Questions tagged [cmrr]

Common-mode rejection ratio (CMRR) is the measure of rejection by the device of unwanted input signals common to both input leads, relative to the wanted difference signal.

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First principles modeling of op amp CMRR

Introduction I'm trying to analyze an op amp circuit from first principles (i.e. without using the two rules of ideal op amp analysis -- virtual short circuit and infinite input impedance). The ...
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ECG / EEG Amplifier design tricks

First of all, sorry, I missed the links / images where I have found the solutions mentioned below (I hope, if you are familiar with this topic, you know them): I have to design an ECG / EEG analog ...
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Why does CMRR degrade in an instrumenation amplifier when the feedback resistor is increased?

Why does CMRR degrade in an instrumenation amplifier when the feedback resistor is increased, keeping all other resistances constant at a fixed value? What mathematical relationship links the feedback ...
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What are the IEC standards/certifications to look for in a DSO while making measurements pertaining analog parameters like CMRR, SNR, THD etc

I am in the process of measuring CMRR for our mixed signal system that deals with bio-signal acquisition. I am using DSOX2014A keysight entry-level oscilloscope to make measurement to derive CMRR, SNR ...
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How can I calculate CM and DM gains for this model?

Regarding the second page of this document, at the first example it calculates the DC CMR due to line imbalance Rs and explanation is given in the first paragraph below(ignore the second example): ...
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Common mode choke to boost cmrr of transformer input

I was wondering, can a common mode choke be used to enhance the CMRR of a transformer coupled amplifier Even further? What are the drawbacks?
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Can someone help me understand why exactly high CMRR is so important, particularly in medical instrumentation like ECG?

So I have spent days reading about specifics of op-amps, instrumentation amps, and ECG circuitry and it just isn't clicking for me. As I understand it, the common mode signal gets amplified and added ...
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Capacitor Array Tolerance of Caps in Same Package

Consider an MLCC capacitor array like CA064X471J5GACTU. Its tolerance is 5% but does this apply to capacitors within the same package? More specifically, I am wondering if the tolerance of caps within ...
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How calculate the error offset or the noise threshold for MyoWare and FSR sensors?

I am working on EMG and FMG signals to extract time domine features and i need a threshold value for some features. I must calculate it from the characteristics of MyoWare and FSR sensors.For the ...
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74 views

How do I find CMRR?

How do I find the common-mode rejection ratio, CMRR for this circuit? I know I have to find differential gain and common-mode gain as 'differential mode gain/commonmode gain' but with current mirrors ...