[leadership REFLECTIONS] Man Mohan Sondhi Reflections on My Career at Bell Labs hen Prof. Nehorai Labs and worked there until my retire- demic atmosphere of the place. That was invited me to con- ment in 2001. Currently, I am a consult- something I had not anticipated in an tribute an article to ant at Avaya Labs Research. industrial research organization. And to this column, I was a I must confess that when I joined add to that, the labs had resources in bit hesitant to Bell Labs, I had intended to stay there equipment and support personnel that Waccept his invitation. I do not really have for just a few years to gain some experi- far exceeded those at a university. Also, any advice for young aspiring engineers ence in industrial research and then join top quality computing facilities were or words of wisdom such as the ones you academia. The research environment, available. (By today’s standards, of will find in some of the earlier articles. however, was so attractive that the few course, the computing facility at Bell Also, unlike other writers in this column, years stretched out to 39. Labs in 1962 is laughable. All computa- I have not managed a large group of sci- tions were done on an IBM 704 computer entists. I headed only a very small group BELL LABS: AN INSIDER’S VIEW in batch mode. The computer had a (about six) of colleagues for a few years. I would like to share with you some of memory of 32 K, and it occupied a large However, Prof. Nehorai assured me that the allure and excitement of working at room in the only air-conditioned build- the “Leadership Reflections” column Bell Labs. Much has already been written ing on the campus. Programs were includes articles that look back on scien- about the preeminence and stature of punched on Hollerith cards and sent to tific careers and the institutions that Bell Labs as a research organization. But the computer via mail carts. However, by nurtured them. So my article is going to by using examples drawn from my per- the standards of the day, the facility was be about my career, mainly about my 39- sonal experience, I hope to provide a dif- top class.) year association with Bell Laboratories. ferent, more intimate, perspective. Another thing that struck me imme- My undergraduate training was in Fortunately, a large part of my career diately was the completely free atmos- India, where I earned degrees in physics at Bell Labs was during the era that has phere. Here were world-famous and electrical communication engineering. been called “the glory days” of Bell Labs. luminaries by the dozen, who were not I wanted to continue further studies in I am not sure when that era began— barricaded behind outer offices and sec- engineering, but in those days (mid-1950s) presumably just after World War II. retaries. You could just walk up to their no graduate program in engineering was However, the end is easier to identify. offered anywhere in India. So I decided to Slow erosion started in 1984 when AT&T EDITOR’S INTRODUCTION go to America for graduate studies. One of was broken up, even though Bell Labs The author of this article, Dr. Mohan the universities that accepted me was the itself was still kept in one piece. The ero- Sondhi, has had a long career in University of Wisconsin, where I earned an sion picked up speed in 1996 when Bell industrial research in speech process- M.S. and a Ph.D. In 1954, while I was on Labs was split up into a part that stayed ing at Bell Labs. In this article he gives the ocean on my way to America, my very with Lucent Technologies and another an account of events chosen from his own association with Bell Labs to first scientific paper (on vibrations of part that formed the new AT&T Research illustrate what he believes were the Indian musical drums) appeared in the Lab. And, at least for the area of Bell Labs most noteworthy characteristics of Journal of the Acoustical Society of where I worked, the end came abruptly that renowned lab—emphasis on cre- America. (Air travel those days was by pro- in 2001 with what I call “an epidemic of ation of knowledge, freedom to peller planes and only for the very rich.) I encouraged retirement.” But I am get- choose research topics, and taking a arrived in New York just about when ting ahead of my story. Let me tell you long-term view of research problems Senator Joseph McCarthy was beginning to about some of the qualities of Bell Labs without being tied to development fall from grace. that made it such a unique place and, of products. He closes with a plea for After finishing my Ph.D. degree at wherever possible, to give you some a re-creation of that type of research Wisconsin, I briefly worked for industry examples from my experience that illus- environment. and at a research institute in India and trate these qualities. —Arye Nehorai “Leadership Reflections” taught at the University of Toronto, One of the first things that impressed Column Editor Canada, for a year. In 1962 I joined Bell me at Bell Labs was the essentially aca- IEEE SIGNAL PROCESSING MAGAZINE [6] JULY 2006 1053-5888/06/$20.00©2006IEEE [leadership REFLECTIONS] continued offices, and they all welcomed you to dis- theory, which was definitely not some- the vocal tract and from them estimate cuss problems with them. thing of direct interest to the depart- its three-dimensional form. This method ment that employed me. (Incidentally, is undesirable for several reasons, the THE IMPORTANCE OF DIVERSITY one of those papers, written in collabo- most important being the need for pro- Diversity was another remarkable aspect ration with David Anick and Debasis longed exposure to X rays. Manfred of the labs. The department that I joined Mitra, actually turned out to be cited far Schroeder suggested using acoustical was ostensibly concerned with various more than any of my papers in acoustics measurements to determine the shape aspects of speech signal processing, cod- or speech.) and derived a method valid when the ing, and transmission. Everyone in the Emphasis was on doing good science tract is only slightly perturbed from a department was interested in one aspect and creating new knowledge without the uniform cross section. B. Gopinath and I or another of speech. But as far as I could immediate goal of practical application. became intrigued by this “inverse” prob- tell, almost none of the members of the Not all research was aimed at developing lem and were able to derive a complete department joined the lab with prior cre- products. The thinking was that with mathematical solution. Later, in collabo- dentials in that area. There were a couple several competent people doing research ration with Jeff Resnick and then with of electrical engineers, a physicist, a phys- with a variety of motivations in an envi- Juergen Schroeter, I was able to reduce ical chemist, a mathematician, and so on. ronment rich with relevant problems, the method to practice and actually pro- And yet, together they were able to pro- some of the research was bound to result duce movies of the dynamic variations of duce some of the best work in the field. in good products. This attitude started the vocal tract. This work did find recog- This approach is in sharp contrast to the changing slowly in 1984, and there was nition in some areas of the scientific modern idea of hiring people who would more and more emphasis on product- community but turned out not to be too “hit the ground running.” oriented research. Some revisionist useful for speech work. Yet its scientific Another aspect of diversity is worth claims have been made to the effect that merit was appreciated, and the work was mentioning. It was the acknowledge- research at Bell Labs was always directed supported at Bell Labs for several years. ment that people have various motiva- towards a product, and the invention of As an example of emphasis on long- tions for doing research. Some (like me) the transistor has been cited as a prime term research, I might mention my work approach it as puzzles to be solved, oth- example of this. I do not agree with that on echo cancellation. In long-distance ers to make a fundamental discovery or assessment. And as far as the invention telephony, echoes are generated at points to make a lasting contribution to society, of the transistor is concerned, I distinctly of impedance mismatch, mainly at the yet others to invent commercially suc- remember a symposium in honor of the interface between the long-distance net- cessful products, and so on. It was recog- 50th anniversary of its invention. Several work and the local network. Several satis- nized that good research can be done scientists who had participated in that factory methods of combating these with a variety of such motivations. activity in the 1940s were at this sympo- echoes had been invented over the Freedom to choose the line of sium. And several of them made state- decades since the advent of long-distance research one wished to pursue was one ments to the effect that the study of telephony. In 1962, however, one week of the most enticing aspects of working semiconductors was presented to them after I joined Bell Labs, the era of satellite at Bell Labs. I can say without hesitation as an area worth investigating with the telephony was ushered in with the launch that in my 39 years there, I was not once potential of yielding breakthrough prod- of the first communications satellite, asked, let alone imposed upon, to work ucts.