Re: [Discuss-gnuradio] Signal reconstruction

[Firas abbas]

Hi,

Sorry about the scope file, I using a modified version and it seems that I being confused with the standrad one. However, there is something strange in the data shown in your picture. Since you are using decimation =8, the data coming across the USB should be complex 8 Msps. But your scope is showing (address@hidden: 4M) which is wrong. another thing, the DDC  be should equal 0 , while in your picture it is being (DDC : -8M) !!!!. 

Firas





Aadil Volkwin <address@hidden> wrote:

The Scope was definitely usrp_oscope.py Used Directly from the from the examples folder:

address@hidden:~/Desktop/GnuRadioResources/gnuradio-3.0.2/gnuradio-examples/python/usrp$ ./usrp_oscope.py

Aadil

On 10/11/2007, Firas abbas <address@hidden> wrote:

Hi,

Input signal level is ok.The scope pictures was not generated by  usrp_oscope.py. What is the program used to generate it ? Test The signal with usrp_oscope.py

Firas

Aadil Volkwin <address@hidden> wrote:

Hi,

I've updated the scope screenshot on the website. Two shots are available, notice there seems to be some kind of modulation??? I've tested the input signal with an external scope and the input signal is fine. I don't know why the usrp scope is "misbehaving"

The input signal level is set at -16.02dBm

Aadil

On 10/11/2007, Firas abbas < address@hidden > wrote:

Hi,

Use center frequency =0 in the usrp scope. If you use center frequency = 250K, you will shift the signal to 0 Hz.

What is your signal input level in dBm ?

Firas

Aadil Volkwin < address@hidden> wrote:

Hi,

Firstly my apologies for posting known quantities, I guessed that members would like to see in what way I tinkered with usrp_rx_cfile.py. point taken though.

Screen shots of the MATLAB plots as well as the usrp_oscop.py output can be found at:

https://rrsg.ee.uct.ac.za/members/aadil/

I'm pretty sure the MATLAB is correct.

I have upped the input freq to 250KHz, now attempting a square wave (in desperation) and
set the options.freq to 0 in ---> self.u.tune(0, self.subdev, options.freq)

I'm Still not getting sensible plots.

Thanks again,

Aadil