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Flashcards in cct4 Deck (237)
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151

The four phases in which a carries is sent in QPSK are at what degrees?

45, 135, 225, 315

152

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)

153

Digital QAM signals carry 2 signals that are referred to as what?

I and Q components

154

This is a measure of signal strength relative to background noise in analog and digital communications.q

Signal-to-noise ratio

155

NPR

Noise Power Ratio

156

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

157

the ratio of the error power to the average power in an ideal QAM signal

Modulation Error Ratio (MER)

158

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)

159

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)

160

Defined as a condition where interfering signals leak into a cable network.

Ingress

161

What is the limit for ingress between 5 and 42 MHz?

-30 dBmV

162

This device passes high frequencies well, but attenuates (or reduces) frequencies lower than the cut-off frequency..

High Pass Filter

163

POP

Proof of Performance

164

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

165

Being able to carry and individually select different channels on a single cable by their unique frequency is called....

frequency division multiplexing (FDM)

166

Usually made of Aluminum, this device prevents ingress/egress and protects the electronics from the weather

Housing

167

Separates or combines the AC current's two parts: the AC power and the RF broadband signals

Power Diplex

168

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.

Diplex Filter

169

Compensates for the unequal attenuation properties of coaxial cable at different frequencies

equalizer

170

These are usually selected for their low noise figure

Forward Amplifier Module (Trunk)

171

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

Response Equalizer

172

AGC

Automatic Gain Control

173

ALS

Automatic Level and Slope Control

174

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)

175

Used to boost the return signals, its bandwidth ranges from 5 to 42 MHz.

Return Amplifier

176

Used at output of bridger module, it is a signal splitting device that plugs into a trunk/bridger chassis.

Feedermaker

177

Provides a means of monitoring the various inputs and outputs without interrupting service.

Test Points

178

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.

Tap

179

How many ports are represented on a circular tap symbol?

2

180

How many ports are represented on a square tap symbol?

4