GB1450071A - Electronic timepiece - Google Patents

Abstract

1450071 Electronic timepieces CITIZEN WATCH CO Ltd 24 Sept 1973 [2 Oct 1972 21 May 1973] 44628/73 Heading G3T [Also in Division G4] In an electronic timepiece comprising a crystal controlled oscillator circuit followed by a frequency divider chain producing a time unit signal which is fed to counters for driving a time display, e.g. comprising liquid crystal or light-emitting diode elements or a pulse motor driving hands via gears, regulation of the running rate of the timepiece is effected by adding, in a frequency adder circuit, the oscillator output frequency to that of an adjustment signal from an adjustment circuit which is selectively controlled by an external signal to adjust for fast or slow operation of the timepiece. The frequency adder output is applied to the divider input which, in effect changes the division ratio of the divider and adjusts the frequency of the time unit signal (nominally 1 Hz). In Fig. 9A output pulses at 2<SP>21</SP> Hz from an oscillator circuit 91 are applied to a frequency divider chain 95 via a frequency adder in the form of an EX-OR gate 911 together with adjustment pulses from a controller 93. In response to a "low" level control input signal at any one or all of input terminals Jo --- J9, calling for adjustment, a respective NOR gate passes a signal from a Q output (Q 1 2 - Q 21 ) of a respective stage in the f divider 95 to EX-OR gates which add the frequencies of the selected outputs Q 1 2 - Q 21 together. The result is applied via a delay element 910 to the frequency adder 911 where it is added to the oscillator output. The divider outputs Q 16 - Q 21 (Fig. 9A) are connected to drive a pulse motor 97. Figs. 8A-8I illustrate logical input terminal circuits which can be set, e.g. by manual setting switches operated from outside the watch to provide the high or low level inputs to the terminals J and some of which have a memory function. In an embodiment described with reference to Figs. 11 and 14 (not shown) the tappings from the f divider, used for correction of running rate, are selectively connected into the correction circuit by a solder bridge or link or by a selector switch.