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Re: [Discuss-gnuradio] Re: TX/RX simultaneously using one USRP board
From: |
Eric Blossom |
Subject: |
Re: [Discuss-gnuradio] Re: TX/RX simultaneously using one USRP board |
Date: |
Sun, 16 Apr 2006 14:23:16 -0700 |
User-agent: |
Mutt/1.5.9i |
On Sun, Apr 16, 2006 at 03:28:51PM -0400, Dawei Shen wrote:
> Hi, Eric
>
> As far as know, Flex 400 only has a single subdevice.
single subdevice for Tx, single subdevice for Rx.
The Flex daughterboards look like two distinct pieces of h/w to the
s/w. They have separate LO's, etc.
> How do you use one Flex400 daughter card for both transmission and
> reception at the same time? Do you mean I use only one antenna using
> the TX/RX port, or I use two antennas with one using Rx2 for
> reception and the other using TX/RX port for transmisson?
If you are transmitting and receiving full duplex (simultaneously),
you'll need to use TX/RX for transmit and RX2 for input (and you'll
need to be TXing and RXing at pretty widely separated frequencies,
and/or use a diplexer).
The rx subdevice class has a method for selecting which antenna port
to use for reception:
def select_rx_antenna(self, which_antenna):
"""
Specify which antenna port to use for reception.
@param which_antenna: either 'TX/RX' or 'RX2'
"""
if which_antenna in (0, 'TX/RX'):
self._u.write_io(self._which, 0, RX2_RX1N)
elif which_antenna in (1, 'RX2'):
self._u.write_io(self._which, RX2_RX1N, RX2_RX1N)
else:
raise ValueError, "which_antenna must be either 'TX/RX' or 'RX2'"
If you're not transmitting and receiving at the same time, you can use
the single Tx/Rx port for both, along with Auto T/R mode
self.subdev.set_auto_tr(True) # must execute on both the Rx and Tx
Eric