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30 March, 2015 - 17:33

1k — 1 × 103

1M — 1 × 106

1G — 1 × 109

Bandwidth — The span of frequencies within the spectrum that is occupied by a given signal.

Channel — It is a medium of communication paths, sometimes also called link. For example, wires, optical fibres, wave guides, air, … etc.

Frequency — The number of cycles (Hertz) per second of a periodic signal.

Full-duplex system — Information can be sent by both parties simultaneously.

Half-duplex system — Information can be sent by either one of the parties to another, but only in one direction at a time.

ITU — The International Telecommunications Union. It is a union to specify the technical communication standards among different countries.

OFTA — The Office of the Telecommunications Authority. It maintains and regulates the technical standards and issues of the telecommunication industries in Hong Kong.

Simplex system — Communication can only be conducted in one direction.

Spectrum — The span of frequencies used in communication systems.

Wavelength — The distance between two adjacent peaks, or between the same points on any adjacent cycles. It is defined mathematically as:

\small wavelength=\frac{velocity}{frequency}