[EAS]Capacitive coupling

pjk pjk at design.eng.yale.edu
Tue Sep 23 18:25:57 EDT 2003

Subject:   Capacitive coupling

(from NewsScan Daily, 23 September 2003)

Sun Microsystems engineers have discovered a way to move data 60 to
100 times fast as the present top speeds allow. The technique,
dubbed "capacitive coupling," involves placing the transmitter of
one chip directly in proximity to its neighbor's receiver,
eliminating some of the circuitry that can cause bottlenecks.
Researchers say the Sun technique could pack hundreds of chips in
face-to-face checkerboard fashion far more densely than is now
possible and could lead to the realization of one of Silicon
Valley's pipe dreams: a computer packaging technique known as 
wafer-scale integration, which would eliminate the need for clunky
circuit  boards. "This is a very novel idea that could give you a
way to make a very compact computer," says David Patterson, a
computer scientist at the University of California at Berkeley.
"From the very beginning people have  been making circuits on wafers
and then chopping them up and then wiring  them back together
again." Stanford University professor William J. Dally  says, "This
is one of those things that could have great potential if they  can
work out the details," which include coming up with ways to cool the
tightly packed chips and mitigate potential interference between
the tiny  transmitters and receivers. (New York Times 22 Sep 2003)

Dear Colleagues -

Despite being specifically technical, it is also a good reminder of
aspects of the culture of technology. "Capacitive coupling", the
means of digital transmission described here, has been known for a
long time, and used at least 15 years ago in integrated circuits by

This then is an example, one of many, that in today's advanced
technologies it usually matters less what the nature of an advance
is, and more who proclaims it and how & when. Without a highly
publicized statement in the press, rather than the professional
literature, that "mine goes to eleven"* the message is often lost.
This tends to be hard on innovators with modesty and the
old-fashioned tendency of getting good results first and publishing
them later in the refereed professional literature. 

Early "publication" in the New York Times used to be frowned on by
the technological community. I remember how Ovshinsky was castigated
20-25 years ago for doing so. Now the press release and newspaper
article in advance of proper publication is even a way of swaying
referees living too hectic a life to sort out what constitutes
originality and importance.


* For those of you not familiar with the reference, it comes from
the parody film "This is Spinal Tap" (1984).

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