Re: [Discuss-gnuradio] USRP1 questions

[osama mohamed]

hi josh,

i tried the example tx_waveforms.cpp using the following arguments  --freq 1000000 --rate 8000000 --gain 20 --wave-type "SQUARE" --wave-freq 200000 --ampl 0.3 --spb 10000 but there is an under run error so is there any suggested answer please

sorry for asking too much questions but i am really stuck

thanks ,

osama riad

> Date: Mon, 12 Dec 2011 08:07:57 -0800
> From: address@hidden
> To: address@hidden; address@hidden
> Subject: Re: [Discuss-gnuradio] USRP1 questions
>
>
>
> On 12/12/2011 01:52 AM, osama mohamed wrote:
> >
> > hi all,
> > i am using USRP1 with basic tx and rx boards and i have been suffering some problems recently so i hope you could answer the following questions(even if not all of them)
> >
> > Q1:
> > when i run the examples tx_timed_samples.cpp and tx_burst.cpp i don't
> > get any output i tried various sampling rates and amplitudes but they
> > still didn't produce any output if there is a certain configuration
> > (i.e. sampling rate and amplitude) that works kindly inform me also i
> > would like to know the output i am expected to see?
> >
> >
>
> Those are examples apps to demonstrate API usage. See tx waveforms or tx
> samples from file for examples that transmit.
>
> > Q2: i would like to tx a signal by setting the NCO frequency on the
> > codec chip through the class codec_ctrl instead of using the PLL, is
> > this doable or not and ,if yes should i use the class multi_usrp or i
> > have to jump to the lower level class usrp1_impl?
> >
> >
> If you have basic TX and usrp1, the only frequency translation occurs in
> the codec. There is no PLL.
>
> > Q3: can i use the low level class usrp1_impl to do the same
> > functions of the examples tx_timed_samples.cpp and tx_burst.cpp
> > through setting the frequency tuning word of the codec through the class
> > codec_ctrl ?
> >
> >
>
> The implementation is not exposed. You will need some "creative" coding
> if you want to access the internal objects.
>
> What do you think is missing in the "multi_usrp" wrapper?
>
> > Q4: as i understand from the constructor of the class usrp1_impl the
> > sampling rates of the tx path are automatically detected and assigned
> > through this constructor is this true or i have to set them through a
> > certian function?
> >
> >
>
> You should manually set the desired sample rate through the API.
> See
> http://files.ettus.com/uhd_docs/doxygen/html/classuhd_1_1usrp_1_1multi__usrp.html#ab8bc17744d3ee94b7c5cdcb75457bd6b
>
> -Josh