Evaluation of ECG and Respiration Specific Functions
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Figure 38. Frequency Response for the IIR Filter
Multiband-pass Filter
Multiband-pass filter (MBF) is used for removing unwanted signals and power line noise from the live data.
The MBF digital filter is a 161 order FIR filter with Hamming window having cut-off at 150Hz and notch at
50/60 Hz. The notch frequency is selectable from the PC application. This filter provides a very sharp cut-
off around 150 Hz with attenuation more than 30 dB at the stop band. The notch at 50/60 Hz provides
attenuation of more than 30 dB. Sampling frequency is 500 samples/ second.
The frequency response of the filter with a 50 Hz notch is shown in
Figure 39
,
Figure 40
, and
Figure 41
.
Figure 39. Frequency Response for the MBF Filter (Full View)
34
ADS1x9xECG-FE Demonstration Kit
SLAU384A – December 2011 – Revised April 2012
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