Re: [Discuss-gnuradio] interpolation and output level

[Javs]

Hey Eric,

I tried various values for the amplitude and looks
like  it works fine anywhere between 10000 and 35000,
giving me ~= 10mV and 35mV respectively. But anywhere
below or beyond its behaving erratic. Is this the
boundary ?

And here is what I get when I boot my usrp and run the
tx_check.py the first time.

address@hidden usrp]$ ./tx_check.py usrp: found usrp rev2
usrp_open_interface: usb_claim_interface: failed conf
0
could not set config 1: Operation not permitted
open_nth_cmd_interface: open_cmd_interface failed
Traceback (most recent call last):
  File "./tx_check.py", line 78, in ?
    main ()
  File "./tx_check.py", line 70, in main
    sg = siggen ()
  File "./tx_check.py", line 17, in __init__
    self._instantiate_blocks ()
  File "./tx_check.py", line 53, in
_instantiate_blocks
    self.usrp = usrp.sink_c (0, self.interp)
  File
"/usr/local/lib/python2.3/site-packages/gnuradio/usrp1.py",
line 692, in sink_c
    return _usrp1.sink_c(*args)
RuntimeError: std::runtime_error

---------

Thanks for looking into it.

Javs

--- Eric Blossom <address@hidden> wrote:
> On Fri, Mar 18, 2005 at 02:05:24PM -0800, Javs
> wrote:
> >  
> > Hello ppl, 
> >  
> 
> > I understand that the interpolation factor changes
> the amplitudes of
> > the signals. The default usrp_siggen.py works fine
> and I can admire
> > 16mV and 100 K on the scope. But if I use the
> default intrp of 64 in
> > the example usrp_siggen.py and try to change the
> amplitude levels
> > using -a option, the signals still come down. Any
> guesses why ?
> 
> What value's are you trying with the -a option?
> Keep them <= 16000.
> 
> > Also, When I first boot my USRP and try an
> example, it fails for the
> > first time. For instance, I tried tx_check.py and
> i had a runtime
> > error. However, it works fine the second time. Is
> this because, it
> > takes its time to load firmware into the FX2 and
> the FPGA or am I
> > missing something here ?
> 
> What's the error?
>   
> Eric
> 

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