| 词条 | Carrierless amplitude phase modulation |
| 释义 |
ApplicationsCAP finds application in HDSL and in early proprietary ADSL variants.[2][3] For HDSL, the American ANSI standard specifies 2B1Q rather than CAP, while the European ETSI ETR 152 and the international ITU-T G.991.2 standards specify both CAP and 2B1Q.[2][4][5] For ADSL deployments CAP was the de facto standard up until 1996, deployed in 90 percent{{Citation needed|date=March 2011}} of ADSL installs. The standardized variants of ADSL, ANSI T1.413 Issue 2 and G.dmt, as well as the successors ADSL2, ADSL2+, VDSL2, and G.fast, do not specify CAP, but rather discrete multi-tone (DMT) modulation. CAP used for ADSL divides the available frequency spectrum into three bands.{{Citation needed|date=January 2014}} The range from 0 to 4 kHz is allocated for POTS transmissions. The range of 25 kHz to 160 kHz is allocated for upstream data traffic and the range of 240 kHz to 1.5 MHz is allocated for downstream data traffic, in a frequency-division duplexing (FDD) scheme. References1. ^1 2 {{citation |mode=cs1 |chapter=Section 5.1: Carrierless Amplitude/Phase Modulation |url=http://www.diva-portal.org/smash/get/diva2:996710/FULLTEXT01.pdf |last=Sjöberg |first=Frank |date=April 2000 |title=A VDSL Tutorial |accessdate=2014-01-20 |issn=1402-1528 |publisher=Luleå University of Technology}} 2. ^1 {{cite book |title=DSL Advances |editor1-last=Starr |editor1-first=Thomas |isbn=0-13-093810-6 |location=Uppser Saddle River, NJ |publisher=Prentice Hall |url=https://books.google.com/books?id=VWaMdIq2w8QC}} 3. ^{{cite book |chapterurl=https://books.google.com/books?id=x33i7TwBhHQC&pg=PA397 |chapter=WAN and Teleworker Connections |url=https://books.google.com/books?id=x33i7TwBhHQC |title=Cisco Network Professional's Advanced Internetworking Guide (CCNP Series) |last=Conlan |first=Patrick J. |publisher=John Wiley & Sons |date=2009-04-20 |location=Indianapolis}} 4. ^{{Cite web |title= G.991.1: High bit rate digital subscriber line (HDSL) transceivers |url= http://www.itu.int/rec/T-REC-G.991.1-199810-I/en |date= 26 August 1998 |publisher= ITU-T |work= International Recommendation |accessdate= 23 June 2013 }} 5. ^{{cite web |title=ETR 152: Transmission and Multiplexing (TM); High bitrate Digital Subscriber Line (HDSL) transmission system on metallic local lines |date=February 1995 |accessdate=2013-12-27 |url=http://www.etsi.org/deliver/etsi_etr/100_199/152/01_60/etr_152e01p.pdf |publisher=ETSI}} Further reading
1 : Radio modulation modes |
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