CH624536B - ELECTRONIC CLOCK PART WITH ANALOGUE DISPLAY INCLUDING AN ADJUSTABLE DIVISION RATE DIVIDER. - Google Patents

Abstract

An electronic watch comprises a stepping motor 6 for driving a mechanism for displaying the time information, a quartz crystal controlled oscillator 1, a frequency divider 2 with an adjustable division ratio, a circuit 7 for adjusting the division ratio eg by suppressing a number of pulses from the oscillator to the divider, a memory 8 containing data corresponding to the number of the pulses to be suppressed in each adjusting, cycle and a logic circuit 10 which, in response to an interrogation signal, (switch 9) produces a measuring signal at the output of gate 19 which is supplied to the coil of the stepping motor and which comprises a series of pulse trains whose distribution is representative of the division factor and the frequency of the oscillator and whose duration is sufficiently short so as not to cause the motor to rotate and sufficiently long to cause a magnetic stray field from the motor which can be detected by an external apparatus for measuring therefrom the rate of the watch. The interrogation signal upon closure of switch 9 causes the divider to divide with its unadjusted value. A gate 11 is enabled by 1 Hz pulses at 11a to pass trains of 256 Hz pulses in alternate half quartz-second intervals. The pulses pass through the gate 19 until their number, counted by counter 17, equals the adjustment number eg 5 held in memory 8. The interrogation signal also acts on switch circuit 4 to disconnect the motor control inputs at 4a 4b of circuit 5 from the divider 2, and apply the measuring signal pulses at input 4e from the gate 19 instead. In the embodiment described, a "quartz-second" is shorter than a normal second, the watch crystal frequency being higher than a nominal frequency, alternatively the measuring signal may be transmitted acoustically. The external measuring apparatus is described in App No. 79/36415. <IMAGE>