Speed signal generating circuit system
AssigneeRobert Bosch GmbH
InventorsVolker Braschel, Reiner Emig
Life of this patent
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Abstract
To provide an unambiguously representative signal responsive to the speed of a vehicle wheel, an inductive pick-up (1a. . . . 1n) is coupled to a suitable star wheel or the like of each one of the wheels, the pick-ups then providing their signals to amplifiers (3a. . . . . 3n) having hysteresis characteristics. At low speeds, an offset signal is superimposed on the voltage from the inductive pick-ups so that the amplifiers respond and provide output signals only at higher amplitudes of the pick-up signals, thereby eliminating inaccuracies or disturbances occurring in the sensor which might simulate changes in speed of the respective wheel.
Claims4
Speed signal generating circuit system to obtain a signal representative of speed of a rotating element having
- a stationary inductive pick-up (1a . . . 1n) responsive to induced flux change upon rotation of the rotating element, and generating an alternating voltage;
- an amplifier (3a . . . 3n) connected to receive the alternating voltge, said amplifier having hysteresis characteristics and providing an output pulse signal when the voltage level of the alternating voltage applied thereto exceeds a first predetermined level and terminates the output pulse signal when the voltage level of the alternating voltage applied thereto drops below a second predetermined level,
- said system comprising, means superimposing a d-c signal (O.sub.f) over the alternating voltage, and terminating superimposition of the d-c signal when the amplifier (3a . . . 3n) provides the pulse output signal.
Speed signal generating circuit system to obtain a signal representative of speed of a rotating element having
- a stationary inductive pick-up (1a . . . 1n) responsive to induced flux change upon rotation of the rotating element, and generating an alternating voltage;
- an amplifier (3a . . . 3n) connected to receive the alternating voltage, said amplifier having hysteresis characteristics and providing an output pulse signal when the voltage level of the alternating voltage applied thereto exceeds a first predetermined level and terminates the output pulse signal when the voltage level of the alternating voltage applied thereto drops below a second predetermined level,
- said system comprising,
- means (4b) for adding a d-c signal (O.sub.f) to the alternating voltage;
- and
- means (4a) for sensing if the amplifier delivers a pulse signal, and for terminating addition of said d-c signal (O.sub.f) to the alternating voltage when said pulse signal is sensed by said pulse signal sensing means.
Dependencies are inferred from the claim text.