US Patent 7283926 Counter circuits and distance estimation methods

Counting circuits applied to distance estimation for ultra wideband (UWB) application, in which a first counting unit generates a sequence of pseudo-random number series not including zero, a first recoding unit records a first series and a second series from the sequence according to a first signal and a second signal, and a transfer unit generates a binary counting value according to the first series and second series from the recording unit.