- The bioelectric amplifiers are used to amplify the bioelectric signals.
- The gain of the bioelectric amplifier may be low, medium or high depending on the type of amplifier and the signal to be amplified.
- Bioelectric amplifiers should have high CMRR and extremely high input impedance.
- Isolation amplifiers are used to provide electrical isolation and an electric safety barrier to the patients during measurements.
- The isolation amplifiers can provide very high insulation in the range of about a lack mega ohms!.
- Isolation amplifiers are very useful when we need to amplify low level signals in multichannel applications and they can eliminate measurement errors caused by ground loops.
- The isolation barrier is generally an energy converter where the electrical energy of the modulator is converted to some other form of energy non-electrical energy). So it can protect the patient.
- Normally we use optical isolation barrier in order to reduce the effect of EMI is the optical fibers are not susceptible to EMI.
- Chopper amplifier is used to breakup the input signal so that it can be processed as if it were an ac signal and then integrate back to the dc signal at the output.
- A DC chopper amplifier provides high accuracy and stability which is a key requirement in biomedical instrumentation field.
- In the case of chopper amplifiers, the signal is sampled to chop (convert) the signal at a frequency that will pass through the ac-amplifier.
- Chopper stabilized amplifiers have very low noise operation, gives high stability, highly useful for EEG amplifiers to get high gain.
- The main aim of input guarding is to avoid the effect of common mode noise. The guard is a conductive PC trace surrounding the input terminals.
- By placing the shield at the common mode signal potential the common mode noise can be rejected.
Author Bio: The Author of this article, Sreejith is writing articles on Chopper Stabilized Amplifier Principle and Trivandrum Portal
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