US Patent 10177752 Frequency comparator and early-late detector

In a receiver facility in an ultra-wideband communication system, a dual-mode circuit adapted to operate in a selected one of three operating modes without changes in circuit topology: a calibration mode adapted to render the circuit substantially independent of circuit component mismatches; a frequency comparator mode adapted to indicate whether the frequency of a first periodic signal is larger or smaller than the frequency of a second periodic signal; and an early-late detector mode adapted to indicate whether the 1st rising edge of the first periodic signal arrived sooner or later than the 1st rising edge of the second periodic signal applied.