CN101741349B - Circuit for filtering stochastic resonance noise and detecting weak periodic signal - Google Patents

Abstract

The invention relates to a circuit for filtering stochastic resonance noise and detecting weak periodic signal. The circuit of the invention comprises a signal amplification circuit, a summing integration circuit and a comparison feedback circuit, wherein the signal amplification circuit comprises two operational amplifiers, a variable resistor and two grounding resistor; the summing integration circuit comprises a summing operational amplifier, an integration operational amplifier, two grounding resistors and an integrator capacitor; the output end of the integration operational amplifier is connected with the integrator capacitor so as to be used as signal output end; and the comparison feedback circuit comprises fix comparators, two reverser, an operational amplifier, fix variable resistors and three grounding resistors. The invention can obviously increase the weak periodic pulse signal in electrical signals with noise, obviously reduce the noise contribution and realize to extract useful weak electrical signals in heavy noise.

Description

A kind of accidental resonance noise filtering and weak periodic signal detecting circuit

Technical field

The invention belongs to the electronic signal process field, relate to a kind of circuit, specifically is a kind of accidental resonance noise filtering and weak periodic signal detecting circuit.

Background technology

To noisy Signal Processing conventional method is to carry out filtering through filter.But filter can only carry out filtering to the signal of certain frequency range.For example: low pass filter passes through low-band signal, the filtering high frequency band signal.High pass filter passes through high frequency band signal, the filters low segment signal.This technology is difficult to utilize noise energy that the useful signal in the very noisy is strengthened, and makes noise attentuation, and with the useful signal and the noise separation of same frequency range, thereby extract useful signal.And based on the non-linear filtering method of accidental resonance principle; Can utilize noise energy that signal is enhanced; Improve signal to noise ratio; The small-signal that is submerged in the noise background is extracted, so, all have wide practical use in fields such as fault detect, bio signal extraction, image and voice messaging identification, DOA estimation.

The phenomenon of accidental resonance is found by scientists such as Benzi at first; That is: when a continuous nonlinear bistable system model is imported faint periodic signal and noise signal simultaneously; Under the suitable parameters condition, when noise was strengthened to a certain intensity, signal to noise ratio not only can not reduce; The phase inverted output signal can significantly be strengthened, and this phenomenon is called as " accidental resonance " phenomenon.Signal processing method based on the accidental resonance principle is a kind of new signal processing method.At present, the signal processing of accidental resonance principle is a core with continuous bistable system Mathematical Modeling mainly.When input, measured signal can not be regulated often, needs to reconcile parameter and reaches best input effect.But relation is complicated between this continuous flip-flop model parameter, and this brings difficulty for regulating parameter rapidly.

We have proposed a kind of piecewise linearity accidental resonance Mathematical Modeling.It is simple that this model has the parameter regulation relation, is easy to different frequency signals is realized the characteristics of accidental resonance.

This model is:

Wherein, T represents the time; expression x (t) differentiates, and x (t) is the output signal after handling, and a, b, c are real parameter; And a＞b＞0, c＞0; S (t)=Ks (t), K is an amplification coefficient,

S (t) is a noisy signal to be detected, s (t)=H (t)+η (t), and H (t) representes input signal to be detected, η (t) representes noise signal;

The relation of this aspect of model value and parameter is: be positioned at x=± b place at the bottom of the trap; Barrier height Δ U=c; About two outside line segments and that axis of abscissas is given

is obvious; Be to concern one to one between characteristic value and the parameter, regulating one of them parameter only can influence a characteristic.Change barrier height, only need to regulate parameter c.The change of parameter c only influences barrier height, can not influence other characteristics such as position at the bottom of the trap.This adjusting for parameter has obvious superiority.

Summary of the invention

The object of the invention just provides a kind of accidental resonance noise filtering and weak periodic signal detecting circuit; This circuit designs according to above-mentioned (1) formula accidental resonance piecewise linearity Mathematical Modeling; Can the weak periodic signal in the very noisy significantly be strengthened; Noise contribution obviously weakens, and can under strong noise background, extract useful ultra-weak electronic signal.

Circuit of the present invention comprises signal amplification circuit, summation integrating circuit, comparison feedback circuit.

