CN102664603B - Auto-zeroing rotation speed tracking anti-aliasing filter - Google Patents
Auto-zeroing rotation speed tracking anti-aliasing filter Download PDFInfo
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Abstract
The invention discloses an auto-zeroing rotation speed tracking anti-aliasing filter which comprises inverting amplifiers (OP1 and OP2), an anti-aliasing filtering unit, a post-filter unit, a sampling and anti-aliasing frequency generator, resistors (R1, R2, R3 and R4) and capacitors (C1 and C2). The low-frequency characteristic of the auto-zeroing anti-aliasing filter can achieve direct current signals; and the anti-aliasing filter is mainly used for realizing auto-zeroing from direct current to the whole frequency band of the anti-aliasing filtering upper frequency limit when adaptive low-pass anti-aliasing filtering of automatic tracking and sampling of the rotation speed is carried out on signals, and ensuring that flat frequency response exists in the filtering frequency band, thereby solving the problem of irregular deviation of direct current working points of the traditional principle type classical anti-aliasing filter as well as the problem of variation of low-frequency transmission characteristics in direct current blocking transmission.
Description
Technical field
The present invention relates to the auto-zero anti alias filter that the signal detection technique category of Diagnosis Technique, particularly a kind of low frequency characteristic can reach direct current signal.
Background technology
In the input field of failure diagnosis, in order to realize the digitized processing of analog signal, need to carry out, after low pass anti-aliasing filtering, by AD converter, being sampled to signal.According to sampling thheorem, for fear of the generation of aliasing, sample frequency should more than the twice for highest signal frequency that is to say, when sample frequency is FC, the signal frequency FM of permission should satisfy condition: FM≤FC/2, otherwise will there is aliasing effect.In order to overcome aliased distortion, need to resist to the input signal UI in signals collecting mixed (low pass) filtering, the corner frequency FH of anti-mixed (low pass) filter should satisfy condition: FH≤FM≤FC/2.For example, when the switching capacity filter of conventional MAX293 and so on forms required anti alias filter, need an anti-mixed control signal given in advance, when its anti-mixed control frequency FK is FK=X*FH, filter will resist mixing rate FH to control as FH=FK/X automatically.X in formula, for anti-mixed control coefrficient, determines by selected anti alias filter, and for example the anti-mixed control coefrficient of MAX293 anti alias filter is X=100, and the anti-mixed control coefrficient of MAX294 anti alias filter is X=50.
Conventional method, in the time need to changing the corner frequency FH of anti alias filter, realizes by artificial in advance given anti-mixed control frequency FK=X*FH, is called " having a grade anti-aliasing filtering ", the category that the frequency F that is only applicable to signal is stabilized frequency.In the process of signal sampling, conventional method is set sample frequency FC:FC=FC0=N*FN0 according to the initial speed frequency FN0 before sampling in advance, N is sample frequency Clock Multiplier Factor, and according to default sample frequency FC=N*FN0, carry out given anti-mixed control frequency FK=X*FC=X*N*FN0, this be a kind of " having a grade anti-aliasing filtering "; The problem that traditional this " having a grade anti-aliasing filtering " exists is: when signal frequency F changes with speed-frequency FN, sample frequency FC but can not change at any time, also can not guarantee all the time corner frequency FH=FC/2=N*FN/2 in the overall process of sampling, can not guarantee that all the time corner frequency FH equals N * FN/2 to reach the requirement of maximum anti-mixing band in the overall process of sampling; Likely at speed-frequency FN, change to while being greater than original frequency FN0, occur that N * FN/2 are greater than N*FN0/2 and the risk that produces aliased distortion; And in rotating-speed tracking sampling, although can guarantee sample frequency FC=N*FN, but because the anti-mixed control frequency arranging is in advance FK=X*FC0=X*N*FN0, on the analysis frequency that can allow, be limited to FH=N*FN0/2, if speed-frequency is reduced to FN<FN0, sample frequency is also reduced to N*FN<N*FN0, thereby just must there is sample frequency, occurs the risk of aliased distortion lower than anti-mixing rate.
