| Both sides previous revisionPrevious revisionNext revision | Previous revision |
| university:courses:electronics:electronics-lab-heartbeat [08 Sep 2020 04:45] – fixing resistor naming Alexanadre Robichaud | university:courses:electronics:electronics-lab-heartbeat [30 Jan 2023 09:19] (current) – [Preamplifier] Antoniu Miclaus |
|---|
| <WRAP centeralign> Figure 1 Heartbeat Measurement Circuit </WRAP> | <WRAP centeralign> Figure 1 Heartbeat Measurement Circuit </WRAP> |
| |
| Since the real circuit uses quad OP484FPZ from the ADALP2000 Analog Parts Kit, the schematic design was implemented with multiple OP184 Precision Rail-to-Rail Operational Amplifiers. They are dual supplied (± 5V) from the ADALM2000 module, operating on a range of 10V. | The LTspice simulation uses OP284s, included in the standard set of LTspice models. The actual circuit is constructed with the quad OP484FPZ from the ADALP2000 Analog Parts Kit, powered by ± 5V from the ADALM2000 module (a total supply voltage of 10V.) |
| |
| ====IR LED==== | ====IR LED==== |
| |
| The input signal from the heartbeat measurement setup is fed into a Differentiator Amplifier Circuit(([[http://www.electronics-tutorials.ws/opamp/opamp_7.html|Differentiator Amplifier]])) (C<sub>1</sub>, A<sub>1</sub>, R<sub>3</sub>). The capacitor blocks any DC content, C<sub>1</sub> and R<sub>3</sub> behaving as a high pass filter with the cut-off frequency F<sub>c1</sub> being determined by the following formula: | The input signal from the heartbeat measurement setup is fed into a Differentiator Amplifier Circuit(([[http://www.electronics-tutorials.ws/opamp/opamp_7.html|Differentiator Amplifier]])) (C<sub>1</sub>, A<sub>1</sub>, R<sub>3</sub>). The capacitor blocks any DC content, C<sub>1</sub> and R<sub>3</sub> behaving as a high pass filter with the cut-off frequency F<sub>c1</sub> being determined by the following formula: |
| <WRAP centeralign><m>F_c1=1/{2 pi R_1C_1}</m></WRAP> | <WRAP centeralign><m>F_c1=1/{2 pi R_3C_1}</m></WRAP> |
| Besides filtering, this stage serves also as an amplifier taking as input the current (I<sub>A1</sub>), and generating at the output an inverted voltage (V<sub>A1</sub>) based on the negative feedback resistance (R<sub>3</sub>): | Besides filtering, this stage serves also as an amplifier taking as input the current (I<sub>A1</sub>), and generating at the output an inverted voltage (V<sub>A1</sub>) based on the negative feedback resistance (R<sub>3</sub>): |
| <WRAP centeralign><m>V_A1=-I_A1*R_1</m></WRAP> | <WRAP centeralign><m>V_A1=-I_A1*R_3</m></WRAP> |
| |
| ====Active Low-Pass Filter=== | ====Active Low-Pass Filter=== |
| ** Lab Resources:** | ** Lab Resources:** |
| * LTSpice files: [[downgit>education_tools/tree/master/m2k/ltspice/heartbeat_ltspice | heartbeat_ltspice]] | * LTSpice files: [[downgit>education_tools/tree/master/m2k/ltspice/heartbeat_ltspice | heartbeat_ltspice]] |
| * ADIsimPE files: [[downgit>education_tools/tree/master/m2k/adisimpe/heartbeat_adisimpe | heartbeat_adisimpe]] | |
| * Fritzing files: [[downgit>education_tools/tree/master/m2k/fritzing/heartbeat_bb | heartbeat_bb]] | * Fritzing files: [[downgit>education_tools/tree/master/m2k/fritzing/heartbeat_bb | heartbeat_bb]] |
| </WRAP> | </WRAP> |
| |
| **Return to Lab Activity [[university:courses:electronics:labs|Table of Contents]].** | **Return to Lab Activity [[university:courses:electronics:labs|Table of Contents]].** |