Signal amplification circuit comprises the first operational amplifier U1, the second operational amplifier U2, first resistance R 1, second resistance R 2, the 3rd resistance R 3, the first variable resistor R101, the first earth resistance R201, the second earth resistance R202.One end of first resistance R 1 is connected with the measured signal input; The reverse input end of the first operational amplifier U1 is connected with the other end of first resistance R 1 and an end of second resistance R 2; The in-phase input end of the first operational amplifier U1 is connected with the end of the first earth resistance R201; The other end ground connection of the first earth resistance R201, the output of the first operational amplifier U1 is connected with the other end of second resistance R 2 and an end of the 3rd resistance R 3; The reverse input end of the second operational amplifier U2 is connected with the other end of the 3rd resistance R 3 and the stiff end of the first variable resistor R101; The input in the same way of the second operational amplifier U2 is connected with the end of the second earth resistance R202; The other end ground connection of the second earth resistance R202, the output of the second operational amplifier U2 is connected with the adjustable end of the first variable resistor R101.

The summation integrating circuit comprises sum operational amplifier U3, integral operation amplifier U4, the 4th resistance R 4, the 5th resistance R 5, the 6th resistance R 6, the 7th resistance R 7, the 3rd earth resistance R203, the 4th earth resistance R204, integrator capacitor C 1.The reverse input end of sum operational amplifier U3 is connected with an end of the 4th resistance R 4, an end of the 5th resistance R 5 and an end of the 6th resistance R 6; The other end of the 4th resistance R 4 is connected with the output of the second operational amplifier U2; The input in the same way of sum operational amplifier U3 is connected with the end of the 3rd earth resistance R203; The other end ground connection of the 3rd earth resistance R203, the output of sum operational amplifier U3 is connected with the other end of the 6th resistance R 6 and an end of the 7th resistance R 7; The reverse input end of integral operation amplifier U4 is connected with the other end of the 7th resistance R 7 and an end of integrator capacitor C 1; The input in the same way of integral operation amplifier U4 is connected with the end of the 4th earth resistance R204; The other end ground connection of the 4th earth resistance R204; The output of integral operation amplifier U4 is connected with the other end of integrator capacitor C 1, and this end is as signal output part.

Relatively feedback circuit comprises the first comparator B1; The second comparator B2; The 3rd comparator B3; The 4th comparator B4; The 5th comparator B5; The 6th comparator B6; The first reverser F1; The second reverser F2; Operational amplifier U5; The second adjustable resistance R102; The 3rd variable resistor R103; The 4th variable resistor R104; The 5th variable resistor R105; The 6th variable resistor R106; The 7th variable resistor R107; The 8th resistance R 8; The 9th resistance R 9; The tenth resistance R 10; The 11 resistance R 11; The 12 resistance R 12; The 13 resistance R 13; The 14 resistance R 14; The 15 resistance R 15; The 16 resistance R 16; The 17 resistance R 17; The 18 resistance R 18; The 19 resistance R 19; The 20 resistance R 20; The 21 resistance R 21; The 22 resistance R 22; The 23 resistance R 23; The 24 resistance R 24; The 25 resistance R 25; The 5th earth resistance R205; The 6th earth resistance R206; The 7th earth resistance R207.The stiff end of the second adjustable resistance R102 is connected with positive supply, another stiff end ground connection, and the stiff end of the 3rd variable resistor R103 is connected with negative supply, another stiff end ground connection.

