<table cellspacing="0" cellpadding="0" border="0" ><tr><td valign="top" style="font: inherit;">Hi Bill <span>Herzog</span> & Folks,<br><br>I am very pleased to hear about the engineering side of the great TBC design efforts that were going on upstairs @ building #3. All this while I was making the move from Helical to Quad. And of course the changes in the Nova project with the project engineer, Charlie Crum leaving to start the Catholic Broadcast Network, a couple of weeks after I moved over to the Broadcast Side of Product Management. <br>Keep up the great work, olde friend, and please give us all more of your engineering insight.<br><br>Bye for now, Bill & Gewyn & Ginger (whoof...whoof)<br><br>--- On <b>Sat, 5/14/11, Bill <i><bherzog@budget.net></i></b> wrote:<br><blockquote style="border-left: 2px solid rgb(16, 16, 255); margin-left: 5px; padding-left: 5px;"><br>From: Bill <bherzog@budget.net><br>Subject: Re: [QuadList] What
is it????<br>To: "Quad List" <quadlist@quadvideotapegroup.com><br>Date: Saturday, May 14, 2011, 11:20 PM<br><br><div id="yiv2104907307">
<p class="yiv2104907307MsoNormal"><span style="font-family: Arial; font-weight: normal;">After the AVR1 was production released there were a lot
of
Redwood City engineers sitting around with very little to do.<span style=""> </span>There were no active development budgets
other than MPD (maintenance of product design), and the camera
projects.<span style=""> </span>I was bootlegging the design
of a NTSC
encoder based on Charley Coleman’s Pal encoder prototype he
designed for the
Universal Colortec project.<span style=""> </span>Somehow I
came up with what I thought was an original error detector
circuit.<span style=""> </span>Instead of comparing sync
versus a reference
and generating an error voltage that controlled a variable delay
line, this
circuit simply looked at the first sync pulse that came along
after the
reference from a series of taps on a long delay line.<span style=""> </span>Whichever tap first produced a sync after
the reference, that was
the tap that should be used and was selected as the output.<span style=""> </span>The video then went into the vernier
corrector exactly as the AVR1.<span style=""> </span>The
vernier corrector was essentially a modern version of Colortec.<span style=""> </span>I built a breadboard to prove the logic and
demonstrated it to Charles Anderson the manager.<span style="">
</span>He liked it and said they had been thinking about a new
model
Quad machine with a box that replaced Amtec, Colortec, Velocity
Comp, and
Processor.<span style=""> </span>Within a month I had a
budget, and the Minibuffer was started with a staff of about 4
men including
myself.<span style=""> </span>We were proceeding quite
rapidly, because a lot of the boards were just lifts from the
AVR1, when
Charles Anderson said to start thinking how to make it helical
as well as
quad.<span style=""> </span>Apparently there was a need for a
helical tbc, and this might fit the bill.<span style="">
</span>In the end the tbc ended up helical only, but there were
months there
that it was to be a dual purpose tbc.<span style="">
</span>There was a significant cost reduction in the delay lines
opposed to those
in the AVR1, because the delay lines were conventional lumped
constant delays passing
baseband video.<span style=""> </span>This was much less
expensive than the rf based mod/demod glass lines used in the
AVR1.<span style=""> </span>I put the rf connectors on the
front panel,
because I didn’t like having to make precise alignment fixtures
so the boards
would plug into the back, as the AVR1.<span style="">
</span>I don’t remember the connector pins being reversed, and
have no
explanation how that happened.<span style=""> </span>The
entire project for the 790 tbc was rather inexpensive as
projects went in those
days, and we had no major delays.<span style=""> </span>Simultaneously
Maurice
Lemoine was championing a digital tbc, but was delayed funding
for
considerable time.<span style=""> </span>There were still a
lot of questions about the “quality” of digital.<span style="">