Because the Frequency response of anti alias filter is direct current for 0Hz(), and the demand of using, for example, during to resonance and demodulation signal filtering, also need LF-response to reach 0Hz, and the DC point stability of most of anti alias filters all can not meet the demands, for example MAX293 is when different frequency filterings is used, and not only maximum DC point skew can reach 1V, and the side-play amount when different frequencies may be also different.In order to solve DC point offset problem, when desired LF-response frequency is not bery low, conventionally with the CR coupling circuit of stopping direct current, solve, but this has not only brought the transient process of CR circuit, the demand that also makes direct current signal pass through anti alias filter can not realize.
Accompanying drawing 1 is the classical circuit model that an inner anti alias filter unit exists DC point skew or drift, although it can transmit direct current signal, and has smooth transmission characteristic in filter pass band, as accompanying drawing 2; But when the working point of input signal is zero, if it is VS1=1V that inner anti alias filter unit exists offset voltage, cause that the DC point skew of 1V appears in anti-aliasing filtering, if the DC amplification factor of follow-up postfilter unit is G=2, through the output of postfilter unit, just there is the DC point skew of 2V, as accompanying drawing 1.
Summary of the invention
Technical problem to be solved by this invention is, not enough for prior art, a kind of auto-zero rotating-speed tracking anti alias filter is provided, overcome anti alias filter unit, postfilter unit because there is offset voltage or drift voltage that switch-capacitor filtering link easily occurs due to DC point offset problem, solve required precise quantification test problems in varying-speed machinery failure diagnosis.
For solving the problems of the technologies described above, the technical scheme that the utility model adopts is: a kind of auto-zero rotating-speed tracking anti alias filter, comprise anti alias filter unit, postfilter unit, also comprise inverting amplifier, control the frequency generator of sampling and anti-aliasing filtering frequency, resistance, electric capacity, when requiring described anti alias filter filter and amplification coefficient to be K, the first inverting amplifier OP1 is by the negative input end of first resistance R 1 access the second inverting amplifier OP2, the positive input terminal ground connection of the second inverting amplifier OP2, the input of the output of the second inverting amplifier OP2 and anti alias filter unit, the second capacitor C 2 connects, the second capacitor C 2 is connected with the second resistance R 2, between second resistance R 2 access the first resistance R 1 and the second inverting amplifier OP2 negative input end, the input of the output access postfilter unit of anti alias filter unit, the output of postfilter unit is connected with the 4th resistance R 4, the 4th resistance R 4 is connected with the 3rd resistance R 3, between the 3rd resistance R 3 access the first resistance R 1 and the second inverting amplifier OP2 negative input end, between first capacitor C 1 one end access the 3rd resistance R 3 and the 4th resistance R 4, the first capacitor C 1 other end ground connection, the anti-mixing rate input of anti alias filter unit is connected with the frequency generator of anti-aliasing filtering frequency with control sampling, when requiring described anti alias filter filter and amplification coefficient for-K, the negative input end of first resistance R 1 access the second inverting amplifier OP2, the positive input terminal ground connection of the second inverting amplifier OP2, the input of the output of the second inverting amplifier OP2 and anti alias filter unit, the second capacitor C 2 connects, the second capacitor C 2 is connected with the second resistance R 2, between second resistance R 2 access the first resistance R 1 and the second inverting amplifier OP2 negative input end, the input of the output access postfilter unit of anti alias filter unit, the output of postfilter unit is connected with the 4th resistance R 4, the 4th resistance R 4 is connected with the 3rd resistance R 3, between the 3rd resistance R 3 access the first resistance R 1 and the second inverting amplifier OP2 negative input end, between first capacitor C 1 one end access the 3rd resistance R 3 and the 4th resistance R 4, the first capacitor C 1 other end ground connection, the anti-mixing rate input of anti alias filter unit is connected with the frequency generator of anti-aliasing filtering frequency with control sampling.
