Re: [Discuss-gnuradio] carrier sensing, usrp2 & xcvr2450

[Stefan Schmid]

unfortunately it doesn't.

I am using two hier_block2, one for the sensing part and one for the
transmitting part. (see code below)

What am I doing wrong? Thanks for your help!

Stefan.

class receive_path(gr.hier_block2):
        def __init__(self, interface="", decim=4, gain=None, freq=None, mac=""):
                gr.hier_block2.__init__(self, "receive_path", 
gr.io_signature(0, 0,
0), gr.io_signature(0, 0, gr.sizeof_gr_complex))
                self.u = usrp2.source_32fc(interface, mac)
                ...
                alpha = 0.001
                thresh = 30
                self.probe = gr.probe_avg_mag_sqrd_c(thresh,alpha)
                self.connect(self.u, self.probe)
        
        def sense(self):
            p = self.probe.level()
            dbm = 10*math.log10(p) #dbm
            return dbm
        
class transmit_path(gr.hier_block2):
    def __init__(self, interface="", interp_rate=4, spb=4,
use_barker=False, mac_addr=None):
        gr.hier_block2.__init__(self, "receive_path", gr.io_signature(0,
0, 0), gr.io_signature(0, 0, gr.sizeof_gr_complex))
        self.u = usrp2.sink_32fc(interface, mac_addr)
        ....
        self.packet_transmitter = bbn_80211b_mod_pkts(spb=spb,
alpha=0.5, gain=self.normal_gain, use_barker=use_barker)
        self.connect(self.packet_transmitter, self.u)

    def send_pkt(self, payload='', send_rate=0, eof=False):
        return self.packet_transmitter.send_pkt(payload, send_rate, eof)

class flow_graph(gr.top_block):
        def __init__(self):
                gr.top_block.__init__(self)
                ....
                self.rxpath = receive_path(interface, decim, gain, freq, mac)
                self.txpath = transmit_path(interface, interp, spb, barker, mac)
                self.connect(self.txpath)
                self.connect(self.rxpath)

On Sat, Jan 15, 2011 at 12:25 AM, Matt Ettus <address@hidden> wrote:
> On 01/14/2011 02:09 PM, Stefan Schmid wrote:
>> Hi all
>>
>> I have an usrp2&  xcvr2450 board and I wrote a simple python script
>> which I use to measure the signal strength and transmit a packet.
>> Since the xcvr2450 does not support full duplex it switches to
>> transmitting mode after sending the first packet. Is there a way to
>> switch back to receiving mode? Or is there another way to implement
>> such an application using the hardware I have?
>
>
> It switched back to receive as soon as it is done transmitting.
>
> Matt
>
>