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Data acquisition and analysis.
Aerosol measurement: principles, techniques, and applications. Willeke K, Baron PA, eds. New York: Van Nostrand Reinhold, 1993 Jan; :521-533
In determining the properties of an aerosol, some physical characteristic of the aerosol, such as its concentration or size, is associated by the measuring device with an output. This output usually takes the form of another physical parameter such as the position of a needle on a meter. An output of this type is an example of analog data. Analog data are represented by physical quantities such as time, temperature, length, weight, and voltage, and can assume any value within defined upper and lower limits. Analog data are continuous in the mathematical sense. The signal from a galvanometer is an example of an analog output. Digital data, on the other hand, are not continuous, but discrete. Digital data are represented by numbers and can only assumed fixed values or steps within the defined lower and upper limits. The numbers stored in a personal computer are in digital form. Although the discussion presented in this chapter is largely from an industrial hygiene perspective, these techniques are generally applicable to other fields in aerosol measurement.
Data-processing; Aerosols; Physical-properties; Weight-factors; Industrial-hygiene
Aerosol measurement: principles, techniques, and applications
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