http://www.edn.com/Pdf/ViewPdf?contentItemId=4433411
Details above. Looks like you can get 3.5ps resolution with an off the shelf PIC after calibration which is pretty impressive!
Details above. Looks like you can get 3.5ps resolution with an off the shelf PIC after calibration which is pretty impressive!
So the price is..
3$ for the microcontroller, 3$ for the 4 ns comparator, and a few cents for the resistors, capacitors, and 7 GHz transistors (I couldn't find the exact model), and probably some dollars for the rest of the materials such as steel rods and tubes. All in all it looks doable for <50$ easily. That's pretty amazing!