WO2008028948A1 - Agencement de circuits et procédé pour la conversion d'un signal - Google Patents

Agencement de circuits et procédé pour la conversion d'un signal Download PDF

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Publication number
WO2008028948A1
WO2008028948A1 PCT/EP2007/059359 EP2007059359W WO2008028948A1 WO 2008028948 A1 WO2008028948 A1 WO 2008028948A1 EP 2007059359 W EP2007059359 W EP 2007059359W WO 2008028948 A1 WO2008028948 A1 WO 2008028948A1
Authority
WO
WIPO (PCT)
Prior art keywords
signal
schmitt trigger
input
adder
output
Prior art date
Application number
PCT/EP2007/059359
Other languages
German (de)
English (en)
Inventor
Manfred Zimmer
Original Assignee
Continental Automotive Gmbh
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Continental Automotive Gmbh filed Critical Continental Automotive Gmbh
Publication of WO2008028948A1 publication Critical patent/WO2008028948A1/fr

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Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K5/00—Manipulating of pulses not covered by one of the other main groups of this subclass
    • H03K5/01—Shaping pulses
    • H03K5/08—Shaping pulses by limiting; by thresholding; by slicing, i.e. combined limiting and thresholding
    • H03K5/082—Shaping pulses by limiting; by thresholding; by slicing, i.e. combined limiting and thresholding with an adaptive threshold
    • H03K5/084—Shaping pulses by limiting; by thresholding; by slicing, i.e. combined limiting and thresholding with an adaptive threshold modified by switching, e.g. by a periodic signal or by a signal in synchronism with the transitions of the output signal
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K3/00—Circuits for generating electric pulses; Monostable, bistable or multistable circuits
    • H03K3/02—Generators characterised by the type of circuit or by the means used for producing pulses
    • H03K3/023—Generators characterised by the type of circuit or by the means used for producing pulses by the use of differential amplifiers or comparators, with internal or external positive feedback
    • H03K3/0233—Bistable circuits
    • H03K3/02337—Bistables with hysteresis, e.g. Schmitt trigger

