2.6.6 - Attenuation and Interference Issues

Flashcards about attenuation and interference issues in network cabling.

What does +3 dB mean?

Doubling

What does -3 dB mean?

Halving

What does +6 dB mean?

Quadrupling

What ratio does -6 dB relate to?

A quarter

What does +10 dB mean?

10 times the ratio

What is -10 dB?

A tenth

What can decibel (dB) loss in a cable link result in?

Signal degradation problems with high error rates, retransmissions and reduced speeds, possibly loss of connectivity

What does insertion loss represent?

The ratio of the received voltage to the original voltage

What unit is insertion loss measured in?

Decibels (dB)

What is a logarithm?

A mathematical tool for performing complex multiplication and division exponential operations as simpler additions and subtractions

When measuring insertion loss, are smaller or larger values better?

Smaller values

What does the margin in cable certification report?

The difference between the actual loss and the maximum value allowed for the cable standard

Are higher or lower margin values better?

Higher margin values

Name some sources of interference for cable placement.

Electrical power cables, fluorescent lights, motors, electrical fans, and radio transmitters

What is EMI?

Electromagnetic Interference

What is alien crosstalk?

Interference from nearby data cables

What is Radio Frequency Interference (RFI)?

EMI that occurs in the frequencies used for radio transmissions