One end of the 8th resistance R 8 is connected with the input in the same way of the first comparator B1, an end of the 11 resistance R 11 is connected with the reverse input end of the second comparator B2, an end of the 12 resistance R 12 is connected with the input in the same way of the 3rd comparator B3, an end of the 15 resistance R 15 is connected with the reverse input end of the 4th comparator B4, an end of the 16 resistance R 16 is connected with the input in the same way of the 5th comparator B5, an end of the 19 resistance R 19 is connected with the reverse input end of the 6th comparator B6, and the other end of the other end of the 8th resistance R 8, the other end of the 11 resistance R 11, the 12 resistance R 12, the other end of the 15 resistance R 15, the other end of the 16 resistance R 16, the other end of 19 resistance R 19 all are connected with the output of integral operation amplifier U4; One end of the 9th resistance R 9 is connected with the reverse input end of the first comparator B1, an end of the tenth resistance R 10 is connected with the input in the same way of the second comparator B2, and the other end of the other end of the 9th resistance R 9 and the tenth resistance R 10 is connected with the adjustable end of the second adjustable resistance R102; One end of the 17 resistance R 17 is connected with the reverse input end of the 5th comparator B5, an end of the 18 resistance R 18 is connected with the input in the same way of the 6th comparator B6, and the other end of the 17 resistance R 17 and the other end of the 18 resistance R 18 are connected with the adjustable end of the 3rd variable resistor R103; One end of the 13 resistance R 13 is connected with the reverse input end of the 3rd comparator B3, the 14 resistance R 14 is connected the other end ground connection of the other end of the 13 resistance R 13 and the 14 resistance R 14 with the input in the same way of the 4th comparator B4.The output of the first comparator B1 is connected with the adjustable end of the 4th variable resistor R104; The output of the second comparator B2 is connected with an end of the 20 resistance R 20; The output of the 3rd comparator B3 is connected with an end of the 21 resistance R 21; The output of the output of the 4th comparator B4 and the 5th comparator B5 is connected with the adjustable end of the 6th variable resistor R106, and the output of the 6th comparator B6 is connected with an end of the 22 resistance R 22;

The reverse input end of the first reverser F1 is connected with the other end of the other end of the 20 resistance R 20, the 21 resistance R 21 and an end of the 23 resistance R 23; The input in the same way of the first reverser F1 is connected with the end of the 5th earth resistance R205; The other end ground connection of the 5th earth resistance R205, the output of the first reverser F1 is connected with the adjustable end of the other end of the 23 resistance R 23 and the 6th variable resistor R106;

The reverse input end of the second reverser F2 is connected with an end of the other end of the 22 resistance R 22 and the 24 resistance R 24; The input in the same way of the second reverser F2 is connected with the end of the 6th earth resistance R206; The other end ground connection of the 6th earth resistance R206, the output of the second reverser F2 is connected with the adjustable end of the other end of the 24 resistance R 24 and the 7th variable resistor R107;

The reverse input end of operational amplifier U5 is connected with the stiff end of the 4th variable resistor R104, the stiff end of the 5th variable resistor R105, the stiff end of the 6th variable resistor R106, the stiff end of the 7th variable resistor R107 and an end of the 25 resistance R 25; The input in the same way of operational amplifier U5 is connected with the end of the 7th earth resistance R207; The other end ground connection of the 7th earth resistance R207; The output of operational amplifier U5 is connected with the other end of the other end of the 25 resistance R 25 and the 5th resistance R 5, constitutes feedback loop.

In the above-mentioned comparison feedback circuit, the first comparator B1 and the 6th comparator B6 are single power supply, when input end signal is greater than the reverse input end signal in the same way, are output as positive high level, otherwise are 0; The second comparator B2, the 3rd comparator B3, the 4th comparator B4 and the 5th comparator B5 are the negative and positive dual power power supply, when input end signal is greater than the reverse input end signal in the same way, are output as positive high level, otherwise are negative high level.

Circuit working principle of the present invention is:

Noisy signal s (t) to be measured imports through signal input part;, signal amplification circuit obtains S (t)=Ks (t) after amplifying; S (t) and the feedback signal U ' that compares feedback circuit sue for peace through sum operational amplifier U3; The output of this summer

is sent into integrator U4 integration again and must be exported signal x (t), and x (t) is the signal after the processing;

Feedback signal U ' is by relatively feedback circuit generation; Relatively the input signal of feedback circuit is x (t); The adjustable end of variable resistor R102 provides benchmark voltage+b, and the adjustable end of variable resistor R103 provides benchmark voltage-b, and power supply ground end provides benchmark voltage 0.

