Re: [Discuss-gnuradio] Simulateous transmission from two daughterboards - I've got it !

[Angilberto Muniz Sb]

Ok, Eric -- I really understand it now.

Im able to start "dual_tx.py" and "dual_fft.py" and I
can see the two signals ! (I have Tx_A -> Rx_A and
Tx_B -> Rx_B)

I can switch the signals by just swapping mux values
-- nice...

Now it seems trivial, but I can upload the
"dual_fft.py" if is there anyone interested...

My next move is try to implement receive diversity
based on MRRC and transmit diversity based on
Alamouti's STBC...

Thank you,

Angilberto.

--- Eric Blossom <address@hidden> wrote:

> On Sat, Mar 11, 2006 at 07:41:02AM -0800, Angilberto
> Muniz Sb wrote:
> > I think I've got it, Eric.
> > 
> > According to "usrp_standard.h" the set_mux method
> > understand the mux value a differente way...
> > 
> > BTW does the same mux value works for rx way?
> > 
> > Angilberto.
> 
> The Tx and Rx mux work differently.
> 
> from class usrp_standard_rx:
> 
>   /*!
>    * \brief Set input mux configuration.
>    *
>    * This determines which ADC (or constant zero) is
> connected to 
>    * each DDC input.  There are 4 DDCs.  Each has
> two inputs.
>    *
>    * <pre>
>    * Mux value:
>    *
>    *    3                   2                   1   
>                    
>    *  1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9
> 8 7 6 5 4 3 2 1 0
>    *
>
+-------+-------+-------+-------+-------+-------+-------+-------+
>    * |   Q3  |   I3  |   Q2  |   I2  |   Q1  |   I1 
> |   Q0  |   I0  |
>    *
>
+-------+-------+-------+-------+-------+-------+-------+-------+
>    *
>    * Each 4-bit I field is either 0,1,2,3
>    * Each 4-bit Q field is either 0,1,2,3 or 0xf
> (input is const zero)
>    * All Q's must be 0xf or none of them may be 0xf
>    * </pre>
>    */
>   bool set_mux  (int mux);
> 
> 
> from class usrp_standard_tx:
> 
>   /*!
>    * \brief Set output mux configuration.
>    *
>    * <pre>
>    *     3                   2                   1  
>                     
>    *   1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9
> 8 7 6 5 4 3 2 1 0
>    * 
>
+-------------------------------+-------+-------+-------+-------+
>    *  |                               | DAC3  | DAC2
>  | DAC1  |  DAC0 |
>    * 
>
+-------------------------------+-------+-------+-------+-------+
>    * 
>    *  There are two interpolators with complex
> inputs and outputs.
>    *  There are four DACs.
>    * 
>    *  Each 4-bit DACx field specifies the source for
> the DAC and
>    *  whether or not that DAC is enabled.  Each
> subfield is coded
>    *  like this: 
>    * 
>    *     3 2 1 0
>    *    +-+-----+
>    *    |E|  N  |
>    *    +-+-----+
>    * 
>    *  Where E is set if the DAC is enabled, and N
> specifies which
>    *  interpolator output is connected to this DAC.
>    * 
>    *   N   which interp output
>    *  ---  -------------------
>    *   0   chan 0 I
>    *   1   chan 0 Q
>    *   2   chan 1 I
>    *   3   chan 1 Q
>    * </pre>
>    */
>   bool set_mux  (int mux);
> 


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