[Laser] PWM of LED in QST

[n5gui at cox.net]

Tom

No bamboo.

First, it is a waste of a structural material that has many good uses.  It has proven to be renewable and biodegradable for millenia.  


And far more importantly, it would be a terrible thing to do to someone who is trying to encourage experimentation and development of light communication systems.  

It would be much wiser to thank him for his efforts and provide him with a clear explantion of both what was correct and what was not.  It could not hurt to provide him with a simple and effective way to demonstrate the potential of optical commuication.


James
 n5gui


---- Tom Becker <GTBecker at RighTime.com> wrote: 
>   OK, I've read the QST article (thanks, Raymond) - and agree with you, 
> James, that the visually-average LED intensity should not vary using 
> this method for voice frequencies.
> 
> I see no assertion of what Vcc the author used (although he writes "If 
> Vcc=12v..." when discussing LED current limiting) but he does suggest a 
> modulation value, 1VRMS (~2.8VPP); he writes that he used audio from a 
> radio and measured it with a DVM.  A DVM is a poor choice to measure 
> audio levels, particularly peaks, so he might well have been providing 
> even more than 2.8VPP.
> 
.
.
.
>
>.............  You're right, he likely 
> inadvertently over-drove the method.
> 
> So, bamboo under his nails?
> 
> Tom
> 
> 
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