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งานนำเสนอกำลังจะดาวน์โหลด โปรดรอ
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Copyright © S.Witthayapradit 2012 020406080100120 -120 -100 -80 -60 -40 -20 0 Frequency Power Spectrum Magnitude (dB) 020406080100120 -120 -100 -80 -60 -40 -20 0 Frequency Power Spectrum Magnitude (dB)
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Analog Filter Digital Filter Passive Filter Active Filter • Resistor • Inductor • Capacito r • Active devices • Resistor • Capacitor IIRFIR • Direct form I • Direct form II • Rectangula r • Hanning • Hamming • Blackman • Kaiser Copyright © S.Witthayapradit 2012
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รู้จักชนิดของวงจรกรองความถี่ทาง อิเล็กทรอนิกส์ ใช้สัมประสิทธิ์ในการออกแบบ วงจรได้ สามารถออกแบบวงจรกรองความถี่ ทางการแพทย์ได้
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Copyright © S.Witthayapradit 2012
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INPUT OUTPUT 1 st Order 2 nd Order 3 rd Order 4 th Order 1 st Order 2 nd Order 1 st Order 2 nd Order
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Copyright © S.Witthayapradit 2012 0 -40 -80 Magnitude(dB) Frequency(Hz) 0.1f 1f 10f 1 st Order 2 nd Order 3 rd Order 4 th Order
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Copyright © S.Witthayapradit 2012 มีช่วงแถบเปลี่ยนกว้าง (Transition band) แต่มีมุม เฟสเชิงเส้นแถบเปลี่ยน ให้ค่า ขนาด คงที่ในช่วงแถบ ผ่าน (pass Band)แถบ ผ่าน มีช่วงเปลี่ยนแคบมาก แต่ ช่วงแถบผ่านมีแรงดัน กระเพื่อม (Pass band Ripple) Bessel Butterwort h Tschebysch eff
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Copyright © S.Witthayapradit 2012 Bessel Butterwort h Tschebysch eff Frequency 100Hz1.0kHz 10kHz -60 -40 -20 --60 --40 --20 0 10 Bessel Butterworth Tschebyscheff Copyright © S.Witthayapradit
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Copyright © S.Witthayapradit 2012 a 1 : Coefficient Order BesselButterworthTschebyscheff(3db) AiAi bibi aiai bibi aiai bibi 11.00000.00001.00000.00001.00000.0000
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Copyright © S.Witthayapradit 2012 a 1 : Coefficient Order BesselButterworthTschebyscheff(3db) AiAi bibi aiai bibi aiai bibi 11.00000.00001.00000.00001.00000.0000
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Copyright © S.Witthayapradit 2012 a 1 : Coefficient Order BesselButterworthTschebyscheff(3db) AiAi bibi aiai bibi aiai bibi 11.00000.00001.00000.00001.00000.0000
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Copyright © S.Witthayapradit 2012
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2 nd OrderBesselButterworthTschebyscheff(3dB) a i 1.36171.41421.065 b i 0.61811.9305 Q0.580.7071.3 a i, b i = สัมประสิทธิ์ (Coefficient) f C = ความถี่ตัด
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Copyright © S.Witthayapradit 2012 “Butterworth” ให้ C 1 = 33nF 2 nd OrderBesselButterworthTschebyscheff(3dB) a i 1.36171.41421.065 b i 0.61811.9305 Q0.580.7071.3 C 2 = 68nF f C = 2kHz
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Copyright © S.Witthayapradit 2012 1.23350.5860.2678R 4 /R 3 1.30.7070.58Q 1.930510.618bibi 1.0651.41421.3617aiai Tschebyscheff(3db)ButterworthBessel2 nd Order Coefficient R 1 = R 2 = R and C 1 = C 2 = C กำหนดค่าของ C แล้ว คำนวณหาค่า ของ R และอัตราขยายได้ เท่ากับ ; f C = ความถี่ตัด = 1/Q
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Copyright © S.Witthayapradit 2012 1.930510.618bibi 1.0651.41421.3617aiai Tschebyscheff(3db)ButterworthBessel2 nd Order Coefficient
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Copyright © S.Witthayapradit 2012 Frequency 100Hz 1.0KHz10KHz -40 -20 0 20 MFB-LPF General LPF Unity Gain LPF
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Copyright © S.Witthayapradit 2012 Frequency 100Hz1.0KHz10KHz -100d 0d 100d -180d 180d MFB-LPF Unity Gain-LPF General-LPF
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Copyright © S.Witthayapradit 2012 [b,a]=butter(5,10/1000,'low '); filter_y=filtfilt(b,a,rec_y ); plot(filter_y) xlabel('Sample number') ylabel('Low Pass Filtered EMG signal') 0100020003000400050006000 0 500 1000 1500 Sample number Rectified EMG signal 01000 2000 30004000 5000 6000 0 50 100 150 200 250 300 350 Sample number Low Pass Filtered EMG signal
