Salt Lake City, Utah
June 20, 2004
June 20, 2004
June 23, 2004
9.202.1 - 9.202.12
An RF Communications Laboratory Capstone Electronic Design Experience
James O. Everly, P.E. University of Cincinnati
A direct conversion short wave receiver is used as a laboratory capstone electronic design experience in the Topics of Electronic Communication Laboratory offered to Electrical Engineering Technology students at the University of Cincinnati. The direct conversion receiver is used to illustrate the reception of continuous wave (CW) and single-sideband (SSB) signals in the 40-41 meter (7.0-7.3 MHz) short wave bands. The receiver is implemented with a low cost, readily available, printed circuit board and two commonly available integrated circuit chips. Electronic assembly time is approximately six hours with a total project cost, excluding resistors and capacitors, under $25. At the outset of the laboratory course, students are given a schematic diagram and are required to develop a project parts list to include component cost and supplier. Students are also required to develop and implement assembly, test, and calibration procedures for the project. Project journals and reports are used to record student ideas and experiences throughout the project.
Time and effort spent experimenting with a properly designed double-sideband direct conversion receiver is an integral part of receiver design education. This experimentation experience is considered a fundamental educational building block by receiver experimenter’s worldwide. Moreover, a simple direct conversion receiver serves as an important benchmark for comparison and it is useful for designers to periodically design, and re-design based on advances in technology, simple direct conversion receivers for applications where relaxed selectivity requirements or better sounding audio are the design objectives. “The Neophyte Receiver,” an original classic work by Dillon , on which this paper is based, is the ultimate in simplicity and serves as an ideal starting point for students and faculty interested in exploring simple short wave receiver design concepts.
This paper presents Dillon's classic design, with slight component modification, of a direct conversion high-frequency short wave receiver. The design is of ultimate simplicity employing only two integrated circuit (IC) devices namely, a Signetics NE602A balanced modulator and an LM386 audio amplifier. The paper starts by outlining the advantages and disadvantages of direct conversion receivers. Solutions are given for most of the direct conversion design flaws. A
Proceedings of the 2004 American Society for Engineering Education Annual Conference & Exposition Copyright 2004, American Society for Engineering Education
Everly, J. (2004, June), An Rf Communication Laboratory Capstone Electronic Design Experience Paper presented at 2004 Annual Conference, Salt Lake City, Utah. https://peer.asee.org/13313
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