ead-Spectrum Communications that limiters could be used when necessary on narrow-band signals (e.g., prior to PLL phase detectors), and that AGC techniques should be used in the wide-band portions of the system. Analytical support for this work came from JPL's own studies of AGC circuits [172], [173], and from Davenport's classic paper on limiters [174]. It was not realized until much later that in some instances the limiter theory was not appropri- ate for coherent signal processing analyses [175]. For further discussion of AGC capture by jamming, see [176]. Many of these kinds of problems remain with the designer today, the dif- ferences being in the technology available to solve them. Both the Sergeant and Jupiter guidance programs were terminated when decisions were made to choose all-inertial jam-proof guidance designs as the baseline for those missile systems. However, CODORAC technology sur- vived in the JPL integrated telemetry, command, tracking, and ranging sys- tem for the Deep Space Program, and in the later projects of subcontractors who had worked for JPL in the Jupiter program. A modified version of CODORAC became the Space Ground Link Subsystem (SGLS) now used routinely in U.S. Department of Defense missile and space instrumentation. 2.2.11 M-Sequence Genesis The multiplicative PN recursion given in [167] and its linear recursion coun- terpart in modulo 2 arithmetic, namely y(t+m)=y(t)+y(t+n) were among those under study by 1954 at several widely separated locations within the United States. Lehan recalls that the idea of generating a binary sequence recursively came out of a discussion which he had with Morgan Ward, Professor of Mathematics at Caltech, who had suggested a similar dec- imal arithmetic recursion for random number generation. It is hard to deter- mine if this idea was mentioned at the (Classified) RDB Symposium held at Caltech in February 1953. Lincoln Laboratory's Bill Davenport remem- bers that the first time that he had seen a PN generator based on the above recursion was in Leha