Comments on “A novel high input impedance front-end for capacitive biopotential measurement”
A front-end for biopotential sensing in wearable medical devices has been recently proposed which is claimed to provide 100 GOinput impedance by manually matching two resistor pairs in a positive- and a negative-feedback loop around an operationalamplifier (op amp); the cost being that the equivalen...
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2019 |
| País: | España |
| Institución: | Universitat Politècnica de Catalunya (UPC) |
| Repositorio: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | inglés |
| OAI Identifier: | oai:upcommons.upc.edu:2117/179818 |
| Acceso en línea: | https://hdl.handle.net/2117/179818 https://dx.doi.org/10.1007/s11517-019-02083-x |
| Access Level: | acceso abierto |
| Palabra clave: | Electrodes Supercapacitors Electronic circuits--Noise Biopotential sensing Capacitive electrodes Voltage-loading effect Noise analysis Elèctrodes Circuits electrònics -- Soroll Àrees temàtiques de la UPC::Enginyeria electrònica |
| Sumario: | A front-end for biopotential sensing in wearable medical devices has been recently proposed which is claimed to provide 100 GOinput impedance by manually matching two resistor pairs in a positive- and a negative-feedback loop around an operationalamplifier (op amp); the cost being that the equivalent input noise voltage doubles with respect to a simple non-inverting amplifier.The ECG acquired with capacitive (sic) electrodes through a cotton shirt is presented as a proof of the performance of theproposed circuit. It turns out, however, that the analysis ignores op amp’s input capacitance hence the effort to achieve a very highinput resistance seems futile. Further, cotton is highly hygroscopic hence not an appropriate dielectric, so that there is no proofthat the electrodes tested were actually capacitive. This comment addresses these two problems and some additional conceptualand methodological inaccuracies found in the paper. |
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