| 摘要 |
PURPOSE:To improve the miniaturization and tuning function of a radio receiver in an electronic watch by synthesizing the local oscillating frequency of the receiver from the oscillating frequency of time standard and setting the intermediate frequency at broadcasting carrier frequency interval at integer-fold. CONSTITUTION:The output of a time standard oscillator 19 selected at the integer- fold of broadcasting carrier frequency interval for an electronic watch is divided in frequency by a frequency divider 20 to drive a time display unit 23, and converted to local oscillating frequency by a PLL consisting of a phase comparator 24, a low pass filter 25, a voltage controlled oscilator 26 and a programmable frequency divider 27, and applied to the frequency converter 30 of a radio receiver. The local oscillating frequency is altered by changing the frequency dividing ratio of the frequency divider 27 by channel selecting buttons 38, 39 to simultaneously display the time together with the receiving frequency by a drive circuit 22. |
