GB1303699A - - Google Patents

Abstract

1303699 Electronic timepieces CENTRE ELECTONIQUE HORLOGER SA 8 Oct 1970 [4 Nov 1969] 48017/70 Heading G3T A pulse discriminator for monitoring a minutes timing signal A, Fig.1, and producing a control signal e.g. for the automatic synchronization of an oscillator serving as a timebase of a clock. The minutes signal A may be transmitted by radio to the discriminator which is effective to cut-off the control signal when parasitic signals superimposed on the minutes signals exceed a certain level, the absence of control information being preferable to incorrect control information. The time signal A comprises a pulse of 0‹1 sec duration at the beginning of each second and two pulses, each having a duration of 0À1 sec and separated by 0À1 sec, at the beginning of each minute. When a trigger circuit comprising monostable units 3, 4, receives the first impulse of the pair it successively emits a first impulse B and then a second impulse C, as illustrated, Fig. 2 (not shown). A counter flip-flop 1 controlled by the timing signal A is returned to a given position by the second impulse from the trigger whereupon the counter emits an impulse D which is differentiated in a unit 2 to produce impulse E. A 'squelch' circuit is provided to cut the minutes timing signal A when parasitic signals P exceeding a certain level are received, and includes an AND gate 5, monostable unit 6, and RC circuit 7. The 'squelch' circuit is controlled by the said first impulse B from the trigger 3 and by impulse D from the counter and produces an impulse H of given duration when two controlling pulses B and D coincide.. A control circuit comprising an AND gate 8 emits an impulse I if the second impulse C from the trigger 4 and the differentiated impulse E from the counter 1 coincide and only in the absence of a 'squelch' impulse H. The impulse I changes the state of a monostable unit 9 having a period of 250m secs. The unit 9 thus produces a control signal U for automatically synchronizing a time keeper, for each unperturbed pair of minute impulses in signal A. The signal J may control illumination of a lamp which may be used for the manual hand setting of the timepiece. A current diagram of the discriminator is illustrated in Fig. 3 (not shown).