Re: AOM strange effect

From: Rene Tschaggelar (none_at_none.net)
Date: 10/05/04 

Date: Tue, 05 Oct 2004 14:39:23 +0200

Luigi Loreti wrote:

> "Rene Tschaggelar" <none@none.net> ha scritto nel messaggio
> news:41614c4e$0$23968$5402220f@news.sunrise.ch...
>
>>The type of modulation is a matter of bandwidth. While PWM is
>>feasible with say 1Mhz clock giving a bandwidth in the audio range,
>>analog modulation can be used for a few hundred MHz.
>>The applications are completely different.
>>
>
> I don't want to be involved in a discussion on LED modulation, but I
> Normally modulate the LED at 65 Mhz in PWM, to have a resolution of 16 bit,
> as the color response of the LED is stright different from CRT.
> May be it's a problem of application, as when you have to drive some
> tenthousands LEDs, as in a big screen, and this is an outdoor configuration,
> temperature, linearity, stability and color response is one of the most
> important thing, do not mention power and reliability.
>
> Anyway, I'm interesting to know how AM modulate at "few hundred MHz" a LED,
> and how this is dependent from temperature, current, wavelength, and which
> resolution (number of gray level or dynamics) and response time, could be I
> learn some more thing :-))
>
> any links or publications or book or data***??

These applications are somewhat different. The focus is just the
datarate. Lookup http://www.analog.com , there
RF/IF Components : 'Fiber Optic Laser Drivers'

They basically have a mean current flowing through the laserdiode
or LED, and modulate a current by inductive or capacitive means.

Rene

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