10 - Automatic test equipment

Abstract

This chapter illustrates different types of automatic test equipment. Automatic test instruments are devices capable of performing and displaying measurements autonomously or in a system; automatic test equipment is a complete measurement system, consisting of one or more automatic test instruments and a computer controller. In the microprocessor-controlled spectrum analyzer functions, such as, frequency scan, center frequency, and resolution bandwidth may be automatically controlled: the microprocessor-controlled spectrum analyzer is an example of an automatic test instrument. Such automatic test equipment requires computer control to ensure correct operation, record the measurements, and correlate the vast amounts of measurement data, presenting it in a form readily understood by the human user. Most modern automatic test instruments are programmable; that is, they feature an interface which allows their internal microprocessor to be controlled by an external computer. Most measurement facilities of an automatic test instrument may be set by a computer via this interface, and measurements taken are similarly relayed back to the computer for correlation and display. Automatic test equipment systems may be used in: design and development, production, reliability and certification test, and service. Main categories of automatic test equipment include: component testers, unpackaged assembly testers, packaged assembly testers, and maintenance and service equipment. Recently a trend has developed, building on the automatic test equipment bus principle, in which the bus is controlled not by a stand-alone computer but by a purpose-built, standard-sized computer controller.