TWI752867B - Circuitry of a biopotential acquisition system - Google Patents
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Abstract
Description
本發明涉及一種電子電路,更具體地,涉及一種用於生物電勢採集系統的電路。 The present invention relates to an electronic circuit, and more particularly, to a circuit for a biopotential acquisition system.
常規醫療設備通常使用大的乾電極(dry electrode)或濕電極(wet electrode)來測量生理信號(physiological signal),以獲得諸如生物阻抗(bio-impedance)或心電圖等的生理特徵。近來,諸如可擕式/可穿戴式醫療設備之類的個人生物感測器,因其能夠隨時提供生理資訊便於使用者參考而變得流行。考慮到這些可擕式醫療設備的使用和設計,較小的乾電極更為合適。但是,較小的乾電極意味著較差的電極阻抗,而較差的電極阻抗(即,較大的電極阻抗)可能會導致心電圖(electrocardiography,ECG)信號的檢測錯誤。此外,由於電極組織阻抗(electrode-tissue impedance,ETI)可能會因接觸因數(contact factors)或運動偽影(motion artifact)而發生很大變化,因此這增加了測量ECG信號的難度。 Conventional medical devices typically use large dry electrodes or wet electrodes to measure physiological signals to obtain physiological characteristics such as bio-impedance or electrocardiograms. Recently, personal biosensors such as portable/wearable medical devices have become popular because they can provide physiological information at any time for user reference. Given the use and design of these portable medical devices, smaller dry electrodes are more suitable. However, smaller dry electrodes mean poor electrode impedance, and poor electrode impedance (ie, larger electrode impedance) may lead to false detection of electrocardiography (ECG) signals. Furthermore, this adds to the difficulty of measuring ECG signals since electrode-tissue impedance (ETI) can vary greatly due to contact factors or motion artifacts.
為了解決乾電極應用中的ECG信號問題,還檢測ETI以減少ECG信號中的運動偽影。在傳統技術中,將用於ETI測量的電流注入到電極中,並且ETI接收器檢測電極上的電壓以確定ETI。然而,傳統技術中將電流注入到電極中可 能會在電極引發額外的雜訊,從而導致ECG信號的檢測誤差。另外,由於具有較低阻抗的電流產生器連接至電極,所以ECG信號的強度可能受到影響,並且ECG信號的輸入範圍變窄。 To address ECG signal issues in dry electrode applications, ETI is also detected to reduce motion artifacts in ECG signals. In conventional techniques, the current used for ETI measurement is injected into the electrodes, and the ETI receiver detects the voltage on the electrodes to determine the ETI. However, the injection of current into the electrodes in conventional techniques can It can induce additional noise at the electrodes, resulting in errors in the detection of the ECG signal. In addition, since the current generator with lower impedance is connected to the electrode, the strength of the ECG signal may be affected, and the input range of the ECG signal is narrowed.
因此,本發明的目的是提供一種生物電勢採集系統,其可以在測量ETI的同時準確地測量ECG信號,以解決上述問題。 Therefore, an object of the present invention is to provide a biopotential acquisition system that can accurately measure ECG signals while measuring ETI, so as to solve the above-mentioned problems.
根據本發明的一個實施例,提供了一種生物電勢採集系統的電路。該電路包括輸入節點、ETI發送器、電容器和ETI接收器。輸入節點被配置為從生物電勢採集系統的電極接收輸入信號。ETI發送器被配置為產生發送器信號。電容器的第一節點耦接到ETI發送器,電容器的第二節點耦接到輸入節點。ETI接收器耦接到輸入節點,被配置為經由電容器接收發送器信號以產生ETI。 According to an embodiment of the present invention, a circuit of a biopotential acquisition system is provided. The circuit includes an input node, an ETI transmitter, a capacitor, and an ETI receiver. The input node is configured to receive input signals from electrodes of the biopotential acquisition system. The ETI transmitter is configured to generate transmitter signals. A first node of the capacitor is coupled to the ETI transmitter, and a second node of the capacitor is coupled to the input node. The ETI receiver is coupled to the input node and is configured to receive the transmitter signal via the capacitor to generate the ETI.
