Modulation Techniqies

Describe the specific modulation techniques that are used in 56K, Asymmetrical Digital Subscriber Line, and Wi-Fi

Modulation can be understood as the variation of a property of an electromagnetic wave or signal, such as its amplitude, frequency or phase ("The Free Dictionary", 2012). ADSL (often simplified as just DSL) is technology that is mostly used for gaining high speed internet access. Generally, the modulation process that may be used in Asymmetric Digital Subscriber Line (ADSL) is using basic copper lines to send and receive data on a digital frequency and thus at very high speeds. The line code that is used for the ADSL interface is the DMT code. The DMT line code has been created to be compatible with the twisted-wire pair channel.

The term 56k is simply a measurement of your internet speed. 56k modems can be simply understood as voice band modems capable of download speeds of up to 56 Kbits (or kilobits per second). With 56kbs modems, only one end of the modulation loop can be analog, the other end must be digital which allows 56k modems to break the traditional 33.6kbs speed barrier.

WIFI is somewhat of an acronym that stands for wireless fidelity. Wifi is a systems that with the support if mobile devices such as lap tops, cell phones and ipods allows individuals to access internet across a radio network wherever needed in many cases. Modulation techniques that are generally utilized for Wi-Fi are called Direct Sequence Spread Spectrum's (DSSS). The DSSS process uses a bunch of different frequencies or channels.

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