Pulsed IR

[skuntz]

Forgive me if this is a very basic question, but at my business we are using IR emitters for gas detection for the first time.

What are the reason(s) that IR sources are pulsed?

 

[IRstuff]

That would depend on the application and the design.

In most simple detection systems, you need to compare "signal" versus "no signal," which can often be accomplished by pulsing the source.

Pulsing, or modulation, can often be used for symchronous detection schemes, that result in substantially lower noise, which affords either better sensitivity, or lower cost detectors.

TTFN

FAQ731-376

 

[skuntz]

How does modulation achieve lower noise?

 

[IRstuff]

Do a read on "lock-in amplifier"

http://www.thinksrs.com/downloads/PDFs/ApplicationNotes/AboutLIAs.pdf

http://en.wikipedia.org/wiki/Lock-in_amplifier

TTFN

FAQ731-376