[Discuss-gnuradio] Odd use of LO phase lock feature on USRP for RFID app
From:
Colby Boyer
Subject:
[Discuss-gnuradio] Odd use of LO phase lock feature on USRP for RFID application
Date:
Tue, 19 Apr 2011 11:38:13 -0700
Hi All,
In RFID applications, a reader receives (backscatter from RFID tag) and transmits (constant tone) at the same frequency. With commercial readers, a single LO will be shared by the RX and TX chain. However, in the USRP case, two separate daughter boards are used so different LOs are in use for the RX and TX chain. So you should end up with some frequency offset in RX chain due to mismatched clocks.
Is it possible to lock the LOs of a TX daughter board and a RX daughter board, as you would for a traditional MIMO 2 TX or 2 RX setup? There appears to numerous discussions and examples of the latter. I'm thinking it would be possible. But I'm more of a systems guy and less of a RF hardware guy, so any comments would be appreciated.