The amplification coefficient of described the first inverting amplifier OP1 is-1.
The parameter designing of described resistance R 1, R2, R3, R4 and capacitor C 1, C2 must meet following formula:
R3=R4；
R3+R4=K*R1；
R2=K*R1/G；
C1*R3*R4/(R3+R4)=C2*R2。
Described the second inverting amplifier OP2 and anti alias filter unit are respectively inverting amplifier and the anti alias filter unit in eight rank low pass elliptic function switching capacity filter MAX293 integrated circuit (IC) chip; Input the input of the first inverting amplifier OP1, the output of the first inverting amplifier OP1 is received one end of the first resistance R 1, the other end of the first resistance R 1 is received the CPIN of MAX293, the CPOUT of MAX293 connects one end of the second capacitor C 2, one end of another termination the second resistance R 2 of the second capacitor C 2, the CPIN end of another termination MAX293 of the second resistance R 2; The CPOUT end of MAX293 is received the IN end of MAX293, and the OUT end of MAX293 is received the input IN2 of post-filtering unit, the final filtering signal that has overcome DC point skew or drift of output O2 output of post-filtering unit; The output O2 of post-filtering unit also receives one end of the 4th resistance R 4, the other end of the 4th resistance R 4 is received one end of the first capacitor C 1 and one end of the 3rd resistance R 3, the other end ground connection GND of the 3rd capacitor C 1, the other end of the 3rd resistance R 3 is received the CPIN end of MAX293, the control signal FK of sampling and anti-mixed frequency generator 3 outputs receives the KLC end of MAX293, the AGND end ground connection GND of MAX293, V+ termination power+5V of MAX293, V-termination power-5V of MAX293.
The frequency generator of described control sampling and anti-aliasing filtering frequency comprises speed probe, sample frequency generator and the anti-mixed frequency generator in the rotating shaft that is arranged on detected machine, the A that equals axle rotational frequency FN of speed probe output tach signal AFN doubly, receive the input FNIN of sample frequency generator, but during the sample frequency FC=N*FN needing, B=N/A frequency multiplication is carried out to AFN signal in sample frequency generator inside, the signal of output FC=N*FN, provides AD converter to carry out the control frequency of rotating-speed tracking sampling; This FC signal is also received the FKIN input of anti-mixed frequency generator, when the anti-mixed control coefrficient of anti alias filter unit used is X, in order to guarantee anti-aliasing filtering upper limiting frequency FH<=FC/2, resist the output frequency FK<=X*FH=X*FC/2 of mixed frequency generator, for this reason, the signal that is FC to the frequency of FKIN input by anti-mixed frequency generator carries out the frequency multiplication of C<=X/2, FK end output FK signal by anti-mixed frequency generator, receive the FK input of anti alias filter unit, as accompanying drawing 12; When using as auto-zero fixed frequency anti alias filter, the frequency generator 3 use frequencies of controlling sampling and anti-aliasing filtering frequency are fixed as the signal generator replacement of FK=X*FC.
The present invention is than the advantage of the anti-dark filter of existing classics: can overcome anti alias filter unit, postfilter unit because there is offset voltage or drift voltage that switch-capacitor filtering link easily occurs due to DC point offset problem, can realize again rotating-speed tracking anti-aliasing filtering and be easy to the object of mating with rotating-speed tracking sampling, ideally solved precise quantification test problems required in varying-speed machinery failure diagnosis, in track traffic, wind power generation and other varying-speed machinery failure diagnosises, had wide practical use.
