Massachusetts Institute of Technology
Department of Electrical Engineering
Graduate Analog Lab
(aka RF Project Laboratory)
This class was offered Spring 1997 as 6.971.
We intend to teach the unteachable in this class, namely, that elusive
quantity called ``real world experience''. We have chosen a collection
of projects that we believe represents a broad spectrum of modern analog
circuits and subsystems, however, we believe that the same concepts
could be presented by any well chosen collection of assignments. This
is not a class about particular circuit topologies, it is a class about
techniques for designing and building complicted systems that we believe
can only be taught by example. Solid State Circuits (6.301) is not a
class about transitors, but is really a class about circuit analysis and
design techniques. The circuit analysis concepts, like open circuit
time constants, taught in 6.301 could just as easily be taught in the
context of MOSFETs or vacuum tubes as bipolar junction transitors.
Likewise, the topics covered in Feedback Sytems (6.302), such as root
locus, Nyquist and Bode, could just as easily be taught with hydralic
systems as with motors and op amps. Thus, if there are additional or
replacement topics that the class can reach concensus on, the staff is
open to suggestions.
The format we will use involves discussing the ways that a particular
function can be accomplished for a few class periods. These
introductions are kept non-rigorous and informal (there is no need to
prove anything --- we have history on our side!), with maximum
``round-table''-type participation. Following each discussion, a design
problem is assigned in the form of a specification sheet. The objective
is to complete a paper design and construction of a circuit that meets
the specifications. The paper design should be detailed, neat, and in a
form that a technician might reasonably be expected to work from.
Unspecified component types or values are unacceptable. A description
of the operation of the circuit, emphasizing its important features, and
analysis demonstrating conformity with specifications are required.
This class is for motivated self starters. While we will be present in
the laboratory, and meeting with you individually to discuss your
designs, the staff is not available to help your troubleshoot your
designs. ``Why doesn't my circuit work?'' is a question that we do not
have an answer for. However, we can, and will, talk at length about
``How to find what is wrong with your circuit''. Likewise, successful
completion of this course may require a significant amount of your time.
We firmly believe that full immersion is the appropriate atmosphere for
teaching these concepts.
Experience shows that the background provided by 6.301 and 6.302 is
essential to successful participation in 6.RFL. No ``or equivalents''
seem to exist, thus these subjects must be firm prerequisites. The
final grading of this course will be relatively generous, since we are
looking for people who have mastered the concepts of 6.301 and 6.302.
However, we do demand that you finish all of the assigned work in order
to receive a passing grade.
The level of the material in the class is intended to be below the
complexity and difficulty of the material and assignments introduced in
Advanced Circuit Techniques (6.331), however the choice of topics
covered in this class are such that this class and 6.331 may be taken in
The class will meet for one or two ninety minute sessions each week to
discuss the appropriate material for the current laboratory projects.
Problem sets concentrating on modeling, feedback, and circuit techniques
that provide background for creative design efforts will be occasionally
assigned. However, as the main thrust of this class is laboratory work,
students are expected to spend a considerable amount of time in the
6.RFL is part of
The Analog Way.
- Lab 1 ``High Speed Amplifier Lab''
After a classroom review
of operational and transimpedance amplifiers, students explore the use
of these devices in the lab. Students compare the topology and
performance of devices such as the LM6171 voltage op amp and the LM6181
transimpedance amp, and attempt to measure the unity gain settling time.
Using the LM6181 and a high speed buffer such as the LH0002, LH0033, or
LH4002, students build an externally compensated version of the LM6171
and explore various open loop transfer function shapes. Traditional op
amp topologies such as the LM301 and LF411 are also used.
- Lab 2 ``Phase Lock Loops Lab''
A brief treatment of phase lock
loops, using modern building blocks and student constructed blocks, is
done, covering the concepts of lock range, acquisition, and performance
specifications. Using the CD4066, students build a number of phase lock
loops, including one to acquire the 19 kHz subcarrier from an FM stereo
- Lab 3 ``FM Stereo Decoder Lab''
Using the results from Lab 2,
students finish the design and construction of a FM stereo composite
signal decoder, similar in function to the (now discontinued) National
- Lab 4 ``Oscillator Lab''
After a review of describing
functions and phase shift topologies, students construct a number of
simple oscillator circuits and analyze them as possible VCOs, with
respect to center frequency stability and tuning range. A frequency
stable and amplitude stable 38 kHz oscillator is built.
- Lab 5 ``Translinear Mixer Lab''
The accuracy and dynamic
range of translinear multipliers can be greatly improved with a few op
amps to provide base current and biasing to some of the devices. A high
accuracy multiplier, suitable for use as an audio frequency mixer, is
constructed from basic parts such as the LM3086 transistor array and
compared to the LM1496.
- Lab 6 ``FM Stereo Encoder Lab''
Using the results from Labs 4
and 5, students finish the design and construction of a FM stereo composite
signal encoder, and test it against the decoder they built in Lab 3.
- Lab 7 ``Frequency Synthesizer Lab''
The students build a
crystal based phase lock loop capable of tuning from 88 MHz to 108 MHz.
- Lab 8 ``RF Communication Lab''
An introduction to the
concerns and tradeoffs in building RF circuits is presented. Using the
results from Labs 6 and 7, students complete the construction of a low
power FM stereo transmitter.
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Last updated: Tue Feb 5 07:16:53 EST 2002,
by Kent Lundberg.