Now here's a new idea

Somebody on this group recently told me that scientists are building an
optical interferometer, with two sensors linked by fiber optic cable. Does
anybody have any thoughts on how to step-down the EM frequency so that the
signal could be transmitted by twisted pair, without losing synchronization
between the two signal sources?










--
"I prefer to detour the repository of tradition, wherever possible."
--James Steranko

"John Schutkeker" wrote in message
. 30.44...

Somebody on this group recently told me that scientists are building an
optical interferometer, with two sensors linked by fiber optic cable.
Does
anybody have any thoughts on how to step-down the EM frequency so that the
signal could be transmitted by twisted pair, without losing
synchronization
between the two signal sources?

Heterodyne the light with a laser. (Hint: it's
not a new idea.)

George

On Fri, 18 Feb 2005 16:31:06 GMT, John Schutkeker
wrote:


Somebody on this group recently told me that scientists are building an
optical interferometer, with two sensors linked by fiber optic cable.
Does anybody have any thoughts on how to step-down the EM frequency so
that the signal could be transmitted by twisted pair, without losing
synchronization between the two signal sources?


It is unlikely to work, even if you could sufficiently down-convert
the original signal to much lower frequencies. Optical interferometers
rely heavily on signal *phase* information, not just amplitude.
While such phase info might be converted as well, the necessary precision
probably would not be acheived, without sending some reference wave as
well. Most lasers loose coherence after a few feet, at best.

Cheers,
larry g.

Actually, the real reason why it wouldn't work is because, having down-
shifted the light, you'd destroy synchronization by running it through a
circuit switched phone system. That's the "new" part that I didn't
mention in my OP. Even if you had a tunable delay circuit that self-
activated every time you redialed, the signal integrity would completely
disintegrate the minute your waveform hit the telco switching machine.

And another headline making idea bites the dust.

USNO built one at Anderson Mesa aobut 6 years ago and it has been in
use for several years. Go to their web site for info.

" wrote in
oups.com:

USNO built one at Anderson Mesa aobut 6 years ago and it has been in
use for several years. Go to their web site for info.

Was it circuit switched or just a frequency step-down?

I really don't know since I was at USNO in DC and only hear rumors
about the Flagstaff operation. Sorry. There was someone I knew out
there who occasionally posted on newsgroups, but I've been retired
for 4 years now and forget everything about that place. Will look his
name up in my empty brain.

Try this: http://www.nofs.navy.mil/projects/npoi/

In article .com,
wrote:
I really don't know since I was at USNO in DC and only hear rumors
about the Flagstaff operation. Sorry. There was someone I knew out
there who occasionally posted on newsgroups, but I've been retired
for 4 years now and forget everything about that place. Will look his
name up in my empty brain.

If someone can repeat the question (I only see replies, not the head
article) I can try to answer the question. I am an employee of USNO.

(Greg Hennessy) wrote in news:d17vv2$in5$1
@tantalus.no-ip.org:

If someone can repeat the question (I only see replies, not the head
article) I can try to answer the question. I am an employee of USNO.

I wanted to build an optical imaging interferometer that worked over a
phone line.