Xref: utzoo rec.video:13113 sci.electronics:12575 rec.ham-radio:21329
Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!wuarchive!emory!ogicse!milton!cfogg
From: cfogg@milton.u.washington.edu (Chad Fogg)
Newsgroups: rec.video,sci.electronics,rec.ham-radio
Subject: HDTV and Waveform Modulation
Summary: new method squeezes an HDTV + NTSC signal in one, compatible channel
Keywords: HDTV waveform PSI
Message-ID: <4454@milton.u.washington.edu>
Date: 26 Jun 90 08:23:39 GMT
Organization: Never Twice a Sane Committee
Lines: 27

A new term to add to the HDTV glossary, waveform modulation is given
a brief mention in the July 1990 issue of _Video_Magazine_, page 50.

According to the article, Production Services, Inc. of Tuscon, Arizona 
claims they can "squeeze a full-blown HDTV signal and a conventional 
NTSC signal within the same 6 MHz frequency channel" by using "a new
modulation technology to add information to the spectrum without inter-
ference."   

Richard Gerdes, PSI co-founder, explains that their technique "alters
the shape of the carrier and transmits the result of that altered wave
shape."

At the NTSC level:

   PSI gas already developed a commercial product using waveform modulation
   for NTSC broadcasts: an encoder and decoder that allows an NTSC station
   to broadcast two channels simultaneously from one transmitter.  "You
   could tune to channel 4A or 4B using the decoder," Gerdes says.  The
   FCC has already granted an experimental license for channel 11 in Tuscon,
   a Fox Network affiliate, to begin testing the system.

----

Article aside, has anyone in Tuscon seen this?  Any elaborations on 
waveform modulation; PSI's technology?   And does WM have implications
for other EM-based communications?