ELEC 226, Spring 2012
Prof. Rich Kozick

Laboratory 6
Design of a Waveform Generator

Objective: In the final lab sessions of this semester, you will use your knowledge of analog circuits to design, simulate, and implement a system that will generate square, triangle, and sine waves with variable amplitude and variable frequency. You will document your design and results in a lab report.

Please work with three (preferred) or two students in each lab group.

Design Specifications:

• Your circuit should produce three simultaneous output signals: the square, triangle, and sine waves, each with zero mean value.
• The amplitude and frequency should be variable using potentiometers.
• Design your system to operate at 1,000 Hz, and strive to make it work over as wide a frequency range as possible. Explain how you would modify your design to make it work over a larger frequency range, both lower and higher.
• The parts that you may use are op amps, resistors, capacitors, inductors, and potentiometers (variable resistors). We will have quad-741 ICs with four op amps available.
• Please simulate your design in PSpice before building the circuit.

There are several ways to design this system, so be creative and have fun! The integrator and differentiator circuits in Lab 5 may be useful.

Testing and Documentation:

• Determine the operating range of your design in terms of the amplitudes and frequencies that you can produce for each waveform. Provide your measured results in the lab report.
• Include a complete circuit diagram of your design, showing all circuit components and their values.
• Show the results of your PSpice simulation.
• Provide a brief explanation of the reasoning that you used to design your system and choose each component value.
• Explain how your design can be modified to allow operation over a wider frequency range. Specify which components would be changed, and what values would be used.
• Prepare a lab report that documents the items listed above. One report will be submitted by each lab group, and I suggest that you complete it and submit at your final lab meeting on April 30 or May 1. However, you can submit the report at the final exam on Friday, May 4 at 8:00 AM. Your report may be submitted on paper or electronically as an email attachment.

Schedule: Prof. Kozick and a lab assistant will be available in Dana 305 for the first 2 hours of each lab session on April 16-17, April 23-24, and April 30 – May 1. Your project is completed once you demonstrate the working PSpice simulation and the circuit on your breadboard. If you finish on April 23-24, then you do not have to attend lab on April 30 – May 1. You should work to complete the project as soon as possible, and do not wait until April 30 – May 1 to build and test your circuit!