ECE 402L: Applications of Analog Integrated Circuits Laboratory was a 1-credit course taught at Michigan State University for Electrical and Computer Engineering majors. The catalog description for this course is: Circuit design using analog integrated circuits. SPICE macromodeling. Operational amplifiers, comparators, timers, regulators,and converters. Design project with hardware and software verification. The prerequisites for this course are ECE 302 and ECE 303.
Lab Manual and e-Notes
The lab experiments consist of e-Notes explaining the ideas and concepts of each lab experiment. This lab is intended to teach design as well as reinforce concepts taught in ECE 402.
The lab lectures are recorded and can be found on the ECE 402L YouTube channel at: https://www.youtube.com/user/ECE402Lmsu
Table of Contents
Lab I – Introduction to the Oscilloscope, Function Generator and Digital Multimeter
The oscilloscope, function generator and digital multimeter are the basic tools in the measurement and testing of circuits. This lab reviews the operation of these instruments along with the use of a compensated probe.
Lab II – DJ Mixer – Crossfader, Microphone Preamp & Power Amp
Over the next several labs we are going to build a DJ Mixer. This is an instrument that allows simultaneous access to several sources of sound.
A crossfader is a circuit which allows two sources of sound to be mixed together. Using a single pot we can select more from one source of sound while having less from the second source of sound. This is used to fade from one song to another while both are being played.
In this lab, you build a crossfader for your DJ Mixer to mix a CD player output with a phonograph output (which will be built in the following lab). We will also add a microphone amplifier with noise cancellation to allow the DJ to address the audience.
Lab III – DJ Mixer – RIAA Playback Equalizer
With this lab we are going to add to our DJ Mixer an input for a phonograph record.
Phonograph playback preamplifiers require special frequency shaping circuits in their feedback paths in order to equalize or correct for the signal coming off the phonograph cartridge.
In this lab, you will design an RIAA Phonograph Playback Equalizer to undo the recording process. This will then be connected to one of the inputs of the crossfader of Lab II.
Lab IV – DJ Mixer – Bass and Treble Tone Controls
Adding bass and treble controls to our mixer will allow us to match the sound to the room acoustics and personal preferences.
In the course notes of Ch. 2, pp 24 – 32, we approached the design of bass and treble control circuits from scratch. That is, we started with the specifications of our circuit and then began putting configurations of components together that could realize these specifications.
In this lab, you will reconsider the design of the bass and treble tone control circuit we did in class. You will also consider lowering the cost of the design by trying to combine functional blocks.
Lab V – DJ Mixer – Audio Spectrum Filters for a Color Organ
A color organ is a system which causes a set of lights to change dynamically with music tones and levels. It consists of four active filters which divide the audio spectrum into distinct color bands. Each band triggers a set of lights which in our design will be red, yellow, green and blue LEDs. In commercial designs these are sometimes flood lights.
In this lab, you will design the active filters for the color organ and add this to our DJ Mixer. In a later lab, we will add the comparators and LEDs.
Lab VI – Designing a Stabilizer for a Differentiator Circuit
Stability is considered by many to be one of the most common problems in getting a design to work. In this lab you will investigate the properties of a differentiator circuit, i.e. a circuit whose output is the derivative of the input times a scalar. This circuit suffers from excessive ringing.
Your main design task is to modify the differentiator circuit to eliminate the ringing while maintaining function.
Lab VII – PSpice Macromodeling of an Op-Amp
Macromodels attempt to capture the linear and nonlinear performance of an IC using a much simplified equivalent circuit of the IC. Macromodeling is an area of virtual design where Spice components are the parts and the design task is to re-create reality.
Your tasks are to measure some of the parameters needed for the PSpice macromodel of an op-amp.
Lab VIII – Crossing Detectors
Comparators are high speed switching circuits which compare two inputs and produces an output state high or low. One advantage of a comparator is that it requires a very small drive current.
Your tasks are to test and measure some of parameters of crossing detectors and crossing detectors with hysteresis. You will also be asked to design a detector in a noisy environment.
Lab IX – DJ Mixer – Color Organ
A color organ is a system which causes a set of lights to change dynamically with music tones and levels. It consists of four active filters which divide the audio spectrum into distinct color bands. Each band triggers a set of lights which in our design will be red, yellow, green and orange LEDs. In commercial designs these are sometimes flood lights.
In this lab, you will build the comparator and LED circuit for the color organ and add this to the audio spectrum filters on our DJ Mixer.
Lab X – Photo-tachometer
Measuring the rotations per minute of a shaft is a common measurement problem. Flashing a constant light source on a shaft will produce a light pattern proportional to the frequency of rotation.
In this lab you will design a photo-tachometer which will take the a pulsing light source and convert it to an average value proportional to frequency of the pulses. Issues of noise and interference will be addressed.
Lab XI – DJ-Mixer – 40 Watt Power Amplifier
A current power booster is added to the basic 2 Watt power amplifier used previously in the DJ-Mixer. Heat sinks are used to handle the added power dissipation.
Feedback is again used to lower distortion. However, the added transistors cause the open-loop gain of the power amplifier to have a poor phase margin. Using β networks, you will design a compensation scheme to make the power amplifier stable.