[Discuss-gnuradio] Could transmitter and receiver alternately work in time on the same USRP1 with LFTX/RX?

[Yan Nie]

Dear all,

I'm developing a radar transmitter and receiver on USRP1 and LFTX/RX. The 
transmitter and receiver are working fine separately on two USRP1 with TX and 
RX daughter board plugged in. I'm trying to make the transmitter and receiver 
alternately work in time on the same USRP1. For instance, transmitting signal 
for 0.52ms then disabling TX and enabling RX simultaneously for signal 
reception for 1ms. Then this process will repeat over and over again. 

Is it possible to get the TX and RX wok on the same USRP1 motherboard with both 
RX and TX? The reason why I'm asking this question is that it seems impossible 
to call usrp_source or usrp_sink block every millisecond to enable TX or RX, 
since usrp_source loads FPGA image only with TX path enabled and usrp_sink does 
only with RX path enabled, if my reading of the source code usrp_standard.cc 
services me right. In addition, loading the whole FPGA image takes longer time 
than 1ms, which will cause USRP overrun problem if shifting TX to RX or RX to 
TX every millisecond as my experiments showed me. Therefore, I'm wondering if 
there is an approach to allow the TX and RX to alternately work in time on the 
same USRP1 board rather than calling usrp_source or usrp_sink to make this 
TX/RX altering. Simply, is there any mean to shift TX and RX back and forth 
every two milliseconds and repeat over and over again by loading FPGA image 
only once for the whole process. 

I will really appreciate if any suggestion on how to solve this problem.

Wish you a great day!

Thanks,
Yan

ynie3.vcf
Description: Card for "Yan Nie" <ynie3@uwo.ca>