2 - PC-based data acquisition

Abstract

The instrumentation and signal processing techniques involved in acquiring and processing human physiological parameters have evolved over the years. Data Acquisition Systems (DAS or DAQ) exist, which have the capability of converting analog real-world physical/biological signals into the digital domain and then utilizing the capability of a computer, these bio-signals can be visualized, stored, analyzed, and can trigger a control command. The first DAQ system was developed by IBM, in the early 1960s which could record scientific data. These were bulky and expensive and required significant programming and setup expertise. A solution to this issue emerged in the form of PC-based DAQ systems. By the mid of 1980s, National Instruments Corp. (NI) devised the GPIB Data Acquisition Cards and DAQ boards which could be interfaced with low-cost PCs. Apart from this breakthrough invention of utilizing the functionality of a personal computer for data acquisition and analysis, a proprietary application software LabVIEW offering a wide spectrum of built-in functions was also released by NI. During 1992, NI released a LabVIEW version, compatible for Windows PCs. This platform can be explored to design and develop in-house real-time DAQ. MATLAB also offers a Data Acquisition Toolbox with featured apps and functions that enable writing data to DAQ analog and digital output channels and processing the detected signals. The essential components of DAQ system include Sensors and Transducers, Data Acquisition System Hardware Signal Conditioning unit, analog-to-digital conversion (ADC), DAC, MUX, Controllers, Power Management etc.], the Interface Units, Data Acquisition System Software (Signal Processing Platforms such as MATLAB, Simulink, and LabVIEW), Computers, etc. which are detailed in this chapter.