Re: [Discuss-gnuradio] Viewing square wave in usrp_oscope

[sudhindra aithal kota]

Hi,
 I made the change but I get the following error when
I run usrp_oscope.py.

.
.
.
File
"/usr/local/lib/python2.3/site-packages/gnuradio/usrp1.py",
line 27, in _swig_getattr
    raise AttributeError,name
AttributeError: set_dc_offset_cl_enable


Regards
Sudhindra

--- "address@hidden"
<address@hidden> wrote:

> I have been able to view square waves down to 1 KHz
> with the usrp_oscope. 
> I do not use a daughterboard and I turned off the
> automatic DC offset.  I
> input the signal into pins 62 and 60 of connector
> J666, of the USRP, with
> the use of appropriate coupling capacitor.  I
> disabled the automatic DC
> offset by adding the following code:
> 
>    self.u = usrp.source_c()                    #
> usrp is data source
>    self.u.set_dc_offset_cl_enable(0x0, 0xf)    #
> Turn off auto dc offset
> 
> I turned off the DC offset to get ride of a drop in
> the square wave.  The
> DC offset algorithm tries to remove what it
> considers DC signal and that
> includes slow varying signals in the KHz range.
> 
> Original Message:
> -----------------
> From: sudhindra aithal kota address@hidden
> Date: Fri, 18 Nov 2005 03:21:09 +0000 (GMT)
> To: address@hidden, address@hidden
> Subject: Re: [Discuss-gnuradio] Viewing square wave
> in usrp_oscope
> 
> 
> Hi,
>  Sorry for the previous mail. Totally out of
> context.
> 
> I gave a square wave input direct from a signal
> generator and the behaviour of usrp_oscope was the
> same as I had explained before. I increased the
> frequency to way above 100KHz. Is there any other
> option to be given?
> 
> Regards
> Sudhindra
> 
> 
> > Hi,
> >  Is it possible to view a square wave using
> > usrp_oscope.py? I have a circuit which produces a
> > square wave that I want to view.
> 
> Yes.
> 
> >  I know usrp_oscope is not a general purpose
> > oscilloscope. We eventually want to manipulate the
> > signal coming from the circuit for our purposes.
> So
> we
> > wanted to know if it is represented properly.
> >  The square wave had spikes in it. It appeared
> more
> > like a capacitor charging and discharging. And at
> high
> > frequencies, it resembles a sine wave. The signal
> > coming from the circuit has a frequency of 41 KHz.
> 
> 
> If you are using the Basic Rx daughterboard as your
> input, the RF
> transformer on it acts as a high pass filter.  
> Try using an input signal > 100kHz.  A megahetz
> would
> be even better.
> 
> >  Has anyone tried working with a square wave
> before
> > and faced this problem? Please let me know how to
> > correct this. Thanks
> 
> The Basic USRP has a 50 Ohm input impedance.  
> Will your circuit drive 50 ohms?
> 
> Eric
> 
> 
> 
>               
>
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