Viavi OneExpert DSL ONX-580, User Manual

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OneExpert DSL User's Guide
22052280, Rev. 015 April 2019
Chapter 15 Test Results
271
Range Resolution Accuracy
Up to 27,000 ft (8229.6 m) up to 5 ± 1
Longitudinal balance
You measure longitudinal balance to measure the quality of the pair – a measurement of
the degree to which the Tip (A) lead is electrically the same as the Ring (B) lead.
The more each lead is electrically identical (capacitance, inductance, impedance), the better
the pair will resist induced noise.
The balance result should be >60 dB. Anything less indicates electrical differences between
Tip (A) and Ring (B) that can lead to noise and other signal problems.
The following table describes the DC current result.
The calculated balance (PI - Noise = Balance) appears below the longitudinal balance.
Power influence (Tip to Ground [A to E] and Ring to Ground [B to E] noise) is the unwanted
current inducted on the pair from power lines and other AC sources. Noise is the unwanted
current that the pair has failed to cancel and which the customer hears as noise.
Load coil
You check for load coils to ensure there are no load coils present on a digital line (such as
ADSL or ISDN). Load coil detection and elimination is essential in the installation of an xDSL
circuit
The following table describes the load coil result.
Range Resolution Accuracy
28 to 70 dB 1 dB ± 2 dB
70 to 120 dB 1 dB indication only