AND VOICE SERVICES CONFIGURATION
PRACTICE EXAM STUDY GUIDE CORRECT
RESPONSES PACK
●● Decibel millivolt (dBmV)
Answer: Absolute # of signal strength.
●● Foreign voltage detector (FVD)
Answer: Detects unwanted voltage on cables/strands; test on plastics
too.
●● Data Over Cable Service Interface Specification (DOCSIS)
Answer: The international standard for adding high-bandwidth data to an
existing cable system.
●● What does SAFE stand for?
Answer: Stop. Assess. Focus. Eliminate.
●● What does NCP stand for?
Answer: Next. Channel. Pointer.
,●● What does SLM stand for?
Answer: Signal. Level. Meter.
●● What is a signal level meter?
Answer: Tool used to run multiple tests involving signal level, MER,
BER and noise level.
●● What does CNR stand for?
Answer: Carrier to Noise Ratio.
●● What is the purpose of CNR?
Answer: Comparing level of desired signal to level of background noise.
●● What is Hum modulation?
Answer: The distortion of both cable video and audio.
●● How can you identify video hum?
Answer: Visually seeing single (60Hz) or double (120Hz) horizontal
bars rolling slowly up from bottom to top of television.
●● How can you identify audio hum?
Answer: By physically hearing a buzzing sound.
, ●● what does BER stand for and what does it do?
Answer: Bit. Error. Ratio.
Overall measure of data quality of the received bit stream.
●● Consequences of BER (2 things).
Answer: 1.) Video: picture fails
2.) Data: loss of dial tone
●● What is the max length of a ground wire?
Answer: 20 feet (want the wire as short as possible).
●● What causes high BER (3 things)?
Answer: 1.) Ingress: poor connections
2.) Distortion: undesired change in electrical signal
3.) Noise: unwanted disturbance to a desired signal
●● What is the desired BER level?
Answer: 1.0E-9
●● What does MER stand for?
Answer: Modulation. Error. Ratio.