Name: ecg signal amplifier design
Uploaded: 2025-07-11T07:24:08.000Z
Duration: 1 min 25 s
Channel: JoVE

심전도 기계에서 전극은 각 심장 박동 동안 심장 근육 탈분극으로 인한 피부의 작은 전기적 변화를 감지합니다.
이러한 마이크로볼트 범위 신호는 잡음이나 간섭에 의해 압도될 수 있습니다.
이 문제를 해결하기 위해 ECG 기계는 계측 증폭기를 사용하여 공통 모드 잡음 신호를 최소화하면서 ECG 파형을 증폭합니다.
계측 증폭기는 차동 증폭기의 일종입니다. 여기에는 6개의 저항, 3개의 단자 및 이득 세트 단자 사이에 연결된 외부 저항이 포함됩니다.
입력 신호 간의 작은 차이를 증폭하는 동시에 두 입력에 공통된 신호를 거부합니다.
출력 전압은 전압 이득과 입력 전압 차이의 곱입니다., 이득은 외부 저항만 변경하여 쉽게 조정할 수 있습니다.
계측 증폭기는 높은 입력 임피던스, 낮은 출력 임피던스, 높은 이득 안정성 및 높은 공통 모드 제거율을 제공합니다.
높은 입력 임피던스는 신호 부하를 피하여 신호 왜곡을 방지하고, 높은 CMRR은 다른 장비의 전기 간섭과 같은 전극 리드에서 포착된 잡음을 제거하는 데 도움이 됩니다.
계측 증폭기는 생체 의학 계측 및 통신에 사용됩니다.

계측 증폭기

심전도(ECG) 기계는 심장의 전기적 활동을 모니터링하는 데 사용되는 필수 의료 장비입니다. 이는 각 심장 박동 동안 심장 근육의 탈분극으로 인해 발생하는 피부의 작은 전기적 변화를 감지하여 작동합니다. 그러나 이러한 신호는 마이크로볼트 범위에 있으므로 잡음이나 간섭으로 인해 쉽게 압도될 수 있습니다.

이러한 문제를 극복하기 위해 ECG 기계는 계측 증폭기를 사용합니다. 이 특수 증폭기는 다른 장치의 전기 간섭과 같은 공통 모드 잡음 신호의 영향을 최소화하면서 ECG 파형을 증폭하도록 설계되었습니다.

계측 증폭기는 차동 증폭기의 한 유형입니다. 회로에는 저항기 6개, 단자 3개, 이득 설정 단자 사이에 연결된 외부 저항기가 포함되어 있습니다. 이 증폭기는 두 입력에 공통된 신호를 거부하면서 입력 신호 간의 작은 차이를 증폭하는 방식으로 작동합니다.

증폭기의 출력 전압은 전압 이득과 입력 전압 차이의 곱에 의해 결정됩니다. 이득은 외부 저항기의 값을 변경하여 쉽게 조정할 수 있으므로 증폭 과정에 대한 유연성과 제어 기능을 제공합니다.

계측 증폭기는 ECG 기계에 사용하기에 이상적인 몇 가지 주요 특성을 나타냅니다. 이 제품은 높은 입력 온저항, 낮은 출력 온저항, 높은 이득 안정성 및 높은 공통 모드 제거비(CMRR)를 갖습니다.

높은 입력 온저항는 신호 로딩을 방지하여 신호 왜곡을 방지하고 심장에서 나오는 전기 신호의 무결성을 보장합니다. CMRR이 높으면 증폭기는 다른 장비의 전기 간섭과 같이 전극 리드에 의해 포착된 잡음을 효과적으로 제거하여 ECG 파형의 품질을 향상시킬 수 있습니다.

ECG 기계에서의 사용 외에도 계측 증폭기는 고유한 특성으로 인해 다양한 생체 의학 계측 및 통신 애플리케이션에 일반적으로 사용됩니다.

심전도 기계에서 전극은 심장 근육 탈분극으로 인한 피부의 작은 전기적 변화를 감지합니다.

Education

교육

JoVE Core

Electrical Engineering

전기공학

Unit 1

제1단원

Operational Amplifiers

연산 증폭기

KEY TERMS AND CONCEPTS

주요 용어 및 개념

Instrumentation Amplifier

ecg signal amplifier design

An ECG signal amplifier helps an electrocardiography machine measure the heart’s electrical activity. ECG electrodes detect tiny voltage changes on the skin that come from depolarization of the heart muscle during each heartbeat. These signals are in the microvolt range, so they can be easily hidden by noise or interference.

To solve this problem, ECG machines use an instrumentation amplifier. This amplifier boosts the ECG waveform while reducing common-mode noise, which is interference that appears on both inputs. It works as a difference amplifier, so it strengthens the small voltage difference between the two input signals and rejects the signals they share.

The circuit uses six resistors, three terminals, and an external resistor connected between the gain set terminals. The output voltage depends on the voltage gain and the input voltage difference. The gain can be adjusted by changing the value of the external resistor, which gives the circuit flexibility.

