| 摘要 |
To provide a composite output pulse in which the pulse length increases relative to the angle of rotation as the speed of a rotating element, typically a rotor coupled to an internal combustion engine increases so that the closing angle of current supply to an ignition coil increases with speed, a magnetic element or other marker on a rotor is exposed to two transducers, one of which provide a signal which is position dependent and the other one a signal which is speed dependent. The output signals from the transducers are combined. The position dependent transducer provides an output pulse of fixed pulse length, relative to angle of rotation of the rotating element, the speed dependent pulse providing output pulses of variable pulse length which overlap with the pulse of fixed pulse length. The speed dependent output is preferably sensed by a threshold or threshold trigger circuit so that when the level of the speed dependent output from the transducer exceeds a certain level a pulse is triggered which will not terminate, however, until the pulse from the position dependent transducer is also obtained. A triggered wave shaping stage, triggered by either of both inputs-position dependent or speed dependent and preferably having a variable response or threshold level, in dependence on battery supply voltage, can provide a single output of a pulse length extending over increasing angular segments of rotation of the rotor as the speed increases, thus maintaining an output pulse the time duration of which can be made to be essentially speed independent.
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