JPH0556942A - Direct-coupled electrocardiograph - Google Patents

Direct-coupled electrocardiograph

Info

Publication number
JPH0556942A
JPH0556942A JP3225473A JP22547391A JPH0556942A JP H0556942 A JPH0556942 A JP H0556942A JP 3225473 A JP3225473 A JP 3225473A JP 22547391 A JP22547391 A JP 22547391A JP H0556942 A JPH0556942 A JP H0556942A
Authority
JP
Japan
Prior art keywords
signal
amplifier
input
output
converter
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP3225473A
Other languages
Japanese (ja)
Inventor
Masaki Shiraishi
正樹 白石
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NEC Corp
Original Assignee
NEC Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by NEC Corp filed Critical NEC Corp
Priority to JP3225473A priority Critical patent/JPH0556942A/en
Publication of JPH0556942A publication Critical patent/JPH0556942A/en
Pending legal-status Critical Current

Links

Classifications

    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10Energy storage using batteries

Landscapes

  • Measurement And Recording Of Electrical Phenomena And Electrical Characteristics Of The Living Body (AREA)

Abstract

PURPOSE:To convert a living body signal to a signal which is scarcely fluctuated, and to fetch it as an electrocardiogram waveform which can be monitored easily and scarcely causes an analytic miss by providing a D/A converter for applying a fluctuation component of an input signal and a sample holding circuit in an inversion input of a correction amplifier. CONSTITUTION:When an input signal e1 is shifted large from a zero level of a base line due to a drift, etc., of a living body side, an output signal is not saturated, when an input range of a differential amplifier 1 is large enough. However, unless an input range of a main amplifier 2 is further widened, an output signal e2 is saturated. As an executable means for enlarging the input range, an analog signal e3 is selected by a multiplexer 3, subjected to A/D conversion, and thereafter, subjected to filtering processing by a data processing part and a base line fluctuation component of about DC-0.5Hz is extracted, and it is applied as a correction value e4 to the main amplifier 2 through a D/A converting part 6 and one piece of channel of a sample holding circuit 5. In such a way, a final correction output from which a fluctuation component of a low frequency is eliminated can be obtained.

Description

【発明の詳細な説明】Detailed Description of the Invention

【0001】[0001]

【産業上の利用分野】本発明は直結形心電計に関し、特
に基線変動を補正した直結形心電計に関する。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direct-coupled electrocardiograph, and more particularly to a direct-coupled electrocardiograph with baseline fluctuation corrected.

【0002】[0002]

【従来の技術】従来の技術による心電計の増幅器は、図
3に示すように前段の差動増幅器1と、主増幅器2との
間に0.05Hz以下の成分をカットする直列キャパシ
タCを有し、一方キャパシタCの電荷を短時間に放電さ
せるためのインストスイッチISWを有している。心電
信号の周波数帯域はDC〜100Hzと低周波域にあ
り、CRの時定数を例えば3.2秒というような大きな
値に設定する必要があるため、抵抗Rも数MΩと大きく
なり、バイアス電流の十分小さい高入力インピーダンス
の主増幅器2を使用している。
2. Description of the Related Art A conventional electrocardiograph amplifier includes a series capacitor C for cutting a component of 0.05 Hz or less between a differential amplifier 1 at a preceding stage and a main amplifier 2 as shown in FIG. On the other hand, it has an instrument switch ISW for discharging the electric charge of the capacitor C in a short time. Since the frequency band of the electrocardiographic signal is in the low frequency range of DC to 100 Hz and the time constant of CR needs to be set to a large value such as 3.2 seconds, the resistance R also increases to several MΩ and the bias A high input impedance main amplifier 2 with a sufficiently small current is used.

【0003】[0003]

【発明が解決しようとする課題】従来の心電計では、生
体で発生する分極電圧や体動による低域周波成分の変動
によって増幅器が飽和してしまわないように、前段の入
力増幅器11と、次段の主増幅器12との間に大きな値
のCR素子を挿入し、0.05Hz以下の低域成分をカ
ットした交流増幅器として動作させている。
In the conventional electrocardiograph, in order to prevent the amplifier from being saturated by the fluctuation of the low frequency component due to the polarization voltage or body movement generated in the living body, the input amplifier 11 in the preceding stage, A CR element having a large value is inserted between the main amplifier 12 in the next stage and the main amplifier 12 is operated as an AC amplifier in which a low frequency component of 0.05 Hz or less is cut.

