| Autor: |
Pallàs Areny R; Department of Electronic Engineering, Universitat Politècnica de Catalunya (BarcelonaTech), Barcelona, Catalunya, Spain. |
| Jazyk: |
angličtina |
| Zdroj: |
Medical & biological engineering & computing [Med Biol Eng Comput] 2020 Feb; Vol. 58 (2), pp. 267-269. Date of Electronic Publication: 2019 Dec 13. |
| DOI: |
10.1007/s11517-019-02083-x |
| Abstrakt: |
A front-end for biopotential sensing in wearable medical devices has been recently proposed which is claimed to provide 100 GΩ input impedance by manually matching two resistor pairs in a positive- and a negative-feedback loop around an operational amplifier (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 the proposed circuit. It turns out, however, that the analysis ignores op amp's input capacitance hence the effort to achieve a very high input resistance seems futile. Further, cotton is highly hygroscopic hence not an appropriate dielectric, so that there is no proof that the electrodes tested were actually capacitive. This comment addresses these two problems and some additional conceptual and methodological inaccuracies found in the paper. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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