Attenuation-to-crosstalk ratio
400px|right
Attenuation-to-crosstalk ratio (ACR) is a parameter that is measured when testing a communication link, which represents the overall performance of the cable.[1] AcR is a mathematical formula that calculates the ratio of attenuation to near-end crosstalk for each combination of cable pairs.[2] ACR is expressed as a figure in decibels (dB), between the signal attenuation produced by a wire or cable transmission medium and the near-end crosstalk (NEXT).[3] In order for a signal to be received with an acceptable bit error rate, the attenuation and the crosstalk must both be minimized.[3] Crosstalk can be reduced by ensuring that twisted-pair wiring is tightly twisted and is not crushed, and by ensuring that connectors between wire and cable media are properly rated and installed.[3]
Positive ACR calculations mean that transmitted signal strength is stronger than that of near-end crosstalk.[4] ACR can be used to define a signal bandwidth (e.g. 250 MHz for category 6 cable) where signal to noise ratios are sufficient to support certain applications.[4] The maximum frequency for which positive ACR is assured provides a benchmark to assess the usable bandwidth of twisted-pair cabling systems.[4] EIA/TIA specifies specific values for ACR in order to meet the various categories of cable.[5]
References
- ↑ "Learning Path: Testing network cable". http://whatis.techtarget.com/definition/0,,sid9_gci1059969,00.html.
- ↑ "Testing Copper Cabling the Right Way". http://ecmweb.com/mag/electric_testing_copper_cabling_2/.
- ↑ 3.0 3.1 3.2 "attenuation-to-crosstalk ratio (ACR) or headroom". http://searchnetworking.techtarget.com/definition/attenuation-to-crosstalk-ratio.
- ↑ 4.0 4.1 4.2 "De-Mystifying Cabling Specifications - Important Definitions". Archived from the original on 2011-04-27. https://web.archive.org/web/20110427191742/http://inetco.com.vn/list.aspx?cat=014. Retrieved 2011-05-06.
- ↑ "CAT 6 Testing Requirements"]. http://www.cat6.com/testing/requirements.aspx.
 |  |
