Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!samsung!uunet!crdgw1!ge-dab!tarpit!bilver!bill
From: bill@bilver.UUCP (Bill Vermillion)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: Re: Baud vs. bps.
Message-ID: <936@bilver.UUCP>
Date: 29 Aug 90 05:18:18 GMT
References: <849@idcapd.idca.tds.philips.nl-> <4188@trantor.harris-atd.com> <5001@pegasus.ATT.COM>
Reply-To: bill@bilver.UUCP (Bill Vermillion)
Organization: W. J. Vermillion - Winter Park, FL
Lines: 42

In article <5001@pegasus.ATT.COM-> dmt@pegasus.ATT.COM (Dave Tutelman) writes:
->>In article <849@idcapd.idca.tds.philips.nl> lexw@idca.tds.PHILIPS.nl (Lex Wassenberg) writes:
->>>
->>>Okay, in some recent articles there were these hints about the difference
->>>between "baud" and "bits per second". Now I for one have always thought that
->>>baud and bps is the same. So what's the difference? Has it something to do
->>>with bits that don't carry actual data like start and stop bits? Or is it
->>>more subtle? Thanks to anyone who can inform me (and others).
->>>      ________________
->
->In article <4188@trantor.harris-atd.com> sonny@trantor.harris-atd.com (Bob Davis) writes:
->>
->>	Baud rate and Bit rate are two different things (although they
->>are sometimes numerically equal).
->>
->>THE LIGHTS DIM AS THE LEGEND BEGINS...
->
->... [ excellent discussion of transmission symbols that carry
->...   more than one bit ]
->... BUT ...
->
->>	THE BIT RATE *ALWAYS* IS EQUAL TO THE BAUD RATE TIMES THE
->>	NUMBER OF INFORMATION BITS CARRIED PER BAUD TIME BY THE MODEM.

Try this - bit rate is equal to baud rate time bits per baud times channels
per carrier.

Take a 7 cycle carrier, phase modulate it up to 6 bits per baud, and that
give you 42 bits/second.   Take 400 of these channels and put them down a
phone line (400 * 7 = 2800hz - enough to fit inside the 3kHz bandwith of a
voice grade line) and you wind up with 6 * 7 * 400 or 16800 bps on what is
nominally a 7 baud (or 42 baud?) signal.

Do you know what that scheme is.  That's a Telebit Trailblazer - getting up
to 18003 bps over a phone line with no compression.  Bits and baud are a
LONG way apart in that machine.



-- 
Bill Vermillion - UUCP: uunet!tarpit!bilver!bill
                      : bill@bilver.UUCP