On Tue, Feb 10, 1998 at 03:03:53AM +0100, Lucky Green wrote:
Now all this was done without the use of a DSP. I can only imagine what one could capture after adding a DSP to the setup.
Miles... Given static screen images and thousands of repetitions in a few seconds the processing gain from integration of the signal verus the uncorrelated noise over thousands of cycles gets quite interesting. And add to that the tricks one can do with comb filters and combining together the correllated energy from several harmonics of the dot clock one can see that getting signal out from under the trash is easy even at considerable distances. It has, in fact, been speculated that the larger NSA geo and near geosync ELINT/COMINT satellites probably have the required capability to accomplish this from orbit (with football field sized antennas this isn't out of the question at all). Also the "frequency generator" you talk about needs not be some extremely expensive HP synthesizer (often of course available for a few dollars at the local ham radio flea markets in any case), but simply a good voltage controlled crystal oscillator on the right frequency. These are $5 parts... -- Dave Emery N1PRE, die@die.com DIE Consulting, Weston, Mass. PGP fingerprint = 2047/4D7B08D1 DE 6E E1 CC 1F 1D 96 E2 5D 27 BD B0 24 88 C3 18