Relatively feedback circuit comprises four feedback selector channels; Arbitrary moment has only a passage by gating; Gating is relatively determined with reference voltage by x (t), and by the gating of comparator B1 control selector channel whether the first feedback selection path has only when x (t)>=b; Comparator B1 just exports high level, amplifies output through U5 $U^{\′}=-\frac{c}{a-b};$ By the gating of comparator B2 and B3 control selector channel whether the second feedback selection path has only when 0≤x (t)＜b, and comparator B2 and B3 just export positive high level simultaneously, export through reverser F1 and amplifier U5 $U^{\′}=\frac{c}{b};$ By the gating of comparator B4 and B5 control selector channel whether the 3rd feedback selection path has only when-b≤x (t)＜0, and comparator B4 and B5 just export positive high level simultaneously, export through amplifier U5 $U^{\′}=-\frac{c}{b};$ The 4th feedback selection path by the gating of comparator B6 control selector channel whether, have only when x (t)＜-during b, comparator B6 just exports high level, amplifies output through U5 $U^{\′}=\frac{c}{a-b}.$

The invention provides a kind of accidental resonance circuit; With this circuit of noisy signal of telecommunication input to be measured; Not only can the useful signal that be submerged in the very noisy be strengthened; Noise is significantly weakened, realize from strong noise background, extracting the purpose of small-signal, and this circuit also has the characteristics that parameter is easy to regulate.This circuit can be applied to many application scenarios.The periodic signal that is submerged in the noise all need be detected and extracted in many application scenarios in the reality.As in plant equipment, because gap, wearing and tearing, small factors such as crackle, be submerged in the faint periodic pulse signal in the noise in fault early stage often existence.Biological information is as breathing also a kind of often periodic signal such as heartbeat.This circuit arrangement can directly combine with transducer, constitutes detecting instrument; Can constitute nonlinear filter, portable and miniature signal supervisory instrument etc.

Description of drawings

Fig. 1 is a schematic block circuit diagram of the present invention;

Fig. 2 is a circuit diagram of the present invention;

Fig. 3 is embodiment of the invention signal detecting result figure;

Fig. 4 is input signal and the comparison displayed map of output signal on oscilloscope.

Embodiment

According to (1) formula and (2) formula, circuit theory of the present invention is expressed as feedback structure shown in Figure 1.This structure by amplification, summation, integration and relatively feedback form.In conjunction with Fig. 1 circuit theory, the circuit diagram of a kind of accidental resonance noise filtering and weak periodic signal detecting circuit is as shown in Figure 2, and this circuit comprises signal amplification circuit, summation integrating circuit, comparison feedback circuit.

Signal amplification circuit comprises the first operational amplifier U1, the second operational amplifier U2, first resistance R 1, second resistance R 2, the 3rd resistance R 3, the first variable resistor R101, the first earth resistance R201, the second earth resistance R202.One end of first resistance R 1 is connected with the measured signal input; The reverse input end of the first operational amplifier U1 is connected with the other end of first resistance R 1 and an end of second resistance R 2; The in-phase input end of the first operational amplifier U1 is connected with the end of the first earth resistance R201; The other end ground connection of the first earth resistance R201, the output of the first operational amplifier U1 is connected with the other end of second resistance R 2 and an end of the 3rd resistance R 3; The reverse input end of the second operational amplifier U2 is connected with the other end of the 3rd resistance R 3 and the stiff end of the first variable resistor R101; The input in the same way of the second operational amplifier U2 is connected with the end of the second earth resistance R202; The other end ground connection of the second earth resistance R202, the output of the second operational amplifier U2 is connected with the adjustable end of the first variable resistor R101.

The summation integrating circuit comprises sum operational amplifier U3, integral operation amplifier U4, the 4th resistance R 4, the 5th resistance R 5, the 6th resistance R 6, the 7th resistance R 7, the 3rd earth resistance R203, the 4th earth resistance R204, integrator capacitor C 1.The reverse input end of sum operational amplifier U3 is connected with an end of the 4th resistance R 4, an end of the 5th resistance R 5 and an end of the 6th resistance R 6; The other end of the 4th resistance R 4 is connected with the output of the second operational amplifier U2; The input in the same way of sum operational amplifier U3 is connected with the end of the 3rd earth resistance R203; The other end ground connection of the 3rd earth resistance R203, the output of sum operational amplifier U3 is connected with the other end of the 6th resistance R 6 and an end of the 7th resistance R 7; The reverse input end of integral operation amplifier U4 is connected with the other end of the 7th resistance R 7 and an end of integrator capacitor C 1; The input in the same way of integral operation amplifier U4 is connected with the end of the 4th earth resistance R204; The other end ground connection of the 4th earth resistance R204; The output of integral operation amplifier U4 is connected with the other end of integrator capacitor C 1, and this end is as signal output part.

