Active Filter สุริยา วิทยาประดิษฐ์ Part : 2 EEET0470 Biomedical Electronics Active Filter Part : 2 สุริยา วิทยาประดิษฐ์ suriya@mut.ac.th w.suriya@yahoo.co.th Mobile : 089-788-6242 082-707-3375

วัตถุประสงค์ รู้จักชนิดของวงจรกรองความถี่ทางอิเล็กทรอนิกส์ Copyright © S.Witthayapradit 2012 รู้จักชนิดของวงจรกรองความถี่ทางอิเล็กทรอนิกส์ สามารถเลือกใช้วงจรกรองถี่ได้เหมาะสมกับงาน สามารถออกแบบวงจรกรองความถี่ทางการแพทย์ได้

Idealized Filter Response Copyright © S.Witthayapradit 2012

Ideal & Practical Response Copyright © S.Witthayapradit 2012

Magnitude Response Frequency Frequency Low Pass Filter Copyright © S.Witthayapradit 2012 Frequency 100Hz 10KHz 10Hz 100KHz -40 -20 Wide Band Narrow Band 1.0kHz Frequency 1.0Hz 10Hz 100Hz 1.0KHz 10KHz 100KHz -40 -20 Low Pass Filter High Pass Filter Band Pass Filter

Magnitude Response Copyright © S.Witthayapradit 2012

Response Filter VDB VCC R1 2.2k R2 220k U1 LF353 3 2 8 4 1 + - Vs VEE Copyright © S.Witthayapradit 2012 VDB VCC R1 2.2k R2 220k U1 LF353 3 2 8 4 1 + - Vs VEE C2 47pF

Response Filter VDB VCC C1 22nF U1 LF353 3 2 8 4 1 + - R1 2.2k Vs VEE Vs VEE C2 47pF R2 220k Copyright © S.Witthayapradit 2012

Band Pass Filter Sallen-Key Multiple Feedback Copyright © S.Witthayapradit 2012 Sallen-Key Multiple Feedback

Sallen-Key Band Pass Filter Copyright © S.Witthayapradit 2012

Sallen-Key Band Pass Filter Copyright © S.Witthayapradit 2012

Multiple Feedback BPF C1 = C2 =C VDB C2 3.3nF C1 U1A LF353 3 2 8 4 1 + Copyright © S.Witthayapradit 2012 VDB C2 3.3nF C1 U1A LF353 3 2 8 4 1 + - V+ V- R2 300k R3 15k VCC VS R1 VEE C1 = C2 =C

Multiple Feedback BPF fM = 10kHz AM = -2 Q = 2 Copyright © S.Witthayapradit 2012 fM = 10kHz AM = -2 Q = 2

Multiple Feedback BPF VDB C2 3.3nF C1 U1A LF353/NS 3 2 8 4 1 + - V+ V- Copyright © S.Witthayapradit 2012 VDB C2 3.3nF C1 U1A LF353/NS 3 2 8 4 1 + - V+ V- OUT R2 300k R3 15k VCC VS R1 VEE

Multiple Feedback BPF C1 = C2 =C Copyright © S.Witthayapradit 2012 VDB C2 10nF C1 U1A LF353 3 2 8 4 1 + - V+ V- R2 180k R3 2.7k VCC VS R1 68k VEE C1 = C2 =C fM = 736Hz , AM =-1.32 , Q = 4.16 , BW = 177Hz

Magnitude & Phase Response Copyright © S.Witthayapradit 2012 Frequency(Hz) 100Hz 1.0KHz 10KHz -20 -10 10 20 Frequency(Hz) 100Hz 1.0KHz 10KHz -300d -200d -100d 0d 100d MFB-BPF Sallen-Key Magnitude(dB) Phase(degree) MFB-BPF Sallen-Key

Phono - Cardigraphy R3 82K U1 MAX4130 4 3 2 5 1 - + VDB C2 1nF R1 330K Copyright © S.Witthayapradit 2012 R3 82K U1 MAX4130 4 3 2 5 1 - + VDB C2 1nF R1 330K VEE VCC Vin C1 0.1uF R2 9.1K 20 15 10 5 1.0Hz 10Hz 100Hz 1.0KHz 10KHz Frequency

