TADディジタル直交検波による電波時計の構成  [in Japanese] Construction of radio-controlled clocks/watches using TAD digital quadrature detection  [in Japanese]

This paper describes Time Analog to Digital Converter(TAD) technology, TAD digital quadrature detection(TAD-DQD), and radio-controlled clock/watch as an application of the TAD-DQD. Proposed receiver circuit for the LF standard time signal consists of CMOS digital circuit except the analog pre-amplifier and is easy to be integrated with other digital circuits such as time-counting, decoder, and controller circuits into a single chip CMOS IC. When the phase data obtained by the TAD-DQD is used with the amplitude data, reliability of the received time code increases and acquisition time decreases as compared to those of conventional envelope detection receiver circuits. Frequency error of the local oscillator in the clock/watch, which is used as a time standard, also can be estimated and corrected.