Saadat Dena User Manual page 29

 Drift Filter: Press to switch ON or OFF. This filter is used to reduce signal oscillations resulting
from patient breathing and movement. -3dB cutoff frequency of this filter is about 0.6 Hz. Using this
filter will remove the frequencies below the cutoff value from the ECG report. If the drift filter is
switched off, the cutoff frequency of the device will be about 0.05Hz. If the drift filter is set On,
"0.5" will be displayed. Otherwise "0.05" will appear on the screen.
0.5 filter is used to remove signal baseline oscillations and
may interfere with the ST Segment analysis.
 EMG Filter: Press to toggle between ON and OFF. This filter is used to reject muscular noise. If
EMG is set On, "+M" will be displayed on the screen and "EMG" will be recorded on the header.
EMG filter is a lowpass filter which varies based on time and the signal slope .The filter bandwidth
varies from one sample to another sample proportional to the signal slope. The purpose of the EMG
filter is to remove skeletal muscle artifact from the ECG baseline. The EMG filter will eliminate
noise from the baseline, but it will not affect QRS complex components. The cut-off frequency of
this filter increases to about 55Hz in areas where the signal slope is high and decreases to about 10Hz
when the signal slope is low.
If the EMG filter is set On, "EMG" will be displayed on the screen.
To remove ECG signal noise, take the following steps:
1. At first remove any noise sources (for more details, please refer to Troubleshooting chapter)
2. If noise is not removed by taking the above action, set On the EMG filter.
3. If the signal is still noisy, set off the EMG filter and use the lowpass filter (25-35Hz).
4. It is necessary to mention, if the LowPass filters are used, the amplitude of the QRS complex
will be reduced
5. If the EMG filter is enabled, the available LowPass filters will be Off, 75 Hz and 150 Hz.
Due to the significant changes in the ECG amplitude, if 25 Hz
or 35 Hz and EMG filter are turned on simultaneously, the
After setting On the EMG filter, wait a few seconds to record.
available LowPass filters are Off, 75 Hz and 150 Hz.
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