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<blockquote data-quote="and-81" data-source="post: 246281" data-attributes="member: 11844"><p>I'm glad you asked!</p><p></p><p>Firstly let me tell you that the .IR files are in Philips Pronto HEX format.</p><p></p><p>This is the IR format used by <a href="http://www.pronto.philips.com/" target="_blank">Philips Pronto</a> universal remote controls. This format is very popular and gives my users the ability to download IR codes from all over the web.</p><p></p><p>It also makes the codes easy to manipulate and re-use because many IR programs support it. It does mean that I have to convert the native format IR data into and out of pronto format to use it, but that's not too difficult.</p><p></p><p>The format is fairly simple once you know how it works...</p><p></p><p>Take the first four numbers: 0000 004A 001A 0000</p><p></p><p>0000 means that it is a learned code (in the oscillated format), 0100 would mean it was unmodulated (no carrier frequency).</p><p></p><p>004A is a multiplier that determines the Carrier frequency, it works out to be 56015 hz in this case. I decoded your sample and it's in the RCA protocol which has a carrier frequency of 56000hz, so 56015 is correct. The +15 difference is because 004A is a multiplier and introduces a small (insignificant) error margin.</p><p></p><p>001A, 0000 means there are 26 pairs of time code for an initial burst, and 0 pairs for repeats.</p><p></p><p>Everything after that makes up the 26 burst pairs. The first number of each pair is the signal <strong>on</strong> time, where the blaster LED flashes the carrier frequency. The second number of each pair is the signal <strong>off</strong> time, where the blaster LED stays off. All burst pair times are multipliers for the carrier frequencies period.</p><p></p><p>That's a quick summary of how the Pronto 0000 learned IR code format works, but there is a better brief introduction to the Pronto IR format here:</p><p></p><p><a href="http://www.remotecentral.com/features/irdisp1.htm" target="_blank">RC: The Pronto's IR Code Format (1)</a></p><p></p><p>There's a more technical description here:</p><p></p><p><a href="http://www.hifi-remote.com/infrared/prontoirformats.pdf" target="_blank">http://www.hifi-remote.com/infrared/prontoirformats.pdf</a></p><p></p><p>You can download lots and lots of Pronto format IR Commands from <a href="http://www.remotecentral.com/" target="_blank">Remote Central</a> but Google can also be of use.</p><p></p><p>You can read about some common IR protocols, including the one you have posted (RCA), here:</p><p></p><p><a href="http://www.sbprojects.com/knowledge/ir/rca.htm" target="_blank">SB-Projects: IR remote control: RCA</a></p><p></p><p>Now, as for your question about variation of the carrier frequency ... Most devices are not very sensitive to the carrier frequency, that is to say: as long as it's within 10khz or so (rough figure) then it should work.</p><p></p><p>But you shouldn't really see that much variance. Though some MCE IR devices are more accurate than others.</p><p></p><p>Hope that helps,</p><p></p><p>PS.</p><p></p><p>I love your scope! If I had one of those, oh how this would be so much easier! <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite1" alt=":)" title="Smile :)" loading="lazy" data-shortname=":)" /></p></blockquote><p></p>
[QUOTE="and-81, post: 246281, member: 11844"] I'm glad you asked! Firstly let me tell you that the .IR files are in Philips Pronto HEX format. This is the IR format used by [URL="http://www.pronto.philips.com/"]Philips Pronto[/URL] universal remote controls. This format is very popular and gives my users the ability to download IR codes from all over the web. It also makes the codes easy to manipulate and re-use because many IR programs support it. It does mean that I have to convert the native format IR data into and out of pronto format to use it, but that's not too difficult. The format is fairly simple once you know how it works... Take the first four numbers: 0000 004A 001A 0000 0000 means that it is a learned code (in the oscillated format), 0100 would mean it was unmodulated (no carrier frequency). 004A is a multiplier that determines the Carrier frequency, it works out to be 56015 hz in this case. I decoded your sample and it's in the RCA protocol which has a carrier frequency of 56000hz, so 56015 is correct. The +15 difference is because 004A is a multiplier and introduces a small (insignificant) error margin. 001A, 0000 means there are 26 pairs of time code for an initial burst, and 0 pairs for repeats. Everything after that makes up the 26 burst pairs. The first number of each pair is the signal [B]on[/B] time, where the blaster LED flashes the carrier frequency. The second number of each pair is the signal [B]off[/B] time, where the blaster LED stays off. All burst pair times are multipliers for the carrier frequencies period. That's a quick summary of how the Pronto 0000 learned IR code format works, but there is a better brief introduction to the Pronto IR format here: [url=http://www.remotecentral.com/features/irdisp1.htm]RC: The Pronto's IR Code Format (1)[/url] There's a more technical description here: [url]http://www.hifi-remote.com/infrared/prontoirformats.pdf[/url] You can download lots and lots of Pronto format IR Commands from [URL="http://www.remotecentral.com/"]Remote Central[/URL] but Google can also be of use. You can read about some common IR protocols, including the one you have posted (RCA), here: [url=http://www.sbprojects.com/knowledge/ir/rca.htm]SB-Projects: IR remote control: RCA[/url] Now, as for your question about variation of the carrier frequency ... Most devices are not very sensitive to the carrier frequency, that is to say: as long as it's within 10khz or so (rough figure) then it should work. But you shouldn't really see that much variance. Though some MCE IR devices are more accurate than others. Hope that helps, PS. I love your scope! If I had one of those, oh how this would be so much easier! :) [/QUOTE]
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