Content











12.3



DSL Technology
 



 


12.3.4



ADSL
 







ADSL features three basic modulation
techniques:


Carrierless amplitude modulation/phase
modulation (CAP)


Discrete Multitone Modulation (DMT)



Consumer/Mass-Market DMT (G.lite), which
is the most popular.



DMT is a line code that is implemented in
ITU 992.1 (G.dmt), ITU 992.2 (G.lite), and ANSI T1.413 Issue 2. DMT
divides the 1 MHz spectrum offered by a phone line into multiple 4 kHz subchannels. Each subchannel is optimized based on the local loop
characteristics.


In contrast, CAP relies on a single
channel for upstream and another single channel for downstream.


An installer must check with the service
provider to determine which modulation technique is being used.The
modulation method used must be matched between the ADSL CPE and the
ADSL modems on the DSLAM.

















 



Web Links

ADSL



http://www.webopedia.com/TERM/A/ ADSL.html