Forum: GNU Radio Range of samples values

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Ujala Q. (Guest)
on 2009-05-25 22:18
(Received via mailing list)
I am trying to capture data samples from USRP for an FM receiver. In
what
range should the values of the samples must be lying?
Eric B. (Guest)
on 2009-05-26 00:02
(Received via mailing list)
On Tue, May 26, 2009 at 12:17:39AM +0600, Ujala Q. wrote:
> I am trying to capture data samples from USRP for an FM receiver. In what
> range should the values of the samples must be lying?

-32768 to 32767
Ujala Q. (Guest)
on 2009-05-26 10:25
(Received via mailing list)
I set my decimation rate to 200 and center_freq to 100.1, but the values
of
my samples is exceeding this range. Please specify the mistake that I'd
be
making. Following are the values of my samples:6029427
0
0
0
0
256
412
1
760826203
668
50
720
722
2
-2097020188
1444
70
1516
746
3
-779299374
2264
70
2336
746
4
-664097490
3084
70
3156
772
5
100
1
266
356
2
44
622
-1414417620
29987719
1
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
6881357
7471203
7536751
6684783
3014772
6881367
6553710
Jason U. (Guest)
on 2009-05-26 18:12
(Received via mailing list)
On Tue, May 26, 2009 at 1:24 AM, Ujala Q. <removed_email_address@domain.invalid>
wrote:
> I set my decimation rate to 200 and center_freq to 100.1, but the values of
> my samples is exceeding this range.

> Please specify the mistake that I'd be making...

This is very hard to do without any information at all regarding how
you captured the samples.

My first guess would be that you are doing on of the following:

Your flowgraph is modifying the values out of the usrp

 - or - (more likely)

Whatever tool you are using to read in the samples is not doing so
correctly.

If you are using Linux I would install Octave and use the scripts in
"{trunk}/gnuradio/gnuradio-core/src/utils" to read the saved data from
a file_sink into Octave and check if you are still getting the same
kind of data.

Jason
Ujala Q. (Guest)
on 2009-05-26 18:15
(Received via mailing list)
And I am basically trying to perform this task through Windows, but even
when i run the same code on Linux, it is giving me the same values.
Ujala Q. (Guest)
on 2009-05-26 18:32
(Received via mailing list)
Is there a way that I can view some of the data samples when the GNU
Radio
is running FM radio? That way I would be able to compare the actual data
values that should be coming, and the values that I am getting through
the
interface I am using.
Ujala Q. (Guest)
on 2009-05-27 11:16
(Received via mailing list)
On Tue, May 26, 2009 at 8:08 PM, Ujala Q. <removed_email_address@domain.invalid>
wrote:
This topic is locked and can not be replied to.