Accompanying drawing explanation
Fig. 1 is the classical circuit that inner anti alias filter unit exists DC point skew or drift;
Fig. 2 is that classical circuit has smooth transmission characteristic schematic diagram in filter pass band;
Fig. 3 is that one embodiment of the invention amplification coefficient is one of auto-zero anti alias filter of 1;
Fig. 4 is that one embodiment of the invention amplification coefficient is two of 1 auto-zero anti alias filter;
Fig. 5 is that one embodiment of the invention amplification coefficient is the direct current signal that 1 auto-zero anti alias filter can accurately transmit input;
Fig. 6 is that one embodiment of the invention amplification coefficient is that one of auto-zero anti alias filter of 1 has good low-frequency transmission characteristic schematic diagram;
Fig. 7 is the auto-zero anti alias filter circuit that parameter designing does not meet design formula;
Fig. 8 is the defective schematic diagram of low-frequency transmission characteristic that parameter designing does not meet the auto-zero anti alias filter circuit of design formula;
Fig. 9 is that one embodiment of the invention amplification coefficient is that two of 1 auto-zero anti alias filter has good low-frequency transmission characteristic schematic diagram;
Figure 10 is the auto-zero anti alias filter that one embodiment of the invention amplification coefficient is-1;
Figure 11 is that one embodiment of the invention is used MAX293 and the auto-zero of internal inverted amplifier the anti alias filter that amplification coefficient is 1;
Figure 12 is the frequency generator structural representation that one embodiment of the invention is controlled sampling and anti-aliasing filtering frequency;
Figure 13 is that one embodiment of the invention postfilter amplification coefficient is that 4 anti-aliasing filtering transmission coefficients are 1 auto-zero rotating-speed tracking anti alias filter schematic diagram;
Figure 14 is that one embodiment of the invention postfilter amplification coefficient is that 4 anti-aliasing filtering transmission coefficients are the design sketch that 1 auto-zero rotating-speed tracking anti alias filter suppresses offset voltage;
Figure 15 is that one embodiment of the invention postfilter amplification coefficient is that 4 anti-aliasing filtering transmission coefficients are the design sketch that 1 auto-zero rotating-speed tracking anti alias filter suppresses offset voltage, transmission direct current signal;
Figure 16 is that one embodiment of the invention postfilter amplification coefficient is that 4 anti-aliasing filtering transmission coefficients are the transmission characteristic of 1 auto-zero rotating-speed tracking anti alias filter;
Figure 17 is that one embodiment of the invention postfilter amplification coefficient is that 4 anti-aliasing filtering transmission coefficients are the logical inband signaling of 1 auto-zero rotating-speed tracking anti alias filter transmission the oscillogram that suppresses offset voltage;
Wherein:
1: anti alias filter unit; 2: postfilter unit; 3: frequency generator; 31: speed probe; 32: sample frequency generator; 33: anti-mixed frequency generator.
Embodiment
As shown in Figure 3, one embodiment of the invention comprises anti alias filter unit, postfilter unit, also comprise inverting amplifier OP1 and OP2, control the frequency generator of sampling and anti-aliasing filtering frequency, resistance, electric capacity, the first inverting amplifier OP1 is by the negative input end of first resistance R 1 access the second inverting amplifier OP2, the positive input terminal ground connection of the second inverting amplifier OP2, the input of the output of the second inverting amplifier OP2 and anti alias filter unit, the second capacitor C 2 connects, the second capacitor C 2 is connected with the second resistance R 2, between second resistance R 2 access the first resistance R 1 and the second inverting amplifier OP2 negative input end, the input of the output access postfilter unit of anti alias filter unit, the output of postfilter unit is connected with the 4th resistance R 4, the 4th resistance R 4 is connected with the 3rd resistance R 3, between the 3rd resistance R 3 access the first resistance R 1 and the second inverting amplifier OP2 negative input end, between first capacitor C 1 one end access the 3rd resistance R 3 and the 4th resistance R 4, the first capacitor C 1 other end ground connection, the anti-mixing rate input of anti alias filter unit is connected with the frequency generator of anti-aliasing filtering frequency with control sampling.
