Timeline for Understanding the relationship between LoRa chips, chirps, symbols and bits
Current License: CC BY-SA 4.0
13 events
| when toggle format | what | by | license | comment | |
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| Apr 23 at 13:15 | comment | added | Erlkoenig | So how are fmin and fmax defined? Based on the bandwidth setting? Or hardwired around the center frequency? | |
| May 24, 2018 at 19:49 | history | edited | efox29 | CC BY-SA 4.0 |
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| S May 24, 2018 at 19:03 | history | suggested | mike65535 | CC BY-SA 4.0 |
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| May 24, 2018 at 15:18 | review | Suggested edits | |||
| S May 24, 2018 at 19:03 | |||||
| Sep 15, 2017 at 13:17 | comment | added | Felix Crazzolara | I spent the last 24h to get into LoRa and stumbled over this question. I was also stuck with chirp rate and how one can see different chips in a chirp and so on. I don't like both of the answers here since they don't address the part labeled Question: If I have time I'll write my own answer, up to that moment I would advise to read this patent. This answer is actually bits of information scrambled from this document. Thanks a lot though for the examples and especially for drawing the boundaries of the chirps this was really helpful! | |
| Jun 7, 2017 at 5:04 | comment | added | uhoh | I'm still stuck on the bits/symbol ~ SF. This looks like something obvious and well known to the signals-savvy, but I don't see why yet. Can you point me to some place I can read further? I just need an "aha!" type clue. Thanks! It seems LoRa has become a really nice learning experience for me. | |
| May 17, 2017 at 12:33 | history | bounty ended | uhoh | ||
| May 14, 2017 at 15:06 | comment | added | uhoh | OK finally I'm getting there :) Thank you for the edit, it's so much clearer now, to me at least. It's what I call an "Aha! moment" for me. All this time I was looking at this with the frame starting at the \$f_{min}\$ and it made no sense. Great! | |
| May 14, 2017 at 15:04 | vote | accept | uhoh | ||
| May 14, 2017 at 12:17 | history | edited | Sylvain | CC BY-SA 3.0 |
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| May 14, 2017 at 12:10 | comment | added | Sylvain | The "irregularities" and "steps" are due to the cyclic-shift. A non shifted up-chirp starts at fmin, and ends up at fmax. A chirp cycle-shifted by 2^(SF-1) samples starts at (fmin+fmax)/2, ramps up to fmax at half the chirp length, then jump to fmin immediately, then ramps up to (fmin+fmax)/2 at the end of the chirp. | |
| May 14, 2017 at 11:37 | comment | added | uhoh | When I look at the waveform I'd call it a simple, ramped frequency modulation rather than a phase modulation, and I'd say the bandwidth is essentially just \$f_{max}-f_{min}\$ (pretty close when I take the FT). In the waveforms I see irregularly spaced sudden, larger steps in frequencies. Can you address these highly distinctive LoRa-specific features directly please? | |
| May 14, 2017 at 10:42 | history | answered | Sylvain | CC BY-SA 3.0 |