Horology: time measuring systems or devices – Time interval – Electrical or electromechanical
Patent
1996-05-08
1997-09-02
Miska, Vit W.
Horology: time measuring systems or devices
Time interval
Electrical or electromechanical
324140R, 324140D, 377 20, 341 6, 341 11, 123487, G04F 800, G01R 700, H03M 130
Patent
active
056639333
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to an electronic meter circuit for a time comparison measurement between two successive periodic events.
BACKGROUND INFORMATION
It is known that in measuring the length of a signal or the time between the occurrence of two events, a clock signal of a certain frequency can be applied to the input of a meter circuit belonging to the comparator. By means of a gate, this clock pulse is switched through to the meter only during the signal time that is of interest but otherwise it is blanked out. Thus the meter does not continue to count during the blanked-out segment. If the meter is reset, preferably to zero, during the signal time that is not of interest, the meter reading corresponds approximately to the length of the signal. If the meter is not reset, the difference in meter readings corresponds to this signal length. To compare signal time ratios between two successive periodic events, at least two of these meter circuits are needed and interim storage of intermediate results is necessary when using only one meter circuit in registers. One disadvantage of this, in addition to the extra expense for components, is that a signal time ratio can be obtained only by subtracting the meter readings provided by the meter circuit, and these readings may be estimated as constants.
SUMMARY OF THE INVENTION
The electronic meter circuit according to the present invention allows the time rations between two times two events to be recognized. Due to the fact that a reference meter is loaded with a reset value when a first event occurs, and the reference meter starts to count at a first clock frequency, and when a second event occurs, the reference meter starts to count in the opposite direction at a second clock frequency until a third event occurs, and when a third event occurs, the meter reading forms a reference value for the ratio of the signal times between the occurrence of the first and second events and between the second and third events. The present invention allows, in a very simple and advantageous manner to resolve this time-based comparison measurement by counting in different directions and to deduce the ratio of the two signal times on the basis of the meter reading at the end of the comparison measurement.
In a another embodiment of the present invention, the reference meter is formed by two separate meters that have different counting directions. This yields another advantageous result that the meter supplying the signal time can be performing a new measurement while the second meter is performing the comparison measurement.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 shows a block schematic of an electronic meter circuit according to a first embodiment of the present invention.
FIG. 2 shows a block schematic of an electronic meter circuit according to a second embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The block schematic of the first embodiment shown in FIG. 1 has a control unit 10 that receives event signals E1, E2 and E3 via input 12. For example, event signals E may be generated by a generator wheel on the crankshaft of a combustion engine. Said generator wheel has teeth distributed over its circumference, with each of these teeth inducing an event signal E. However, event signals E can also be generated by a segment generator on the camshaft of a combustion engine, where a positive flank, for example, will generate a first event signal E1 and a negative flank will generate a second event signal E2, and the positive flank of the next segment generates a third event signal E3.
Control unit 10 is connected to a first input 14 of reference meter 16. When an event signal E1 occurs, control unit 10 delivers a signal t0 to reference meter 16, causing reference meter 16 to be loaded with reset value RW from a register 18. Reset value RW preferably has a value of zero. A second input 20 of reference meter 16 receives clock frequency t1 that is used by reference meter 16 to count up incrementally, starting with rese
REFERENCES:
patent: 3967271 (1976-06-01), Day
patent: 4133323 (1979-01-01), Adler
patent: 5264844 (1993-11-01), Itou et al.
Miska Vit W.
Robert & Bosch GmbH
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