How do I properly disable/enable the WBX receiver with UHD?

GNU Radio
1

I am testing the tunnel.py program on a USRP1 w/ WBX dboard and UHD. My
goal
is to disable to receiver while I am transmitting, and then re-enable it
once I’m done. I looked at db_wbx_common.cpp and found the enabler
functions. Each of these programs a few GPIO bits. Using that as a guide
I
was able to disable the receiver, but after I re-enabled it I didn’t get
any
more packets.

disable:

db_iface.set_gpio_out(UNIT_RX, RX_POWER_DOWN, RX_POWER_UP |
RX_POWER_DOWN)

enable:

db_iface.set_gpio_out(UNIT_RX, RX_POWER_UP, RX_POWER_UP | RX_POWER_DOWN)

UNIT_RX, RX_POWER_DOWN, and RX_POWER_UP are set correctly as in the
reference code. I verified that the bits were being set correctly by
checking get_gpio_out() before and after I called set_gpio_out(). I’d
prefer
to do this in Python if possible.

Now, I know this may not be the correct method of doing this, so I ask
my
question:

Using a USRP1 w/ WBX dboard and UHD, what is the proper way to disable
(and
then re-enable) the receiver?

Thanks for looking!

-Tom

2

Using a USRP1 w/ WBX dboard and UHD, what is the proper way to disable (and
then re-enable) the receiver?

I usually don’t think to disable the receiver. Running the transmitter
on demand and always running the receiver is a fine model of use.

Perhaps you could shutoff your demodulator when you transmit? Or reject
the echo’d packets in a mac layer?

-josh

3

On 03/06/2011 12:17 PM, Josh B. wrote:

Also, doing this is not going to be daughterboard-agnostic–not all
daughterboards can have their RX analog chain disabled this way, as
far as I know, and also, does the RX chain “forget” its previous
programming across such a power-down/disable operation? If it does,
then you have the added latency of re-configuring the analog hardware
back to where it was before you shut it down.

A better approach is to simply “ignore” whatever you’re receiving while
transmitting–either by using a valve, or a x0 multiplier somehwere
in the RX chain, which will effectively cause the demodulator to not
see any useful signal.