Wednesday, September 19, 2007


Made a little progress on gnuradio today. At least my input matches my output and I've gotten rid of the intermittent response. The decimation of the input needs to be half of the interpolation in order to avoid shifting the frequency. I still to not understand the phase. I am trying to force a phase shift with a complex multiply but the results always seems to be real until I mess with the tune frequency. Hmmmmm

Friday, September 07, 2007

GnuRadio USRP Puzzle

I think I have a misunderstanding regarding tuning the USRP.

I have connected the TX-A directly to RX-A. I am plotting the FFT of both the transmitted and received signal. I have tuned RX to 0 Hertz so I expect the positive frequencies to look the same up to noise affects.

What I get instead is mostly noise:

Occasionally I get blips of a signal like this:

The GRC graph is also included: