From: Adrian Shiner ([email protected])
Date: Thu Dec 23 1999 - 12:09:12 PST
Back to the clean sheet of paper.. signalling onto and out of a circuit
which is integrated into a circuit of any size and chemical implementation.
For unambiguity, a truly positive signal is the presence of a carrier signal
or not. If the creator circuit of the signal fails in any state then the
signal is negative, Detection of the carrier is inherantly noise cancelling.
Hence signals should not be 1 or 0 (logic) states represented by DC levels
but an AC carrier which maybe a constant or varying frequency at any
frequency from 0 to infinity Herz.
Stochastic computing techniques offer some other avenues to explore. I made
my final year B.Sc course dissertation on aspects of this subject and it has
been sadly neglected.
Then there are RF to light frequency signals which really side step the old
SI problems. If you need to go "off chip" then this is really the best
exploring in total application economics terms. Do not physically connect
the circuit but transmit the encoded information to the required place..it
might be an adjacent circuit or circuits. Easy if you use correlation
techniques with suitable encoding. I do not see the need to use fibre optic
or other physical link connections in this context.
For our commercial readers such as Intel etc.. I wrote these ideas today. I
believe I have the prior publication and copyright on these ideas. This
email is printed and locked away in a secure place in a sealed and dated
envelope.
Aren't paradigm shifts wonderful things?
Adrian
----- Original Message -----
From: Lee Ritchey <[email protected]>
To: <[email protected]>
Sent: 23 December 1999 17:38
Subject: Re: [SI-LIST] : Clean sheet of paper
> Use Thevenin Equivalents.
>
> Bruce Rosenquist wrote:
>
> > I was skimming the latest SI news, and your final comment caught my
interest.
> > I am new to high-speed issues and controlling board impedances, and
working
> > on a design which contains a lot of parallel termination for LVPECL
signals.
> > This requires a termination voltage, which must, as you say, both sink
and source current.
> >
> > How do the pros typically do this? Are there any DC-DC converters that
are made
> > specifically for this function? What are some of the nasties you speak
of ?
> > What are the tricks ?
> >
> > Bruce Rosenquist, Designer
> > DesignPRO Inc.
> > 35 Stafford Rd., Unit 1
> > Nepean, Ontario
> > K2H 8V8 CANADA
> >
> > http://www.designpro.org
> >
> > [email protected]
> >
> > phone: (613) 596-5030 fax: (613) 596-5163
> >
> > D. C. Sessions wrote:
> >
> > > With the year wrapping up and my inbox filling with
> > > "Out of Office Autoresponse" messages, I thought I'd
> > > kick off something more interesting than the joys of LVDS.
> > >
> > > In particular, what would we use for signaling if we could
> > > start with a totally clean sheet of paper? Rather than
> > > immediately jump to a solution, I'm looking for some criteria:
> > >
> > > * It has to be scalable. Given silicon technology trends, it
> > > should migrate gracefully to lower-voltages and less
> > > voltage-stress-tolerant semiconductors.
> > >
> > > * It has to be SI clean. Output impedance should be matched
> > > (stringency variable) to the line across the switching range.
> > > Inputs switchpoints should be symmetrical and well-defined
> > > (ie differential receivers). Power plane proliferation
> > > leads to bad SI and wasted money, so separate termination
> > > supplies are a Bad Thing.
> > >
> > > * It has to be versatile. Single-ended, balanced single-ended, or
> > > differential; multidrop or point-to-point; uni- or bidirectional;
> > > all should be minor variations on the same system.
> > >
> > > * It should be economical. Wasted power is a Bad Thing, so low
> > > swing is a must. Padrings are some of the most expensive real
> > > estate around, so pincount should be minimized. Line termination
> > > can dominate a PWB so KISS is the rule. Power supplies (esp.
> > > ones that can both sink and source current) are expensive and
> > > nasty to deal with, so do without (both for termination and
> > > funny analog functions in the I/O circuits.)
> > >
> > > What can we add to the list? Remove? Priorities? (This is
> > > engineering, we make tradeoffs.) Where does this take us?
> > >
> > > --
> > > D. C. Sessions
> > > [email protected]
> > >
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