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Design Of A Hardware Platform For Analog Communications Laboratory

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Conference

2008 Annual Conference & Exposition

Location

Pittsburgh, Pennsylvania

Publication Date

June 22, 2008

Start Date

June 22, 2008

End Date

June 25, 2008

ISSN

2153-5965

Conference Session

Laboratory Development in ECE Education

Tagged Division

Electrical and Computer

Page Count

17

Page Numbers

13.367.1 - 13.367.17

Permanent URL

https://peer.asee.org/4333

Download Count

465

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Paper Authors

biography

Bruce Dunne Grand Valley State University

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Since 2003, Bruce E. Dunne has been an Assistant Professor in the School of Engineering at Grand Valley State University. Prior to joining GVSU, he spent 16 years as a practicing engineer working for several large corporations. Professor Dunne received his B.S.E.E. and M.S. from the University of Illinois at Urbana-Champaign and a Ph.D. from the Illinois Institute of Technology, all in Electrical Engineering. His interests include digital signal processing and communications systems.

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Melvin Cooke GE Aviation

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Abstract
NOTE: The first page of text has been automatically extracted and included below in lieu of an abstract

Design of a Hardware Platform for Analog Communications Laboratory

Introduction

In the typical electrical engineering curriculum, analog communications is usually a junior or senior year elective. Such a course typically focuses on analog radio, covering the topics of amplitude modulation (AM) and frequency modulation (FM). Also included is the study of noise effects in communication systems and other related concepts in signals and systems. Increasingly, the laboratory portion of an analog communications course has migrated to simulation-based experiments using MATLAB1 or to quasi- simulation methods based on the capabilities of LabVIEW2. The motivation for this move has been to sidestep the difficulties associated with having the students construct analog communications circuitry where often the communications experimentation is undesirably dominated by analog hardware build and debug. While simulation is a useful supplement, the move away from hardware does not fully satisfy the desire of students to experiment with “real” signals and systems.

Fortunately, with the increase of integration of communications circuitry towards stand alone ICs the difficulty associated with constructing analog communications circuits has been greatly reduced. It is thus possible to quickly assemble and begin experimenting with analog communications. Our approach has been to combine several of these circuits onto an all-in-one communications board that can be simply configured for a variety of experiments. The communication circuits, along with filtering and amplification stages, are connected in various configurations to allow for the emulation of a full communications system, including modulation, transmission, reception under the conditions of noise, tuning and demodulation. Furthermore, these circuits allow for experimentation at relatively low frequencies, thus avoiding higher frequency measurement issues while requiring only standard medium-range laboratory test equipment.

Our communications board allows for the emulation of modulation and demodulation for both AM and FM. AM is generated using the MC1496 balanced modulator3, with demodulation achieved via envelope detection. FM modulation is achieved through the use of the VCO ICL838 IC4. Alternatively, FM generation is also achieved through the use of a modified Colpitts Oscillator5 circuit. FM Demodulation is performed through a bandpass discriminator combined with an envelope detector. Filtering and buffering stages are included, along with an audio output circuit and signal multiplexor. Other circuitry includes a tunable broadcast quadrature detector FM receiver based on the TDA7000 IC6. Furthermore, other similar complexity circuits, which could optionally be used for this type of platform, are described including AM DSB-SC modulation using the SA6027 and PLL-based FM demodulation using the LM565C8. The communications

Dunne, B., & Cooke, M. (2008, June), Design Of A Hardware Platform For Analog Communications Laboratory Paper presented at 2008 Annual Conference & Exposition, Pittsburgh, Pennsylvania. https://peer.asee.org/4333

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