[Discuss-gnuradio] Rfid 866MHz and PR-ASK modulation

[Thom L]

Hello,

First, I want to thank you for the quality of this list. The skill and kindness of the participants is just exceptional.

Well, my problem is the following one. Not really a GNU radio problem but rather a theoretical problem...

I work on a project concerning the RFID 866 MHz. Using usrp B210 real part and magnitude of the signal centered on 866MHz corresponds perfectly with  documentation EPCglobalGen2:

https://www.gs1.org/sites/default/files/docs/epc/uhfc1g2_2_0_0_standard_20131101.pdf

It seems to be a modulation Phase Reverse Amplitude Shift Keying (PR-ASK). I can't understand how in annex H (p143 of the documentation) the modulated waveform is obtained from baseband signal...

I can understand and decode signal but this little thing has disturbed me for too long ...
Everything is summarized on attached file. What I don't understand is indicated by interrogation marks.

There may be something obvious that I don't see?

Thank you for your attention,

Best regards,

Thomas

RFID 866 PR-ASK.pdf
Description: Adobe PDF document