NEC1
Joined: 03 Jul 2010 Posts: 56
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Posted: Wed Oct 29, 2014 10:39 pm Post subject: Calculating error rate of carrier vs micro frequency |
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In the Tools section, I added a handy calculator (made out of curiosity) for determining the error rate of an infrared carrier frequency when the system clock is (and can only be) divided by a whole number.
This led me to discover why an 115.2K IRDA port had a short range on a Panasonic TV (36.7kHz carrier), even with two 5mm IR emitters added, because the carrier frequency had too much error (1.7 kHz/4.2% vs. a 38.4kHz carrier (115.2K divided by 3) from the IRDA port and therefore a 115.2K IRDA port is not particularly suitable for infrared remote control applications, since division of frequency can only be done in whole numbers.
A 4 Mbit (or even better, a 16 Mbit) IRDA port would be suitable for infrared remote control applications, provided that you can add a more powerful IR emitter.
If you are implementing an infrared carrier frequency generator/measurement in a microcontroller project, this calculator can be of help. _________________ "The best thing possible to do with knowledge is to share it". |
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