16 qam vhdl code

Discussion in 'VHDL' started by tal, Apr 8, 2004.

  1. tal

    tal Guest

    hi
    i'm doing a project and i need a vhdl code for 16 qam modulation.

    thanks
     
    tal, Apr 8, 2004
    #1
    1. Advertising

  2. tal a écrit:
    > hi
    > i'm doing a project and i need a vhdl code for 16 qam modulation.


    Shouldn't be too hard to do, that's just two identical AM modulators fed
    with quadrature carriers...
    2 hours work at worst. Come on, you can do it can't you?

    --
    ____ _ __ ___
    | _ \_)/ _|/ _ \ Adresse de retour invalide: retirez le -
    | | | | | (_| |_| | Invalid return address: remove the -
    |_| |_|_|\__|\___/
     
    Nicolas Matringe, Apr 9, 2004
    #2
    1. Advertising

  3. tal

    tal Guest

    Nicolas Matringe <> wrote in message news:<>...
    > tal a écrit:
    > > hi
    > > i'm doing a project and i need a vhdl code for 16 qam modulation.

    >
    > Shouldn't be too hard to do, that's just two identical AM modulators fed
    > with quadrature carriers...
    > 2 hours work at worst. Come on, you can do it can't you?


    hi
    i did the vhdl code for the maping but i dont known how to convert the
    i an q bits to sine wave.

    Anyone could help?
    thanks.
     
    tal, Apr 9, 2004
    #3
  4. tal

    Guenter Guest

    tal wrote:
    > Nicolas Matringe <> wrote in message news:<>...
    >
    >>tal a écrit:
    >>
    >>>hi
    >>>i'm doing a project and i need a vhdl code for 16 qam modulation.

    >>
    >>Shouldn't be too hard to do, that's just two identical AM modulators fed
    >>with quadrature carriers...
    >>2 hours work at worst. Come on, you can do it can't you?

    >
    >
    > hi
    > i did the vhdl code for the maping but i dont known how to convert the
    > i an q bits to sine wave.
    >
    > Anyone could help?
    > thanks.


    Andraka consulting has a paper about modulation/demodulation techniques
    with FPGA, maybe that helps.

    http://www.andraka.com/papers.htm

    Guenter
     
    Guenter, Apr 9, 2004
    #4
  5. tal

    Ray Andraka Guest

    I did have a QAM64 example in a prior incarnation of that presentation. That one doesn't have it in there.
    Basically, you need to pass the I and Q bits through a nyquist filter (this is just an FIR filter with a usually
    root raised cosine response). You'll need to upsample as you filter, which is equivalent to stuffing zeros between
    each IQ sample and then low pass filtering. It is more efficiently done as a polyphase interpolating filter, which
    lets the filter work at the IQ rate rather than the upsampled rate. The filtered IQ is your complex baseband.
    You'll mix that with a complex exponential (sine and cosine) to get your IF or broadcast carrier. If you can set
    the sample rate of the IQ to be 4x the carrier (or IF) then the mixer's local oscillator is 1,j,-1,-j, which can be
    accomplished with a pair of adder/subtractors.

    tal wrote:

    > Nicolas Matringe <> wrote in message news:<>...
    > > tal a écrit:
    > > > hi
    > > > i'm doing a project and i need a vhdl code for 16 qam modulation.

    > >
    > > Shouldn't be too hard to do, that's just two identical AM modulators fed
    > > with quadrature carriers...
    > > 2 hours work at worst. Come on, you can do it can't you?

    >
    > hi
    > i did the vhdl code for the maping but i dont known how to convert the
    > i an q bits to sine wave.
    >
    > Anyone could help?
    > thanks.


    --
    --Ray Andraka, P.E.
    President, the Andraka Consulting Group, Inc.
    401/884-7930 Fax 401/884-7950
    email
    http://www.andraka.com

    "They that give up essential liberty to obtain a little
    temporary safety deserve neither liberty nor safety."
    -Benjamin Franklin, 1759
     
    Ray Andraka, Apr 13, 2004
    #5
    1. Advertising

Want to reply to this thread or ask your own question?

It takes just 2 minutes to sign up (and it's free!). Just click the sign up button to choose a username and then you can ask your own questions on the forum.
Similar Threads
  1. walala
    Replies:
    3
    Views:
    4,881
    walala
    Sep 18, 2003
  2. yvonnewong

    16 QAM

    yvonnewong, Feb 5, 2004, in forum: VHDL
    Replies:
    2
    Views:
    829
    Marcus Schaemann
    Feb 6, 2004
  3. lomtik
    Replies:
    3
    Views:
    2,281
    lomtik
    Dec 27, 2004
  4. afd
    Replies:
    1
    Views:
    8,561
    Colin Paul Gloster
    Mar 23, 2007
  5. Wing Chun
    Replies:
    7
    Views:
    943
Loading...

Share This Page