In order to guarantee to obtain the low frequency characteristic of good transmission coefficient K=1, when the DC amplification factor G=2 of postfilter unit 2, the parameter of resistor R1, R2, R3, R4 and capacitor C1, C2 and design must meet following formula::
R3=R4；
R3+R4=K*R1=R1；
R2=K*R1/G=?R1/2；
C1*R3*R4/(R3+R4)=C2*R2
For example accompanying drawing 3, establish R3=R4=100k, R1=R3+R4=200k, and R2=R1/2=100k, when C2 is 470nF, C1=2*C2=940nF; Owing to meeting above-mentioned design formula, therefore it has the smooth until smooth Frequency response of direct current as accompanying drawing 6.For example, otherwise if any running parameter, accompanying drawing 7 increases 1 times to 1.88uF by the C1 of accompanying drawing 3, as accompanying drawing 8, there is the resonance peak of 3.54dB in low frequency characteristic variation at 2.5Hz.
For example, in order to guarantee to obtain the low frequency characteristic of good transmission coefficient K=1, when the DC amplification factor G=1 of postfilter unit 2, the parameter of resistor R1, R2, R3, R4 and capacitor C1, C2 and design must meet following formula:
R3=R4；
R3+R4=K*R1=R1；
R2=K*R1/G=?R1；
C1*R3*R4/(R3+R4)=C2*R2
As accompanying drawing 4, establish R3=R4=100k, R1=R3+R4=200k, R2=R1=200k, when C2 is 470nF, C1=4*C2=1.88uF; Owing to meeting above-mentioned design formula, therefore it has, the smooth Frequency response of direct current is as accompanying drawing 9.
If allow the output of this filter anti-phase, filter and amplification coefficient is-1, can save inverting amplifier OP1, input signal is directly received to one end of resistor R1.As accompanying drawing 10.
If adopt eight rank low pass elliptic function switching capacity filter MAX293 integrated circuit (IC) chip, anti alias filter unit is used the anti alias filter unit of MAX293 inside, if allow the inverting amplifier of the inside of MAX293 to have large offset voltage and the impact on output services point stability, inverting amplifier OP2 is used the inverting amplifier of the inside of MAX293, as shown in Figure 11, circuit contains inverting amplifier OP1, include the MAX293 of inverting amplifier OP2 and anti-aliasing filtering unit, postfilter unit and resistor R1, R2, R3, R4, capacitor C1, C2, input signal is received the input of the inverting amplifier OP1 that amplification coefficient is-1, the output of OP1 is received one end of resistor R1, the other end of resistor R1 is received the CPIN of MAX293 that is it includes the negative input end of inverting amplifier OP2, the positive input terminal ground connection GND of inverting amplifier OP2, the output of inverting amplifier OP2 that is the CPOUT of MAX293 connect one end of capacitor C2, one end of the other end termination resistor R2 of capacitor C2, the negative input end of another termination inverting amplifier OP2 of resistor R2 that is the CPIN of MAX293 end, the output of inverting amplifier OP2 that is the CPOUT of MAX293 end, also receive the IN end of MAX293 that is the input IN1 of anti-aliasing filtering unit, the output O1 of anti-aliasing filtering unit that is the OUT of MAX293 end, receive the input IN2 of postfilter unit, the final filtering signal that has overcome DC point skew or drift of output O2 output of postfilter unit, the output O2 of postfilter unit also receives one end of resistor R4, the other end of resistor R4 is received one end of capacitor C1 and one end of resistor R3, the other end ground connection GND of capacitor C1, the other end of resistor R3 is received the negative input end of inverting amplifier OP2 that is the CPIN of MAX293 end, the control signal FK of frequency generator output receives the KLC end of MAX293, that is the anti-mixing rate input FK of anti-aliasing filtering unit, the AGND end ground connection GND of MAX293, V+ termination power+5V of MAX293, V-termination power-5V of MAX293, as accompanying drawing 11.
