Hi all, I just started working on Gnu Radio, and am working on a digital communication project usig the USRP. In this scheme, the transmitter would send a single frequency tone (not necessarily at the carrier frequency) for a short time as a preamble before beginning a long, uninterrupted transmission of bits. The receiver would be listening for this tone to synchronize with the transmitter, and would only process further samples from the USRP once this tone is detected. The amplitude of this tone is also important, as I hope to infer distance to the transmitter based on this.
Although I am planning to test the scheme with FSK first, I hope to make it independent of any modulation technique used, hence am not relying on the default blocks such as gr_simple_framer/correlator and others used in fsk_tx/rx.py. Hence if the normal flow graph looks like: src -> mod -> usrp(tx) ----> usrp(rx) -> demod -> sink I need a block "sync_tx/rx" such that the flow graph looks like: src -> mod -> sync_tx -> usrp(tx) ---> (rx)usrp -> sync_rx -> demod -> sink Sync_tx simply prepends a synchronization tone before any transmission, and sync_rx does not forward any incoming samples to the subsequent blocks until it detects this tone and determines its amplitude. Could anyone please let me know the easiest way to implement such a sync_tx/rx block? I have started writing a C++ signal processing block, but it's getting a bit tough. What Gnu radio blocks (gr_fft_*, gr_quadrature_demodulator, etc) should I look into for code re-use? I was wondering if there was maybe away to do it in python itself? Thanks! Kunal _______________________________________________ Discuss-gnuradio mailing list [email protected] http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
