Dear Sylvain, >On Fri, Mar 14, 2014 at 2:17 PM, Sylvain Munaut <246...@gmail.com> wrote: > First thing, square waves have infinite bandwidth, the DAC can't > generate them properly, the ADC can't capture them properly and > they'll be modified by the IF filters. The effect of that is to "round > off the edges".
I am using Ettus SBX daughtercard at the transmitter USRP to transmit complex square wave (means the signal is in IQ form). https://www.ettus.com/product/details/SBX I understand that SBX performs quadrature up-conversion automatically, and this feature cannot be disabled. Hence, the signal sent to the transmitter antenna is no longer square waves, but IQ up-converted signal. That's why I guess the "round off the edges" effect is no longer applicable here. At the receiver side, another SBX daughtercard should have automatically down-converted the signal back into IQ form. Here I expect the signal output from SBX become (nearly) square wave. > And since you sample at 32k, that's probably going to > be fairly visible. I repeat the test with sampling rate changed to 1MHz at both sides, this gain similar undesirable result. > Then the second and major thing is that I & Q aren't magically > transmitted and received perfectly aligned. Now I am focusing on the frequency and phase alignment issue. Thank you very much. _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