在本發明的生物電勢採集系統中,通過在ETI發送器和生物電勢採集系統的輸入節點之間設計電容器,在測量ETI時不會影響到ECG信號的測量。因此,生物電勢採集系統可以同時準確地測量ECG信號和ETI。 In the biopotential acquisition system of the present invention, by designing a capacitor between the ETI transmitter and the input node of the biopotential acquisition system, the measurement of the ECG signal will not be affected when the ETI is measured. Therefore, the biopotential acquisition system can accurately measure ECG signal and ETI simultaneously.
在閱讀了在各個附圖和附圖中示出的優選實施例的以下詳細描述之後,本發明的這些和其他目的無疑對於本領域的習知技藝者將變得顯而易見。 These and other objects of the present invention will no doubt become apparent to those skilled in the art after reading the various drawings and the following detailed description of the preferred embodiments shown in the accompanying drawings.
100:生物電勢採集系統 100: Biopotential Acquisition System
102,104:電極 102,104: Electrodes
110:ETI發送器 110: ETI transmitter
120:ECG接收器 120: ECG receiver
130:ETI接收器 130: ETI receiver
112:DAC 112:DAC
114:濾波器 114: Filter
122:低雜訊放大器 122: Low Noise Amplifier
124:低通濾波器 124: low pass filter
126:ADC 126: ADC
132_1:第一放大器 132_1: First amplifier
132_2:第二放大器 132_2: Second amplifier
134_1:第一低通濾波器 134_1: first low pass filter
134_2:第二低通濾波器 134_2: Second low pass filter
136:多工器 136: Multiplexer
138:ADC 138: ADC
202_1~202_N,204_1~204_N:電流源 202_1~202_N, 204_1~204_N: Current source
SW1_1~SW1_N,SW2_1~SW2_N:開關 SW1_1~SW1_N, SW2_1~SW2_N: switch
C11_1~C11_N,C12_1~C12_N:電容器 C11_1~C11_N, C12_1~C12_N: capacitors
R11_1~R11_N,R12_1~R12_N:電阻器 R11_1~R11_N, R12_1~R12_N: Resistors
在附圖的圖中,通過示例而非限制的方式示出了本發明,在附圖中,相似的附 圖標記指示相似的元件。當結合某實施例描述特定的特徵、結構或特性時,應當認為,結合其他實施例來實現這樣的特徵、結構或特性屬於本領域習知技藝者的知識範圍,不論是否沒有明確指示。 The invention is shown by way of example and not limitation in the figures of the accompanying drawings, in which similar figures are attached. Symbols indicate similar elements. When a particular feature, structure or characteristic is described in connection with one embodiment, it should be considered that it is within the knowledge of those skilled in the art to implement such feature, structure or characteristic in connection with other embodiments, whether or not expressly indicated.
第1圖是示出根據本發明的一個實施例的生物電勢採集系統的示意圖。 FIG. 1 is a schematic diagram illustrating a biopotential acquisition system according to an embodiment of the present invention.
第2圖示出了根據本發明的一個實施例的電流DAC。 Figure 2 shows a current DAC according to one embodiment of the present invention.
第3圖示出了根據本發明的一個實施例的電容器DAC。 Figure 3 shows a capacitor DAC according to one embodiment of the present invention.
第4圖示出了根據本發明的一個實施例的電阻器DAC。 Figure 4 shows a resistor DAC according to one embodiment of the present invention.
第5圖是示出根據本發明的一個實施例的濾波器的示意圖。 FIG. 5 is a schematic diagram illustrating a filter according to one embodiment of the present invention.
第6圖是示出根據本發明的另一實施例的濾波器的示意圖。 FIG. 6 is a schematic diagram illustrating a filter according to another embodiment of the present invention.
