PICK-UP DEVICES FOR DETECTING THE PASSAGE OF A MOVABLE MEMBER OF A SCALE ASSEMBLY OF AN APPARATUS FOR ACCURATELY MEASURING THE SPECIFIC CONSUMPTION OF INTERNAL COMBUSTION ENGINE
A pick-up device, used with a scale having a pointer movable in front of a dial, the measuring scale carrying a plurality of pick-ups, which comprises a transistorized circuit with a frequency modulated inductance-capacitance circuit, an impedance changer with a quartz filter to which it transmits the oscillator signal, an impedance changer interposed between said filter and an amplifier stage, and transmitting to said stage only the signals generated by said oscillator which correspond to the inherent frequency of quartz, a signal detector rectifying through a doubler the HF voltage having passed through said quartz filter and amplified through said amplifier, and a shaping device for delivering at a low impedance value a high-amplitude logic signal.
A sensor, especially for detecting misfeeds in a stream of sheets of paper, comprises a pair of sensing plates sensing changes in the capacitance between the plates, a first oscillator providing an output signal at a frequency representative of the capacitance, a second oscillator set to a reference frequency which is the same as or close to that frequency generated by the first oscillator when no object is between the sensing plates, gating means to produce an output representative of the frequency difference between the oscillator outputs, a low-pass filter, and a microprocessor which responds to changes in the difference frequency.
An apparatus includes a first circuit, a second circuit, and a capacitor. The first circuit includes a sense element. The capacitor couples the first circuit to the second circuit. The first feedback path couples the second circuit to the first circuit. And the second feedback path couples the second circuit to the first circuit. A method includes generating, for an oscillator signal having an amplitude and a gain, a substantially direct current signal related to an amplitude, and controlling the gain with the substantially direct current signal.
