Forum: GNU Radio Maximum value of samples

Announcement (2017-05-07): www.ruby-forum.com is now read-only since I unfortunately do not have the time to support and maintain the forum any more. Please see rubyonrails.org/community and ruby-lang.org/en/community for other Rails- und Ruby-related community platforms.
Sebastiaan H. (Guest)
on 2009-02-27 17:07
(Received via mailing list)
Hi

Does anyone have an idea as to what the maximum value of a sample when
read in matlab is?  I've got a BasicRx board and I'm injecting a 10dBm
signal into RX-A.  Using max(abs(sig)) in matlab results in
8.6458e+03.  Is this what I should get, or should the maximum reading
be higher?

Also, can someone quickly tell me about the two inputs on the BasicRx
board.  Are they two different channels for sampling two different
signals?  If so, how do I get access to both in a Gnuradio app?

Thank you in advance.

Sebastiaan

--
Sebastiaan H.
Radar and Remote Sensing Group, University of Cape Town
Tel:  +27 83 305 5667
Josh B. (Guest)
on 2009-02-28 00:02
(Received via mailing list)
Sebastiaan H. wrote:
> Hi
>
> Does anyone have an idea as to what the maximum value of a sample when
> read in matlab is?  I've got a BasicRx board and I'm injecting a 10dBm
> signal into RX-A.  Using max(abs(sig)) in matlab results in
> 8.6458e+03.  Is this what I should get, or should the maximum reading
> be higher?
>

USRP values are signed 16 bit values, so +/- 32768 range.

> Also, can someone quickly tell me about the two inputs on the BasicRx
> board.  Are they two different channels for sampling two different
> signals?  If so, how do I get access to both in a Gnuradio app?
>

They are 2 different antennas for 2 different signals. Or both antennas
can be used in combination for a complex IQ signal.

For usrp_fft.py (side A):

-R A:0 uses the first antenna
-R A:1 uses the second
-R A:2 uses both antennas (IQ)

-Josh
This topic is locked and can not be replied to.