CN2912512Y - ECG detection circuit with excellent noise suppressing function - Google Patents
ECG detection circuit with excellent noise suppressing function Download PDFInfo
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- CN2912512Y CN2912512Y CN 200620078990 CN200620078990U CN2912512Y CN 2912512 Y CN2912512 Y CN 2912512Y CN 200620078990 CN200620078990 CN 200620078990 CN 200620078990 U CN200620078990 U CN 200620078990U CN 2912512 Y CN2912512 Y CN 2912512Y
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Abstract
The utility model relates to a detection circuit of electrocardiogram signal (ECG signal), in particular to an ECG detection circuit which can greatly restrain the interruption of noises. The utility model is characterized in that a resistor of the resistor net of the inverting phase input of a first amplifier electrically is connected with a resistor of the inverting phase input net of a second amplifier; the electrical joint is introduced to the in-phase port of a fourth amplifier which is a voltage follower; the output of the voltage follower electrically is connected with the shielding port of the shielding cable of the educing wire; the joint enters the input of a fifth amplifier and is output by the fifth amplifier as a signal port of the ECG signal. The utility model has high common-mode rejection ratio, large enough pre-amplifier magnification times and appropriate bandwidth, therefore outputting genuine ECG signal.
Description
Technical field
This utility model relates to a kind of testing circuit of electrocardiosignal, particularly has the high electrocardio testing circuit that suppresses the noise ability.
Background technology
Electrocardiosignal (ECG) amplifying circuit with high signal source internal resistance characteristics, except being used for increasing signal amplitude, so that outside further dealing with, show or writing down, the regulating action that also is used for the isolation signals source and carries out signals such as bandwidth compression.The design of sort circuit often will be considered:
1, input impedance
Since under electrocardioelectrode and the human epidermal between the muscular tissue or contact resistance than high many of the resistance of tissue itself, and easily variation, its equivalent circuit as shown in Figure 1.Wherein, Re is surface contacted resistance (tens K Ω is to hundreds of M Ω), and Ce is surface electrode equivalent capacity (tens pf are to several thousand pf), and Es is the uneven electromotive force (several MV are to tens MV) of electrode, and Rt is muscular tissue resistance (tens Ω are to tens K Ω).Capacitance Coupled when upper frequency between electrode and the tissue becomes important, but in fact electrocardiosignal is lower frequency, so the influence of capacitor C e can be ignored, but the resistance of Re, Es and Rt can directly influence quality of signals and amplitude when lower frequency.
2, common mode inhibition
When detecting electrocardio, because input impedance is very high, two pole plate effects that human body and near 220V alternating current power supply or near power line just play capacitor Cp (seeing Fig. 1 about 10Pf), with the air is medium, civil power 50Hz signal has been coupled in the human body,, has been added to amplifier input terminal by muscular tissue and electrode because the inflow of slight electric current is arranged, just because of the existence of this signal, can directly have a strong impact on the collection of electrocardiosignal.
3, Zui Jia signal to noise ratio
Because the electrocardio frequency is lower, the frequency band range of suitable control amplifier and amplification could obtain best signal to noise ratio showing or writing down in the cardiac electrical process.
And existing electrocardiosignal amplifying circuit all is to adopt measuring amplifier that three general discharge circuits the constitute amplifying circuit as electrocardiosignal, and its existing problem is also as three aspect reasons of last surface analysis.
Summary of the invention
The purpose of this utility model provides a kind of high electrocardio testing circuit that suppresses the noise ability that has, and it not only has high common mode rejection ratio and sufficiently high preposition amplification and suitable bandwidth.Make electrocardiosignal output undistorted.