Relatively feedback circuit comprises the first comparator B1; The second comparator B2; The 3rd comparator B3; The 4th comparator B4; The 5th comparator B5; The 6th comparator B6; The first reverser F1; The second reverser F2; Operational amplifier U5; The second adjustable resistance R102; The 3rd variable resistor R103; The 4th variable resistor R104; The 5th variable resistor R105; The 6th variable resistor R106; The 7th variable resistor R107; The 8th resistance R 8; The 9th resistance R 9; The tenth resistance R 10; The 11 resistance R 11; The 12 resistance R 12; The 13 resistance R 13; The 14 resistance R 14; The 15 resistance R 15; The 16 resistance R 16; The 17 resistance R 17; The 18 resistance R 18; The 19 resistance R 19; The 20 resistance R 20; The 21 resistance R 21; The 22 resistance R 22; The 23 resistance R 23; The 24 resistance R 24; The 25 resistance R 25; The 5th earth resistance R205; The 6th earth resistance R206; The 7th earth resistance R207.The stiff end of the second adjustable resistance R102 is connected with positive supply, another stiff end ground connection, and the stiff end of the 3rd variable resistor R103 is connected with negative supply, another stiff end ground connection.

One end of the 8th resistance R 8 is connected with the input in the same way of the first comparator B1, an end of the 11 resistance R 11 is connected with the reverse input end of the second comparator B2, an end of the 12 resistance R 12 is connected with the input in the same way of the 3rd comparator B3, an end of the 15 resistance R 15 is connected with the reverse input end of the 4th comparator B4, an end of the 16 resistance R 16 is connected with the input in the same way of the 5th comparator B5, an end of the 19 resistance R 19 is connected with the reverse input end of the 6th comparator B6, and the other end of the other end of the 8th resistance R 8, the other end of the 11 resistance R 11, the 12 resistance R 12, the other end of the 15 resistance R 15, the other end of the 16 resistance R 16, the other end of 19 resistance R 19 all are connected with the output of integral operation amplifier U4; One end of the 9th resistance R 9 is connected with the reverse input end of the first comparator B1, an end of the tenth resistance R 10 is connected with the input in the same way of the second comparator B2, and the other end of the other end of the 9th resistance R 9 and the tenth resistance R 10 is connected with the adjustable end of the second adjustable resistance R102; One end of the 17 resistance R 17 is connected with the reverse input end of the 5th comparator B5, an end of the 18 resistance R 18 is connected with the input in the same way of the 6th comparator B6, and the other end of the 17 resistance R 17 and the other end of the 18 resistance R 18 are connected with the adjustable end of the 3rd variable resistor R103; One end of the 13 resistance R 13 is connected with the reverse input end of the 3rd comparator B3, the 14 resistance R 14 is connected the other end ground connection of the other end of the 13 resistance R 13 and the 14 resistance R 14 with the input in the same way of the 4th comparator B4.The output of the first comparator B1 is connected with the adjustable end of the 4th variable resistor R104; The output of the second comparator B2 is connected with an end of the 20 resistance R 20; The output of the 3rd comparator B3 is connected with an end of the 21 resistance R 21; The output of the output of the 4th comparator B4 and the 5th comparator B5 is connected with the adjustable end of the 6th variable resistor R106, and the output of the 6th comparator B6 is connected with an end of the 22 resistance R 22.

The reverse input end of the first reverser F1 is connected with the other end of the other end of the 20 resistance R 20, the 21 resistance R 21 and an end of the 23 resistance R 23; The input in the same way of the first reverser F1 is connected with the end of the 5th earth resistance R205; The other end ground connection of the 5th earth resistance R205, the output of the first reverser F1 is connected with the adjustable end of the other end of the 23 resistance R 23 and the 6th variable resistor R106.