在說明書及申請專利範圍當中使用了某些詞彙來指稱特定的元件。本領域習知技藝者應可理解,電子設備製造商可以會用不同的名詞來稱呼同一元件。本說明書及申請專利範圍並不以名稱的差異來作為區別元件的方式,而是以元件在功能上的差異來作為區別的基準。在通篇說明書及後續的申請專利範圍當中所提及的“包含”是開放式的用語,故應解釋成“包含但不限定於”。此外,“耦接”一詞在此是包含任何直接及間接的電氣連接手段。因此,若文中描述第一裝置電性連接於第二裝置,則代表該第一裝置可直接連接於該第二裝置,或通過其他裝置或連接手段間接地連接至該第二裝置。 Certain terms are used throughout the specification and claims to refer to particular elements. It should be understood by those skilled in the art that electronic device manufacturers may refer to the same element by different nouns. This specification and the scope of the patent application do not use the difference in name as a way to distinguish elements, but use the difference in function of the elements as a basis for differentiation. The "comprising" mentioned in the entire specification and the subsequent scope of the patent application is an open-ended term, so it should be interpreted as "including but not limited to". Furthermore, the term "coupled" herein includes any means of direct and indirect electrical connection. Therefore, if it is described herein that the first device is electrically connected to the second device, it means that the first device can be directly connected to the second device or indirectly connected to the second device through other devices or connecting means.
第1圖是示出根據本發明的一個實施例的生物電勢(biopotential)採集系統(acquisition system)100的示意圖。如第1圖所示,生物電勢採集系統100是具有兩個電極102和104的兩電極生物電勢採集系統,電極102和104用於連接到右側身體(例如,右手)和左側身體(例如,左手),以獲得人體的生物電勢
信號,生物電勢採集系統100可以處理和分析生物電勢信號,以確定諸如心電圖(ECG)信號之類的生理信號,並且生理特徵可以顯示在生物電勢採集系統100的螢幕上。在此實施例中,生物電勢採集系統100可以內置在任何可擕式電子設備或可穿戴電子設備中。
FIG. 1 is a schematic diagram illustrating a
生物電勢採集系統100包括ETI發送器110、ECG接收器120和ETI接收器130,其中ETI發送器110包括數位類比轉換器(digital-to-analog converter,DAC)112和濾波器114;ECG接收器120包括低雜訊放大器122、低通濾波器(low-pass filter,LPF)124和類比數位轉換器(analog-to-digital converter,ADC)126;ETI接收器130包括具有混頻器的第一放大器132_1、具有混頻器的第二放大器132_2、第一低通濾波器134_1、第二低通濾波器134_2、多工器(MUX)136和ADC 138。此外,生物電勢採集系統100還包括第一電容器C1和第二電容器C2,其中第一電容器C1的第一節點耦接到濾波器114,第一電容器C1的第二節點耦接到生物電勢採集系統100的一個輸入節點(即,第二節點耦接至電極104和低雜訊放大器122的負輸入端子);第二電容器C2的第一節點耦接到濾波器114,第二電容器C2的第二節點耦接到生物電勢採集系統100的另一個輸入節點(即,第二節點耦接到電極102和低雜訊放大器122的正輸入端子)。
The
當電極102和104連接到人體時,形成ETI,使得生物電勢採集系統100可以具有較大的輸入阻抗,並且由於接觸因數或運動偽影,輸入阻抗可能會發生很大變化。在第1圖所示的實施例中,電極102/104的ETI阻抗被建模為並聯連接的電阻器REL和電容器CEL。在生物電勢採集系統100的操作中,當電極102和104與人體接觸並且生物電勢採集系統100開始測量ECG信號時,ECG接收器120的低雜訊放大器122開始從電極102和104接收信號VIP和VIN(生物電勢信號),以產
