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Re: [Discuss-gnuradio] USRP tuning time
From: |
Mat Mat |
Subject: |
Re: [Discuss-gnuradio] USRP tuning time |
Date: |
Mon, 10 Aug 2015 14:00:25 +0200 |
hey man,
many many thanks for the detailed reply! Based on it, I decided to
achieve frequency hopping not by changing the centre frequency of the
USRP, but by multiplying my signal with a sine of a certain frequency
offset and then transmit that signal over the USRP with a fixed USRP.
Unfortunately, a new problem has arisen. you can see my flowgraph
attached
I want my signal to be transmitted on 5.804GHz. to this end, the centre
frequency is set to 5.799GHz, and the signal that I wish to transmit is
multiplied with a sine wave of 5MHz. (I'm storing everything as a file
before transmitting, as things are otherwise too slow). The problem now
is that when I transmit the signal over the USRP, it is not transmitted
on 5804 MHz but on approx. 5802 MHz. Furthermore, this error appears to
become bigger with bigger frequency offsets: When I want the signal to
be transmitted with 20MHz offset to the centre frequency of the usrp
(thus using a sine wave of 20MHz), the difference between the intended
signal frequency and the true signal frequency is almost 10 MHz!
Am I doing anything wrong here??
kind regards and thanks so much,
Mat
Attachments:
http://www.ruby-forum.com/attachment/10982/modulator.jpg
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