【0004】そして、アーチファクト(外乱)により入
力信号の急激な変動に対し、出力信号レベルが基線位置
に復帰するのに6秒以上の時間を要すため、インストス
イッチISWを強制的にオンにして、ハイ・インピーダ
ンスの入力抵抗8を短絡し、キャパシタCの残留電荷を
急速放電させて出力波形を基線レベルに戻している。こ
のインストスイッチISWがオンの間、心電波形は出力
されず観測できない。また、0.05Hz〜数Hzの変
動分はそのまま出力され、主増幅器の入力レンジを越え
るような大きい変動に対しては、出力が飽和してしまう
問題があった。さらに、入力変動幅が大きく、200m
s以上に渡って継続する様なケースでは、インストスイ
ッチISWをオンにしても完全に零レベルには戻らず、
基線がCR(=3.2秒)の時定数で変動してしまうと
いう問題があった。
Since it takes 6 seconds or more for the output signal level to return to the base line position in response to a sudden change in the input signal due to an artifact (disturbance), the instrument switch ISW is forcibly turned on. , The high impedance input resistor 8 is short-circuited, the residual charge of the capacitor C is rapidly discharged, and the output waveform is returned to the baseline level. While the instrument switch ISW is on, the electrocardiographic waveform is not output and cannot be observed. Further, the fluctuation of 0.05 Hz to several Hz is output as it is, and there is a problem that the output is saturated for a large fluctuation exceeding the input range of the main amplifier. Furthermore, the input fluctuation range is large, 200 m
In the case of continuing for more than s, even if the instrument switch ISW is turned on, it does not completely return to the zero level,
There was a problem that the base line fluctuates with a time constant of CR (= 3.2 seconds).

【0005】[0005]

【課題を解決するための手段】本発明の直結形心電計
は、心電図信号を入力する前段の差動増幅器と、前記差
動増幅器の出力の変動成分を打ち消す補正用の主増幅器
と、前記主増幅器の出力を選択してA/D変換器へ送付
するマルチプレクサと、前記マルチプレクサの出力をデ
ィジタルデータに変換するA/D変換器と、前記A/D
変換器でディジタル化されたデータを演算するデータ処
理部と、前記処理部で処理された補正データを出力する
D/A変換器とこの出力を各々8CHの補正用主増幅器
の反転入力へ印加するサンプルホールド回路とを備えて
構成される。
A direct-coupled electrocardiograph according to the present invention comprises a differential amplifier at a front stage for inputting an electrocardiogram signal, a main amplifier for correction for canceling a fluctuation component of the output of the differential amplifier, and A multiplexer that selects the output of the main amplifier and sends it to the A / D converter; an A / D converter that converts the output of the multiplexer into digital data;
A data processing unit for calculating the data digitized by the converter, a D / A converter for outputting the correction data processed by the processing unit, and this output are applied to the inverting input of the correction main amplifier of 8CH, respectively. And a sample hold circuit.

【0006】[0006]

【実施例】次に本発明について図面を参照して説明す
る。
The present invention will be described below with reference to the drawings.