The purpose of this utility model is to realize like this, has the high electrocardio testing circuit that suppresses the noise ability, which comprises at least core signal sensor, the measuring amplifier that the lead-out wire shielded cable of core signal sensor and three discharge circuits constitute, wherein the in-phase input end of measuring amplifier first amplifier that constitutes with three discharge circuits respectively of two of lead-out wire shielded cable holding wires and the in-phase input end of second amplifier are electrically connected, the output of first amplifier is electrically connected with the in-phase end and the end of oppisite phase of the 3rd amplifier respectively with the output of second amplifier, carry out electrocardiosignal by the 3rd amplifier and amplify output, first amplifier's inverting input and second amplifier's inverting input are amplified network by resistor network and outfan formation separately respectively, it is characterized in that: resistance in the resistor network of first amplifier's inverting input is electrically connected with a resistance in the second amplifier's inverting input network, its electric connection point is input to the in-phase end with the 4th amplifier, the 4th amplifier is a voltage follower, the output of voltage follower is electrically connected with the shielding end of above-mentioned lead-out wire shielded cable, its junction point enters the 5th amplifier input terminal, by the signal end of the 5th amplifier output as electrocardiosignal.
The output of described third level amplifier enters the electrocardiosignal treatment circuit after forming L type high pass filter by C3 and R10, the desirable 1.0uF of the C3 in the high pass filter wherein, and between the desirable 270k Ω of R10-330k Ω, optimum is got 300k Ω.
The output of described first amplifier is input to third level amplifier's inverting input by resistance R 5, and the output of second amplifier is input to the in-phase input end of third level amplifier by resistance R 6; Third level amplifier's inverting input and outfan and connecting resistance R7 and capacitor C 2; Between the in-phase input end of third level amplifier and the ground and connecting resistance R9 and capacitor C 1.
The optional precision of described third level amplifier is low floats the type operational amplifier, and R7 and R9 get 20k Ω, C1 and C2 gets 100pF.
Characteristics of the present utility model are: because resistance in the resistor network of first amplifier's inverting input is electrically connected with a resistance in the second amplifier's inverting input network, its electric connection point is input to the in-phase end with the 4th amplifier, the 4th amplifier is a voltage follower, the output of voltage follower is electrically connected with the shielding end of above-mentioned lead-out wire shielded cable, its junction point enters the 5th amplifier input terminal, by the signal end of the 5th amplifier output as electrocardiosignal.This " floating ground " circuit design, common-mode signal by resistance in the resistor network of getting first amplifier's inverting input respectively and a resistance in the second amplifier's inverting input network, amplify the right lower limb (RL) that goes to drive human body by the two-stage of the 4th amplifier, the 5th amplifier and make circuit have very high common mode inhibition capacity, can eliminate significantly for the interference of 50HZ alternating current power supply and extraneous other electrical noise interference simultaneously.
Description of drawings
Below in conjunction with the embodiment accompanying drawing this utility model is described further.
Fig. 1 is that surface electrode detects the electrocardio equivalent circuit;
Fig. 2 is this utility model circuit theory diagrams.
Among the figure: 1, lead-out wire shielded cable; 2, shielding end; 3, electrocardiosignal; 4, the electrocardiosignal treatment circuit 4; U1, first amplifier; U2, second amplifier; U3, the 3rd amplifier; U4, the 4th amplifier; U5, the 5th amplifier.
The specific embodiment
As shown in Figure 2, the three amplifiers typical case difference amplifier of forming to R7, R9, R11, R12, C1 and C2 by the first amplifier U1, the second amplifier U2, the 3rd amplifier U3, R1.Resistance R 3 one ends are electrically connected with the RA of electrocardiosignal 3, and the other end is electrically connected with the in-phase end of the first amplifier U1; Resistor network R1, the R11 that the first amplifier U1 inverting input connects determines the amplification of the first amplifier U1, and its amplification is approximately equal to the value of R11/R1.Resistance R 4 one ends are electrically connected with the LA of electrocardiosignal 3, and the other end is electrically connected with the in-phase end of the second amplifier U2; Resistor network R2, the R12 that the second amplifier U2 inverting input connects determines the amplification of the second amplifier U2, and its amplification is approximately equal to the value of R12/R2; The end of oppisite phase of the first amplifier U1 and the second amplifier U2 is connected with R2 by resistance R 1 respectively, junction point is input to the in-phase end of the 4th amplifier U4 again, the 4th amplifier U4 is a voltage follower, the output of voltage follower is electrically connected with the shielding end 2 of lead-out wire shielded cable 1, its junction point enters the inverting input of the 5th amplifier U5, the 5th amplifier U5 and resistance R 8, R13 constitute inverting amplifier, and R13/R8 is an amplification.Pass through the signal end RL of resistance R 14 backs by the 5th amplifier U5 output as electrocardiosignal 3.
