Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!helios!bcm!rice!uw-beaver!milton!dali.cs.montana.edu!uakari.primate.wisc.edu!sdd.hp.com!ucsd!pacbell.com!tandem!netcom!gandrews
From: gandrews@netcom.COM (Greg Andrews)
Newsgroups: comp.dcom.modems
Subject: Re: PEP vs. v.32
Summary: QAM doesn't mean just four bits/symbol.
Message-ID: <26471@netcom.COM>
Date: 2 Mar 91 04:40:43 GMT
References: <6895.27CDE02A@zswamp.fidonet.org>
Followup-To: comp.dcom.modems
Organization: Netcom - Online Communication Services  UNIX System {408 241-9760 guest}
Lines: 18

In article <6895.27CDE02A@zswamp.fidonet.org> root@zswamp.fidonet.org (Geoffrey Welsh) writes:
>
>   For instance, I've noticed that the trend in 9600+ bps modems is to 
>increase the resolution in the coding constellation.  PEP still uses sixteen 
>point QAM; has DSP technology not improved enough to enable us to code more 
>than four bits per baud in a multicarrier scheme?
>

PEP isn't limited to a 16 point constellation.  In the cleanest parts
of the line you'll see carriers using a 64 point (6 bit) constellation.

Unless the modem decides the line won't support that kind of signal
resolution...

-- 
.-------------------------------------------.
| Greg Andrews      |   gandrews@netcom.COM |
`-------------------------------------------'