GB1355936A - Electronic timepieces - Google Patents

Abstract

1355936 Electronic timepieces SUWA SEIKOSHA KK 7 Feb 1972 [18 Feb 1971] 5578/72 Heading G3T An electronic timepiece with digital display (e.g. liquid crystal or light emitting means) functions both to indicate the time of day and as a stop watch to indicate a time interval t 2 -t 1 . A time standard pulse generator 1 Fig.1 (e.g. quartz crystal, tuning fork or atomic particle) output is frequency divided at 2, 3, the divider 3 dividing down to signals at the smallest time interval to be displayed e.g. seconds and the divider 2 having an output f 1 of several KHz if the time display is to read down to 1/1000 sec (for stop watch operation). TIME OF DAY INDICATING. 1Hz pulses from divider 3 are fed to counters 4 to 9 which produce respective outputs for the control of the secs, tens of secs, mins, tens of mins, hours, tens of hours display indication. For a 24 hour clock the counter 9 would be a 1/3 divider circuit for indicating 0, 1 and 2 in the tens column of the hours display. With a switch WC in the 'W' position, AND gates 20 are opened to pass the contents of counters 4 to 9 to OR gates 22 and thence to signal distributors 23 to 28 to supply operating signals to appropriate elements of seven-element numeric display devices 29-34, to indicate time of day. TIME INTERVAL INDICATING (STOP WATCH). The output f 1 of divider 2 is fed to a divider 10 which divides f 1 into signals of for example 1/10 sec or 1/100 sec or 1/1000 sec period depending upon degree of precision required. The output of 10 (say at 1/100 sec period) is fed to counters 11 to 16 which produce respectively outputs for the control of 1/100 sec, 1/10 sec, 1 sec, 10 secs, 1 min, 10 mins. Switch WC is moved to the 'C' position so that the AND gates 20 are closed and AND gates 21 opened. A reset button (not shown) is pressed and a reset signal at R resets divider 10 and counters 11-16 to zero and the display will indicate zero. To start timing a push switch (not shown) connected at S is pressed at instant t 1 and a flip-flop 17 changes state so that divider 10 commences to transmit 1/100 sec signals and counters 11-16 commence counting and produce on the display the appropriate count. When the switch at S is pressed a second time at an instant t 2 the flip-flop 17 is reset, the divider 10 stops and likewise the counters 11-16, and a time interval t 2 -t 1 will be displayed on the same time display devices as were used for time of day indication. If the time interval range to be measured is wide e.g. 1/100 sec to 1 hour, a separate display array may be provided. An arrangement whereby more than one time interval at a time can be measured by one timepiece, is described with reference to Fig. 2 (not shown). Dividers, logic circuits &c. may be M.O.S. integrated circuits.