CN201327496Y

CN201327496Y - Rotating-speed measurement converter

Info

Publication number: CN201327496Y
Application number: CNU200820129653XU
Authority: CN
Inventors: 封锡凯; 李辉
Original assignee: 11 Research Institute of 6th Academy of CASC
Current assignee: 11 Research Institute of 6th Academy of CASC
Priority date: 2008-12-17
Filing date: 2008-12-17
Publication date: 2009-10-14
Anticipated expiration: 2018-12-17

Abstract

The utility model relates to a rotating-speed measurement converter which comprises a signal pre-processing circuit connected with an output terminal of a rotating-speed sensor, and also comprises a first-stage verification comparison reshaper, an integral circuit and a second-stage verification comparison reshaper which are sequentially connected with the output terminal of the signal pre-processing circuit, wherein, the first-stage verification comparison reshaper which is a single threshold voltage comparator is used for transforming sine wave signals which are pre-processed into square wave signals; the integral circuit comprising a resistor and a capacitor is used for transforming the square wave signals into semi-circular wave signals; and the second-stage verification comparison reshaper which is the single threshold voltage comparator is used for transforming a true value and undesired signals into semi-circular waves in different amplitudes, and transforming the semi-circular waves into the square wave signals after selecting true value signals through comparison, wherein, the true value is obtained from the integral circuit. The rotating-speed measurement converter solves the technical problem in the prior art that the rotating-speed measurement of the prior rotating-speed measurement converter is abnormal owing to environmental impacts, and has the advantages of simple structure, low cost, high reliability, etc.

Description

The tachometric survey transducer

Technical field

The utility model relates to a kind of tachometric survey transducer.

Background technology

After the tachometric survey transducer all adopted passband, stopband and band to be connected with source filtering in the past, amplify shaping and handle, be transformed into the signals such as frequency that are directly proportional with the axle rotating speed.Because the influence of factors such as environment, pump does not rotate, and transducer just has the output pulse, causes tachometric survey normally to carry out.

Summary of the invention

The purpose of this utility model provides a kind of tachometric survey transducer, and it has solved prior art medium speed measurement translator and has caused the unusual technical matters of tachometric survey because of environmental impact.

Technical solution of the present utility model is:

A kind of tachometric survey transducer, comprise the signal pre-processing circuit that is connected the speed probe output terminal, its special character is: it comprises that also relatively reshaper, integrating circuit and second level Jianzhen compare reshaper to the first order Jianzhen who is connected to the signal pre-processing circuit output terminal in turn; Described first order Jianzhen relatively reshaper is a simple gate limit voltage comparator, is used for converting pretreated sine wave signal to square-wave signal; Described integrating circuit comprises resistance and electric capacity, is used for converting square-wave signal to semicircle ripple signal; Described second level Jianzhen relatively reshaper is a simple gate limit voltage comparator, is used for the semicircle ripple that true value that integrating circuit is obtained and undesired signal convert different amplitudes to, compare select the true value signal after, convert square-wave signal to.

Above-mentioned tachometric survey transducer also comprises the attenuator that is arranged between first order Jianzhen comparison reshaper and the integrating circuit, and described attenuator is a resistance, is used to limit the relatively amplitude of the square-wave signal of reshaper output of first order Jianzhen.

Above-mentioned signal pre-processing circuit comprises that the train of impulses that connects successively suppresses circuit, power screening circuit, amplitude limiter circuit and filtering circuit; It is ferrite absorption-type wave filter that described train of impulses suppresses circuit; The resistance of described power screening circuit and the output impedance of speed probe are complementary; Described amplitude limiter circuit is a nonlinear filter; Described filtering circuit is a π type passive filter.

The utlity model has following advantage: the utility model circuit adopts passive filtering, simple in structure, cost is low, reliability is high, when the signal of speed probe passes through transducer of the present utility model, signal suppresses circuit, power screening circuit, amplitude limiter circuit, filtering circuit, the relatively relatively processing of reshaper of reshaper, attenuator, integrating circuit and second level Jianzhen of first order Jianzhen through train of impulses respectively, can realize the purpose of accurately measuring.

Description of drawings

Fig. 1 compares reshaper and input and output waveform thereof for the utility model Jianzhen;

Fig. 2 is the utility model tachometric survey converter principle figure.

Embodiment

Referring to Fig. 2, the utility model provides a kind of and has comprised that the train of impulses inhibition circuit, power screening circuit, amplitude limiter circuit, filtering circuit, the first order Jianzhen that are linked in sequence compare relatively reshaper of reshaper, attenuator, integrating circuit and second level Jianzhen, and above-mentioned each device effect is respectively:

1, train of impulses suppresses circuit: suppress circuit at the train of impulses of circuit input end setting and generally adopt the absorption-type wave filter, the fast transient burst interference that interference sources such as the crane in the time of can be with work, test motor produce absorbs.The absorption-type wave filter is made of the consume device, ferrite absorption-type wave filter just, and effect is that the systemic noise energy of stopband is converted into heat energy loss, thereby reaches filter effect.Ferrite absorption-type wave filter constitutes low-pass filter with ferrite as inductor, provide perception-capacitive path when low frequency, and loss is bigger when upper frequency.In actual applications, iron core can suppress any spurious oscillation, can decay induction be transferred on the component down-lead or the cable that is attached thereto in the high frequency garbage signal.High-frequency current by the elimination or the electromagnetic interference source of greatly decaying unshakable in one's determination suppresses Conduction Interference.Adopt ferrite can provide sufficiently high high frequency to reduce high-frequency current.Theoretically, impedance unshakable in one's determination depends on frequency, and desirable ferrite can provide high impedance at high frequency, and provides zero impedance on every other frequency range.