The anti-anti-mixed control frequency FK that mixes control signal that supplies with the KLC end of MAX293 provides with the frequency generator of anti-aliasing filtering frequency by controlling sampling, this frequency generator contains the speed probe in the rotating shaft that is arranged on detected machine, sample frequency generator and anti-mixed frequency generator, the A that equals axle rotational frequency FN of speed probe output tach signal AFN doubly, receive the input FNIN of sample frequency generator, but during the sample frequency FC=N*FN needing, B=N/A frequency multiplication is carried out to AFN signal in sample frequency generator inside, the signal of output FC=N*FN, provide AD converter as the control frequency that carries out rotating-speed tracking sampling, this FC signal is also received the FKIN input of anti-mixed frequency generator, when the anti-mixed control coefrficient of anti-aliasing filtering unit used is X, in order to guarantee anti-aliasing filtering upper limiting frequency FH<=FC/2, resist the output frequency FK<=X*FH=X*FC/2 of mixed frequency generator, for this reason, the signal that is FC to the frequency of FKIN input by anti-mixed frequency generator carries out the frequency multiplication of C<=X/2, FK end output FK signal by anti-mixed frequency generator, receive the FK input of anti-aliasing filtering unit, as accompanying drawing 12.Wherein, sample frequency generator and anti-mixed frequency generator, combine by known frequency divider and frequency multiplier.For example: in sample frequency generator, can carry out N frequency multiplication to the signal frequency FNIN=A*FN of input, then carry out A frequency division and realize the frequency multiplication of B=A * N/A=N, obtain FC=N*FN; For example: in anti-mixed frequency generator, can carry out C≤X/2 frequency multiplication to the signal frequency FKIN=N*FN=FC of input, and obtain the frequency multiplication requirement of FK=N*FN*C≤N*FN*X/2; Described frequency multiplier can use known CD4046 phaselocking frequency multiplier or other frequency multipliers.
As accompanying drawing 13, owing to being outputed to the amplitude of the signal UI of this anti alias filter by lowpass pre-filter, reach 10VP, and this anti alias filter is while being used MAX293 to make anti-aliasing filtering unit, allowing the supply voltage using is V+=5V, V-=-5V, in order to guarantee to obtain the low frequency characteristic that good transmission coefficient is K=1, and don't as for making MAX293 that amplitude limit occur, need to be to attenuated input signal to 1/4, therefore postfilter should be designed to the fixed low-pass filters that direct current and low passband amplification coefficient are G=4, resistor R1, R2, R3, R4 and capacitor C1, the parameter of C2 designs with following formula:
Recommend R3=R4=150k;
R3+R4=K*R1; R1=(R3+R4)/K=300k
R2=K*R1/G=1*300k/4=75k
Get C2=470nF,
By: C1*R3*R4/ (R3+R4)=C2*R2
C1=C2*R2* (R3+R4)/(R3*R4)=C2*75* (150+150)/(150*150)=C2=470nF
When the DC component of input signal is 1V, when anti-aliasing filtering unit does not have offset voltage (VS1=0V), post-filtering output voltage is 1V, and circuit has correctly transmitted the direct voltage of signal, as accompanying drawing 13.
When the DC component of input signal is 0V, when anti-aliasing filtering unit exists 1V offset voltage (VS1=1V), post-filtering output voltage is 0V, and circuit has suppressed the offset voltage of anti-aliasing filtering unit effectively, as accompanying drawing 14.
When the DC component of input signal is 1V, when anti-aliasing filtering unit exists 1V offset voltage (VS1=1V), post-filtering output voltage is 1V, and circuit has suppressed the offset voltage of anti-aliasing filtering unit effectively, correctly transmitted the direct voltage of signal, as accompanying drawing 15 simultaneously.
When anti-mixed control frequency FK=100kHz, the frequency response of post-filtering output is-2.96dB, meets the requirements when FK/X=100kHz/100=1kHz; The flat frequency response that has 0dB in 1uHz ~ 1kHz frequency band, meets the requirements; See accompanying drawing 16.
