Assignment - Project Description

The second project in the course will involve the design of a biopotential signal chain to measure EEG, ECG/EKG and/or EMG signals (your choice) that are present on the surface of the skin. Your regulator from the first project will be used to regulate the supply voltage for the amplifiers and filters in the signal chain. The supply for the A/D converter and microcontroller can be provided by the battery associated with a laptop.

While it is encouraged that you use electrodes connected to the human body with your designed system to make actual biopotential measurements, it is not absolutely required that you do so. If you decide to make actual biopotential measurements, NO system/equipment should be attached/connected to the electrical power grid. Instead, your linear regulator/amplifiers/filters should be powered by a 9V battery and the A/D converter/microcontroller/laptop should be powered by the laptop's internal battery (with the laptop computer itself having been disconnected from the power grid).

At a minimum, you must verify your system's overall behavior by designing/building appropriate test circuits to "emulate" signals that are comparable in amplitude and frequency to the biopotential signals of interest at the surface of the skin, in addition to including:

• 60Hz common-mode noise (with an appropriate amplitude) with electrode impedance imbalance effects to investigate your system's ability towards rejecting common-mode noise (i.e. common-mode rejection ratio, CMRR), and
• Electrode DC offset imbalance to investigate your system's ability towards rejecting "large" input DC/low-frequency differential signals

In order to gauge the effectiveness of your system, the A/D converted signals should be analyzed both in the time- and frequency-domains in MATLAB (or another comparable program) to see whether the desired biopotential signal(s) can still be detected in spite of the above bullet points that are present in the "real world."

As possible starting points for the above bullet points, you may find the following references useful:

• Figure 6 of the posted "AC-coupled front-end for biopotential measurements" research paper
• The "signal composition" section on Page 3 of the posted "Getting the most out of your in-amp design" application note

Furthermore, reference laboratory documents from other universities have been posted to serve as starting points towards designing/building appropriate biopotential signal chain systems, in addition to building test circuits to "emulate" biopotential signals.

In addition to the Analog Devices OP90 opamps, you may obtain from the instructor an Analog Devices AD620 instrumentation amplifier chip to use in your signal chain. Furthermore, you may obtain from the instructor BIOPAC EL503 electrodes if you are interested in using your designed system to make actual biopotential measurements.

In addition to having a functional signal chain, the goal of your project is to have made design decisions/efforts aimed at improving specs/parameters often used to gauge the effectiveness of a biopotential measurement system.

Design Project Report -

Must follow the following format:

Title/Cover Page

Objectives/Application: Describe the purpose of your system (regulator, biopotential signal chain) and the specifications/goals. Describe what would be the application for your designed system? Where/how could it be used?

Circuit Schematic/Description: Provide the schematic of your designed system and a description of how it works. This should also include a discussion of which blocks/transistors perform each function of the design, in addition to the specifications associated with the block/transistor parameters.

This section must include a clear, well-organized description of your design process. Explain why you chose the particular topology/structure depicted in your schematic and how this topology/structure compares to alternatives that you considered (and the associated tradeoffs).

Analysis Calculations: Provide appropriate calculations that explain/show how the important parameters associated with each block in the system were determined/designed. Your discussion must also include the process/calculations followed towards determining the schematic component (e.g. resistor, capacitor, etc.) and parameter (e.g. current) values.

Simulations: Provide SPICE simulation results that verify your analysis calculations. Did you have to make adjustments/modifications to your design based on simulation results (from those calculated by hand)? If so, provide a discussion on this matter.

Experiments: Provide a description of the manner in which you performed the experiments necessary to verify your design, placing all of your data in easy to read table(s) such that hand calculations can be compared to both simulated and measured results.

For your laboratory measurements, you will also need to provide appropriate snapshots (e.g. oscilloscope traces with cursors and/or measure numbers displayed). To complement this information, you may also provide separate video files (narrated by the team) that show the proper functionality/operation of the design.

Discussion: Convey your thoughts regarding your results and how well your system met the design goals originally intended, describing in the process any design issues, difficulties, and/or critical relationships/tradeoffs observed for your project. Also discuss any failures, successes, and possible suggestions for improvement.

The quality of your written report is just as important (if not more) as your design. It is not only expected that your report follows the above format, but that it also has a "professional look" with easy-to-follow text/calculations and clear/well-labeled tables, figures, schematics, etc.

Attachment:- Assignment Files.rar