On 29 Sep 96, Dave Hatch wrote to Paul Wankadia --



PW> Yes -- could someone (anyone?) explain what that polynomial supposedly

PW> called "scrambling" is for?

 DH> The scrambler function is to control the statistical probability

 DH> function of the encoded signal.  Without a scrambler, the probability

 DH> of steady 1 and steady 0 are pretty high.  With an adequate

 DH> pesudo-random overlay, NOTHING gets a favoured look-in.



So the scrambler turns "0000000011111111110000000" into
"0101010101010101010"

(or something like that) ???



 DH> Bingo - the maths pay off, and the spectrum is used evenly.  Without,



Oh?  I thought the "spectrum" was just one frequency -- the
carrier?  Please

explain to this know-nothing at 3:640/772.3 :)



[other bits about STN ratios deleted]



 DH> A "perfect" modem transmission would be sending pure
white noise as

 DH> the encoded signal.  The scrambler pretends this is so, to a moderate

 DH> degree of success.



I've picked up the phone a few times in the middle of modem sessions and it

certainly sounds like pure white noise to me...  Of course, that could be

because I was transferring a nice big file... 



 DH>   And what do half of those TLAs actually MEAN

PW> what some of them STAND for, but what do they MEAN?) ...?

 DH> Lots of people are too lazy to string together jawbreaker words, AND

 DH> they like to look smart at the same time...:-)



Yeah -- I was actually hopping for some enlightenment there :)  For a start,

what does QAM stand for AND what does it mean?  Ditto for PCM and TAM and

line probing and all that sort of thing!



Chow.



Junyer Hakker.



--- PPoint 2.00