CN203935184U - A kind of electrocardiosignal pre-amplification circuit - Google Patents
A kind of electrocardiosignal pre-amplification circuit Download PDFInfo
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- CN203935184U CN203935184U CN201420222485.4U CN201420222485U CN203935184U CN 203935184 U CN203935184 U CN 203935184U CN 201420222485 U CN201420222485 U CN 201420222485U CN 203935184 U CN203935184 U CN 203935184U
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Abstract
An electrocardiosignal pre-amplification circuit, is characterized in that, comprises the differential amplifier circuit of both-end input, both-end output, common mode sampling drive circuit, and resaistance-capacity coupling circuit, and both-end is inputted, the differential amplifier circuit of Single-end output; The double input end of the differential amplifier circuit of described both-end input, both-end output is connected with organism contact electrode, and double input end is connected with the double input end of the differential amplifier circuit of both-end input, Single-end output with resaistance-capacity coupling circuit through common mode sampling drive circuit successively.The preamplifier circuit that this utility model adopts is simple in structure, can be in the situation that suppressing direct current interference, high common mode rejection ratio is provided, it has high input impedance, can suppress the interference of organism electrocardiosignal, there is high-gain and low drift, insensitive to direct current signal, the high-acruracy survey of especially applicable electro-physiological signals.
Description
Technical field
This utility model relates to signal processing and amplifying technical field, specifically a kind of electrocardiosignal pre-amplification circuit.
Background technology
Electrocardiosignal is a kind of typical physiology signal, has the universals of bioelectrical signals, and fainter, amplitude is greatly about 0.1mV to 5mV.Electrocardiosignal is ultra-low frequency signal, and frequency range is about 0.05Hz to 100Hz; Electrocardiosignal is conventionally with strong noise jamming, mainly contain the 50Hz power frequency interference that external communication electric power system causes, the interference that inner electromyographic signal, respiratory wave signal, EEG signals etc. cause, ecg signal amplifier electrode contacts the interference of the polarizing voltage (polarizing voltage shows as unsettled direct current signal, and amplitude can reach 300mV) producing etc. with organism; Electrocardiosignal is high impedance signal source, and impedance is from thousands of Europe to hundreds of kilo-ohms.
Because bioelectrical signals amplitude is little, frequency is low and be subject to external environmental interference, for gathering and measurement has brought difficulty, therefore electrocardiosignal pre-amplification circuit is had to following requirement:
(1) high input impedance, should be more than 1M Ω.
(2) adopt the differential amplifier circuit of high cmrr (CMRR), the interference of carrying to suppress organism electrocardiosignal.
(3) have higher gain and low drift, electrocardiosignal pre-amplification circuit voltage gain should have hundreds of times.
(4) insensitive to direct current signal, electrocardiosignal pre-amplification circuit should be an intrasonic AC signal amplifying circuit, to suppress polarizing voltage, disturbs.
Utility model content
For above-mentioned deficiency, this utility model provides a kind of electrocardiosignal pre-amplification circuit, has high input impedance, can suppress the interference of organism electrocardiosignal, has high-gain and low drift, insensitive to direct current signal.
This utility model solves the technical scheme that its technical problem adopts: a kind of electrocardiosignal pre-amplification circuit, it is characterized in that, the differential amplifier circuit that comprises both-end input, both-end output, common mode sampling drive circuit, resaistance-capacity coupling circuit, and both-end is inputted, the differential amplifier circuit of Single-end output; The double input end of the differential amplifier circuit of described both-end input, both-end output is connected with organism contact electrode, and double input end is connected with the double input end of the differential amplifier circuit of both-end input, Single-end output with resaistance-capacity coupling circuit through common mode sampling drive circuit successively.
Further, the differential amplifier circuit of both-end input described in the utility model, both-end output comprises the first operational amplifier U1, the second operational amplifier U2, resistance R 1, resistance R 2 and resistance R 3, described common mode sampling drive circuit comprises the 3rd operational amplifier U3, resistance R 4 and resistance R 5, described resaistance-capacity coupling circuit comprises capacitor C 1, capacitor C 2, resistance R 6 and resistance R 7, and the differential amplifier circuit of described both-end input, Single-end output comprises instrument amplifier A1 and varistor R8; The positive input of described the first operational amplifier U1 and the second operational amplifier U2 is connected with organism contact electrode respectively, series resistance R3 between reverse input end, difference series resistance R1 and resistance R 2 between the reverse input end of the first operational amplifier U1 and the second operational amplifier U2 and outfan; After the outfan series capacitance C1 of described the first operational amplifier U1, be connected with the reverse input end of instrument amplifier A1, after the outfan series capacitance C2 of described the second operational amplifier U2, be connected with the positive input of instrument amplifier A1; The positive input of described the 3rd operational amplifier U3 is connected with the outfan of the second operational amplifier U2 with the first operational amplifier U1 with resistance R 5 through resistance R 4 respectively, inverting input is connected with outfan, and outfan is connected with positive input with the reverse input end of instrument amplifier A1 with resistance R 7 through resistance R 6 respectively; Described varistor R8 is the external gain-adjusted resistance of instrument amplifier A1.