In input signal, there is no DC component, but the AC signal that has 1VP50Hz, when anti-aliasing filtering unit exists 1V offset voltage (VS1=1V), the direct voltage (mean value) of post-filtering output is 0.0001036V, and circuit has suppressed the offset voltage of anti-aliasing filtering unit effectively; AC signal is about 1.01019VP50Hz simultaneously, has transmitted the alternating voltage of signal, as accompanying drawing 17 with 1% error.
Claims (4)
1. an auto-zero rotating-speed tracking anti alias filter, comprise anti alias filter unit, postfilter unit, it is characterized in that, also comprise inverting amplifier, control the frequency generator of sampling and anti-aliasing filtering frequency, resistance, electric capacity, when requiring described anti alias filter filter and amplification coefficient to be K, the first inverting amplifier OP1 is by the negative input end of first resistance R 1 access the second inverting amplifier OP2, the positive input terminal ground connection of the second inverting amplifier OP2, the input of the output of the second inverting amplifier OP2 and anti alias filter unit, the second capacitor C 2 connects, the second capacitor C 2 is connected with the second resistance R 2, between second resistance R 2 access the first resistance R 1 and the second inverting amplifier OP2 negative input end, the input of the output access postfilter unit of anti alias filter unit, the output of postfilter unit is connected with the 4th resistance R 4, the 4th resistance R 4 is connected with the 3rd resistance R 3, between the 3rd resistance R 3 access the first resistance R 1 and the second inverting amplifier OP2 negative input end, between first capacitor C 1 one end access the 3rd resistance R 3 and the 4th resistance R 4, the first capacitor C 1 other end ground connection, the anti-mixing rate input of anti alias filter unit is connected with the frequency generator of anti-aliasing filtering frequency with control sampling, when requiring described anti alias filter filter and amplification coefficient for-K, the negative input end of first resistance R 1 access the second inverting amplifier OP2, the positive input terminal ground connection of the second inverting amplifier OP2, the input of the output of the second inverting amplifier OP2 and anti alias filter unit, the second capacitor C 2 connects, the second capacitor C 2 is connected with the second resistance R 2, between second resistance R 2 access the first resistance R 1 and the second inverting amplifier OP2 negative input end, the input of the output access postfilter unit of anti alias filter unit, the output of postfilter unit is connected with the 4th resistance R 4, the 4th resistance R 4 is connected with the 3rd resistance R 3, between the 3rd resistance R 3 access the first resistance R 1 and the second inverting amplifier OP2 negative input end, between first capacitor C 1 one end access the 3rd resistance R 3 and the 4th resistance R 4, the first capacitor C 1 other end ground connection, the anti-mixing rate input of anti alias filter unit is connected with the frequency generator of anti-aliasing filtering frequency with control sampling,
The amplification coefficient of described the first inverting amplifier OP1 is-1;
The parameter designing of described resistance R 1, R2, R3, R4 and capacitor C 1, C2 meets following formula:
R3=R4；
R3+R4=K*R1；
R2=K*R1/G；
C1*R3*R4/(R3+R4)=C2*R2；
Wherein, K is the low-frequency transmission coefficient of auto-zero rotating-speed tracking anti alias filter, and G is the DC amplification factor of postfilter unit.
2. auto-zero rotating-speed tracking anti alias filter according to claim 1, it is characterized in that, described the second inverting amplifier OP2 and anti alias filter unit are respectively inverting amplifier and the anti alias filter unit in eight rank low pass elliptic function switching capacity filter MAX293 integrated circuit (IC) chip; Input signal is received the input of the first inverting amplifier OP1, the output of the first inverting amplifier OP1 is received one end of the first resistance R 1, the other end of the first resistance R 1 is received the CPIN of MAX293, the CPOUT of MAX293 connects one end of the second capacitor C 2, one end of another termination the second resistance R 2 of the second capacitor C 2, the CPIN end of another termination MAX293 of the second resistance R 2; The CPOUT end of MAX293 is received the IN end of MAX293, and the OUT end of MAX293 is received the input IN2 of post-filtering unit, the final filtering signal that has overcome DC point skew or drift of output O2 output of post-filtering unit; The output O2 of post-filtering unit also receives one end of the 4th resistance R 4, the other end of the 4th resistance R 4 is received one end of the first capacitor C 1 and one end of the 3rd resistance R 3, the other end ground connection GND of the first capacitor C 1, the other end of the 3rd resistance R 3 is received the CPIN end of MAX293, the control signal FK that controls the frequency generator output of sampling and anti-aliasing filtering frequency receives the KLC end of MAX293, the AGND end ground connection GND of MAX293, V+ termination power+5V of MAX293, V-termination power-5V of MAX293.