Definitions

  • the invention relates to a circuit arrangement and a method for converting a signal, in particular a si ⁇ nusförmigen signal, in a rectangular signal, wherein the circuit arrangement comprises a Schmitt trigger.
  • a transmission or crank ⁇ wave For detecting rotational speeds of rotating components in a motor vehicle, such.
  • sensors are usually used. Based on the frequency of the output signal of such speed sensors, the speed of the respective component can be determined. With the aid of the rotational speeds thus determined, for example, the speed of the motor vehicle can be determined.
  • an inductive sensor is used as a speed sensor.
  • This sensor is arranged at a small distance from a gear, which is connected to the component whose speed is to be detected. A rotation of the gear leads to a sinusoidal signal voltage of the sensor.
  • this sinusoidal voltage is usually supplied ei ⁇ ner circuit that converts the sinusoidal in a fairly ⁇ eckförmiges signal.
  • Electromagnetic interference of the sensor signal can, for. B. caused by long lines between the sensor and the controller.
  • a Schmitt trigger is used for the conversion of the sinusoidal Sig ⁇ Nals in a recheckförmiges signal.
  • the Schmitt trigger is a comparator in which the levels for switching (high level at the output of the comparator) and the switching off (low level at the output of the
  • the turn-on and turn-off of the Kompara- tors are designated as upper and lower switching threshold ⁇ net.
  • the switching thresholds of the Schmitt trigger are fixed via the ⁇ sen hysteresis. Due to the disturbances occurring in the motor vehicle, the hysteresis must be chosen to be relatively large. However, this causes the problem that the sensitivity of the Schmitt trigger decreases with increasing hysteresis. So z. B.
  • Object of the present invention is therefore processing arrangement, a general arrangement and to provide a method available, which also occur in an environment in which electromagnetic Stö ⁇ approximations, an error-free conversion of a signal, in particular a sinusoidal signal, in a rechteckför- Miges signal using a Schmitt trigger.
  • the present task is solved by means ⁇ ge that change the hysteresis of the Schmitt trigger function of the amplitude of the signal.
  • the switching thresholds of the Schmitt trigger are automatically adjusted to the amplitude of the signal.
  • the Schmitt trigger For signals with very small amplitude, the Schmitt trigger a low hysteresis, and thus be ⁇ sits a very high sensitivity.
  • the hysteresis of the Schmitt trigger This also insensitivity ge ⁇ genüber electromagnetic disturbances which are superposed on the signal increases. The greater the hysteresis, the larger the interference superimposed on the signal can fail, without causing an error in the conversion.
  • the device according to the invention thus has the advantage that both signals of small amplitudes as well as signals of high amplitudes, with large superimposed interference, can be converted without error into a rectangle-shaped device.
  • Miges signal to be converted since an automatic Anpas ⁇ solution of the sensitivity of the Schmitt trigger to the Amplitu ⁇ de of the signal takes place.
  • the commonly used ver ⁇ Schmitt trigger with hysteresis constant the disadvantage in that, for a high hysteresis small-amplitude signals can not be converted, whereas at a low hysteresis, the sensitivity to interference of the signal is high.
  • circuit arrangement according to the invention the advantages that an automatic adjustment of HystE ⁇ rese performed on the signal amplitudes of different sensors and that aging effects of a sensor, the z. B. may have a decreasing amplitude result, are taken into account.
  • An advantageous embodiment of the method according to the invention consists in that a first input of the Schmitt trigger is connected to the signal, and the means comprise the following components:
  • a positive peaking rectifier whose input is connected to the signal and whose output voltage depends on the positive half-wave of the signal
  • a negative peaking rectifier whose input is connected to the signal and whose output voltage depends on the negative half-wave of the signal
  • a first adder wherein one input of the adder is connected to the output of the positive peak rectifier and another input is connected to a DC voltage
  • a second adder one input of the adder connected to the output of the negative peaking rectifier and another input connected to a DC voltage, and a switch having a control input connecting either a second input of the Schmitt trigger to the output of the first Adder or with the output of the second adder connects, wherein the control input of the switch is connected to the output of the Schmitt trigger.
  • the hysteresis increases proportionally with the amplitude of the signal.
  • the upper switching threshold is changed depending on the amplitude of the positive half-wave of Sig ⁇ Nals and the lower switching threshold as a function of Ampli tude ⁇ the negative half cycle of the signal.
  • the upper switching threshold corresponds approximately to 0.667 times the difference between the positive and the negative peak value of the signal.
  • the lower switching threshold ⁇ corresponds to about the 0.333 times the difference between the positive and the negative peak value of the Sig- Nals. This design can be produced inexpensively.
  • the switch is realized by a Transis ⁇ tor.
  • a transistor can be produced particularly inexpensively.
  • the circuit arrangement can preferably be used for converting the signal of a sensor for detecting a rotational speed in a motor vehicle.
  • the speed to be measured is determined by the frequency of the output signal from the comparator. Since considerable electromagnetic disturbances may occur in the motor vehicle and the exact ⁇ accuracy of the speed measurement is dependent on the conversion of the signal, the above-mentioned advantages connected with the invention are particularly strong to bear.
  • the circuit arrangement comprises a low-pass filter for filtering the signal.
