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 Posted - 01/25/2008 : 8:14:33 PM
Here is a question....on the AFC (now Tellabs) DLC equipment, there is a feature to monitor your DSL customers "bits per tone"....any advice on what this does and how to apply to customer line quality??
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frnkblk
Newbie
10 Posts
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Posted - 02/09/2008 : 4:35:24 PM
The most common metric for line quality appears to be BER.
Frank
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admin
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Posted - 02/09/2008 : 6:06:29 PM
Thanks Frank....Can you elaborate on that post? I assume you are referring to 'bit error rate?"
If you have more data, please post. Thanks!
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bktom2
Newbie
8 Posts
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Posted - 02/13/2008 : 8:57:16 PM
An ADSL forum at: http://mybroadband.co.za helped me to understand the bits per tone measurement.
To paraphrase;
"A check of bits per tone, signal to noise ratios, and power per tone can help to troubleshoot XDSL slow service problems. Dips in a bit per tone graph indicate interference. Checking the frequency of the interference often makes it possible to identify its cause. If the bits per tone are taking a hit and it is determined that noise is not the cause, then the cause could be a DC fault, such as a bridge tap or a wet section. Very low or nonexistent bits per tone in the high frequency band indicate the presence of a long loop. If there is a major dip in the bits-per-tone, but noise power-per-tone does not show any abnormalities, the most likely troubles are bridged taps or wet sections on the span. If the bits per tone are low across the whole bandwidth, the cause is most likely DC troubles on the loop, such as shorts or grounds. A major dip in bits per tone indicates AC trouble on the loop. To verify the type of AC trouble, compare the bits per tone to SNR. If the noise influence and bits per tone dip occur at the same frequency, the degraded performance is most likely due to a transmission influence. The particular frequency helps identify the source of influence or crosstalk."
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admin
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Posted - 02/14/2008 : 05:54:34 AM
Thanks for the post bktom2! Identifying 'dips' in the bits per tone graph/data and then following up with a spectrum analyzer should help identify any interference on the dsl line. Great info....thanks!!
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