This paper describes radio-controlled clocks/watches employing digital quadrature detection based on the Time Analog to Digital Converter (TAD) technology. In-phase and quadrature components of the input modulated signal are obtained by only addition and substitution processes of the data digitized by the TAD with sampling clock of the frequency quadruple to the carrier frequency. Since the TAD digital quadrature detection also acts as a precise bandpass filter, quartz filters used by the conventional radio-controlled clocks/watches are not necessary. The CMOS digital circuit structure of the TAD makes it possible to integrate the receiver circuit into the clock/watch digital circuit on a single chip.