Frequency-division multiple access

Frequency- division multiplexing ( Sheet Frequency Division Multiplexing, FDM, or Frequency Division Multiple Access, FDMA ) is a communications engineering multiplexing method, may be transmitted simultaneously with the plurality of distributed signals on multiple carriers. The carriers are assigned to several different frequencies, which is why the term frequency-division multiplexing is employed. There are a variety of other multiplexing methods. For example, are transmitted interleaved in time on a support with time-division multiplexing signals.

Now in use for the transmission of digital signals mostly orthogonal frequency division multiplexing ( OFDM) as a specific implementation of the FDM, which uses multiple orthogonal carrier signals of a digital data transmission, in which the crosstalk is minimized between the multiplexed signals.

Initially, the implementations of the FDM were expensive because for each carrier channel has its own modulator had to be used. Today FDM signals with fast signal processors can be digitally produced and processed, their costs are so low that this modulation method can be used also with built- in signal processors error correction method and protocol handlers in mass products. DSL modems are an example of such products.

  • Multiplexing technique
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