A novel low-complexity digital filter design for wearable ECG devices

Figures

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  Fig 1. A schematic presentation of a wearable ECG device where the captured signal is transmitted (through a wireless channel) to a remote backend system for further processing.

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  Fig 2. Illustration of target filter for two scenarios: (a) Scenarios I described in [13] with a sampling frequency of 200 Hz, (b) Scenario II described in [10] with a sampling frequency of 300 Hz.

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  Fig 3. Magnitude response of the complement filter U(z) for Scenario I.

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  Fig 4. IFIR filter technique employs a cascade of two filters to reduce the number of multipliers and structural adders.

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  Fig 5. Magnitude responses of the sub-filters for Scenario II-Scheme A: (a) sub-filter H1(z); (b) sub-filter H2(z).

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  Fig 6. Optimum Stretch Factor for IFIR implementation of UPartial(z).

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  Fig 7. Magnitude responses (dB) of IFIR components of UPartial(z): G(z20) and I(z).

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  Fig 8. Magnitude response (dB) of the conventional implementation of UPartial(z).

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  Fig 9. Magnitude responses of IFIR components of U(z): G(z20) and I2(z4).

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  Fig 10. Double-stretch- factor IFIR implementation of H(z).

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  Fig 11. The optimally factored-cascade IFIR implementation of U(z) = βG(z20) I2(z4).

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  Fig 12. Magnitude responses of the optimally factored-cascade IFIR implementation of H(z) for two different values of post-filter-multiplier: a) β = (1.010100111)2; b) β = (1.0)2.