USRP1 questions

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?

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?

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 ?

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?

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)
Those are examples apps to demonstrate API usage. See tx waveforms or tx

What do you think is missing in the “multi_usrp” wrapper?

http://files.ettus.com/uhd_docs/doxygen/html/classuhd_1_1usrp_1_1multi__usrp.html#ab8bc17744d3ee94b7c5cdcb75457bd6b

-Josh

hi Josh,
thanks a lot for your support.

the problem with the “multi_usrp” wrapper is that if i use another board
for example WBX it will generate the desired frequency through the PLL
except

for frequencies less than the minimum threshold (which is as i remember
62 MHZ for WBX) so in the later case it will set the PLL to the minimum

frequency (i.e. 62 MHZ) and will compensate the difference through the
NCO (as i understand)

i want to do the same by myself even if the target frequency is in the
supported range by the WBX (for example : i want to set the PLL to 935
MHZ and

tune the NCO by +or - 44MHZ to get the up and down link ranges of the
GSM system ), the reason for using the NCO instead of the PLL is that
the NCO

tuning is instantaneous unlike that of the PLL which takes about 200
micro secs

i think this request is not supported by the “multi_usrp” wrapper ??

thanks,
osama riad

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

Use the advanced tuning parameters.

http://files.ettus.com/uhd_docs/manual/html/general.html#tuning-notes

2011/12/12 osama mohamed [email protected]:

2011/12/12 osama mohamed [email protected]:

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

Leave spb at the default value. Does it overflow then? Does it
overflow with rate=4e6 or rate=6.4e6?

–n

This forum is not affiliated to the Ruby language, Ruby on Rails framework, nor any Ruby applications discussed here.

| Privacy Policy | Terms of Service | Remote Ruby Jobs