Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Chrysalis]

I seen asbokid's post and thought cool he is back,l then noticed was an old thread

[konrado5]

les-70: could you check my Hlin on DELT mode? Perhaphs phase datas will be useful in contrast to Hlin on Showtime mode.

[les-70]

We did not find a way of getting anything useful from Hlin.  It contains a hard to identify phase shift negotiated between the DSLAM and the modem which masks other possible signals.  Even if that was controlled it would probably at most give a line length estimate and only show rough indications of other defects if they were very big.  It is why Hlog which omits the phase info is used in some diagnostics.

[konrado5]

But I suspect that Hlin(f) stats from DELT mode (diagnostic mode) contains useful phase datas.

As I mentioned I wondered over the DELT test mode.  That seemed to try to sync but fail to sync for me.

Could you check above attached datas from DELT test mode?

Best regards
konrado5

[les-70]

  I did look at the data you attached.  I shows a 2pi phase shilft roughly every 13 tones.  That looks as though DELT mode may not have made a difference.   If real it I think it would correspond to a line length of about 4km.  What is the expected line length?

[les-70]

  Further the above reply, if you collect a  4-5 sets of Hlin in delt mode, after resyncs of the connection a day or so apart, you can check whether the number of tones per 2pi change in phase changes. Normally it does but you can get same value a few times running.  Currently you have about 13 tones.  If that number changes then nothing could be deduced.  Equally unless the actual line length 4km nothing is worthwhile.  Even then Hlog is going to give a much more accurate info on line issues such as bridged taps.  The evidence is that all that Hlin could give is an indication of the line length and that estimate can be done by hand counting the number of tones per 2pi.  In short really don't think any other analysis is worth doing.

[boost]

HLOG ftw?

[konrado5]

Currently you have about 13 tones.  If that number changes then nothing could be deduced.  Equally unless the actual line length 4km nothing is worthwhile.

My actual line lenght is about 1.2km. Could you check other hlin DELT mode stats?

Even then Hlog is going to give a much more accurate info on line issues such as bridged taps.

What about translate Hlin to TDR ?

Best regards
konrado5

[les-70]

  I don't know what DELT mode should give give, but  your HLins differ and the line length does not match your line length.  In short there is nothing useful to be done.   Due to the imposed phase variations we can't even deduce the line length from HLin.  And for similar reasons you can't translate HLin into a crude TDR. I really can't offer anything at all.

[konrado5]

It is strange that Hlin is useless. Why is it measured? Could you look one again at my Hlog ? I've noticed on some frequiences (300-400 tone) my attenuation is curiously low. On other circuit, attenuation on these tones is higher despite lower attenuation on low frequiences.