Author Topic: IR Question. (Read 972 times)

marcus_01 · « **on:** February 20, 2008, 11:47:42 PM »

Pano gumagana ang Frequency Modulated IR Headphones..eh diba ang Ir led is Constant ang frequency/Wavelength???

Philippine Electronics Forum · « **on:** February 20, 2008, 11:47:42 PM »

marcus_01 · « **Reply #1 on:** February 21, 2008, 12:03:19 AM »

Quote from: marcus_01 on February 20, 2008, 11:47:42 PM

Pano gumagana ang Frequency Modulated IR Headphones..eh diba ang Ir led is Constant ang frequency/Wavelength???

Mods..pwede po pakilipat..naduling ako sa pagkabasa..wire comm pala..kala ko wireless comm..sorry..hehe..

Philippine Electronics Forum · « **Reply #1 on:** February 21, 2008, 12:03:19 AM »

Born2BeWired · « **Reply #2 on:** February 21, 2008, 07:24:36 AM »

Quote from: marcus_01 on February 20, 2008, 11:47:42 PM

Pano gumagana ang Frequency Modulated IR Headphones..eh diba ang Ir led is Constant ang frequency/Wavelength???

The optical wavelenght of the IR device is fixed, so you are right in saying di ito pwedeng frequency modulate. But it can be pulsed/amplitude modulated.

Kaya sa mga IR headphones, the IR is actually amplitude modulated at ultrasonic-hypersonic(>60KHz) frequencies - used as the carrier signal. The carrier signal is in turn frequency modulated by the audio signal. Kaya hayan, FM IR headphones na.

Philippine Electronics Forum · « **Reply #2 on:** February 21, 2008, 07:24:36 AM »

krayziebone · « **Reply #3 on:** February 22, 2008, 02:59:18 AM »

hindi ka pwedeng palipat lipat ng pwesto nito kc IR diba?

Philippine Electronics Forum · « **Reply #3 on:** February 22, 2008, 02:59:18 AM »

marcus_01 · « **Reply #4 on:** February 22, 2008, 08:14:34 AM »

Quote from: Born2BeWired on February 21, 2008, 07:24:36 AM

The optical wavelenght of the IR device is fixed, so you are right in saying di ito pwedeng frequency modulate. But it can be pulsed/amplitude modulated.

Kaya sa mga IR headphones, the IR is actually amplitude modulated at ultrasonic-hypersonic(>60KHz) frequencies - used as the carrier signal. The carrier signal is in turn frequency modulated by the audio signal. Kaya hayan, FM IR headphones na.

ah...aryt..so that makes things clear..pero isa pang question po...di AM yung Carrier na iFFrequencey modulate..eh di ba para maging stereo sa pagkakaalam ko..may 19 khz pilot tone tapus interleaved yung left and right???so ibig sabihin ang daming modulation na ginagawa sa IR headphones????hayz.....balak ko kasi gumawa out of scratch eh...as in walang modules, or ready made blocks...

ang dame palang kailangan gawin sa signal...nakagawa na kasi ako ng IR pero AM modulated mono lang..

thanks po!

Philippine Electronics Forum · « **Reply #4 on:** February 22, 2008, 08:14:34 AM »

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