3. auto-zero rotating-speed tracking anti alias filter according to claim 1, is characterized in that, described control sampling comprises with the frequency generator of anti-aliasing filtering frequency speed probe, sample frequency generator and the anti-mixed frequency generator being connected successively.
4. auto-zero rotating-speed tracking anti alias filter according to claim 3, it is characterized in that, when described auto-zero rotating-speed tracking anti alias filter is used as auto-zero fixed frequency anti alias filter, controlling sampling is the fixing signal generator of frequency with the frequency generator of anti-aliasing filtering frequency.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210185888.1A CN102664603B (en) | 2012-06-06 | 2012-06-06 | Auto-zeroing rotation speed tracking anti-aliasing filter |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210185888.1A CN102664603B (en) | 2012-06-06 | 2012-06-06 | Auto-zeroing rotation speed tracking anti-aliasing filter |
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| Publication Number | Publication Date |
|---|---|
| CN102664603A CN102664603A (en) | 2012-09-12 |
| CN102664603B true CN102664603B (en) | 2014-10-15 |
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| CN201210185888.1A Active CN102664603B (en) | 2012-06-06 | 2012-06-06 | Auto-zeroing rotation speed tracking anti-aliasing filter |
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7212139B1 (en) * | 2005-11-15 | 2007-05-01 | Texas Instruments Incorporated | System for suppressing aliasing interferers in decimating and sub-sampling systems |
| CN201429461Y (en) * | 2009-06-26 | 2010-03-24 | 武汉钢铁(集团)公司 | Vibration signal acquisition unit |
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2012
- 2012-06-06 CN CN201210185888.1A patent/CN102664603B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7212139B1 (en) * | 2005-11-15 | 2007-05-01 | Texas Instruments Incorporated | System for suppressing aliasing interferers in decimating and sub-sampling systems |
| CN201429461Y (en) * | 2009-06-26 | 2010-03-24 | 武汉钢铁(集团)公司 | Vibration signal acquisition unit |
Non-Patent Citations (4)
| Title |
|---|
| Design ofA Trigeminal Neuralgia Pressure-pained detector Based on MSP430;Xiaojuan Chen 等;《Proceedings ofthe 2009 IEEE International Conference on Mechatronics and Automation》;20090812;第1033-1038页 * |
| Xiaojuan Chen 等.Design ofA Trigeminal Neuralgia Pressure-pained detector Based on MSP430.《Proceedings ofthe 2009 IEEE International Conference on Mechatronics and Automation》.2009,第1033-1038页. |
| 基于MAX293的抗混滤波器研制;陈照章 等;《半导体技术》;20021231;第27卷(第12期);第34-36、47页 * |
| 陈照章 等.基于MAX293的抗混滤波器研制.《半导体技术》.2002,第27卷(第12期),第34-36、47页. |
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| CN102664603A (en) | 2012-09-12 |
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Application publication date: 20120912 Assignee: TANGZHI SCIENCE & TECHNOLOGY HUNAN DEVELOPMENT Co.,Ltd. Assignor: Tang Deyao Contract record no.: 2014430000172 Denomination of invention: Auto-zeroing rotation speed tracking anti-aliasing filter Granted publication date: 20141015 License type: Exclusive License Record date: 20141229 |
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