The Design Of Receiving System For Radio Controlled Timepieces

The means of RCT is the Radio Controlled Timepieces. The principle of RCTis: the standard time signal is encoded by the National Time StandardCenter(NTSC), the business time signal would be encrypted. Then the code islaunched as the Long-wave radio by the carrier of LF(20KHz~80KHz). The LFradio time signal is received by the inside mini radio receiving system of the RCT,the time signal is demodulated by the special chip, then the clock time is controlledby the inside controlled system of the RCT. According to the technical process, allof the time of RCT clock is synchronous as the time of NTSC. So all of the RCTwill show the same times.We introduce the history and evaluation of RCT technique as well as the statusquo. We describe the principle and main features of RCT, including the digitalsystem and the analog system. The designing and the results of the preamplifier，tuned amplifier, AGC, detection circuit, peck detection circuit, comparator areshowed.The main features of RCT is receiving the time signal launched by NTSC,demodulating and extracting the time signal and sending it to the MCU to deal withthe signal. The RCT receiving system is low power, high sensitivity, wide frequencyrange and wide voltage.All the design is fabricated in a0.35μm BiCOMS process. Layout is used bythe Virtuoso of the Canence System.