【0007】図1は本発明の一実施例のブロック図で、
各点の動作波形の様子を図3に示す。入力信号e1は、
生体側のドリフトまたは何らかのアーチファクトによ
り、基線の零レベルから大きく正または負の方向にシフ
トすると、増幅度A1を有する前段の差動増幅器1の出
力e2の変動はA1倍されて変動する。前段の入力レン
ジが十分大であれば出力信号は飽和することはないが、
2段目の主増幅器2の入力ダイナミックレンジをさらに
広くしておかねば、出力信号e2はすぐにも飽和してし
まう。実行的な入力ダイナミックレンジを拡大する手段
として、2段目の増幅器2の反転入力に低域のドリフト
成分と同等な信号を入力する。アナログ信号e3をマル
チプレクサ3で選択し、A/D変換後、データ処理部で
フィルタリング処理をしてDC〜0.5Hz程度の基線
変動成分を抽出し、その結果を補正値e4としてD/A
変換部6とサンプルホールド5の1個のチャネルを経由
して主増幅器2へ印加され、低周波の変動成分を除去し
た最終補正出力を得る。この時、データ処理部は0.5
ms以内で実行されるディジタルフィルタで構成され
る。
FIG. 1 is a block diagram of an embodiment of the present invention.
The state of the operation waveform at each point is shown in FIG. The input signal e1 is
When a shift from the zero level of the baseline to a large positive or negative direction is caused by a living body side drift or some artifact, the fluctuation of the output e2 of the differential amplifier 1 of the preceding stage having the amplification degree A1 is changed by being multiplied by A1. If the input range of the previous stage is large enough, the output signal will not be saturated,
If the input dynamic range of the second-stage main amplifier 2 is further widened, the output signal e2 will be saturated immediately. As a means for practically expanding the input dynamic range, a signal equivalent to a low frequency drift component is input to the inverting input of the second stage amplifier 2. The analog signal e3 is selected by the multiplexer 3 and, after A / D conversion, filtering processing is performed by the data processing unit to extract a baseline fluctuation component of about DC to 0.5 Hz, and the result is used as a correction value e4 for D / A.
It is applied to the main amplifier 2 via one channel of the conversion unit 6 and the sample and hold 5 to obtain the final corrected output from which the low frequency fluctuation component is removed. At this time, the data processing unit is 0.5
It consists of a digital filter that is executed within ms.

【0008】なお、サンプルホールド回路は、8チャネ
ルのホールドキャパシタCdと、サンプル/ホールドス
イッチSW1〜SW8と、これらスイッチをオン/オフ
コントロールするデコーダから構成され、D/A変換器
6の出力が各々のチャネルに分配されている。
The sample-hold circuit comprises an 8-channel hold capacitor Cd, sample / hold switches SW1 to SW8, and a decoder for on / off controlling these switches, and the outputs of the D / A converters 6 are respectively provided. Are distributed over the channels.

【0009】[0009]

【発明の効果】以上説明したように本発明は、前段差動
増幅器1の後段の補正増幅2の反転入力に、入力信号の
DC〜0.5Hz付近の変動成分を印加するためのD/
A変換器およびサンプルホールド回路と、データ処理部
7として、上記低周波成分のみを抽出するディジタルフ
ィルタを有しているので、心電図波形の様な分極成分お
よび基線変動のドリフト成分を含む生体信号を変動の少
い信号に変換して、モニタし易く解析ミスの少い心電波
形として取り出すことができる効果を有する。さらに前
段の差動増幅器1と2段目の補正用の主増幅器2との間
にDC分をカットするための大容量のキャパシタおよび
このキャパシタと組み合わせ、3.2秒以上の時定数を
有する入力抵抗がないため急激な変動に対し波形が基線
レベルに安定する迄の時間が瞬時(=4ms)におこな
われ、キャパシタに充電されている電荷を放電させるた
めのインストスイッチISW不要となり、入力部にハイ
・インピーダンスの増幅器を使用する必要がないため、
基板面のリークや部品素子のリークを考慮しなくて良
く、組立も簡単になる。また、信号は結合キャパシタを
直接通過せぬため、素子による波形歪が発生しないなど
の効果を有する。
As described above, according to the present invention, the D / s for applying the fluctuation component in the vicinity of DC to 0.5 Hz of the input signal to the inverting input of the correction amplification 2 at the rear stage of the front stage differential amplifier 1.
Since the A converter, the sample and hold circuit, and the data processing unit 7 have a digital filter for extracting only the low-frequency component, a biological signal including a polarization component such as an electrocardiogram waveform and a drift component of the baseline fluctuation can be obtained. It has an effect that it can be converted into a signal with little fluctuation and can be extracted as an electrocardiographic waveform that is easy to monitor and has few analysis errors. Further, a large-capacity capacitor for cutting DC component between the differential amplifier 1 in the previous stage and the main amplifier 2 for correction in the second stage and an input having a time constant of 3.2 seconds or more in combination with this capacitor Since there is no resistance, the time until the waveform stabilizes at the baseline level against an abrupt change is instantaneously (= 4 ms), and the instrument switch ISW for discharging the charge stored in the capacitor is no longer required, and the input section Since it is not necessary to use a high impedance amplifier,
It is not necessary to consider the leak of the board surface and the leak of the component element, and the assembly is easy. Further, since the signal does not directly pass through the coupling capacitor, there is an effect that waveform distortion due to the element does not occur.

