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    3.
    发明专利
    未知

    公开(公告)号：DE1562255B1

    公开(公告)日：1970-12-10

    申请号：DE1562255

    申请日：1965-10-30

    Applicant: IBM

    Inventor： JULIUSBURGER HANS YOHANAN ,  ABRAMSON PAUL ,  CHIN PAO HSIUNG

    IPC: G11C27/02 ,  H03K5/26

    Abstract: 1,116,394. Detecting pulses. INTERNATIONAL BUSINESS MACHINES CORPORATION. 6 Oct., 1965 [4 Nov., 1964], No. 42493/65. Heading H3T. Pulses are detected by their effect on a stored electric charge which is periodically set to a definite value and subsequently sensed, the input pulses being applied at a frequency lower than that of the alternate setting and sensing of the charge. In the Figure, a rotating magnet 10 generates sinusoidal oscillations in coils 14, 14 1 which are anti-phase and are fed respectively to two identical detecting circuits 8, 8 1 . The half-cycle in which the top of the coil is negative drives current through diode 20 and transformer primary 36P, inducing a voltage in the secondary 36S which charges capacitor 34 through diode 32. In the next half-cycle current flows through diode 18, base-emitter path of transistor 24, resistor 50 and diode 42, the latter short-circuiting the transformer primary to prevent any signal appearing at the secondary. Transistor 24 then conducts and capacitor 34 discharges through transistor 24, the baseemitter path of transistor 46, resistor 52 and transformer secondary 36S. Transistor 46 then conducts and a signal appears on the output line 56. The current through the winding 36S induces a voltage in winding 36P which passes current through resistor 50, emitter-base junction of transistor 24, diode 18 and coil 14. Transistor 24 is thus maintained conducting until capacitor 34 has discharged completely. If the pulse generator 26 produces a signal between the above two half-cycles, this is applied through diode 27 to transistor 24 and discharges the capacitor prematurely so that the output signal at 56 occurs before the second half-cycle in coil 14. An identical circuit 8 1 is supplied with anti-phase sinusoidal signals from coil 14 1 but in-phase pulses from generator 26 through diode 27 1 . The output of circuit 8 1 is delayed by a half-period at 62 so that signals will coincide on lines 56 and 60 only if no pulse has been suppllied by the generator. This coincidence is sensed by AND-gate 58 and detector 66. Provided that the frequency of the pulse generator is not greater than that of rotation of the magnet 12, simultaneous turning- on of transistor 24 by both inputs will not result in loss of detection of the pulse since this cannot occur in both circuits 8 and 8 1 . If the frequency of the pulse generator is lower than that of rotation of the magnet, a signal should appear at 66 at least every few cycles. Failure of this indicates mal-functioning of the circuit which thus has a " fail-safe " feature. If the pulses from the generator 26 are sufficiently short, the angle between the coils 14 and 14 1 may be less than 180 degrees. The generator 26 may be a piezo-crystal or magnetic pick-up.

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