| 摘要 |
A first contact arm on the minute shaft of a clockwork switches, once every 30 minutes, the mode of energization of an electronic gating circuit with two sections in the inputs of an inverting anticoincidence (NOXOR) gate working into a setting input of a flip-flop which controls the driving circuit of a striking mechanism, each section having two parallel branches of relatively inverting character and with a relative phase delay whereby any switchover results in a brief de-energization of that setting input and thus in a setting of the flip-flop. A pulse generator, included in or energized by the driving circuit, works into a stepping input of a binary pulse counter provided with four output leads whose pattern of energization represents the numerical values from 1 through 12. A logic network, connected to a resetting input of the flip-flop and to a clearing input of the pulse counter, discriminates between switch-overs at the full hour and at the half-hour in response to the state of energization of the gating circuit; on the half-hour, the flip-flop is reset and the pulse counter is cleared upon the energization of the No. 1 output lead of the counter, whereas on the full hour these events take place under the control of a second contact arm carried on the hour shaft of the clockwork whenever the pulse count matches the position of that contact arm.
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