Version 1.0, 11/2017. Copyright 2012 Hitron Technologies
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Version 1.0, 11/2017. Copyright 2017 Hitron Technologies
25
Hitron E31N2V1 User’s Guide
Since more information can be represented by a single character, a higher number
indicates a higher data transfer rate.
1.1.9
TDMA, FDMA and SCDMA
Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA)
and Synchronous Code Division Multiple Access (SCDMA) are channel access
methods that allow multiple users to share the same frequency channel.
TDMA allows multiple users to share the same frequency channel by splitting
transmissions by time. Each user is allocated a number of time slots, and
transmits during those time slots.
FDMA allows multiple users to share the same frequency channel by assigning a
frequency band within the existing channel to each user.
SCDMA allows multiple users to share the same frequency channel by assigning
a unique orthogonal code to each user.
1.1.10
OFDM
Orthogonal Frequency-Division Multiplexing (OFDM) is a physical-layer data
encoding method for transmitting and receiving data on Radio Frequency (RF)
media, such as the E31N2V1’s cable connection.
OFDM takes a single wide-band signal and separates it into multiple simultaneous
subcarriers across the available RF spectrum, separated by the minimum frequency
necessary to ensure non-interference among sub-carriers. “Orthogonal”, in this
usage, refers to this non-interfering quality of the technique.
The primary advantage of OFDM is that a signal encoded using the method can
withstand suboptimal conditions on the RF medium. Depending on its
implementation, OFDM can also enable faster signal throughput.
1.1.11
FFT
The Fast Fourier Transform (FFT) is an algorithm for rapidly implementing Fourier
analysis of a data stream, used by modulation methods such as OFDM. Fourier
analysis is a mathematical technique that enables the representation of data using
simpler trigonometric functions.
