| 摘要 |
1347220 Pulse delay circuits NORTH AMERICAN ROCKWELL CORP 16 March 1972 [30 April 1971] 12211/72 Heading H3P [Also in Division D1] In a circuit for producing pulses suitable for effecting operation of a rotary knitting machine at a desired point in the cycle which is independent of the speed, which pulses are delayed with respect to transitions of a variable frequency input signal, the transitions are used to initiate a pulse having a width varying with the frequency and these pulses together with the signal are fed to a bi-stable circuit to provide the delayed pulse. Pulses having a phase delay independent frequency may thus be obtained. As shown, a clock signal A is supplied to a transition detector 10 providing a pulse at each positive and negative going edge of the pulse. These trigger a monostable multivibrator 14. The pulses are also applied to an "electric tachometer" 12 which produces a control voltage proportional to frequency and this is used, via control circuit 16, to vary the timing circuit of the multivibrator so that its output pulse width varies inversely with frequency. The trailing edge of these pulses trigger a bi-stable circuit 48 to a state which depends upon the erect and inverted clock inputs at its J and K terminals and the edges of the respective Q and Q outputs operate monostable circuits to produce the desired output pulses. The transition detector may be a pair of monostable multivibrators responsive respectively to leading and trailing edges of the clock, the outputs being combined in an AND circuit. The "electronic tachometer" 12 may be a monostable circuit followed by an averager (Fig. 3, not shown). |