The reverse input end of the second reverser F2 is connected with an end of the other end of the 22 resistance R 22 and the 24 resistance R 24; The input in the same way of the second reverser F2 is connected with the end of the 6th earth resistance R206; The other end ground connection of the 6th earth resistance R206, the output of the second reverser F2 is connected with the adjustable end of the other end of the 24 resistance R 24 and the 7th variable resistor R107.

The reverse input end of operational amplifier U5 is connected with the stiff end of the 4th variable resistor R104, the stiff end of the 5th variable resistor R105, the stiff end of the 6th variable resistor R106, the stiff end of the 7th variable resistor R107 and an end of the 25 resistance R 25; The input in the same way of operational amplifier U5 is connected with the end of the 7th earth resistance R207; The other end ground connection of the 7th earth resistance R207; The output of operational amplifier U5 is connected with the other end of the other end of the 25 resistance R 25 and the 5th resistance R 5, constitutes feedback loop.

In the above-mentioned comparison feedback circuit, the first comparator B1 and the 6th comparator B6 are single power supply, when input end signal is greater than the reverse input end signal in the same way, are output as positive high level, otherwise are 0; The second comparator B2, the 3rd comparator B3, the 4th comparator B4 and the 5th comparator B5 are the negative and positive dual power power supply, when input end signal is greater than the reverse input end signal in the same way, are output as positive high level, otherwise are negative high level.

Wherein, the actual measured signal that contains noise is through the reverse input end input of the first operational amplifier U1, through U1, U2 amplify S (t);

U3 is a summer, input signal S (t) and feedback signal U ' are sued for peace $\stackrel{\·}{x}\left(t\right)=U^{\′}+S\left(t\right).$

U4 is an integrator, and input signal

integration is got x (t); X (t) is the signal after the processing.

R102, R103 provide respectively ± the b comparative voltage.Regulate R102, R103, the voltage of R102, R103 intermediate node is respectively ± b, supply in comparator voltage as a reference.

The feedback selection path mainly constitutes (frame of broken lines part among Fig. 2) by comparator bank.

Selection path 1 is controlled by comparator B1.Comparator B1 is a single power supply, is used for detecting the signal of x >=b.When x>=b, comparator B1 is output as high level U _MaxOtherwise, be 0, U _MaxAmplify output through U5 $U^{\′}=-\frac{c}{a-b}.$

Selection path 2 is by comparator B2 and comparator B3 control.Comparator B2 and comparator B3 are the negative and positive dual power power supply, are used for detecting the signal of 0≤x＜b.When x＜b, comparator B2 is output as U _Max, and when x>=b, comparator B2 is output as-U _Max, when x>=0, comparator B3 is output as U _Max, and when x＜0, comparator B3 is output as low level-U _MaxSo, having only when 0≤x＜b, comparator B2 and the coefficient path of comparator B3 could be exported high level, otherwise are 0, through reverser F1 and amplifier U5 output $U^{\′}=\frac{c}{b}.$

Selection path 3 is by comparator B4 and comparator B5 control.Comparator B4 and B5 also are negative and positive dual power power supplies, with selection path 3 in like manner, be used for the signal of detection-b≤x＜0.Have only when-b≤x (t)＜0, comparator B4 and B5 just export positive high level simultaneously, export through amplifier U5 $U^{\′}=-\frac{c}{b}.$

Selection path 4 is controlled by comparator B6.Comparator B6 is single supply U _MaxPower supply, be used for detecting x＜-signal of b.When x＜-during b, comparator B6 is output as U _MaxOtherwise, be 0, have only when x (t)＜-during b, comparator B6 just exports high level, amplifies output through reverser F2 and amplifier U5 $U^{\′}=\frac{c}{a-b};$

Once confirmed the value of parameter a, b, c and K in (1) formula; Just can regulate resistance value in view of the above; It is met the demands, and K can realize that parameter a, b, c can realize its satisfied (2) formula through regulating resistance R 104, R105, R106, R107 and R25 through regulating R101.Present embodiment is got a=2, b=1, c=0.5, K=10.

The result is referring to Fig. 3 in the present embodiment Experiment of Electrical Circuits, in order to clearly illustrate the effect of this circuit, produces input signal H (the t)=A of standard especially with signal generator ₀Cos (2 π ft) is as measured signal, A ₀Be the cosine signal amplitude, f is a signal frequency.With input signal H (t) addition s (t)=H (the t)+η (t) of noise signal η (t) with standard, send into input, circuit is exported x (t) signal collect, and draw on computers by digital oscilloscope.

