Thomas McGahee <PICLIST@MITVMA.MIT.EDU> wrote:

> Among other things, a "chopped" signal now has a well defined
> AC characteristic that allows you to use AC coupled amplifiers.
> AC amplifiers can then reduce DC bias effects.
>
> Another reason for chopping certain signals is that you can
> then generate a "background" and a "signal+background"
> that can then be handled differentially so that the signal
> is removed from the background noise.

    Both of these are very good points; IR-receiver amplifiers have
    a LOT of gain, and IR remote controls have to work well in the
    presence of ambient infrared light, so anything that helps with
    either of those issues is a very good thing.

    One point that hasn't been mentioned is that chopping the IR
    signal SIGNIFICANTLY reduces the current-draw of the device...
    Which is sorta essential for battery-powered consumer
    applications.

    -Andrew


=== Andrew Warren --- aiw@cypress.com
=== Cypress Semiconductor Corporation
=== Interface Products Division, S.D.
===
=== The opinions expressed above do
=== not necessarily represent those of
=== Cypress Semiconductor Corporation.

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