Spec. of a IR LED

[Lanfeust23]

Hello,
I just want to know what is the nominal range (in average) in emitting frequency for the Infrared LED. I guess if its should be more than 4MHz.
Thanks

 

[IRstuff]

Your question is unclear. It seems as if you are asking about the spectral emission of an IR LED, which has a wavelength greater than 800 nm, which makes the frequency of its emission somewhere in the hundreds of THz.

Your poser suggests that you are actually asking about the modulation frequency, which is dependent on application.

TTFN

 

[Lanfeust23]

Ya, I admit my question is not clear. I just would like to know if I can transmit a 4MHz signal using infrared LED.
I mean, LEDs have surely rise time which limits the data rate of transmision ?

 

[IRstuff]

Sure. IRDA is specified to operate at 4Mb/s data rates:

http://www.irda.org/standards/standards.asp

http://www.deyselectronics.com/id1.html

TTFN

 

[Lanfeust23]

Thanks but I would not use the IRDA protocol. I have just a signal I would like to transmit as fast as I can. I said 4Mb/s because I known its possible with this protocol but without any protocol (just untreated binary signal), what is the limit ? I have not datasheet about my LED so I just want an idea about that in general.
Excuse me about my lack of clarity but its the first time I make this kind of design and I don't always ask the good questions.

 

[IRstuff]

My point was that since a protocol uses at least as much bandwidth as the data rate, if the IRDA interface is specified for 4 Mb/s, then the diodes must have at least that bandwidth to support the protocol.

TTFN