Tektronix OI1125, Instruction Manual

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OI1125 E/O Transmitter Instruction Manual
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Glossary
Accuracy
The closeness of the indicated value to the true value.
Attenuation
A decrease in magnitude of current, voltage, or power of a signal.
Attenuator
A transducer that reduces the amplitude of a signal.
Bandwidth
The difference between the high and low frequencies of a transmission band.
The range of frequencies handled by a device or system. Bandwidth is a
measure of network capacity. Analogue bandwidth is measured in cycles per
second. Digital bandwidth is measured in bits of information per second.
BER
An acronym for Bit Error Ratio (or Rate). The principal measure of quality
of a digital transmission system. BER is defined as:
BER = Number of Errors/Total Number of Bits
BER is usually expressed as a negative exponent. For example, a BER of
10
–7
means that on average 1 bit out of 10
7
bits is in error.
BER Floor
A limiting of the bit-error-ratio in a digital system as a function of received
power due to the presence of signal degradation mechanisms or noise.
Bit Error
An incorrect bit. Also known as a coding violation.
Bit Rate
The number of bits transmitted in a specified (usually 1 second) time.
Channel
A communications path or the signal sent over a channel.
Channel capacity
The maximum usable data rate for a given channel.
Chirp
Optical frequency chirp is a transient change in optical frequency (wave-
length) when a laser or optical modulator is transitioned quickly between
zero and one power levels.