Help required for dpsk_loopback.grc

GNU Radio
1

Dear All,

I am very new to GNU Radio and currently trying to explore the example
grc blocks available with the package. For example, I tried to execute
the example given in the example folder as “dpsk_loopback.grc”
(/home/ubuntu/examples/digital/demod/dpsk_loopback.grc). I have
following doubts:

  1. There is no readme or document available which can explain about the
    total block or example in detail. Can I get any tutorial/document which
    will give complete info about all such examples?? i.e.Each grc example
    file to be explained in detail. If any such details are available,
    kindly give me the link for the same.

  2. In the subject example, there is a signal source which is generating
    a cosine wave from 500Hz to 5KHz. This cosine wave after the throttle
    block is fed to packet encoder. Here, what is the role of packet
    encoder?? In the packet encoder block properties there are many fields
    like “samples/symbol”, “bits/symbol”, etc. These fields are generally
    related to data, not the analog signal which is fed to it. How does the
    packet encoder take cosine wave and use the fields like samples/symbol
    and bits/symbol??? Do we have any document which will explain in detail
    about all such blocks???

  3. I want to analyze the output of packet encoder. How is it possible??
    Which block will you suggest to analyze the output???

  4. As I am very new to the GNU field and I quite poor in software
    domain, I would like to get some help in the beginners level. Please
    provide me any link, if it is available.

Regards,

SACHIN M. REGUNDWAR

Hyderabad, India.

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2

On Wed, Mar 4, 2015 at 5:18 AM, SACHIN REGUNDWAR [email protected]
wrote:

will give complete info about all such examples?? i.e.Each grc example file
to be explained in detail. If any such details are available, kindly give
me the link for the same.

Nope. The examples show you how to use the various blocks but don’t have
write-ups on their own. You can find what each block does in the manual:

gnuradio.org/doc/doxygen

  1. In the subject example, there is a signal source which is generating a
    cosine wave from 500Hz to 5KHz. This cosine wave after the throttle block
    is fed to packet encoder. Here, what is the role of packet encoder?? In the
    packet encoder block properties there are many fields like
    “samples/symbol”, “bits/symbol”, etc. These fields are generally related to
    data, not the analog signal which is fed to it. How does the packet encoder
    take cosine wave and use the fields like samples/symbol and bits/symbol???
    Do we have any document which will explain in detail about all such
    blocks???

It is a bit strange, I’ll admit, but that sine wave is just digital
samples
that are shaped like a sine wave. So passing them through as digitally
modulated samples is the same as passing any value.

  1. I want to analyze the output of packet encoder. How is it possible??
    Which block will you suggest to analyze the output???

There are plenty of display widgets (QT or WX) that you can use here. Or
dump it to a file and analyze the raw bytes anyway you know how.

  1. As I am very new to the GNU field and I quite poor in software domain,
    I would like to get some help in the beginners level. Please provide me any
    link, if it is available.

Regards,

SACHIN M. REGUNDWAR
Hyderabad, India.

To get a good feel for GNU Radio:
http://gnuradio.org/redmine/projects/gnuradio/wiki/Guided_Tutorials

And for other reading:
http://gnuradio.org/redmine/projects/gnuradio/wiki/SuggestedReading

Tom