Bell System Technical Journal at the Internet Archive

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The Bell System Tech Journal has moved around to a number of different free and pay-walled sites over the years. I'm glad to see it is now on the Internet Archive. A number of seminal papers were published there. Here are some of my favorites.

​Shannon's Mathematical Theory of Communications, published in two parts. This is arguably the most influential scientific work of the 20th century.
  1. Bell System Technical Journal, 27: 3. July 1948 pp 379-423. A Mathematical Theory of Communication. (Shannon, C.E.)
  2. Bell System Technical Journal, 27: 4 October 1948 pp 623-656. A Mathematical Theory of Communication (Shannon, C.E.)
Pierce's "less mathematical" book on Shannon's work is also on the Internet Archive. It was the textbook for Bob Krull's course on Info Theory that I took at RPI in 1976, which has had a deep influence on my thinking.  

The following papers are on Bell Labs' work on "Auditory Perspective" in the early 1930s -- what we now call stereo. Bell Labs was interested in live transmission of symphony orchestra concerts to audiences in distant halls because it would be an application for AT&T's long-distance lines.
  1. ​Bell System Technical Journal, 13: 2. April 1934 pp 239-244. Symposium on Wire Transmission of Symphonic Music and Its Reproduction in Auditory Perspective, Basic Requirements. (Fletcher, Harvey)​
  2. Bell System Technical Journal, 13: 2. April 1934 pp 245-258. Physical Factors, Symposium on Wire Transmission of Symphonic Music and Its Reproduction in Auditory Perspective. (Steinberg, J.C.; Snow, W.B.)​
  3. Bell System Technical Journal, 13: 2. April 1934 pp 259-277. Loud Speakers and Microphones, Symposium on Wire Transmission of Symphonic Music and Its Reproduction in Auditory Perspective. (Wente, E.C.; Thuras, A.L.)
Fletcher was Millikan's Ph.D. student who actually performed the famous "Oil Drop" experiment that determined the charge on an electron. Wente is the inventor of the condenser microphone. 

During this same period, Blumlein at EMI in England was working on "binaural" audio.  EMI was interested in recorded sound for motion pictures. AT&T's approach was to capture and reproduce the wavefronts as they crossed an imaginary plane separating the musicians from the listeners. Blumlein's approach started with Strutt's (Lord Rayleigh) duplex theory of human directional hearing and working backward through the system to a microphone system that could capture appropriate signals for this.  

In some sense, these two approaches represent the two paradigms still present in recoding: bringing the performers into the listeners space or transporting the listener into the performers space. 

These papers were the primary technical references for the construction of "Blue Boxes" that allowed one to make free long-distance phone calls.  A number of my friends at RPI built these; so did Wozniak. They were made obsolete by the introduction of 4ESS, replacing the 4a crossbar and earlier switching systems that used in-band signaling. Every hard copy of these volumes that I've seen has had these pages razor-bladed out.

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