Maximum Heart Rate(MHR) Copyright © S.Witthayapradit 2012

Heart Rate Monitoring http://rick.mollprojects.com/ Copyright © S.Witthayapradit 2012 http://rick.mollprojects.com/

Heart Rate Monitoring Copyright © S.Witthayapradit 2012

www.maximintregrated.com Application Note : 3845 Copyright © S.Witthayapradit 2012 Application Note : 3845

Idealized & Practical of BSF Copyright © S.Witthayapradit 2012

Wide Band : Band Stop Filter Copyright © S.Witthayapradit 2012 Frequency 100Hz 1.0KHz 10KHz -20 -15 -10 -5 -0 VCC R2 5.6K VDB RA 20K R1 C1 100n C2 10n RB VEE Vin U3 MAX4130 4 3 2 5 1 - + RF LPF HPF BSF

Characteristic : Band Stop Filter Copyright © S.Witthayapradit.2009 Copyright © S.Witthayapradit 2012

Band Stop Filter Twin-T Wien Robinson Copyright © S.Witthayapradit.2009 Copyright © S.Witthayapradit 2012 Twin-T Wien Robinson

Twin-T Band Stop Filter Copyright © S.Witthayapradit 2012

Twin-T Band Stop Filter Copyright © S.Witthayapradit 2012 fO=50Hz , Q = 2.75 and C = 68nF

Twin-T Band Stop Filter Copyright © S.Witthayapradit 2012 Magnitude Response Phase Response Frequency 10Hz 30Hz 50Hz 90Hz -100d 0d 100d -30 -20 -10

Twin-T Band Stop Filter Copyright © S.Witthayapradit 2012 Time 0s 2.0s 4.0s Output Signal -0.5V 0.5V 1.0V Input Signal 0V VCC C2 68nF C1 R5 100K VEE Vn FREQ = 50Hz VAMPL = 50m R4 10K U1 MAX4130 4 3 2 5 1 - + V- V+ OUT V R3 23.5K R1 47K C3 136nF R2 Ve ecg4sec.txt U2

Twin-T Band Stop Filter Copyright © S.Witthayapradit 2012

Wien Robinson BSF R2 R1 VCC U2 4 3 2 5 1 - + RB U1 RA CB CA VEE R5 Vin Copyright © S.Witthayapradit 2012 R2 R1 VCC U2 4 3 2 5 1 - + RB U1 RA CB CA VEE R5 Vin R3 R4

Wien Robinson BSF a = 3Q-1 b = -AO x 3Q Copyright © S.Witthayapradit 2012 Specify BW or Q and Determine a Define fO and C and calculate R with: a = 3Q-1 Specify AO and Determine b b = -AO x 3Q R2 18K R1 1K VCC U2 4 3 2 5 1 - + RB 47K U1 RA CB 68nF CA VEE R5 2K VDB Vin R3 2.2K R4 Define R2 and calculate R3 and R4 R3 = R2 / a And R4 = R2 / b And R5 = 2 R1

Wien Robinson BSF Magnitude Response Phase Response Copyright © S.Witthayapradit 2012 Magnitude Response Phase Response

Reference 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” , 8th Edition , Prentice Hall , 2008. [4] Thomas L.Floyd , “Electronic Devices” , 7th Edition , Prentice Hall Inc. , 2005. [5] http://rick.mollprojects.com/ , HRM Receiver , 2009. [ 6 ] http://www.maxim-ic.com , application note 3845 , 2009.

Active Filter The End Q & A Active Filter Part : 1 EEET0470 Biomedical Electronics Active Filter Part : 1 Active Filter Part : 2 The End Q & A สุริยา วิทยาประดิษฐ์ suriya@mut.ac.th w.suriya@yahoo.co.th Mobile : 089-788-6242 082-707-3375

Exercises Copyright © S.Witthayapradit 2012 ให้ออกแบบวงจรกรองความถี่หยุดผ่าน เพื่อขจัดคลื่นไฟฟ้าสอดแทรก(Interference) ในคลื่นไฟฟ้าหัวใจจากสเปกตรัมที่วัดได้ 20 40 60 80 100 120 -120 -100 -80 -60 -40 -20 Frequency Power Spectrum Magnitude (dB)