【図面の簡単な説明】[Brief description of drawings]

【図1】本発明の一実施例の構成を示すブロック図。FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

【図2】図1に示すブロック図の各部の信号波形を示す
波形図。
FIG. 2 is a waveform diagram showing signal waveforms of respective parts of the block diagram shown in FIG.

【図3】従来の技術による心電計の増幅器の概要を示す
回路図。
FIG. 3 is a circuit diagram showing an outline of an electrocardiograph amplifier according to a conventional technique.

【符号の説明】[Explanation of symbols]

1 差動増幅器 2 主増幅器 3 マルチプレクサ 4 A/D変換器 5 サンプルホールド回路 6 D/A変換器 7 データ処理部 1 differential amplifier 2 main amplifier 3 multiplexer 4 A / D converter 5 sample and hold circuit 6 D / A converter 7 data processing unit

Claims (1)

【特許請求の範囲】[Claims] 【請求項1】 心電図信号を入力する初段の差動増幅器
と、前記差動増幅器の出力の変動成分を打ち消す補正用
の主増幅器と、前記主増幅器の出力を選択してA/D変
換器へ送付するマルチプレクサと、前記マルチプレクサ
の出力をディジタルデータに変換するA/D変換器と、
前記A/D変換器でディジタル化されたデータを演算す
るデータ処理部と、前記処理部で処理された補正データ
を出力するD/A変換器とこの出力を各々8CHの補正
用主増幅器の反転入力へ印加するサンプルホールド回路
とを備えて成ることを特徴とする直結形心電計。
1. A first-stage differential amplifier for inputting an electrocardiogram signal, a main amplifier for correction for canceling a fluctuation component of the output of the differential amplifier, and an output of the main amplifier are selected to an A / D converter. A multiplexer for sending, an A / D converter for converting the output of the multiplexer into digital data,
A data processing unit for calculating data digitized by the A / D converter, a D / A converter for outputting correction data processed by the processing unit, and an output of the D / A converter for inverting a main correction amplifier of 8CH. A direct-connection type electrocardiograph comprising a sample-hold circuit for applying to an input.
JP3225473A 1991-09-05 1991-09-05 Direct-coupled electrocardiograph Pending JPH0556942A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP3225473A JPH0556942A (en) 1991-09-05 1991-09-05 Direct-coupled electrocardiograph

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP3225473A JPH0556942A (en) 1991-09-05 1991-09-05 Direct-coupled electrocardiograph

Publications (1)

Publication Number Publication Date
JPH0556942A true JPH0556942A (en) 1993-03-09

Family

ID=16829870

Family Applications (1)

Application Number Title Priority Date Filing Date
JP3225473A Pending JPH0556942A (en) 1991-09-05 1991-09-05 Direct-coupled electrocardiograph

Country Status (1)

Country Link
JP (1) JPH0556942A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003144404A (en) * 2001-11-14 2003-05-20 Noritz Corp Electrocardiographic signal processor
WO2023079998A1 (en) * 2021-11-05 2023-05-11 ソニーグループ株式会社 Biopotential measurement device, information processing device, and biopotential measurement method

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003144404A (en) * 2001-11-14 2003-05-20 Noritz Corp Electrocardiographic signal processor
WO2023079998A1 (en) * 2021-11-05 2023-05-11 ソニーグループ株式会社 Biopotential measurement device, information processing device, and biopotential measurement method

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