le to those of stationary systems. Both the M.I.T. and JPL programs have left a legacy of excellent documentation on spread-spectrum signal processing, spectral analysis, and synchronization, and have provided some of the finest modern textbooks on communications. A very successful long-term SS system investigation began at Sylvania Buffalo under Madison Nicholson and later under Jim Green, and ended up merging with some JPL-based experience at Magnavox in the development and production of the ARC-50 family of systems. The ARC-50 was the first deployed SS system with any of the following characteristics: 1. avionics packaging, 2. fully coherent reception (including carrier tracking), 3. a several megahertz chip rate, and 4. voice capability. References Figure 2.34. VIP's at the IEEE NAECON '81 included Robert Larson, Wilbur Davenport, Paul Green, B. Richard Climie, Mrs. Mortimer Rogoff, Mortimer Rogoff, Mrs. Louis deRosa, and Robert Price. Featured at this meeting was the presentation of the Pioneer Award to deRosa (posthumously), Rogoff, Green, and Davenport for their ground-breaking work in the development of spread-spectrum communications. (Photo courtesy of W. Donald Dodd.) Although losing the ARC-50 final design and production contract to Magnavox, Sylvania continued on to develop BLADES, the earliest FH-SS communication system used operationally. Moreover, BLADES repre- sented, by publication (e.g., [124]) and actual hardware, the start of real- world application of shift-register sequences to error correction coding, an algebraic specialty that would flourish in coming years. Since the 1950s when the SS concept began to mature, the major advances in SS have been for the most part technological, with improvements in hard- ware and expansion in scope of application continuing to the present day. Now with the veil of secrecy being lifted, the contributions of some of the earliest pioneers of SS communications are being recognized (see Figure 2.34). We hope that this historical review has also served that purp