to develop a digital communication link for transmission of voice in matlab

Discussion in 'Programmer's Corner' started by alind, Jan 31, 2008.

  1. alind

    Thread Starter New Member

    Jan 31, 2008
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    hi,
    can ny1 help me in writin a code for developing a digital communication link for transmission of voice in matlab...
    the problem is coming in writing a matlab based code for modulating a 01010 type bit stream usning ny digital modulation scheme nd decoding a 0101 type bit streame to get sample values of an audio data.
     
  2. Dave

    Retired Moderator

    Nov 17, 2003
    6,960
    144
    I can probably give you some input, but you need to detail what your trying to do in a little more detail.

    Are you looking configuring a comms link?

    Are you looking at using an existing comms protocol?

    How is the voice data formatted?

    What modulation scheme are you looking at?

    Does it require an encrypted channel?

    Dave
     
  3. alind

    Thread Starter New Member

    Jan 31, 2008
    3
    0
    hi,
    actually my problem is focussed on developing a digital communication link for transmission of audio data in matlab. for this i proceede as follows...
    at first i took a small audio file of 1-2 kb (.wav format) then i opened that audio file in matlab with the help of wavread function then i got the sample values of the .wav file in matlab . then those sampled values were encoded by the huffman coding technique to obtain the encoded form of the file now all we need to do is to modulate the huffman encoded file .. (the modulation scheme i have choosen is Quadrature Amplitude Shift Keying Modulation scheme)
    now the following problems are arising-
    1. How to Modulate/Demodulate the huffman encoded file.
    2.How to transmit that modulated file in matlab( use of the protocols i.e how to use them) the medium provided to us is simple copper wire.
    3. How to Demodulate that Huffman encoded file.
    someone plz help me out with these troubles.
     
  4. Dave

    Retired Moderator

    Nov 17, 2003
    6,960
    144
    Ok, I can see some of what you are trying to achieve. To achieve most of what you want you are most likely going to need to the Communications Toolbox for Matlab.

    To modulate using QASK you need to use the DMODCE function. You can pass as the third argument the parameter QASK that will modulate it using the QASK modulation scheme. See the usage.

    I cannot offer any advice on this; a simple copper wire is a little ambiguous. Is it a case of you are given a copper wire and expected to create the transmission?

    You can demodulate the signal using the DDEMODCE function. Again you will need to pass as the third argument the parameter QASK. There are various filtering parameters, but you will need to see if these are required. See the usage.

    Dave
     
  5. alind

    Thread Starter New Member

    Jan 31, 2008
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    0
    i have come got my problems of modulatin/ demodulation nd decoding now the problem is how to transmit tht QASK encoded file from one PC to another...
    that what protocol should be used... what code should i write to make an interface between the matlab nd the system port used for the transmission/
    nd how shouldi do that..
    the transmission is to be done form one pc to another using the CAT-5 cable.
    nd i do not want to use any windows based software or program to transmit my modulated file fromone pc to another.
    our motive is... to take an audio file.. process it in matlab.. an then transmit it from one pc to another using matlab.. and on the reciever pc the file should directly be opened in matlab nd again re-processd to retrive the audio data again..
     
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