生放大的信號,並且該放大的信號由低通濾波器124和ADC 126處理,以確定諸如ECG信號的生理資訊。此時,由於運動偽影,輸入阻抗(即,REL和CEL)可能會發生很大變化,因此ECG信號可能不準確。因此,為了解決ETI問題,同時,控制ETI發送器110和ETI接收器130以確定ETI,以使生物電勢採集系統100將運動偽影問題通知給用戶或者調整/補償ECG接收器120產生的ECG信號。
When
關於ETI發送器110的操作,DAC 112接收數位的ETI輸入信號Din以生成類比的ETI輸入信號,其中DAC 112可以由任何合適的DAC來實現,例如電流DAC、電容器DAC或電阻器DAC。第2圖示出了根據本發明的一個實施例的電流DAC,其中,電流DAC包括多個電流源202_1至202_N和多個電流源204_1至204_N,多個電流源202_1至202_N經由多個開關SW1_1至SW1_N選擇性地連接到DAC 112的輸出節點NDAC,並且多個電流源204_1至204_N經由多個開關SW2_1至SW2_N選擇性地連接至DAC 112的輸出節點NDAC。第3圖示出了根據本發明的一個實施例的電容器DAC,其中電容器DAC包括多個電容器C11_1至C11_N和多個電容器C12_1至C12_N,多個電容器C11_1至C11_N經由多個開關SW1_1至SW1_N選擇性地連接至DAC 112的輸出節點NDAC,多個電容器C12_1至C12_N經由多個開關SW2_1至SW2_N選擇性地連接至DAC 112的輸出節點NDAC。第4圖示出了根據本發明的一個實施例的電阻器DAC,其中,該電阻器DAC包括多個電阻器R11_1至R11_N和多個電阻器R12_1至R12_N,多個電阻器R11_1至R11_N經由多個開關SW1_1至SW1_N選擇性地連接至DAC 112的輸出節點NDAC,多個電阻器R12_1至R12_N經由多個開關SW2_1至SW2_N選擇性地連接至DAC 112的輸出節點NDAC。
Regarding the operation of the
在該實施例中,由ETI發送器110生成的發送器信號的頻率高於ECG
信號。例如,ECG信號頻率可以低於幾百赫茲,但是由ETI發送器110生成的發送器信號可以是幾千赫茲。
In this embodiment, the frequency of the transmitter signal generated by the
接著參考第1圖,濾波器114對類比的ETI輸入信號進行濾波以去除諧波(harmonic tones),以生成發送器信號。第5圖是示出根據本發明的一個實施例的濾波器114的示意圖。如第5圖所示,濾波器114包括連接至DAC 112的第一輸出節點的電容器CF1和電阻器RF1,並且濾波器114還包括連接至DAC 112的第二輸出節點(舉例而言,DAC 112具有差分的輸出信號時,可以具有第一輸出節點和第二輸出節點)的電容器CF2和電阻器RF2。在第5圖所示的實施例,如果DAC 112是由電流DAC實現,則電容器CF1和CF2用於去除發送器信號的高階諧波,並且電阻器RF1和RF2用於將電流信號轉換為電壓信號。第6圖是示出根據本發明的另一實施例的濾波器114的示意圖。如第6圖所示,濾波器114是有源濾波器,其包括輸入電阻器RF4、回饋電阻器RF3、回饋電容器CF和放大器610,其中輸入電阻器RF4連接在DAC 112和放大器610的輸入端之間,並且回饋電阻器RF3和回饋電容器CF並聯耦接在放大器610的輸入端和輸出端之間。
Referring next to FIG. 1, a
接著,經過濾波的發送器信號在經過電容器C1和C2之後由ETI接收器130接收。然後,ETI接收器130接收濾波後的發送器信號以生成ETI。具體地,ETI接收器130包括同相路徑和正交路徑,同相路徑包括具有混頻器的第一放大器132_1和第一低通濾波器134_1,正交路徑包括具有混頻器的第二放大器132_2和第二低通濾波器134_2。具有混頻器的第一放大器132_1被配置為將發送器信號與振盪信號混頻以生成第一混頻信號(低頻或DC),然後低通濾波器134_1對第一混頻信號進行濾波以生成第一濾波信號。具有混頻器的第二放大器132_2被配置為將發送器信號與振盪信號混頻以生成第二混頻信號(低頻或DC),然後低
通濾波器134_2對第二混頻信號進行濾波以生成第二濾波信號。然後,第一濾波信號和第二濾波信號被多工器136和ADC 138處理以生成ETI。另外,由於ETI接收器130的操作是本領域習知技藝者已知的,並且本發明著重於ETI發送器110、第一電容器C1和第二電容器C2,因此這裡省略了對ETI接收器130的詳細描述。
Next, the filtered transmitter signal is received by the
設計在生物電勢採集系統100的輸入節點和ETI發送器110之間的第一電容器C1和第二電容器C2,可以使得ECG的測量將更加準確,並且輸入信號VIP和VIN的輸入範圍不會變窄。具體地,因為第一電容器C1和第二電容器C2在較低頻率下具有大電容,所以由DAC 112產生的低頻雜訊的僅一小部分被傳送到生物電勢採集系統100的輸入節點,即,輸入信號VIP和VIN僅受DAC 112產生的低頻雜訊的較小影響。此外,由於第一電容器C1和第二電容器C2在較低頻率下具有大電容,因此ECG接收器120的輸入阻抗(高阻抗)將不會因ETI發送器110而受到影響。另外,由於第一電容器C1和第二電容器C2在較高頻率下具有較小的電容,因此可以將濾波後的發送器信號發送到ETI接收器130而不會遭受過多損耗。此外,因為生物電勢採集系統100的輸入節點連接到第一電容器C1和第二電容器C2,所以輸入信號VIP和VIN具有軌到軌範圍(rail-to-rail range),即,生物電勢採集系統100的輸入範圍將不受影響。
