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I am a student. I acquired EMG signal (sampled at 1KHz) by using dry electrodes. At first, it was all noisy. I then applied a Notch Filter (@50Hz) and the signal looks better but still not great.

Any suggestions on the further processing of the signal? Thanks in advance.

I attach Signal vs Notch filtered Signal

FFT of the original signal

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  • \$\begingroup\$ Thanks for your comment. Unfortunately, for the moment, I am trying to do acquisitions from a commercial system. \$\endgroup\$ – Student91 Jan 9 '18 at 17:29
  • \$\begingroup\$ EMG = Electromyography - electrical activity of muscles. \$\endgroup\$ – JRE Jan 9 '18 at 17:42
  • \$\begingroup\$ Place chicken wire electro=static shield around the test-person. Connect a GND wire to the chicken-wire using alligator clips into the steel wires. Make the shield a foot larger than the test-person, so very little 50Hz couples to the test-person. \$\endgroup\$ – analogsystemsrf Jan 10 '18 at 3:03
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50Hz is within your band of interest. You should use better hardware (starting from good shielded wires and high CMRR amplifier) to suppress it in the input.

Your QSR complex will be as high as 1-2mV, so level of 50Hz junk should be way lower, tops 20uV.

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