbit/s – First generation
375MB/s3,000,000,000375,000,000Computer data interfacesSATA II 3Gbit/s – Second generation
500MB/s4,000,000,000500,000,000Computer data interfacesPCI Express x1 v2.0
5.0Gbit/s5,000,000,000625,000,000Computer data interfacesUSB 3.0 SuperSpeed - a.k.a. USB 3.1 Gen1
750MB/s6,000,000,000750,000,000Computer data interfacesSATA III 6 Gbit/s – Third generation
1067MB/s8,533,333,3331,066,666,667Computer data interfacesPCI-X 64 bit 133 MHz
10Gbit/s10,000,000,0001,250,000,000Computer data interfacesUSB 3.1 SuperSpeed+ - a.k.a. USB 3.1 Gen2
1250MB/s10,000,000,0001,250,000,000Computer data interfacesThunderbolt
2500MB/s20,000,000,0002,500,000,000Computer data interfacesThunderbolt 2
5000MB/s40,000,000,0005,000,000,000Computer data interfacesThunderbolt 3
8000MB/s64,000,000,0008,000,000,000Computer data interfacesPCI Express x16 v2.0
12000MB/s96,000,000,00012,000,000,000Computer data interfacesInfiniBand 12X QDR
16000MB/s128,000,000,00016,000,000,000Computer data interfacesPCI Express x16 v3.0

See also

  • Binary prefix
  • Bit rate
  • List of device bandwidths
  • Orders of magnitude (bit rate)
  • Orders of magnitude (data)
  • SI prefix

Notes

1. ^{{citeweb| url=https://www.pennmedicine.org/news/news-releases/2006/july/penn-researchers-calculate-how|title=Penn Researchers Calculate How Much the Eye Tells the Brain|date=26 July 2006}}
2. ^Koch K, J McLean, R Segev, MA Freed, MJ Berry II, V Balasubramanian, P Sterling. 2006. How much the eye tells the brain. Current Biology 16:1428-1434., 26 July 2006
3. ^{{cite web |url=http://www.fujitsu.com/global/news/pr/archives/month/2005/20051213-01.html|title=Fujitsu Completes Construction of SEA-ME-WE 4 Submarine Cable Network|accessdate=2008-01-31|date=2005-12-13|work=Fujitsu Press Releases|publisher=Fujitsu|archiveurl=https://web.archive.org/web/20070317223056/http://www.fujitsu.com/global/news/pr/archives/month/2005/20051213-01.html|archivedate=2007-03-17}}
4. ^{{cite web|url=http://www.tomshardware.com/reviews/samsung-overtakes-a-bang,1730-9.html|title=Samsung overtakes}}

References

  • International Electrotechnical Commission (2007). "[https://web.archive.org/web/20090403051731/http://www.iec.ch/zone/si/si_bytes.htm Prefixes for binary multiples]". Retrieved on 2007-05-06.
  • IEC 60027-2 "Letter symbols to be used in electrical technology – Part 2: Telecommunications and electronics+
  • Donald Knuth: "What is a kilobyte?"

External links

  • [https://tools.valid8.com/#dataRate Valid8 Data Rate Calculator]
{{DEFAULTSORT:Data Rate Units}}

4 : Data transmission|Units of flow|Units of information|Units of temporal rate
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