How to build a 802.15.4/Zigbee O-QPSK demodulatorThis is a discussion on How to build a 802.15.4/Zigbee O-QPSK demodulator within the DSP forums in Other Technologies category; Hello, I have searched thoroughly all over the internet for information on how to demodulate 802.15.4/Zigbee O-QPSK (MSK) signals. Slide 10 on http://www.ceesar.ch/cms/upload/pdf/...W2008_talk.pdf shows the base band signal, and also says (slide 12) that O-QPSK may be demodulated both with and without regenerating the carrier (coherent and non-coherent demodulation). Is this true? Figure 5 on http://members.tripod.com/michaelgellis/mixerscom.html shows a Costas loop that can be used for QPSK; my first thought was to use it as O-QPSK demodulator, but it doesn't seem to work, I suspect due to the absense of amplitude changes in O-QPSK. I had a look at Tim Wescott's ... | ||||||||
| | ||||||||
| ||||||||
| Register | FAQ | Calendar | Search | Today's Posts | Mark Forums Read |
|
#1
08-22-2008, 08:58 AM
| |||
| |||
 How to build a 802.15.4/Zigbee O-QPSK demodulator Hello, I have searched thoroughly all over the internet for information on how to demodulate 802.15.4/Zigbee O-QPSK (MSK) signals. Slide 10 on http://www.ceesar.ch/cms/upload/pdf/...W2008_talk.pdf shows the base band signal, and also says (slide 12) that O-QPSK may be demodulated both with and without regenerating the carrier (coherent and non-coherent demodulation). Is this true? Figure 5 on http://members.tripod.com/michaelgellis/mixerscom.html shows a Costas loop that can be used for QPSK; my first thought was to use it as O-QPSK demodulator, but it doesn't seem to work, I suspect due to the absense of amplitude changes in O-QPSK. I had a look at Tim Wescott's MSK paper, page 18 (thanks for sharing), but still don't get it. I intend to implement the demodulator with analog circuits. Thanks, Henning Petersen Senior RFIC designer www.silicide.dk  |
 |
| Thread Tools | |
| Display Modes | |
Linear Mode
