Re: [Discuss-gnuradio] Re: Re: Re: Tx Path

[Eric Blossom]

On Fri, Apr 20, 2007 at 08:26:25PM +0200, Anmar wrote:
> Eric Blossom wrote:
> > On Wed, Apr 18, 2007 at 01:49:36PM +0200, Anmar wrote:
> >
> > You can control the phase in the FPGA. However, we're using the
> > digital upconverter in the AD9862.  That DUC has its own phase
> > register.
> 
> Loading the code below, I connected the two daughterboard’s to the X and
> Y channel of the scoop. every time I load the code I get a different
> angel on the scoop(but there is a constant change with it). how can I
> explain why this is happening?

OK, here goes, one more time: there is state in the AD9862 -- its DUC
phase register -- that we can't control from software.  

Do you understand what that means?
Have you looked at the AD9862 data sheet?

If you cycle power on the USRP _each time_ before you run the
experiment, do you get repeatable results?

What daughterboards are you using?

Have you read and understood
http://gnuradio.org/trac/wiki/USRPClockingNotes ???


> def main():
>         interp = 128
>         waveform_type = gr.GR_COS_WAVE
>         waveform_ampl = 16000
>         waveform_freq1 = 40e3
>   waveform_freq2 = 10e3
>         waveform_offset = 0
>         fg = gr.flow_graph ()
>         sink = usrp.sink_c (0, interp)
>   sink.set_nchannels(2)
>   sink.set_mux(0xba98)
>         usb_freq = sink.dac_freq() / interp
>         siggen1 = gr.sig_source_c (usb_freq,
>                                        gr.GR_SIN_WAVE,
>                                        waveform_freq1,
>                                        waveform_ampl,
>                                        waveform_offset)
> 
>         siggen2 = gr.sig_source_c (usb_freq,
>                                        gr.GR_SIN_WAVE,
>                                        waveform_freq2,
>                                        waveform_ampl,
>                                        waveform_offset)
> 
>   inter = gr.interleave(gr.sizeof_gr_complex)
>   fg.connect (siggen1, (inter, 0))
>   fg.connect (siggen2, (inter, 1))
>   fg.connect (inter, sink)
>   fg.start()
>   raw_input('Press enter to stop\n')
>   fg.stop()
> 
> if __name__ == '__main__':
>   main()
> 
> thanks
> anmar