Timeline for 802.15.4 - how are the baseband and RF signals related?
Current License: CC BY-SA 3.0
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| Oct 2, 2016 at 10:28 | comment | added | kfx | Marki's article is the best so far, as it has the actual formulas; graphing 4 bits modulated on the carrier wave produces this: i63.tinypic.com/2w6rkp3.png - the two curves are the output signal and the OS shifted by 2pi to compare with itself. So it seems that the QPSK output signal both amplitude modulates, phase-shifts, and even a little bit frequency modulated the carrier wave? | |
| Oct 2, 2016 at 10:23 | comment | added | kfx | Thanks for the intuitive explanation! So you say the output is basically AM of the carrier wave? What I found confusing about the whole business is whether the term "phase shift" in QPSK refers to the baseband signal sine pulses (as I initially assumed) or to the modulated carrier. I've read Wikipedia page about PSK so many times, but now see that it's missing some things and not particularly helpful. But the wiki picture shows that the carrier wave is phase-shifted (it does not look AM), so that's different from what you're saying? | |
| Oct 1, 2016 at 18:47 | history | edited | metacollin | CC BY-SA 3.0 |
added 707 characters in body
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| Oct 1, 2016 at 18:36 | history | answered | metacollin | CC BY-SA 3.0 |
