BDS RF Fundamentals and Signal Theory 2

Question 1

What does the term 'carrier-to-noise ratio' (CNR) describe in a cable system?

Accepted Answer

The ratio of carrier power to thermal noise floor

Answer

CNR measures the power of a specific carrier relative to the thermal noise floor, determining the usable quality of that signal.

Question 2

Which distortion product results from third-order nonlinearity and falls on active carrier frequencies?

Accepted Answer

Composite Triple Beat (CTB)

Answer

Composite Triple Beat (CTB) is a third-order distortion product that clusters on active channel frequencies and degrades picture quality.

Question 3

What is ingress noise in a cable plant?

Accepted Answer

External RF signals leaking into the cable system

Answer

Ingress is unwanted external RF energy (such as amateur radio or FM broadcast signals) that leaks into the cable plant through damaged connectors or loose fittings.

Question 4

What is the standard impedance of coaxial cable used in HFC distribution networks?

Accepted Answer

75 ohms

Answer

HFC cable systems use 75-ohm coaxial cable, which optimizes the balance between power handling and signal loss for broadband distribution.

Question 5

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

Accepted Answer

The quality of a digitally modulated signal compared to an ideal signal

Answer

MER measures the ratio of average symbol power to error vector power, serving as a key quality metric for digitally modulated signals like QAM.

BDS - Broadband Distribution Specialist Practice Test

BDS - Broadband Distribution Specialist Practice Test

BDS RF Fundamentals and Signal Theory 2