In the broadest terms, an instrumentation system performs the functions of acquiring and presenting data to the user. A functional instrumentation system is a product of hardware, software, and processes employed to orchestrate the subsystem interactions to acquire and deliver data and/or information relating to a specific test or measurement event. The specifics on how an instrumentation system performs its functions will be covered in this handbook. In the context of the instrumentation system environment, the instrumentation engineer s product is data. This handbook gives the instrumentation engineer the necessary background to understand the operation of an instrumentation system. Topics include signal sources, signal conditioning, data collection, data formatting, telemetering, recording, and data reconstruction. Also addressed are calibration and the related issues of measurement uncertainty and operational considerations.