[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Discuss-gnuradio] Question about Basic TX/RX boards, the I, Q
From: |
njm25 |
Subject: |
Re: [Discuss-gnuradio] Question about Basic TX/RX boards, the I, Q |
Date: |
Mon, 26 Mar 2007 15:04:48 -0400 |
I can't get the output to the fm_tx_2_daughterbaords.py example to work. I am
testing with 2 complex signals and on each signal, the I channel is a sinusoid
and the Q channel is a sinusoid of a different frequency. I have connected
each of the 4 SMA connectors from the 2 Basic TX daughterboards to a different
channel on an oscope. I expect to see a sinusoid on each channel but that is
not the case. I see some weird waveform on the different channels on the
oscope. Originally I didn't think the TX mux was set correct because the
comments at the beginning of the example says that it transmits SSB (USB) and
that is not what I'm looking for. I want each of the 4 different waveforms (2
sines on the I's and 2 sines on the Q's, all with different frequencies) to
come out of the 4 SMA connectors. Any help would be greatly appreciated.
Thanks,
Nick
----- Original Message -----
From: Eric Blossom <address@hidden>
Date: Wednesday, March 21, 2007 9:45 pm
Subject: Re: [Discuss-gnuradio] Question about Basic TX/RX boards, the I, Q
> On Wed, Mar 21, 2007 at 05:31:36PM -0400, address@hidden wrote:
>
> > Thanks again for the help. I think I better understand how to set
> > the RX mux. I am now working on the multi_file.py example to
> > receive using 2 daughterboards on the same USRP. I want to do the
> > same type of thing using 2 antennas where RX-A and RX-B (on side A)
> > will receive signal 1's I and Q and RX-A and RX-B (on side B) will
> > receive signal 2's I and Q. If my understanding is correct, I would
> > set the mux to (0x32103210). Let me know if this is not correct.
>
> Correct.
>
> > My question now comes on the TX side. I don't quite understand how
> > to set the TX mux. I want to transmit using 2 daughterboards on 1
> > USRP so I am using the fm_tx_2_daughterboards.py example. I want
> > daughterboard 1 to transmit the I (RX-A) and Q (RX-B) of signal 1
> > and daughterboard 2 to transmit the I (RX-A) and Q (RX-B) of signal
> > 2. This example uses the command:
> >
> > self.u.set_mux(0xba98)
> >
> > which I don't think is right for what I want to do, but I don't
> > really understand how to set the TX mux in the same way I understand
> > how to set the RX mux (it seems to be different). How would I set
> > the TX mux to do what I want?
>
> self.u.set_mux(0xba98) ;)
>
> It is different, it's the Tx mux, not the Rx mux...
>
> /*!
> * \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);
>
>
> > Thanks
> > Nick
>
> You're welcome!
>
> Eric
>
- Re: [Discuss-gnuradio] Question about Basic TX/RX boards, the I, Q, njm25, 2007/03/16
- Re: [Discuss-gnuradio] Question about Basic TX/RX boards, the I, Q, njm25, 2007/03/18
- Re: [Discuss-gnuradio] Question about Basic TX/RX boards, the I, Q, njm25, 2007/03/20
- Re: [Discuss-gnuradio] Question about Basic TX/RX boards, the I, Q, njm25, 2007/03/21
- Re: [Discuss-gnuradio] Question about Basic TX/RX boards, the I, Q,
njm25 <=