The output of the first above-mentioned amplifier U1 is input to the inverting input of third level amplifier U3 by resistance R 5, and the output of the second amplifier U2 is input to the in-phase input end of third level amplifier U3 by resistance R 6; The inverting input of third level amplifier U3 and outfan and connecting resistance R7 and capacitor C 2; Between the in-phase input end of third level amplifier U3 and the ground and connecting resistance R9 and capacitor C 1.
The operational amplifier of first amplifier U1 in above-mentioned and the optional FET input type of the second amplifier U2, its input impedance can reach more than the 100m Ω.The low type operational amplifier, the desirable 10k Ω of R3 and R4, R1 and the desirable 1.0k Ω of R2, R11 and the desirable 20k Ω of R12, R5 and the desirable 10k Ω of R6, R7 and the desirable 20k Ω of R9, C1 and the desirable 100pF of C2 of floating of the optional precision of third level amplifier U3.Consider the existence of the polarization potential Es (see figure 1) of surface electrode, this part amplification should be controlled at about 20 times.
Need to prove by the 4th amplifier U4, the 5th amplifier U5 and R8, R13, R14 with from human body left arm, right arm input line gauze screen (shielding end 2) and forms " floating ground ".The operational amplifier of the 4th amplifier U4, the optional FET input type of the 5th amplifier U5 wherein, the desirable 10k Ω of R8, the desirable 390k Ω of R13, the desirable 510k Ω of R14.This part is owing to adopted " floating ground " circuit design, by getting the common-mode signal on R1 and the R2, amplify right lower limb (RL) and the screen layer that removes to drive human body by the 4th amplifier U4, the 5th amplifier U5 two-stage, make circuit have very high common mode inhibition capacity, can eliminate significantly for the interference of 50HZ alternating current power supply and extraneous other electrical noise interference.
The output of third level amplifier U3 enters electrocardiosignal treatment circuit 4 after forming L type high pass filter by C3 and R10, the desirable 1.0uF of the C3 in the high pass filter wherein, and between the desirable 270k Ω of R10-330k Ω, optimum is got 300k Ω.This part is mainly cut off the polarization potential that has been placed to, the time constant unsuitable excessive, otherwise signal is too slow.
This device passes through the actual use of " multi-functional electrocardio comprehensive tester ", " remote ecg telephone transmission system ", its anti-interference, reliability, and stability, very good etc. effect, all reached the requirement and the purpose of expecting.
Claims (4)
1, has the high electrocardio testing circuit that suppresses the noise ability, which comprises at least core signal sensor, the measuring amplifier that the lead-out wire shielded cable of core signal sensor and three discharge circuits constitute, wherein the in-phase input end of measuring amplifier first amplifier that constitutes with three discharge circuits respectively of two of lead-out wire shielded cable holding wires and the in-phase input end of second amplifier are electrically connected, the output of first amplifier is electrically connected with the in-phase end and the end of oppisite phase of the 3rd amplifier respectively with the output of second amplifier, carry out electrocardiosignal by the 3rd amplifier and amplify output, first amplifier's inverting input and second amplifier's inverting input are amplified network by resistor network and outfan formation separately respectively, it is characterized in that: resistance in the resistor network of first amplifier's inverting input is electrically connected with a resistance in the second amplifier's inverting input network, its electric connection point is input to the in-phase end with the 4th amplifier, the 4th amplifier is a voltage follower, the output of voltage follower is electrically connected with the shielding end of above-mentioned lead-out wire shielded cable, its junction point enters the 5th amplifier input terminal, by the signal end of the 5th amplifier output as electrocardiosignal.