Instrumentation amplifiers are well suited for ECG systems because they have high input impedance, low output impedance, high gain stability, and a high common mode rejection ratio, or CMRR. High input impedance helps prevent signal loading, so the heart signal is not distorted. High CMRR helps block interference picked up by the electrode leads, such as noise from other equipment, and improves the ECG waveform. These amplifiers are also used in other biomedical instrumentation and telecommunication applications.

ECG Signal Amplifier Design

operational amplifiers

Operational Amplifier Pinout and Signal Use

An operational amplifier, or op-amp, is a flexible circuit building block used in many electronic designs. It can act like a voltage-controlled voltage source, and it can also be used to create a voltage- or current-controlled current source. When resistors and capacitors are connected to its terminals, an op-amp can perform mathematical operations on signals. Op-amps are able to sum signals, amplify a signal, integrate it, or differentiate it. These features make them useful in practical...

characteristics of opamp

Op-Amp Gain, Feedback, and Saturation

An operational amplifier, or op-amp, is an electronic circuit component used with other circuit parts to carry out a signal-processing task. It is often described with an equivalent circuit model. In that model, the output section includes a voltage-controlled source in parallel with the output resistance, R o. The model also shows the input resistance, R i, which is the Thevenin equivalent resistance seen at the input terminals. The differential input voltage, v d, is the difference between...

design example: vintage mixing console

Op-Amp Preamp for a Vintage Console

A sound engineer designs an op-amp pre-amplifier for a vintage mixing console. The console’s output is too low for modern recording equipment, so the signal must be boosted before it can be used. The goal is to build a preamp that raises the audio level without changing the console’s character. The design must meet three clear requirements. It needs a gain of 10, an input impedance above 10 kilo-ohms so the console is not overloaded, and a frequency range that covers the full audio spectrum...

inverting and non-inverting opamps

Op-Amp Gain: Inverting, Noninverting, Buffer

Operational amplifiers can be used as inverting, noninverting, and buffer amplifiers. In these circuits, the output voltage depends on the input voltage and the resistor setup around the op-amp. In an inverting amplifier, the input voltage is sent through a resistor to the inverting terminal. The non-inverting terminal is grounded, and a feedback resistor links the inverting terminal to the output. Using Kirchhoff's Current Law and an ideal op-amp model, the gain can be found. This circuit...

sum and difference opamps

Op-Amp Adders and Subtractors

Operational amplifiers can be wired to add or subtract signals. In these two op-amp setups, the summing amplifier combines several input signals into one output, while the difference amplifier compares two inputs and amplifies their difference. A summing amplifier is also called an adder. Input signals, such as audio signals, enter through input resistors. These resistors send currents through the feedback resistor, which produces an output voltage. Using Kirchhoff's current law and Ohm's Law,...

characteristics of practical op amps

Op Amp Noise Rejection and Buffering

Practical op amps are used to separate useful signals from unwanted noise. A difference amplifier should ideally amplify only the difference between two input signals. In real circuits, though, the output depends on both differential gain and common-mode gain. The common-mode rejection ratio, or CMRR, measures how well an op amp rejects common-mode signals. Common-mode signals are the same on both inputs. A higher CMRR helps an op amp ignore noise and amplify the wanted signal, such as music...

integrator and differentiator

Op-Amp Circuits in Cruise Control

Op-amp circuits are used in cruise control systems to help cars keep a constant speed. In these systems, operational amplifiers, or op-amps, can work as integrators and differentiators. Both circuits use resistors and capacitors, which makes them compact and cost-effective. An integrator circuit produces an output that is proportional to the integral of the input signal. It is made by replacing the feedback resistor in a standard inverting amplifier with a capacitor. The output and input...

cascaded op amps

Op Amp Stages in Series

Operational amplifiers can be connected in series as separate stages. This cascade works because op-amps have very high input resistance and very low output resistance. Those properties help each stage keep its input-output relationship while driving the next stage. In a cascaded op-amp circuit, the output of one stage becomes the input of the next. Each stage adds gain to the signal as it passes through. The overall gain is the product of the gain of each stage. This design can improve...

instrumentation amplifier

An ECG signal amplifier helps an electrocardiography machine measure the heart’s electrical activity. ECG electrodes detect tiny voltage changes on the skin that come from depolarization of the heart muscle during each heartbeat. These signals are in the microvolt range, so they can be easily hidden by noise or interference. To solve this problem, ECG machines use an instrumentation amplifier. This amplifier boosts the ECG waveform while reducing common-mode noise, which is interference that...

key terms and concepts

Learn how an instrumentation amplifier helps an ECG machine boost tiny heart signals, reject noise, and improve waveform quality using adjustable gain and high CMRR.

ECG Signal Amplifier Design | JoVE K12

JoVE Core Electrical Engineering offers easy-to-understand animated videos that cover fundamental concepts of electric circuits along with circuit analysis techniques. It incorporates first-order and second-order circuits using operational amplifiers and circuit transformation concepts. The inclusion of practical design examples and real-world applications through scientist-in-action videos adds significant educational value, making complex concepts accessible.

electrical engineering

ECG Signal Amplifier Design

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