Preferably, the first operational amplifier U1 described in the utility model, the second operational amplifier U2 and the 3rd operational amplifier U3 all adopt OP07CS chip.
Preferably, instrument amplifier A1 described in the utility model adopts AD620 amplifier.
The utlity model has following outstanding beneficial effect: the differential amplifier circuit of the input of this utility model both-end, both-end output adopts the parallel connection type double operational instrumentation amplifier being comprised of two OP07CS chips, the advantage of parallel connection type double operational instrumentation amplifier is not need accurate build-out resistor, its common mode rejection ratio is infinitely great in theory, and the matching degree of resistance peripheral with it is irrelevant.But parallel connection type double operational instrumentation amplifier is output as both-end differential output signal, if will no longer there is this advantage during only with Single-end output signal, so the differential amplifier circuit of both-end input, Single-end output adopts integrated instrumentation amplifier AD620, and both-end differential output signal is converted to conventional Single-end output signal.Integrated instrumentation amplifier has better performance, but because its common mode rejection ratio is proportional to difference mode gain, and simultaneously there is higher offset voltage and conventionally have larger DC offset voltage (polarizing voltage when detected electro-physiological signals and the zero migration voltage in sensor) in signal source in device, when directly application integration instrumentation amplifier is as preamplifier, do not obtain the highest common mode rejection ratio performance, so this utility model is being used integrated instrumentation amplifier and is adopting resaistance-capacity coupling circuit isolated DC signal, thereby can make integrated instrumentation amplifier obtain higher difference mode gain, thereby obtain very high common mode rejection ratio performance.Common mode sampling drive circuit makes common-mode signal without the dividing potential drop of resaistance-capacity coupling circuit, directly be added in the input of integrated amplifier, has avoided not mating due to resaistance-capacity coupling circuit the common mode rejection ratio that reduces circuit integral body.
The preamplifier circuit that this utility model adopts is simple in structure, can be in the situation that suppressing direct current interference, high common mode rejection ratio is provided, it has high input impedance, can suppress the interference of organism electrocardiosignal, there is high-gain and low drift, insensitive to direct current signal, the high-acruracy survey of especially applicable electro-physiological signals.
Accompanying drawing explanation
Below in conjunction with accompanying drawing, the utility model is described in further detail:
Fig. 1 is theory diagram of the present utility model;
Fig. 2 is circuit theory diagrams of the present utility model.
The specific embodiment
As shown in Figure 1, a kind of electrocardiosignal pre-amplification circuit of the present utility model, it comprises the differential amplifier circuit of both-end input, both-end output, common mode sampling drive circuit, resaistance-capacity coupling circuit, and both-end is inputted, the differential amplifier circuit of Single-end output; The double input end of the differential amplifier circuit of described both-end input, both-end output is connected with organism contact electrode, and double input end is connected with the double input end of the differential amplifier circuit of both-end input, Single-end output with resaistance-capacity coupling circuit through common mode sampling drive circuit successively.
Further, as shown in Figure 2, the differential amplifier circuit of both-end input described in the utility model, both-end output comprises the first operational amplifier U1, the second operational amplifier U2, resistance R 1, resistance R 2 and resistance R 3, described common mode sampling drive circuit comprises the 3rd operational amplifier U3, resistance R 4 and resistance R 5, described resaistance-capacity coupling circuit comprises capacitor C 1, capacitor C 2, resistance R 6 and resistance R 7, and the differential amplifier circuit of described both-end input, Single-end output comprises instrument amplifier A1 and varistor R8; The positive input of described the first operational amplifier U1 and the second operational amplifier U2 is connected with organism contact electrode respectively, series resistance R3 between reverse input end, difference series resistance R1 and resistance R 2 between the reverse input end of the first operational amplifier U1 and the second operational amplifier U2 and outfan; After the outfan series capacitance C1 of described the first operational amplifier U1, be connected with the reverse input end of instrument amplifier A1, after the outfan series capacitance C2 of described the second operational amplifier U2, be connected with the positive input of instrument amplifier A1; The positive input of described the 3rd operational amplifier U3 is connected with the outfan of the second operational amplifier U2 with the first operational amplifier U1 with resistance R 5 through resistance R 4 respectively, inverting input is connected with outfan, and outfan is connected with positive input with the reverse input end of instrument amplifier A1 with resistance R 7 through resistance R 6 respectively; Described varistor R8 is the external gain-adjusted resistance of instrument amplifier A1.Wherein, the first described operational amplifier U1, the second operational amplifier U2 and the 3rd operational amplifier U3 all adopt OP07CS chip, and described instrument amplifier A1 adopts AD620 amplifier.
