Flashcards in cct4 Deck (237)
The four phases in which a carries is sent in QPSK are at what degrees?
45, 135, 225, 315
This is a digital modulation scheme that allows 2 channels of information to be transmitted at the same time on a particular frequency by changing the phase and amplitude.`
Quadrature Amplitude Modulation (QAM)
Digital QAM signals carry 2 signals that are referred to as what?
I and Q components
This is a measure of signal strength relative to background noise in analog and digital communications.q
Noise Power Ratio
What test uses a white noise generator to simulate the data filled spectrum and a band-pass filter to limit the spectrum?
Noise power ratio test
the ratio of the error power to the average power in an ideal QAM signal
Modulation Error Ratio (MER)
A method where additional data bits are added to the digital video bit stream to help identify and correct any errors that may be caused by the transmission system
Forward Error Correction (FEC)
This is displayed as a ratio of the number of errors to correct data bits and is given in scientific notation
Bit Error Rate (BER)
Defined as a condition where interfering signals leak into a cable network.
What is the limit for ingress between 5 and 42 MHz?
This device passes high frequencies well, but attenuates (or reduces) frequencies lower than the cut-off frequency..
High Pass Filter
Proof of Performance
These tests help to ensure that cable systems' forward signals meet FCC standards as outlined in CFR 47, Part 76.605(a)(1-12) of the FCC regulations.
The Proof-of-Performance tests
Being able to carry and individually select different channels on a single cable by their unique frequency is called....
frequency division multiplexing (FDM)
Usually made of Aluminum, this device prevents ingress/egress and protects the electronics from the weather
Separates or combines the AC current's two parts: the AC power and the RF broadband signals
This device separates and recombines the forward and reverse signals fro the coaxial cable so they can be routed to the appropriate components within the amplifier station.
Compensates for the unequal attenuation properties of coaxial cable at different frequencies
These are usually selected for their low noise figure
Forward Amplifier Module (Trunk)
Sometimes called a Mop-Up, this device is used to try and correct for any undesired peaks or valleys within the passband of the amplifier
Automatic Gain Control
Automatic Level and Slope Control
Similar to AGC, maintains the proper tilt (caused by temperature change in a specified amount of coaxial cable) and output level despite changes in the input signals.
Automatic Level and Slope Control (ALS)
Used to boost the return signals, its bandwidth ranges from 5 to 42 MHz.
Used at output of bridger module, it is a signal splitting device that plugs into a trunk/bridger chassis.
Provides a means of monitoring the various inputs and outputs without interrupting service.
This is used to divert a specific amount of signal from the feeder system and distribute it to 2, 4, or 8 output ports for connection of customer drops.
How many ports are represented on a circular tap symbol?