(b1) is A among Fig. 3 ₀The oscillogram of input signal when the intensity D of=0.15V, f=1HZ, noise η (t) is 0.15V; (b2) be the oscillogram of output signal.

(c1) is A among Fig. 3 ₀The oscillogram of input signal when the intensity D of=0.15V, f=1HZ, noise η (t) is 0.35V; (c2) be the oscillogram of output signal.

Fig. 4 is input signal and the contrast displayed map of output signal on oscilloscope, and the curve that amplitude is big is the output signal.

As can be seen from the figure this circuit can obviously weaken noise, and signal is obviously strengthened, and reaches the purpose that from noise background, detects weak periodic signal.

Claims (1)

1. accidental resonance noise filtering and weak periodic signal detecting circuit comprise signal amplification circuit, summation integrating circuit, comparison feedback circuit, it is characterized in that:

Signal amplification circuit comprises the first operational amplifier U1, the second operational amplifier U2, first resistance R 1, second resistance R 2, the 3rd resistance R 3, the first variable resistor R101, the first earth resistance R201, the second earth resistance R202; One end of first resistance R 1 is connected with the measured signal input; The reverse input end of the first operational amplifier U1 is connected with the other end of first resistance R 1 and an end of second resistance R 2; The in-phase input end of the first operational amplifier U1 is connected with the end of the first earth resistance R201; The other end ground connection of the first earth resistance R201, the output of the first operational amplifier U1 is connected with the other end of second resistance R 2 and an end of the 3rd resistance R 3; The reverse input end of the second operational amplifier U2 is connected with the other end of the 3rd resistance R 3 and the stiff end of the first variable resistor R101; The input in the same way of the second operational amplifier U2 is connected with the end of the second earth resistance R202; The other end ground connection of the second earth resistance R202, the output of the second operational amplifier U2 is connected with the adjustable end of the first variable resistor R101;

The summation integrating circuit comprises sum operational amplifier U3, integral operation amplifier U4, the 4th resistance R 4, the 5th resistance R 5, the 6th resistance R 6, the 7th resistance R 7, the 3rd earth resistance R203, the 4th earth resistance R204, integrator capacitor C 1; The reverse input end of sum operational amplifier U3 is connected with an end of the 4th resistance R 4, an end of the 5th resistance R 5 and an end of the 6th resistance R 6; The other end of the 4th resistance R 4 is connected with the output of the second operational amplifier U2; The input in the same way of sum operational amplifier U3 is connected with the end of the 3rd earth resistance R203; The other end ground connection of the 3rd earth resistance R203, the output of sum operational amplifier U3 is connected with the other end of the 6th resistance R 6 and an end of the 7th resistance R 7; The reverse input end of integral operation amplifier U4 is connected with the other end of the 7th resistance R 7 and an end of integrator capacitor C 1; The input in the same way of integral operation amplifier U4 is connected with the end of the 4th earth resistance R204; The other end ground connection of the 4th earth resistance R204; The output of integral operation amplifier U4 is connected with the other end of integrator capacitor C 1, and this end is as signal output part;

Relatively feedback circuit comprises the first comparator B1; The second comparator B2; The 3rd comparator B3; The 4th comparator B4; The 5th comparator B5; The 6th comparator B6; The first reverser F1; The second reverser F2; Operational amplifier U5; The second adjustable resistance R102; The 3rd variable resistor R103; The 4th variable resistor R104; The 5th variable resistor R105; The 6th variable resistor R106; The 7th variable resistor R107; The 8th resistance R 8; The 9th resistance R 9; The tenth resistance R 10; The 11 resistance R 11; The 12 resistance R 12; The 13 resistance R 13; The 14 resistance R 14; The 15 resistance R 15; The 16 resistance R 16; The 17 resistance R 17; The 18 resistance R 18; The 19 resistance R 19; The 20 resistance R 20; The 21 resistance R 21; The 22 resistance R 22; The 23 resistance R 23; The 24 resistance R 24; The 25 resistance R 25; The 5th earth resistance R205; The 6th earth resistance R206; The 7th earth resistance R207; The stiff end of the second adjustable resistance R102 is connected with positive supply, another stiff end ground connection, and the stiff end of the 3rd variable resistor R103 is connected with negative supply, another stiff end ground connection;

