Lesson 7 - Addressing Return Path Challenges

What location in the network is common path distortion (CPD) most severe?

At the output of a forward amplifier because the forward levels are highest and the return levels are lowest.

How can the amount of thermal noise added to a network be minimized?

By ensuring that the RF input is at or above the specified minimum input level to all amplifiers.

How is impulse noise characterized when viewed on a spectrum analyzer?

Impulse noise will appear as random spikes of energy across the entire return path frequency spectrum (5-42 MHZ).

What distinguishes a micro reflection from other types of signal reflections?

In micro-reflections, the echoed signals arrive back at the source with a time delay relative to the incident or transmitted signal, ranging from nanoseconds(ns) to a few microseconds (μs)

What recourse do broadband cable operators have if citizens band (CB) and ham radio signals ingress into their network?

None, as long as the radio transmissions are at or below legal power levels, it is the cable operator's obligation to prevent these signals from entering their network.

What practice can uncover potential return path problems in the drop system that can be mitigated before entering the network?

Prescreening the drop system for ingress or egress.

Why is it imperative to keep all ingress and impulse noise, even that outside the frequency range of the RF return carriers, to a minimum?

Regardless of the frequency, if the impulse noise or ingress is high enough, it can cause laser clipping.

Why is installing high-pass filters (HPF) at the tap on drops without two-way services considered a short-term solution to ingress and impulse noise migrating into the hybrid fiber/coax (HFC) network?

The HPF will have to be removed when cable modems and digital set-top boxes (STB) are activated at the addresses that have an HPF installed.