Wednesday, December 12, 2007

What is this?

Any idea what this is a picture of?

Ok, so it is a cellular automation, but where did the symmetry come from? Here is the generating snipit of python code.
   def getArray(self):
if self.count == 0:
out = random((self.w + 1, self.h + 1))
out =[:,:]
out[:,0] = 0
out[:,-1] = 0
out[0,:] = 0
out[-1,:] = 0
out[1:-1,1:-1] = (out[2:, 1:-1] +
out += .01
i_s, j_s = where(greater(out, 1))
for i, j in zip(i_s, j_s):
out[i, j] = 0
r = out.ravel()
self.count += 1 = out
return out

Saturday, December 01, 2007

Hex Clock

Revolutionary new clock. Forget the binary clock, meet the Hex Clock!

The day is divided into 4096 Binutes, which are sub-divided into 16 tics each. The top three squares display the Binutes Past Midnight (BMP). The bottom square displays 16ths of a Binute, a "tic" which is about 1.3 seconds.

Each side of a square is a bit. The right side is least significant bit, with increasing significance in the counter clockwise direction.


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:

Wednesday, August 22, 2007

Gnuradio and Gnuradio Companion (GRC)

I've been struggling with gnuradio for a bit when I came accross the gnuradio companion (GRC) written by Josh Blum. This puts the power of gnuradio at your finger tips. The framework is fully extensible too so if something doesn't exist you can create it. GRC has cut my
project time by 4! (see

Check out this screenshot.