User's Manual

SPEEDLAN 9000 Series Installation and Operation User Guide
Glossary-5
Data Terminal Equipment (DTE)
Hardware that provides for data communications. See also DCE above.
dBm
Decibels (dB) relative to 1 milliwatt.
dBw
Decibels (dB) relative to 1 watt.
Decibel (dB)
The standard unit of measurement for expressing relative signal power. It is dimensionless and is instead referenced to a
certain level.
Diffraction
The distortion of a wave as it is partially obstructed by an object in its path.
Digital Signal Processor (DSP)
A specialized computer chip designed to perform speedy and complex operations on digitized waveforms.
Direct Sequence (DS)
A type of spreading technique that multiplies a higher rate PN code to the signal in order to spread the energy of the nar-
row band signal over a much wider bandwidth for transmission.
Direct Sequence Speed Spectrum (DSSS)
DSSS may be seen as the result of two processes. Data is multiplied with a higher rate digital sequence (spreading code).
The sequence has many “chips” for every data bit. The resultant signal modulates the RF carrier.
E1
European Standard also used in South American nations, among others. Speed is 2.048 Mega bits per second (Mbps).
Uses the G.703 data interface.
Elevation
1. Height above sea level. 2. The vertical angle in degrees between the ground and the direction the antenna is pointed.
ESD
Electro-Static Discharge happens when there is a transfer between objects at diverse voltages.