SMC Networks 7724M/VSW - annexe 1, Manual

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Management Guide CLI
TigerAccess™ EE
SMC7824M/VSW 75
5.3 VDSL Port Configuration
5.3.1 Modulation of VDSL Signal
The switch provides both Internet and telephone communication through existing tele-
phone line with using DSL technology. DSL communication system requires technique to
convert digital signal into analog signal and return the analog signal into the digital signal.
Fig. 5.1 shows process of signal transmission in DSL system.
Fig. 5.1 Transmission in DSL System
In the above picture, Modulator converts digital signal into analog signal to be sent over
the channel. Also, the analog signal is returned into digital signal at the Demodulator.
5.3.1.1 DMT Modulation
DMT builds on some of the ideas of QAM. Imagine having more than one constellation
encoder. Each encoder receives a set of bits that are encoded using a constellation en-
coder as described in the previous sections. In this basis, DMT is referred as multi carrier
In DMT modulation, frequency channel is named frequency bins, bins, tone, DMT tones,
and sub-channel.
Fig. 5.2 shows process of DMT modulation.