Designing the first capacitor C1 and the second capacitor C2 between the input node of the
簡要地概述,在本發明的生物電勢採集系統中,通過在ETI發送器和生物電勢採集系統的輸入節點之間設計電容器,在測量ETI時不會影響到ECG信號的測量。因此,生物電勢採集系統可以同時準確地測量ECG信號和ETI。 In brief overview, in the biopotential acquisition system of the present invention, by designing a capacitor between the ETI transmitter and the input node of the biopotential acquisition system, the measurement of the ECG signal is not affected when ETI is measured. Therefore, the biopotential acquisition system can accurately measure ECG signal and ETI simultaneously.
本領域習知技藝者將容易地認識到,在保持本發明的教導的同時,可以對裝置和方法進行多種修改和變更。因此,以上公開內容應被解釋為僅由所附申請專利範圍的界限來限定。 Those skilled in the art will readily recognize that various modifications and variations can be made in the apparatus and method while maintaining the teachings of the present invention. Accordingly, the above disclosure should be construed as being limited only by the limits of the scope of the appended claims.
以上所述僅為本發明之較佳實施例,凡依本發明申請專利範圍所做之均等變化與修飾,皆應屬本發明之涵蓋範圍。 The above descriptions are only preferred embodiments of the present invention, and all equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope of the present invention.
100:生物電勢採集系統 100: Biopotential Acquisition System
102,104:電極 102,104: Electrodes
110:ETI發送器 110: ETI transmitter
120:ECG接收器 120: ECG receiver
130:ETI接收器 130: ETI receiver
112:DAC 112:DAC
114:濾波器 114: Filter
122:低雜訊放大器 122: Low Noise Amplifier
124:低通濾波器 124: low pass filter
126:ADC 126: ADC
132_1:第一放大器 132_1: First amplifier
132_2:第二放大器 132_2: Second amplifier
134_1:第一低通濾波器 134_1: first low pass filter
134_2:第二低通濾波器 134_2: Second low pass filter
136:多工器 136: Multiplexer
138:ADC 138: ADC
Claims (10)
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US17/219,910 US11937947B2 (en) | 2020-04-24 | 2021-04-01 | Low-noise biopotential acquisition system for dry electrode application |
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CN104825154A (en) * | 2014-02-06 | 2015-08-12 | Imec非营利协会 | System and method for acquisition of biopotential signals with motion artifact reduction in real time operation |
TW202023474A (en) * | 2018-11-23 | 2020-07-01 | 聯發科技股份有限公司 | Circuit applied to biopotential acquisition system |
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