SIGNAL ACQUISITION

Overview of Biosignal Data Acquisition Biological signals are very small and contain unwanted noise or interference w/c has the detrimental effect of obscuring relevant information that may be available in the measured signal To extract meaningful information from a signal that may be crucial in understanding a particular biological system or event, sophisticated data acquisition techniques and equipment are commonly used

High-precision low-noise equipment is often necessary to minimize the effects of unwanted noise Since these signals are often used to aid the diagnosis of pathological disorders , the proced-ures of amplification, analog filtering, and A/D conversion should not generate misleading or untraceable distortions. Distortions in a signal measurement could lead to an improper diagnosis.

Sensors, Amplifiers, and Analog Filters A sensor converts a physical measure and into an electric output and provides an interface between biological systems and electrical recording instruments.

Block diagram Data acquisition system Analog signal conditioner Data storage and display Digital signal processing sensors Parameter to be observed

A/D Conversion used to transform biological signals from continuous analog waveforms to digital sequences A/D conversion is particularly important , due to advances in computer technology, the storage and analysis of biosignals is becoming increasingly computer based.

Process involved in A/D conversion Sampling is the process by which a continuous signal is first converted into a discrete sequence in time Quantization is the process by which the continuous amplitudes of the discrete signal are digitized by a computer