  • the Störunempfind- sensitivity of the circuit arrangement is increased.
  • the invention includes a method for converting a signal, in particular a sinusoidal Sig ⁇ nals, in a rectangular signal, wherein the signal a Input of a Schmitt trigger is supplied and the rectangular-shaped signal is taken at the output of the Schmitt trigger and the hysteresis of the Schmitt trigger is changed depending on the amplitude of the signal.
  • a first input of the Schmitt trigger is connected to the signal advantageous and it carries out the following process steps ⁇ :
  • the signal is fed to a low-pass filter for filtering before conversion.
  • a da ⁇ of is shown schematically in the drawing with reference to several figures and described below. Show it:
  • Figure 1 is a block diagram of a circuit arrangement according to the invention and FIG. 2 shows an example of a sinusoidal signal supplied to the circuit arrangement according to FIG. 1 and the resulting converted rectangular signal.
  • circuit arrangement of Figure 1 and parts thereof are shown as block diagrams. However, this does not mean that the circuit arrangement according to the invention is limited to a realization with the aid of individual circuits corresponding to the blocks. Rather, the circuit arrangement according to the invention can be realized in a particularly advantageous manner with the aid of highly integrated circuits.
  • the circuit arrangement 1 shows an embodiment of an inventive ⁇ SEN circuit arrangement 1 is illustrated.
  • the circuit arrangement 1 is supplied with a sinusoidal signal Ue of a sensor 2 for detecting a rotational speed in a motor vehicle.
  • the speed corresponds to the frequency of the sinusoidal signal Ue.
  • the signal Ue is converted by the circuit arrangement 1 into a rectangular signal Ua. Filtering with the low-pass filter 3 lowers the sensitivity of the circuit arrangement 1 to interference that may be superimposed on the signal Ue.
  • the resistors Rl and R2 serve only to establish a fixed relationship between the signal Ue and the supply voltage Vcc and ground of the circuit arrangement 1.
  • the signal is fed both to a negative input of a Schmitt trigger 9, the parator by a com- 9 is realized, as well as to the inputs of a po ⁇ sitiven peak detector 4 and a negative peak detector 5.
  • the output voltage of positive peak value detector 4, which is realized by a diode Dl and a Kondensa ⁇ tor Cp is proportional to the peak value of the positive half-wave of the signal Ue.
  • the output voltage of the negative peak detector 5 which is realized by a diode D2 and a capacitor Cn, pro ⁇ portional to the peak value of the negative half-wave of the signal Ue.
  • the output voltage of the positive peak value rectifier 4 is connected to an input of a first adder 6. Another input of the first adder 6 is acted upon by a voltage divider formed by a resistor R3 and R4, with a DC voltage.
  • R3 has the same value as R4, so that the DC voltage is half of Vcc.
  • the output voltage of the first adder 6 corresponds to the sum of the output voltage of the positive peak value rectifier 4 with the DC voltage.
  • the output voltage of the negative peak value rectifier 5 is connected to an input of a second adder 7. Another input of the second adder 7 is applied via the voltage divider, formed by the resistor R3 and R4, with the DC voltage.
  • the output voltage of the second adder ⁇ 7 corresponds to the sum of the output voltage of the negative peak rectifier 5 with the DC voltage.
  • a switch 8 connects either the output of the first adder 6 or the output of the second adder 7 to the positive input of the comparator 9. The control input of
  • Switch 8 is connected to the output of the comparator 9, that is, the switching between the outputs of the adder 6, 7 takes place in dependence on the output voltage of Kompara ⁇ sector 9.
  • the switch 8 can, for. B. be realized by a transistor.
  • the comparator 9 is thus a comparison of the filtered sinusoidal signal Ue either with the sum of the DC voltage and the output voltage of positive peaking rectifier 4 or the sum of the DC voltage and the output voltage of the negative peaking rectifier 5.
  • the hysteresis of the Schmitt trigger 9 is automatically sent to the amplitude the signal Ue adapted.
  • switch 8 is sure ⁇ made that for the positive half-wave of the signal Ue a comparison with the upper switching threshold of the Schmitt trigger 9 takes place, whereas the comparison for the negative half-wave of the signal Ue takes place with the lower switching threshold of the Schmitt trigger 9.
  • the output of the Schmitt trigger 9 can be connected to the input of a microcontroller, wel ⁇ cher determined based on the frequency of the rectangular signal Vout to be detected with the sensor 2 speed.
  • FIG. 2 shows the time courses of a sinusoidal signal Ue supplied to the circuit arrangement 1 according to FIG. 1 and the resulting rectangular signal Ua at the output of the circuit arrangement 1. It can be seen that the sinusoidal signal Ue is superimposed by disturbances. Despite the superimposed interference, the sinusoidal signal Ue is converted without error into the rectangular signal Ua. The error-free conversion is ensured by the automatic adaptation of the hysteresis to the amplitude of the sinusoidal signal Ue.
  • the upper switching threshold of the comparator 9 is approximately 0.667 times the difference Vss between the positive and the negative peak value of the sinusoidal signal Ue.
  • the lower switching threshold corresponds to approximately 0.333 times the difference between the positive and the negative peak value of the sinusoidal signal Ue. This Ver ⁇ ratio between the thresholds and the peak values of the sinusoidal signal Ue is maintained even with changes in the peak values, since the switching arrangement 1 automatically adjusts the switching thresholds to the peak values.
  • the output of comparator 9 has a low level, a high level between times t1 and t2, and a low level between t2 and t3. Since the filtered sinusoidal signal Ue is supplied to the negative input of the Schmitt trigger 9, this is

