BDS RF Technology and Spectrum Management

Question 1

What is composite second order (CSO) distortion in a cable RF system?

Accepted Answer

Distortion products that fall at frequencies equal to the sum or difference of two carrier frequencies

Answer

Distortion products at twice the frequency of a single carrier

Answer

Noise generated by the amplifier's thermal characteristics

Answer

Interference caused by overlapping channel bandwidths

Question 2

What is the standard RF channel bandwidth for a US cable television channel?

Accepted Answer

6 MHz

Answer

7 MHz

Answer

8 MHz

Answer

12 MHz

Question 3

Which modulation format offers the highest spectral efficiency for downstream cable broadband transmission?

Accepted Answer

QAM-1024

Answer

QPSK

Answer

QAM-64

Answer

QAM-256

Question 4

What is ingress noise in a cable return path system?

Accepted Answer

Unwanted signals from external sources that enter the coaxial plant through poor connectors or damaged cables

Answer

Noise generated internally by cable amplifier transistors

Answer

Noise floor added by the CMTS upstream receiver

Answer

Distortion products from upstream QAM modems

Question 5

What does MER (Modulation Error Ratio) measure in a digital cable system?

Accepted Answer

The ratio of the ideal QAM constellation point power to the error vector power, indicating signal quality

Answer

The ratio of the desired carrier power to the noise power floor

Answer

The number of bit errors per second in the digital data stream

Answer

The ratio of upstream power to downstream power at the CMTS

Question 6

What is the purpose of a diplexer in a cable distribution amplifier?

Accepted Answer

To combine or separate the downstream (forward) and upstream (return) frequency bands

Answer

To split the signal equally between two output ports

Answer

To equalize the frequency response across the amplifier's passband

Answer

To amplify both upstream and downstream signals simultaneously