On Thu, 25 Aug 2005, Martin Dvh wrote: > Hi Chuck, > > > > When the other cable between J19 & 48 is removed the scope > > channels 3 & 4 flatline, just as expected. > Just checking we understand each other. > If you remove the cable between J19 & 48 both 1&2 and 3&4 receive channels > flatline? > > The purpose of my question is to see if the two channels interact > (cross-modulate). > This is easally seen if you just pas through one of the channels and see if > the waveform of the still connected channel changes. > If it changes, there is some interaction. > If it doesn't change, there is some other problem. >
Just two channels flatline when one cable is disconnected - when J19 is disconnected channels 1&2 go flat, but 3&4 are still there. And when J18 is disconnected channels 3&4 go flag, and 1&2 are sill there. The Rx side makes sense - it's the Tx side I don't understand. With Tx mux = 0x0008 there's still a signal coming from DAC1, or at least from J49. Oh, the docs in usrp1_sink_base.h and usrp1_source_base.h point out that in set_tx_freq and set_rx_freq the channel must be 0. So it looks like all DUC and DDC must be at the same frequency. --Chuck _______________________________________________ Discuss-gnuradio mailing list [email protected] http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