2, the electrocardio testing circuit with high inhibition noise ability according to claim 1, it is characterized in that: the output of described third level amplifier enters the electrocardiosignal treatment circuit after forming L type high pass filter by C3 and R10, the desirable 1.0uF of the C3 in the high pass filter wherein, between the desirable 270k Ω of R10-330k Ω, optimum is got 300k Ω.
3, the electrocardio testing circuit with high inhibition noise ability according to claim 1, it is characterized in that: the output of described first amplifier is input to third level amplifier's inverting input by resistance R 5, and the output of second amplifier is input to the in-phase input end of third level amplifier by resistance R 6; Third level amplifier's inverting input and outfan and connecting resistance R7 and capacitor C 2; Between the in-phase input end of third level amplifier and the ground and connecting resistance R9 and capacitor C 1.
4, the electrocardio testing circuit with high inhibition noise ability according to claim 3, it is characterized in that: the optional precision of described third level amplifier is low floats the type operational amplifier, and R7 and R9 get 20k Ω, C1 and C2 gets 100pF.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200620078990 CN2912512Y (en) | 2006-05-17 | 2006-05-17 | ECG detection circuit with excellent noise suppressing function |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200620078990 CN2912512Y (en) | 2006-05-17 | 2006-05-17 | ECG detection circuit with excellent noise suppressing function |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN2912512Y true CN2912512Y (en) | 2007-06-20 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 200620078990 Expired - Fee Related CN2912512Y (en) | 2006-05-17 | 2006-05-17 | ECG detection circuit with excellent noise suppressing function |
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| CN (1) | CN2912512Y (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102499671A (en) * | 2011-11-28 | 2012-06-20 | 中国科学技术大学 | Ventricular repolarization high-frequency wave double-limb electrode detecting device |
| CN103796580A (en) * | 2011-09-21 | 2014-05-14 | 索尼公司 | Biological signal measuring device |
| CN104622460A (en) * | 2014-12-31 | 2015-05-20 | 北京瀚景锦河科技有限公司 | ECG signal collecting device |
| CN108186010A (en) * | 2018-03-02 | 2018-06-22 | 南京大学 | A kind of active electrode for electro-physiological signals detection |
| CN111387972A (en) * | 2020-04-20 | 2020-07-10 | 广州易风健康科技股份有限公司 | Weak current signal acquisition circuit and have this acquisition circuit's seat circle and toilet lid |
-
2006
- 2006-05-17 CN CN 200620078990 patent/CN2912512Y/en not_active Expired - Fee Related
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103796580A (en) * | 2011-09-21 | 2014-05-14 | 索尼公司 | Biological signal measuring device |
| CN103796580B (en) * | 2011-09-21 | 2016-03-16 | 索尼公司 | Biological signal measuring device |
| CN102499671A (en) * | 2011-11-28 | 2012-06-20 | 中国科学技术大学 | Ventricular repolarization high-frequency wave double-limb electrode detecting device |
| CN102499671B (en) * | 2011-11-28 | 2013-11-06 | 中国科学技术大学 | Ventricular repolarization high-frequency wave double-limb electrode detecting device |
| CN104622460A (en) * | 2014-12-31 | 2015-05-20 | 北京瀚景锦河科技有限公司 | ECG signal collecting device |
| CN108186010A (en) * | 2018-03-02 | 2018-06-22 | 南京大学 | A kind of active electrode for electro-physiological signals detection |
| CN111387972A (en) * | 2020-04-20 | 2020-07-10 | 广州易风健康科技股份有限公司 | Weak current signal acquisition circuit and have this acquisition circuit's seat circle and toilet lid |
| CN111387972B (en) * | 2020-04-20 | 2023-10-31 | 广州易风健康科技股份有限公司 | Weak current signal acquisition circuit and seat ring and toilet cover with same |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |