[email protected] said: > sequential tone ranging: by putting a "ranging tone" at, say, 1 MHz, on the > carrier
Thanks. The part that attracted my attention was your "spectrally pure signal" for the VCO. I think the answer I was fishing for is that the modulation has to be easy to filter out. Many years ago, I did some work on radar. The only part I remember was the range-velocity ambiguity. It's the radar version of Heisenberg for signal processing. You can't measure both frequency and time of a signal with high accuracy. Radar uses distance and velocity rather than time and frequency. The plot I remember was 3D, range and velocity error in X-Y and probability or signal-power or something like that in Z. For a simple radar pulse of a given duration, the plot is a bell curve. Make the pulse longer and the curve gets narrower in velocity but wider in distance. Make the pulse shorter and you get better distance but poorer velocity. The volume was constant. In radar, you can do things like chirp and pulse trains, but they just push the ambiguity over to someplace else. > Tone ranging also requires that you have a good a-priori estimate to pick a > suitable set of tones. That lets you pick a signal that puts some of the ambiguity someplace where you can ignore it. ----- I still have the little red book from those days. I wonder how long it would take me to get back to where I could understand most of it. P M Woodward: Probability and Information Theory with Applications to Radar. 1953 Small world. There is a more direct time-nuts connection. https://en.wikipedia.org/wiki/Philip_Woodward#W5_clock https://en.wikipedia.org/wiki/Philip_Woodward#Achievements_in_horology -- These are my opinions. I hate spam. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
