[Discuss-gnuradio] gmsk transmit woes

[Michael Ford]

Hello,

I'm having a curious problem that I'd like to figure out.  What I'm trying to do is to have two different gmsk packet sources, modulate them on different frequencies, add these signals together and then transmit them simultaneously (with their destination being two separate usrp's tuned to the different frequencies).  Here is a sketch of what I have so far:

self.packet_transmitter1 = blks.gmsk2_mod_pkts(...)
self.packet_transmitter2 = blks.gmsk2_mod_pkts(...)

self.chan_filt1 = gr.freq_xlating_fir_filter_ccc(...freq1...)
self.chan_filt2 = gr.freq_xlating_fir_filter_ccc
(...freq2...)

self.adder = gr.add_cc()

fg.connect(self.packet_transmitter1, self.chan_filt1, (self.adder,0))
fg.connect(self.packet_transmitter2, self.chan_filt2, (self.adder,1))

fg.connect(self.adder
, self.amp, self.u)

for now, I have both the xlating_fir's as all-pass filters, just to take advantage of their frequency translating.  The strange problem is that when I run the script, it stalls; the code gets 2 dots into the transmitting and then stops, and I have to ctrl-z (ctrl-c doesn't even work).  What is possibly going wrong?  

Thanks!

-Michael Ford-