2, power screening circuit: power screening circuit is arranged on train of impulses to be suppressed to be also referred to as impedance/power attenuation circuit after the circuit.Because characteristics such as undesired signal has than true value signal impedance height, and power is low equate with the output impedance of speed probe so power screens the resistance of circuit, can effectively reduce input and disturb.

3, amplitude limiter circuit: by power screening back amplitude limiter circuit the input speed signal is carried out amplitude limit, input amplitude maximum is controlled at 0.7V.Amplitude limiter circuit is made up of resistance and diode, and purpose is to prepare for the input of amplifier, and signal value is further decayed.The amplitude limiter circuit that adopts diode to constitute also claims nonlinear filter.Impulsive noise is a kind of important form of expression of sensor noise, and its amplitude is bigger usually, causes harmful effect bigger to circuit, and spike pulse often damages circuit, also becomes surge.It contains direct current composition tremendously high frequency composition, can not this noise of filtering with common linear filter, adopt nonlinear filter, this noise of filtering effectively.

4, filtering circuit: the filtering circuit behind the limiter is formed π type passive filter by RC, but by controlling RC choosing value filtering speed probe the input frequency signal signal and the reduction noise amplitudes of frequency in addition.π type passive filter is a kind of frequency selection circuit, and useful signal is passed through, and suppresses (or big high attenuation) unwanted frequency signal simultaneously.

5, first order Jianzhen compares reshaper: referring to Fig. 1, Jianzhen compares the simple gate limit voltage comparator that reshaper is made up of resistance, operational amplifier, its effect is the near sinusoidal tach signal that filtering circuit transmits to be carried out amplitude voltage relatively amplify, the voltage to frequency value of output constant amplitude.Because the open-loop voltage enlargement factor of integrated transporting discharging is very big, the computing output voltage V _INLess than reference voltage V _REF, i.e. V _LD=(V _IN-V _REF)＜0 o'clock computing output voltage V ₀Be low level V _OLOtherwise, work as V _INBe elevated to and be slightly larger than V _REFBe V _LD=(V _IN-V _REF)＞0 o'clock V ₀Be high level.By above analysis as can be known, comparer output voltage V ₀Critical switch condition be integrated transporting discharging ground differential input voltage V _ID=0 is V _IN=V _REFWork as V _INUprise through V by low _REFThe time V ₀By V _OLBecome V _OHOtherwise, work as V _INBy high step-down process V _REFThe time V ₀By V _OHBecome V _OLWe export V to comparer ₀Corresponding input voltage V when a level jumps to another level _INValue is called threshold voltage or threshold voltage V _TUse above principle, constitute Jianzhen's comparer and suppress undesired signal (being the EMI signal), sine wave is become square-wave pulse signal output.

6, attenuator: the square-wave pulse that the attenuator of being made up of resistance is imported after with the shaping of Jianzhen's comparer decays to 1/3 amplitude.The purpose of taking the amplitude limit measure is to determine the threshold voltage value, avoids the circuit chips to enter degree of depth saturation region, thereby improves response speed.

7, integrating circuit: integrating circuit carries out integration with the square-wave pulse that attenuator transmits.Utilize pulse width to differentiate true and false signal, the output that pulse width is big is big, and the output of the little noise spike of pulse width is little, so noise can be removed.Signal pulse is wide, signal amplitude height behind the integration; Disturbing pulse is narrow, and signal amplitude is little behind integration.RC integration circuit time constant τ selects a door level to be set when suitable, and the disturbing pulse that amplitude is little removes, thereby reaches the purpose that suppresses disturbing pulse.

8, second level Jianzhen compares reshaper: by the signal of integrating circuit input, after second level Jianzhen compared the reshaper processing, the speed-frequency pulse signal of output constant amplitude exported TT﹠C system to.Relatively reshaper is similar with the first order for second level Jianzhen.

Claims

1, a kind of tachometric survey transducer, comprise the signal pre-processing circuit that is connected the speed probe output terminal, it is characterized in that: it comprises that also relatively reshaper, integrating circuit and second level Jianzhen compare reshaper to the first order Jianzhen who is connected to the signal pre-processing circuit output terminal in turn; Described first order Jianzhen relatively reshaper is a simple gate limit voltage comparator, is used for converting pretreated sine wave signal to square-wave signal; Described integrating circuit comprises resistance and electric capacity, is used for converting square-wave signal to semicircle ripple signal; Described second level Jianzhen relatively reshaper is a simple gate limit voltage comparator, is used for the semicircle ripple that true value that integrating circuit is obtained and undesired signal convert different amplitudes to, compare select the true value signal after, convert square-wave signal to.

2, tachometric survey transducer according to claim 1, it is characterized in that: described tachometric survey transducer also comprises the attenuator that is arranged between first order Jianzhen comparison reshaper and the integrating circuit, described attenuator is a resistance, is used to limit the relatively amplitude of the square-wave signal of reshaper output of first order Jianzhen.

3, tachometric survey transducer according to claim 1 and 2 is characterized in that: described signal pre-processing circuit comprises that the train of impulses that connects successively suppresses circuit, power screening circuit, amplitude limiter circuit and filtering circuit; It is ferrite absorption-type wave filter that described train of impulses suppresses circuit; The resistance of described power screening circuit and the output impedance of speed probe are complementary; Described amplitude limiter circuit is a nonlinear filter; Described filtering circuit is a π type passive filter.