Forum: GNU Radio unexpected low frequency component in received USRP signal

2dc1bd62e0e8db26726b5b28cdd9a2e2?d=identicon&s=25 Alex Zhang (Guest)
on 2014-01-09 20:12
(Received via mailing list)
Attachment: iq.png (4 KB)
Hello,

This is a radio problem I can not explain:

Transmitter: USRPN210, BPSK, linkrate = 100kbps, TX-gain=15
Receiver: USRPN210, Rx-gain=15
TX-RX: 1.5m.

Below is what the I/Q samples I get, after timing synchronization. There
is
no center frequence offset as I share the same clk for tx and rx.

It looks like the if the I or Q amplitude is low, a frequency leakage is
displayed in this picture. I have used the tune_request for both the tx
and
rx to the same offset of sample rate.

And I have monitored the radio spectrum by measuring the noise, no
interference is found.

Really confused for this observation.

--

Alex,
*Dreams can come true  just believe.*
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