![Copyright © S.Witthayapradit 2012 [b,a]=butter(5,10/1000, low ); filter_y=filtfilt(b,a,rec_y ); plot(filter_y) xlabel( Sample number ) ylabel( Low Pass Filtered EMG signal ) Sample number Rectified EMG signal Sample number Low Pass Filtered EMG signal](http://images.slideplayer.in.th/8/1963309/slides/slide_21.jpg "Copyright © S.Witthayapradit 2012 [b,a]=butter(5,10/1000, low ); filter_y=filtfilt(b,a,rec_y ); plot(filter_y) xlabel( Sample number ) ylabel( Low Pass Filtered EMG signal ) Sample number Rectified EMG signal Sample number Low Pass Filtered EMG signal")
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Copyright © S.Witthayapradit 2012 5 th Order Unity-gain Butterworth Low Pass Filter with f C = 10Hz C 1 = 82nF R 1 = 200K C 2 = 22nF C 3 = 10nF R 2 = 560K R 3 = 2M C 4 = 390nF C 5 = 33nF R 4 = 100K R 5 = 200K
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Copyright © S.Witthayapradit 2012 Input Signal Output Signal
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Copyright © S.Witthayapradit 2012
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a 1 : Coefficient Order BesselButterworthTschebyscheff(3db) AiAi bibi aiai bibi aiai bibi 11.00000.00001.00000.00001.00000.0000
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Copyright © S.Witthayapradit 2012 a 1 : Coefficient Order BesselButterworthTschebyscheff(3db) AiAi bibi aiai bibi aiai bibi 11.00000.00001.00000.00001.00000.0000
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Copyright © S.Witthayapradit 2012
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C 1 = C 2 = C a 1, b 1 = Coefficient
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Copyright © S.Witthayapradit 2012 C 1 = C 2 = C = 56nF f C =10kHz ; Butterworth 1.930510.618bibi 1.0651.41421.3617aiai Tschebyscheff(3db)ButterworthBessel2 nd Order Coefficient
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Copyright © S.Witthayapradit 2012 C 1 = C 2 = C a 1, b 1 = Coefficient
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Copyright © S.Witthayapradit 2012 C 1 = C 3 = C
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Copyright © S.Witthayapradit 2012 Frequency 100Hz1.0KHz10KHz100KHz -40 -20 0 20 MFB HPF General HPF Unity Gain HPF
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Copyright © S.Witthayapradit 2012 Frequency 100Hz 1.0KHz 10KHz100KHz -100d 0d 100d -180d 180d MFB HPF General HPF Unity-Gain HPF
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Copyright © S.Witthayapradit 2012 y=load('emg.txt'); subplot(211) plot(y) xlabel('Sample number') ylabel('EMG signal') Remove any DC offset of the signal subplot(212) y2=detrend(y) xlabel('Sample number') ylabel('EMG signal') 0200040006000 -1000 0 1000 2000 3000 Sample number 0200040006000 -2000 -1000 0 1000 2000 Sample number
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Copyright © S.Witthayapradit 2012 Frequency 100mHz1.0Hz10Hz Vdb(OUT) -30 -20 -10 0
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Copyright © S.Witthayapradit 2012 Time 0s5s10s v in v out -2.0V 0V 2.0V
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Copyright © S.Witthayapradit 2012 Order BesselButterworthTschebyscheff(3db ) aiai bibi aiai bibi aiai bibi 11.00000.00001.00000.00001.00000.0000 21.36170.61801.41421.00001.06501.9305 30.7560 0.9996 0.0000 0.4772 1.0000 0.0000 1.0000 3.3496 0.3559 0.0000 1.1923 41.3397 0.7743 0.4889 0.3890 1.8478 0.7654 1.0000 2.1853 0.1964 5.5339 1.2009 50.6656 1.1402 0.6216 0.0000 0.4128 0.3245 1.0000 1.6180 0.6180 0.0000 1.0000 5.6334 0.7620 0.1172 0.0000 2.6530 1.0686
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Copyright © S.Witthayapradit 2012 [1] Sergio Franco, “Design with Operational Amplifiers and Analog Integrated Circuits”, Third edition, McGraw-Hill, 2002. [2] Ron Mancini, “ Op Amps for Everyone”, Texas Instruments,2002. [3] James W.Nilsson, Susan A.Riedel, “Electric Circuits”, 8 th Edition, Prentice Hall, 2008. [4] Thomas L.Floyd, “Electronic Devices”, 7 th Edition, Prentice Hall Inc., 2005.
![Copyright © S.Witthayapradit 2012 [1] Sergio Franco, Design with Operational Amplifiers and Analog Integrated Circuits , Third edition, McGraw-Hill, 2002.](http://images.slideplayer.in.th/8/1963309/slides/slide_38.jpg "[2] Ron Mancini, Op Amps for Everyone , Texas Instruments,2002. [3] James W.Nilsson, Susan A.Riedel, Electric Circuits , 8 th Edition, Prentice Hall, [4] Thomas L.Floyd, Electronic Devices , 7 th Edition, Prentice Hall Inc.,")
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