why do we choose 38Khz as a carrier frequency for transmission?
i have done a project in infrared remote controlled car , where i have used a t.v. remote and a tsop receiver which also used 38Khz as a carrier frequency.can anyone explain me?
To some extent, the IR receiver IC's come in various specified frequencies, but they aren't super-critical (a 38KHz IC works perfectly at 36KHz or 40KHz) - but why would you want to use something different?.
Depends. The last time I ordered TOSP's they had narrow band ones as expected but they also hand one that would cover all of the bands. A sort of one shoe fits all ditty. But then again I could have been dreaming.
EDIT: I feel like I am follow a few people around posting contradictions. It is not my intent to be negative.
That datasheet makes no such suggestion?, as far as I'm aware the BPF in the chips is fairly wide and flat - the datasheet doesn't even mention it at all.
That datasheet makes no such suggestion?, as far as I'm aware the BPF in the chips is fairly wide and flat - the datasheet doesn't even mention it at all.
I've always wondered that myself - like I said, try them and see - in my experience it makes not the slightest bit of difference, even at well over normal remote control ranges. I presume you will lose ultimate range by not accurately following the specified frequency?, but should you be trying to use IR at those distances?.
I've always wondered that myself - like I said, try them and see - in my experience it makes not the slightest bit of difference, even at well over normal remote control ranges. I presume you will lose ultimate range by not accurately following the specified frequency?, but should you be trying to use IR at those distances?.
So it would appear that the units have different BP center frequencies, but the filter rolloff is not very steep, thus they will still operate well at other frequencies. It may be as you say, it only affects the maximum operating range slightly.
I don't have one to try, but it would make an interesting experiment.
So it would appear that the units have different BP center frequencies, but the filter rolloff is not very steep, thus they will still operate well at other frequencies. It may be as you say, it only affects the maximum operating range slightly.
I don't have one to try, but it would make an interesting experiment.
I've always only ever stocked one specific type as a replacement, and used it in all manner of different TV's - it's always worked perfectly.
I've also used them with microcontollers, and certainly varied the frequency about considerably with no ill effects - I might give it a try one day, see how far off frequency you have to go .