The Philosophy of PCM [Bell Monograph, later printing]
New York, N.Y. Bell Telephone Laboratories, Incorporated May 1956. Later printing. -8 pages. 10 7/8 x 8 3/8 inches (275 x 213 mm) Self-wrappers. "MONOGRAPH B-1611 | Reissued May, 1956" upper right. Five holes punched at the spine as issued. The staples are rusty and affect the paper. Unlike many Bell System Monographs, this re-issue was apparently not issued with the characteristic blue/grey wrappers. Very Good. Wraps. 
The Proceedings of the Institute of Radio Engineers, Vol 36, pp. 1324-1331, November 1948 first published this paper. There is no known IRE offprint for this paper. Hence, the first printing of the Bell Telephone Systems Monograph (#B-1611, 1948) constitutes the first separate edition. This Bell Monograph was also later reprinted, as here, in May 1956.
While the foundations for Pulse Code Modulation (PCM) were laid many years before, Shannon, Oliver, and Pierce were inducted into the National Inventors Hall of Fame for its invention. The US Patent Office granted Shannon and Oliver US Patent US2801281A for a "Communication system employing pulse code modulation,” and John R. Pierce U.S. Patent 2,437,707 for a similar invention.
Most people have no idea what PCM is, even though they use it every day on their computers, phones, and CDs - it is found nearly anywhere that requires the digitization of analog signals. This paper explains for the average engineer the basics of PCM directly from the minds of the inventors.
"Recent papers describe experiments in transmitting speech by PCM (pulse code modulation). This paper shows in a general way some of the advantages of PCM and distinguishes between what can be achieved with PCM and with other broadband systems, such as large-index FM. The intent is to explain the various points simply rather than to elaborate on them in detail. The paper is for those who want to find out about PCM rather than for those who want to design a system. Many important factors will arise in the design of a system which are not considered in this paper." (Summary)
PROVENANCE: The personal files of Claude E. Shannon (unmarked). The last of two examples of this item in Shannon's files.
Sloane and Wyner, "Claude Elwood Shannon Collected Papers," #40
National Inventors Hall of Fame (invent dot org)
COLLECTORS NOTE: The Bell Telephone System Monograph series offered a way to obtain individual articles by Bell scientists regardless of where their work was first published. Many Monographs significantly postdate the original article publication. Because of this, they rarely constitute the coveted (and traditional) article offprint. If the journal of record issued no offprint, the Monograph might be the first separate publication - the closest the collector can come to a traditional offprint. We have done our best to place each Monograph properly in the article’s publishing history and welcome any corrections or additional information, especially regarding issues unknown to us.