</span>Number of bits, sampling frequency, multigeneration, etc.<span style=""> </span>Maurice had to bootleg his A to D for quite
a while before he actually got funded.<span style="">
</span>I don’t know for sure, but I always assumed that the
powers that be
considered my approach to another tbc the safer route at that
time.<span style=""> </span></span></p>
Bill Herzog<br>
<br>
On 5/14/2011 9:07 AM, Don Norwood wrote:
<blockquote type="cite">
<style></style>
<div><font size="3">Hi Chris:</font></div>
<div> </div>
<div><font size="3">I'll agree that the IVC interchange was
better. Beyond that, both the electronics and the transports
had issues. While the transport looked very "professional", a
check underneath revealed some serious shortcomings,
especially the lack of direct drive servo system for the
drum. As the machines aged, this became even more apparent
when the pulley wore to the point that the head could never
achieve speed!</font></div>
<div> </div>
<div><font size="3">As for the TBC designs, the analog TBC-790
came out in '72. At that point, I'd guess that the cost of
digital was still too high for the helical market. Two years
later in '74, the TBC-800 was introduced as Ampex's first DTBC
for helical. Weighing in at a mere 100 lbs compared to the
120 lbs of the 790, it had a 1-H correction window and list
price was $11,500 plus an additional $3,500 for Velcomp. The
790 had been priced at $10,000 for the base unit and only had
a correction window of +/-1.5 usec, so for about the same
price, there was a huge performance increase in two years.
Then, in another two years ('76), the TBC-1 at $12,800 plus
only $1,500 for Velcomp offered a +/-6H window for less cost
than the TBC-800. It was also down to a lightweight 80 lbs!</font></div>
<div> </div>
<div><font size="3">Don Norwood<br>
Digitrak Communications, Inc.<br>
<a rel="nofollow" target="_blank" href="http://www.digitrakcom.com">www.digitrakcom.com</a></font></div>
<blockquote style="border-left: 2px solid rgb(0, 0, 0); padding-left: 5px; padding-right: 0px; margin-left: 5px; margin-right: 0px;">
<div style="font: 10pt arial;">----- Original Message ----- </div>
<div style="font: 10pt arial; background: none repeat scroll 0% 0% rgb(228, 228, 228);"><b>From:</b> <a rel="nofollow" title="Chill315@aol.com" ymailto="mailto:Chill315@aol.com" target="_blank" href="/mc/compose?to=Chill315@aol.com">Chill315@aol.com</a> </div>
<div style="font: 10pt arial;"><b>To:</b> <a rel="nofollow" title="quadlist@quadvideotapegroup.com" ymailto="mailto:quadlist@quadvideotapegroup.com" target="_blank" href="/mc/compose?to=quadlist@quadvideotapegroup.com">quadlist@quadvideotapegroup.com</a>
</div>
<div style="font: 10pt arial;"><b>Sent:</b> Saturday, May 14,
2011 7:02 AM</div>
<div style="font: 10pt arial;"><b>Subject:</b> Re: [QuadList]
What is it????</div>
<div><br>
</div>
<font id="yiv2104907307role_document" size="2" color="#000000" face="Arial">
<div>Bill</div>
<div> </div>
<div>Very interesting history. I have used a few different
models of the EIPD machines. 7000, 7500, 5000 series and a
7800. They were decent but had issues. When IVC came
along, a number of us wished that one could combine the
Ampex electronics with the IVC transport because it held
interchange a whole lot better. Actually we were
complaining about the swing arms in the EIPD machines. </div>
<div> </div>
<div>The TBC designed for the 7900 was interesting. I still
wonder why that path was chosen for the design. Was it
because it was so early in the digital age that the cost was
too high to produce a TBC? Was it too early for the
engineering skills? Was there a time issue to get the
product for market? Or was the culture at Ampex such that
it had lost its way.</div>
<div> </div>
<div>I remember being told about the letter for the
discontinuance of InstaVision. It said something like "Due
to the unprecedented success of Instavision, we are
discontinuing the product." A fellow by the name of Doug
Mumley was working for EIPD here in Detroit and saved the
letter.</div>
<div> </div>
<div>Chris Hill</div>
<div>WA8IGN</div>
</font></blockquote>
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