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  • Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • Transmission And Conversion Of Sensor Element Output (AREA)

Abstract

L'invention concerne un agencement de circuits et un procédé (1) pour la conversion d'un signal (Ue), en particulier d'un signal sinusoïdal (Ue), en un signal rectangulaire (Ua), dans lequel l'agencement de circuits comporte une bascule de Schmitt (9) et dans lequel des moyens modifient l'hystérésis de la bascule de Schmitt (9) en fonction de l'amplitude du signal (Ue).
PCT/EP2007/059359 2006-09-08 2007-09-07 Agencement de circuits et procédé pour la conversion d'un signal WO2008028948A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102006042184.1 2006-09-08
DE200610042184 DE102006042184A1 (de) 2006-09-08 2006-09-08 Schaltungsanordnung und Verfahren zur Umwandlung eines Signals

Publications (1)

Publication Number Publication Date
WO2008028948A1 true WO2008028948A1 (fr) 2008-03-13

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Application Number Title Priority Date Filing Date
PCT/EP2007/059359 WO2008028948A1 (fr) 2006-09-08 2007-09-07 Agencement de circuits et procédé pour la conversion d'un signal

Country Status (2)

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DE (1) DE102006042184A1 (fr)
WO (1) WO2008028948A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102195620A (zh) * 2010-03-18 2011-09-21 中国科学院电子学研究所 无源宽带时钟输入转换方法及电路
CN109921796A (zh) * 2017-12-13 2019-06-21 林项武 一种将周期变化的电信号转换为直流信号电平的电路

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3208262A1 (de) * 1982-03-08 1983-09-15 Robert Bosch Gmbh, 7000 Stuttgart Vorrichtung zur erzeugung einer drehzahlabhaengigen signalfolge
WO1984000452A1 (fr) * 1982-07-06 1984-02-02 Motorola Inc Limiteur a hysterese dynamique
EP0590190A1 (fr) * 1992-09-30 1994-04-06 Siemens Aktiengesellschaft Générateur de signaux

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3015771C2 (de) * 1980-04-24 1983-08-25 AEG-Telefunken Nachrichtentechnik GmbH, 7150 Backnang Schmitt-Trigger mit signalabhängiger Hysterese
DE19910352C1 (de) * 1999-03-09 2000-06-15 Siemens Ag Kompensationsschaltung für Treiberschaltungen
DE102005027362A1 (de) * 2004-12-15 2006-06-22 Robert Bosch Gmbh Verfahren zur Bestimmung eines Schaltpunktes bei der Auswertung der Signale einer Magnetsensoranordnung

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3208262A1 (de) * 1982-03-08 1983-09-15 Robert Bosch Gmbh, 7000 Stuttgart Vorrichtung zur erzeugung einer drehzahlabhaengigen signalfolge
WO1984000452A1 (fr) * 1982-07-06 1984-02-02 Motorola Inc Limiteur a hysterese dynamique
EP0590190A1 (fr) * 1992-09-30 1994-04-06 Siemens Aktiengesellschaft Générateur de signaux

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102195620A (zh) * 2010-03-18 2011-09-21 中国科学院电子学研究所 无源宽带时钟输入转换方法及电路
CN109921796A (zh) * 2017-12-13 2019-06-21 林项武 一种将周期变化的电信号转换为直流信号电平的电路

Also Published As

Publication number Publication date
DE102006042184A1 (de) 2008-03-27

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