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High CMRR Instrumentation Amplifier (Schematic and Layout) design for biomedical applications

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Instrumentation amplifiers are intended to be used whenever acquisition of a useful signal is difficult. IA’s must have extremely high input impedances because source impedances may be high and/or unbalanced. bias and offset currents are low and relatively stable so that the source impedance need not be constant. Balanced differential inputs are provided so that the signal source may be referenced to any reasonable level independent of the IA output load reference. Common mode rejection, a measure of input balance, is very high so that noise pickup and ground drops, characteristic of remote sensor applications, are minimized.Care is taken to provide high, well characterized stability of critical parameters under varying conditions, such as changing temperatures and supply voltages. Finally, all components that are critical to the performance of the IA are internal to the device. The precision of an IA is provided at the expense of flexibility. By committing to the one specific task of
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CIRCUIT BOARD AND MICROCONTROLLER SOFTWARE DESIGN FOR A SATELLITE POWER SYSTEM

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Out of Violet’s electrical subsystems, the Power subsystem is the most critical because it is housed on a single board that supplies power to all other subsystems and is designed in-house. The Power System functions include using solar panels to collect energy, storing energy in batteries with appropriate protection systems, sampling components’ and subsystems’ sensors to monitor their power consumption, distributing power from solar cells and batteries, acting as a controller for the Flight Computer, and communicating with the Flight Computer through data packets. Hence, the Power microcontroller (MCU) serves as power controller and power monitor. Revision 1 of the Power Board layout was completed, and the populated board was tested in a Flat-sat setup. MCU code was written to execute the major control, monitoring, and communication functions. Correct functionality of the software functions was verified on a STK500-based testbench, which closely resembles the interfaces of the power system in the satellite. In the near future, further testing of the software will be done on a Revision 2 Power Board with a programmed MCU in order to model flight-like conditions.

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