Re: External Analog to Digital Converters

"Richard Crowley" <rcrowley@xxxxxxxxx> wrote in message
news:558cmrF24cgrvU1@xxxxxxxxxxxxxxxxxxxxx
Do you mean 25 feet of the cheap plastic extruded stuff,
or 25 feet of proper optical fiber? I don't think the cheap
plastic extruded stuff is defined for use longer than 1m
or so, is it?

Over 15 years ago, when plastic fiber was pretty new, I did some experiments
with transferring an HF signal. The original transmitters could do up to a
couple of MHz over up to 30 feet. I tuned one transmitter with some extra
components and I also polished the ends of the fiber exactly perpendicular
to the the fiber. Instead of using the supplid polishing paper I used a sort
of lime stone block normally used to hone chisels (think grit 16000). All
this resulted in a limit of 12MHz over 250 feet of fibre.

What I learned from this is that simply cutting the fibre with a sharp
Stanley knife with a new blade is not enough to get maximum performance.
Polishing the ends shiny and exactly perpendicular to the fibre is doing
great things for the maximum bandwith. This effectively gives the digital
audio signal steeper flanks and less clock jitter. Oh and sharp radii
smaller than 1" just ruin the cable. It produces microscopic fractures at
the surface of the fibre, ruining the reflection.

Meindert


.

Relevant Pages

  • Re: External Analog to Digital Converters
    ... Over 15 years ago, when plastic fiber was pretty new, I did some experiments ... couple of MHz over up to 30 feet. ... What I learned from this is that simply cutting the fibre with a sharp ... Polishing the ends shiny and exactly perpendicular to the fibre is doing ...
    (rec.audio.pro)
  • Re: APC vs. AFC: confused
    ... According to the data sheet I have this was a special order fiber. ... Now we changed to a setup where we employ two mirrors for the adjustment of the beam. ... So our source now is this laser then two mirrors then the AOTF and finally the coupler. ... You are operating a single mode fibre below its cut off wavelength. ...
    (sci.optics.fiber)
  • Re: too much fiber
    ... >> rice is helpful to me but I'm wondering what else would be. ... > Sensitivity of fiber is a transitional state seen in almost everyone ... > that has been living for a very long time on highly refined food free ... Also what kind of fibre are you having now? ...
    (sci.med.nutrition)
  • [opensuse] Fiber, Copper, and Telcos... Oh My! [Was: Top 3 Applications You Wish Existed in Linux]
    ... right-of-ways to install the cable. ... So do the telcos, but I think they saw fibre as being too expensive ... Fiber connection in the mid-90s with two facilities linked by the fiber ...
    (SuSE)
  • Re: Multimode Fiber Output Model
    ... Physical Optics to simulate better the real situation. ... minimum distance of 100 feet from the fiber. ... Lens Data Editor, set the distance from your fiber face to the next ...
    (sci.optics)
Loading