Re: [Discuss-gnuradio] Help with rx_sample_to_file.cpp program and modulation scheme change in UHD

[shantharam balasubramanian]

Dear Josh,

Thanks for the reply. I have some questions regarding installing grc.
The questions are probably too naive since we are still at the
beginning level of using gnuradio.

We work in WINLAB, Rutgers University. It has a 400 grid testbed and 2
sandboxes that are compatible with GNUradio. There are SD cards
inserted in the nodes. We just load gnuradio images before starting
any experiment (using commands like: omf-5.2 load all
gnuradio-uhd-3.1.2-usrp1.ndz). Now, when you ask us to install gr-uhd,
do you mean that we should install it in the SD cards? Because
gnuradio is not installed in our computers. We just load the image in
the SD cards (inserted in the nodes), ssh to the nodes and then run
the example programs.

Your feedback will be very appreciated.

Thanks,

Shantharam

On Tue, Sep 20, 2011 at 1:45 PM, Josh Blum <address@hidden> wrote:
>
>
> On 09/20/2011 10:25 AM, shantharam balasubramanian wrote:
>> Hi
>>
>> I am pretty new to UHD. I was looking for some example programs which
>> can send and receive a text file, and I came across two programs in
>> the website
>> (http://code.ettus.com/redmine/ettus/projects/uhd/repository/revisions/master/show/host/examples)
>> named rx_samples_to_file.cpp and tx_samples_to_file.cpp.
>>
>> I ran these programs in USRP1. and gave the following arguements:
>> 1)./tx --rate 500000 --freq 10000000  --file rr.txt[this is the name
>> of the file i transferred]
>> 2)./rx --rate 500000 --freq 10000000 --file r1.txt[this is the name of
>> the file where i store the received text]
>>
>
> Those files are supposed to contain baseband samples.
>
>> When I tried to transmit and receive some sample text files, the
>> sender transmitted it correctly, but the receiver is not receiving
>> anything. When I opened the received file, I found that the file was
>> more than 10MB and there were some gibberish text in the file. The
>> programs specify in the help options that they transmit and receive
>> binary samples, so I don't know if I am working with the correct
>> programs or if I am giving the correct arguments while running them.
>>
>
> You have scared me.
>
>> I also need to change the modulation schemes for different channel
>> environments. Actually, I am working on adaptive modulation schemes in
>> my experiments. However, I don't find an option to change the
>> modulation schemes in UHD. (I saw those options in python based
>> non-uhd codes, e.g. benchmar_Rx and benchmark_Tx). Are there any
>> programs like that in UHD codes that allow change of modulation
>> schemes?
>>
>
> Gnuradio implements many modulation schemes. UHD provides an interface
> to send/recv baseband samples. You should use gnuradio w/ UHD to
> implement a receiver and transmitter chain.
>
> I highly recommend installing gr-uhd component and getting familiar w/
> gnuradio-companion:
> http://code.ettus.com/redmine/ettus/projects/uhd/wiki#Gnuradio-UHD
>
> -Josh
>
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>



-- 
Regards

Shantharam Balasubramanian
MS in Electrical and Computer Engineering
Rutgers University
Ph:732-543-6863
Email:address@hidden