De EMG Lowpass maakt alle signalen gelijk
Dependencies: HIDScope biquadFilter mbed
Fork of EMGfilter by
Diff: main.cpp
- Revision:
- 6:da06585e106c
- Parent:
- 5:02b3550e1ff0
- Child:
- 7:a928724ef731
--- a/main.cpp Tue Oct 25 18:32:01 2016 +0000 +++ b/main.cpp Tue Oct 25 20:38:53 2016 +0000 @@ -10,23 +10,28 @@ //Creating two scope channels HIDScope scope(3); +//Low-pass filter at 200Hz to avoid alliasing +BiQuadChain low_pass_200; +BiQuad bq1( 0.73638326364, 1.47272205824, 0.73638326364, 1.36239603912, 0.48048795767); +BiQuad bq2( 0.83856791742, 1.67684080778, 0.83856791742, 1.68114429812, 0.7942832489); + //Notch filter BiQuadChain notch_50; -BiQuad bq1( 1.00007369335,-1.61815834791, 1.00007369335, -1.60983662066, 0.98986119869); -BiQuad bq2( 1.00000000000,-1.61803910919, 1.00000000000, -1.60936554071, 0.99545624832); -BiQuad bq3( 0.99035034846,-1.60242559561, 0.99035034846, -1.61934542233, 0.9955088075); +BiQuad bq3( 1.00007369335,-1.61815834791, 1.00007369335, -1.60983662066, 0.98986119869); +BiQuad bq4( 1.00000000000,-1.61803910919, 1.00000000000, -1.60936554071, 0.99545624832); +BiQuad bq5( 0.99035034846,-1.60242559561, 0.99035034846, -1.61934542233, 0.9955088075); //High pass filter BiQuadChain high_pass; -BiQuad bq4( 0.83315051810,-1.66630103620, 0.83315051810, -1.55025104412, 0.60696783282); -BiQuad bq5( 0.86554941044,-1.73109882088, 0.86554941044, -1.74142633961, 0.78400451004); -BiQuad bq6( 0.92490714701,-1.84981429401, 0.92490714701, -1.90032503529, 0.9352152620); +BiQuad bq6( 0.83315051810,-1.66630103620, 0.83315051810, -1.55025104412, 0.60696783282); +BiQuad bq7( 0.86554941044,-1.73109882088, 0.86554941044, -1.74142633961, 0.78400451004); +BiQuad bq8( 0.92490714701,-1.84981429401, 0.92490714701, -1.90032503529, 0.9352152620); //Low pass filter BiQuadChain low_pass; -BiQuad bq7( 0.00040400257, 0.00080800515, 0.00040400257,-1.92223307595, 0.92384908624); -BiQuad bq8( 0.00040816681, 0.00081633362, 0.00040816681,-1.94204639240, 0.94367905964); -BiQuad bq9( 0.00041558628, 0.00083117256, 0.00041558628,-1.97734803172, 0.9790103768); +BiQuad bq9( 0.00040400257, 0.00080800515, 0.00040400257,-1.92223307595, 0.92384908624); +BiQuad bq10( 0.00040816681, 0.00081633362, 0.00040816681,-1.94204639240, 0.94367905964); +BiQuad bq11( 0.00041558628, 0.00083117256, 0.00041558628,-1.97734803172, 0.9790103768); //Ticker Ticker emgSampleTicker; @@ -48,6 +53,7 @@ bool go_emgSample; bool go_find_minmax; double emg_sample[3]; +double emg_low_passed_200[3]; double emg_notch[3]; double emg_high_passed[3]; double emg_low_passed[3]; @@ -91,9 +97,10 @@ int main() { //combine biquads in biquad chains for notch/high- low-pass filters - notch_50.add( &bq1 ).add( &bq2 ).add( &bq3 ); - high_pass.add( &bq4 ).add( &bq5 ).add( &bq6 ); - low_pass.add( &bq7 ).add( &bq8 ).add( &bq9 ); + low_pass_200.add( &bq1 ).add( &bq2 ); + notch_50.add( &bq3 ).add( &bq4 ).add( &bq5 ); + high_pass.add( &bq6 ).add( &bq7 ).add( &bq8 ); + low_pass.add( &bq9 ).add( &bq10 ).add( &bq11 ); led.write(1); change_state.attach( &calibrate,5); @@ -115,8 +122,11 @@ emg_sample[2] = emg2.read(); for (int i = 0; i < 3; i++){ + //low pass at 200Hz to avoid alliasing + emg_low_passed_200[i] = low_pass_200.step(emg_sample[i]); + //filter out the 50Hz components with a notch filter - emg_notch[i] = notch_50.step(emg_sample[i]); + emg_notch[i] = notch_50.step(emg_low_passed_200[i]); //high pass the signal (removing motion artifacts and offset) emg_high_passed[i] = high_pass.step(emg_notch[i]);