Albuquerque, New Mexico
June 24, 2001
June 24, 2001
June 27, 2001
6.226.1 - 6.226.7
Automated Measurement of Frequency Response of Electrical Networks, Filters and Amplifiers
M.G. Guvench, S. Gile and S. Qazi University of Southern Maine
This paper describes the design, operation and use of a PC controlled automated frequency response measurement system using the standard bench-top test equipment available in undergraduate electronics laboratories. The system described employs the waveform data acquisition and processing capabilities of digital oscilloscopes to extract amplitudes (rms or peak), periods, frequencies and relative time delays of waveforms measured at the input and output terminals of a circuit under test. In combination with GPIB control of oscilloscope settings and the frequency of a signal generator, full automation of the frequency response measurement is achieved in a cost-effective manner by using a LabView code developed. The frequency range is of the current system is 12mHz to 12MHz, more than needed for most electronic/acoustic and electromechanical systems frequency tests, and can be expanded by employing a signal generator with higher frequency range. Frequency response measurements are not unique to electronic circuits, amplifiers and filters. The measurement system described here can easily be adapted to determine the frequency response of mechanical, acoustical and other electromechanical and nonelectrical systems as long as appropriate transducers/sensors are introduced to do the required conversions from electrical to non-electrical quantities and vice versa.
Being a much faster alternative to manual measurements, such automated measurements meet a need recently created by the heavy emphasis put on "design" in the electronics curriculum. In the design of analog electronic circuits, in particular those requiring a narrow range of specifications to be met, the cycle time of the test has become a critical factor in fitting a large number of redesign-and-test iterations into a time-limited laboratory session.
This paper describes the design, operation and use of a PC controlled automated frequency response measurement system using the standard bench-top test equipment available in undergraduate electronics laboratories. Being a much faster alternative to manual measurements, such automated measurements meet a need recently created by the heavy emphasis put on "design" in the electronics curriculum, in particular, in the design of analog circuits requiring a high degree of precision to be achieved. In the implementation of such high precision circuit designs, it is not possible to hit all of the design specifications with high degree of precision even though well established design procedures and codes that convert these procedures into a MathCad, Mathematica, MathLab, C file for automated design may have already been developed and used. Ultimately, the design will be put on breadboard and tested against the design specifications, if failing to meet the specifications within their allowed range or "window", the design has to be redone by either restarting from scratch, or more often, by an iterative method of tweaking on some circuit parameters, and testing the new circuit, and repeating these steps in a series of iterations until all of the targets are hit. The higher the required level of precision in the design specifications (or, the narrower the window of tolerance) the larger the number of the iterations, (i.e. design + simulate + verify + protoboard + test + if not passing redesign or modify + test +…repeat) are needed, therefore forcing a quick turn around time for testing in order to fit such design experiments into the limited hours of a weekly laboratory schedule.
Qazi, S., & Gile, S., & Guvench, M. (2001, June), Automated Measurement Of Frequency Response Of Electrical Networks, Filters And Amplifiers Paper presented at 2001 Annual Conference, Albuquerque, New Mexico. https://peer.asee.org/8943
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