The differential amplifier circuit of the input of this utility model both-end, both-end output adopts the parallel connection type double operational instrumentation amplifier being comprised of two OP07CS chips, the advantage of parallel connection type double operational instrumentation amplifier is not need accurate build-out resistor, its common mode rejection ratio is infinitely great in theory, and the matching degree of resistance peripheral with it is irrelevant.But parallel connection type double operational instrumentation amplifier is output as both-end differential output signal, if will no longer there is this advantage during only with Single-end output signal, so the differential amplifier circuit of both-end input, Single-end output adopts integrated instrumentation amplifier AD620, and both-end differential output signal is converted to conventional Single-end output signal.Integrated instrumentation amplifier has better performance, but because its common mode rejection ratio is proportional to difference mode gain, and simultaneously there is higher offset voltage and conventionally have larger DC offset voltage (polarizing voltage when detected electro-physiological signals and the zero migration voltage in sensor) in signal source in device, when directly application integration instrumentation amplifier is as preamplifier, do not obtain the highest common mode rejection ratio performance, so this utility model is being used integrated instrumentation amplifier and is adopting resaistance-capacity coupling circuit isolated DC signal, thereby can make integrated instrumentation amplifier obtain higher difference mode gain, thereby obtain very high common mode rejection ratio performance.Common mode sampling drive circuit makes common-mode signal without the dividing potential drop of resaistance-capacity coupling circuit, directly be added in the input of integrated amplifier, has avoided not mating due to resaistance-capacity coupling circuit the common mode rejection ratio that reduces circuit integral body.
It should be noted that illustrated parts are not necessarily drawn in proportion in the accompanying drawings.This utility model has omitted the description of known assemblies and treatment technology and technique to avoid unnecessarily limiting this utility model.
The above is preferred implementation of the present utility model; for those skilled in the art; not departing under the prerequisite of this utility model principle, can also make some improvements and modifications, these improvements and modifications are also regarded as protection domain of the present utility model.
Claims (4)
1. an electrocardiosignal pre-amplification circuit, is characterized in that, comprises the differential amplifier circuit of both-end input, both-end output, common mode sampling drive circuit, and resaistance-capacity coupling circuit, and both-end is inputted, the differential amplifier circuit of Single-end output; The double input end of the differential amplifier circuit of described both-end input, both-end output is connected with organism contact electrode, and double input end is connected with the double input end of the differential amplifier circuit of both-end input, Single-end output with resaistance-capacity coupling circuit through common mode sampling drive circuit successively.
2. a kind of electrocardiosignal pre-amplification circuit according to claim 1, it is characterized in that, the differential amplifier circuit of described both-end input, both-end output comprises the first operational amplifier U1, the second operational amplifier U2, resistance R 1, resistance R 2 and resistance R 3, described common mode sampling drive circuit comprises the 3rd operational amplifier U3, resistance R 4 and resistance R 5, described resaistance-capacity coupling circuit comprises capacitor C 1, capacitor C 2, resistance R 6 and resistance R 7, and the differential amplifier circuit of described both-end input, Single-end output comprises instrument amplifier A1 and varistor R8; The positive input of described the first operational amplifier U1 and the second operational amplifier U2 is connected with organism contact electrode respectively, series resistance R3 between reverse input end, difference series resistance R1 and resistance R 2 between the reverse input end of the first operational amplifier U1 and the second operational amplifier U2 and outfan; After the outfan series capacitance C1 of described the first operational amplifier U1, be connected with the reverse input end of instrument amplifier A1, after the outfan series capacitance C2 of described the second operational amplifier U2, be connected with the positive input of instrument amplifier A1; The positive input of described the 3rd operational amplifier U3 is connected with the outfan of the second operational amplifier U2 with the first operational amplifier U1 with resistance R 5 through resistance R 4 respectively, inverting input is connected with outfan, and outfan is connected with positive input with the reverse input end of instrument amplifier A1 with resistance R 7 through resistance R 6 respectively; Described varistor R8 is the external gain-adjusted resistance of instrument amplifier A1.
3. a kind of electrocardiosignal pre-amplification circuit according to claim 2, is characterized in that, the first described operational amplifier U1, the second operational amplifier U2 and the 3rd operational amplifier U3 all adopt OP07CS chip.
4. a kind of electrocardiosignal pre-amplification circuit according to claim 2, is characterized in that, described instrument amplifier A1 adopts AD620 amplifier.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420222485.4U CN203935184U (en) | 2014-05-04 | 2014-05-04 | A kind of electrocardiosignal pre-amplification circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420222485.4U CN203935184U (en) | 2014-05-04 | 2014-05-04 | A kind of electrocardiosignal pre-amplification circuit |
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| CN203935184U true CN203935184U (en) | 2014-11-12 |
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| CN201420222485.4U Expired - Fee Related CN203935184U (en) | 2014-05-04 | 2014-05-04 | A kind of electrocardiosignal pre-amplification circuit |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104000583A (en) * | 2014-05-04 | 2014-08-27 | 山东中医药大学 | Electrocardiosignal preamplifier circuit |
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2014
- 2014-05-04 CN CN201420222485.4U patent/CN203935184U/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104000583A (en) * | 2014-05-04 | 2014-08-27 | 山东中医药大学 | Electrocardiosignal preamplifier circuit |
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| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20141112 Termination date: 20180504 |