Tektronix OI1125, Instruction Manual

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Glossary
OI1125 E/O Transmitter Instruction Manual
71
Digital Signal
A signal made up of a series of on and off pulses.
Digital Transmission System
A transmission system where information is transmitted in a series of on and
off pulses.
Dispersion (example in fiber)
In an optical system, the broadening and distortion of a pulse due to
multipath waveform propagation.
Electro-optic effect
A change in the refractive index of a material under the influence of an
electric field.
ES
An acronym for Errored Second. A second with at least one error.
Error Detection
Checking for errors in data transmission. A calculation is made on the data
being sent and the results are sent along with it. The receiving station then
performs the same calculation and compares its results with those sent. Each
data signal conforms to specific rules of construction so that departures from
this construction in the received signals can be detected. Any data detected
as being in error is either deleted from the data delivered to the destination,
with or without an indication that such deletion has taken place, or delivered
to the destination together with an indication that it is in error.
Extinction Ratio
The ratio of the high-level optical power to the low-level optical power in a
transmission system.
Error Rate
The ratio of the number of data units in error to the total number of data
units.
Fiber optics
A method of transmitting information in which light is modulated and
transmitted over high-purity filaments of glass. The bandwidth of fiber optic
cable is much greater than that of copper wire.
Fiber Optics Transmission System (FOTS)
A transmission system transmitting light through thin glass fibers.
FEC: Forward Error Correction
Additional bits and/or coding added to a data stream to allow for automatic
error detection and correction at the receiving end. These extra bits and/or
coding tend to increase a serial data rate above the original non-FEC data
stream in order to accommodate the extra information added by the FEC.