developed. Based on their success, a bank of thirty-two "channel" filters was implemented for an M-ary FSK optional mode to transmit a full char- acter (five bits) per baud. Loss of a single baud in this case meant loss of a full character because the (15,5) decoder could only correct three bit errors per codeword. A "noodle slicer" was implemented to avoid this problem by interleaving five different codewords, to that each baud car- ried one bit from each word. This interleaving technique was the subject of a patent filed in 1962 by Sylvania engineers Vincent Oxley and William De Lisle [128]. Noodle slicing was never employed in the FH binary FSK mode. 15-BIT RECEIVED SEQUENCE (3121110987654320 READ IN MAJORITY DECISION CIRCUIT MAJORITY DECISION CIRCUIT SHIFT REGISTER DRIVE - 15 14 13 12 1111098765432 15-BIT CONSTRUCTED SEQUENCE READ-OUT 54321 DRIVE I'S GEN. NOTE: REPRESENTS MOD-2 ADDITION READ OUT READ-1 - IN BIT RATE SHIFT REGISTER DRIVE RATE READ-OUT BIT RATE Figure 2.14. The (15,5) error-correcting code used in BLADES consisted of a (15,4) code and its complement. The (15,4) code in turn was composed of the all-zeros 15-tuple and the fifteen cyclic shifts of a length-15 m-sequence. Fryer's description of the (15,5) decoder (shown above) indicated that the received word was majority-logic decoded as a member of the (15,4) code, using the two 15-stage registers, and the result compared to the received code word. The complement of the decoded word was assumed transmitted if and only if more than seven bit changes were made in the (15,4) decoding process. (Diagram from [125].) The Historical Origins of Spread-Spectrum Communications BLADES occupied nearly 13 kHz of bandwidth in its highest protection mode. In addition to being a practical AJ system, as Vincent Oxley recalls, during initial breadboard on-air tests, the system also served very well as an unintentional jammer, efficiently clearing all other users from the assigned frequency band. After considerable in-house and on-air testing between the Amherst La