Retrieval of a Missed Opportunity and Why We Use Sine Waves to Test Systems
Have you ever wondered at the omnipresence of sine waves in audio? Here’s Ernst Adolph Guillemin on that subject.
Ernst Adolph Guillemin (1898 – 1970) lived in Wellesley Hills, MA during the 1950s, as we did from 1955 to 1958. Through my ignorance of my betters, we never met. (That’s why you should read the current literature from the IEEE, AES, etc. I was alert enough to meet Leo Beranek of BBN and Arthur Fiedler, Director/Conductor of the Boston Pops.)
By 1955 Guillemin had written five books among which were the classic two volume “Communication Networks,” Vol. I in 1931 and Vol. II in 1935. His “Introductory Circuit Theory” was published in 1955. A reading of it would have propelled me into an early understanding of the value of pole-zero analysis. He wrote,
Ernst Adolph Guillemin
“These examples were constructed by starting from assumed pole-zero configurations for the desired transfer functions and synthesizing the pertinent networks.”
Then he dropped this bomb into a textbook designed for sophomores at MIT.
“Thus for the first time in the history of textbooks on Transient Analysis, the reader is presented with illustrative examples involving higher than second order systems….He will find a multiple order pole problem, other than the hackneyed RLC circuit for the critically damped case; and he will find examples that are representative of useful response characteristics, as well as illustrative of the theoretical analysis that precedes them…..If a circuit with more than two or three meshes was assumed, being able to start from a pole-zero pattern and work in both directions (to a network on one hand, and to its transient response on the other) opens up a host of possibilities not available to the textbook writer in the past.”
A further jewel for all of us who have worked with circuit configurations is his
“Systemic elimination procedures, solution by determinants, special artifices applicable, where various types of symmetry prevail, short methods usable with ladder structures, wye-delta transformations, source transformations (which are what Thevenin’s and Norton’s theorems amount to), the reciprocity theorem (frequently an effective aid in obtaining a desired result), a knowledge of how power calculations must be made (the fact these effects when caused by separate sources are not additive in contrast to voltages and currents which are), the transformations that leave power relations invariant, the equivalence relations pertinent to the tee, pi, bridged tee and lattice structures – all these things are useful when we are dealing with the business of constructing solutions.”
I ask, does your check list match Mr. Guillemin’s list?
Have you ever wondered at the omnipresence of the sine wave in audio? Here’s Guillemin on that subject.
“When an electrical network consisting of linear elements is excited by a voltage or current source that is a sinusoidal time function, the resulting stationary voltages and currents in all parts of the network are likewise, sinusoidal time functions, differing from each other, and from the excitation function at most in their respective amplitudes and time phases…..The network may have a structure of unlimited complexity, (i.e., a room), still the voltages and currents everywhere in this entire system are time function which in essence are identical in form, namely, sinusoidal. No other periodic time function can claim such distinction.”
Finally we can so usefully employ Fourier because of the sinusoidal.
It took 53 years, but I’ve finally met the spirit if not the dust of Ernst Adolph Guillemin.
In his 1953 book, “Introduction Circuit Theory,” he wrote,
“Linear, passive, lumped, finite, bilateral circuit theory is the electrical engineer’s bread and butter…..The student needs to know this subject before he tackles any of the other subjects in the curriculum.”
I particularly like Guillemin’s view that
“We refer to things being advanced only so long as we understand them insufficiently ourselves to be able to make them clear in simple terms.”
The reason Guillemin’s books are still so valuable is the fact that they included no active devices, but sources and loads, thus the mathematics are forever.
Dr. R. A. Greiner, Richard C. Heyser, and Dr. Eugene Patronis are men in my life that possessed this gift and could descend to the level of my thought and bring it up to theirs on a given subject. dbd