In the above-mentioned comparison feedback circuit, the first comparator B1 and the 6th comparator B6 are single power supply, when input end signal is greater than the reverse input end signal in the same way, are output as positive high level, otherwise are 0; The second comparator B2, the 3rd comparator B3, the 4th comparator B4 and the 5th comparator B5 are the negative and positive dual power power supply, when input end signal is greater than the reverse input end signal in the same way, are output as positive high level, otherwise are negative high level;

One end of the 8th resistance R 8 is connected with the input in the same way of the first comparator B1, an end of the 11 resistance R 11 is connected with the reverse input end of the second comparator B2, an end of the 12 resistance R 12 is connected with the input in the same way of the 3rd comparator B3, an end of the 15 resistance R 15 is connected with the reverse input end of the 4th comparator B4, an end of the 16 resistance R 16 is connected with the input in the same way of the 5th comparator B5, an end of the 19 resistance R 19 is connected with the reverse input end of the 6th comparator B6, and the other end of the other end of the 8th resistance R 8, the other end of the 11 resistance R 11, the 12 resistance R 12, the other end of the 15 resistance R 15, the other end of the 16 resistance R 16, the other end of 19 resistance R 19 all are connected with the output of integral operation amplifier U4; One end of the 9th resistance R 9 is connected with the reverse input end of the first comparator B1, an end of the tenth resistance R 10 is connected with the input in the same way of the second comparator B2, and the other end of the other end of the 9th resistance R 9 and the tenth resistance R 10 is connected with the adjustable end of the second adjustable resistance R102; One end of the 17 resistance R 17 is connected with the reverse input end of the 5th comparator B5, an end of the 18 resistance R 18 is connected with the input in the same way of the 6th comparator B6, and the other end of the 17 resistance R 17 and the other end of the 18 resistance R 18 are connected with the adjustable end of the 3rd variable resistor R103; One end of the 13 resistance R 13 is connected with the reverse input end of the 3rd comparator B3, the 14 resistance R 14 is connected the other end ground connection of the other end of the 13 resistance R 13 and the 14 resistance R 14 with the input in the same way of the 4th comparator B4; The output of the first comparator B1 is connected with the adjustable end of the 4th variable resistor R104; The output of the second comparator B2 is connected with an end of the 20 resistance R 20; The output of the 3rd comparator B3 is connected with an end of the 21 resistance R 21; The output of the output of the 4th comparator B4 and the 5th comparator B5 is connected with the adjustable end of the 6th variable resistor R106, and the output of the 6th comparator B6 is connected with an end of the 22 resistance R 22;

The reverse input end of the first reverser F1 is connected with the other end of the other end of the 20 resistance R 20, the 21 resistance R 21 and an end of the 23 resistance R 23; The input in the same way of the first reverser F1 is connected with the end of the 5th earth resistance R205; The other end ground connection of the 5th earth resistance R205, the output of the first reverser F1 is connected with the adjustable end of the other end of the 23 resistance R 23 and the 5th variable resistor R105;

The reverse input end of the second reverser F2 is connected with an end of the other end of the 22 resistance R 22 and the 24 resistance R 24; The input in the same way of the second reverser F2 is connected with the end of the 6th earth resistance R206; The other end ground connection of the 6th earth resistance R206, the output of the second reverser F2 is connected with the adjustable end of the other end of the 24 resistance R 24 and the 7th variable resistor R107;

The reverse input end of operational amplifier U5 is connected with the stiff end of the 4th variable resistor R104, the stiff end of the 5th variable resistor R105, the stiff end of the 6th variable resistor R106, the stiff end of the 7th variable resistor R107 and an end of the 25 resistance R 25; The input in the same way of operational amplifier U5 is connected with the end of the 7th earth resistance R207; The other end ground connection of the 7th earth resistance R207; The output of operational amplifier U5 is connected with the other end of the other end of the 25 resistance R 25 and the 5th resistance R 5, constitutes feedback loop.

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