Topband: Light fiber question

[Tom W8JI]

>I see your point, since the signal is undergoing a conversion. My thinking 
>was modulator = baseband to some kind of RF or digital signal, i.e. 
>something very different from the original signal in terms of content of 
>the waveform. I wasn't thinking of using a band-limited section of spectrum 
>being converted to an amplitude-modulated light source as a "modulator" in 
>this case.
>
> What I had meant was that the electrical->optical conversion doesn't have 
> to be a particularly fancy system when you're only trying to run about 
> 200kHz of spectrum over the fiber in the 2(ish)MHz range. The basics I 
> mentioned before and some op amps are all that are needed. The op amps 
> will likely be the limiting factor for dynamic range.

It isn't the small bandwidth that matters, it is the dynamic range.

The most important part is people seem to think all noise comes from common 
mode, and that suppressing common mode to non-harmful levels requires 
extremes in isolation. That just isn't factual at all.

If someone has noise that is cured by going to a balanced line or extremes 
in cable shielding or choking, they have something else wrong with their 
system.

Some antennas and feed systems are just troublesome or nearly impossible to 
design correctly, and some systems are designed incorrectly.