allest SNR to provide a guaranteed Pb of 10-5 in any kind of non-adap- tive jamming, we would use the Odenwalder (7,1) binary convolutional code: this requires EIN = 10.38 dB for worst case partial-band noise, with bet- ter performance for any other jammer. By comparison, if we adopted the same system design philosophy for uncoded signalling with optimum diver- Coding Countermeasures ORTHOGONAL CONVOLUTIONAL CODE WC PARTIAL-BAND NOISE Eb/Nj, dB Figure 2.76. Variation with K in performance of orthogonal convolutional codes with FH/MFSK signals in worst case partial-band noise, assuming soft decision energy detection with linear combining metric and perfect jamming state side information. Performance is generally poor, but improves with K. ORTHOGONAL CONVOLUTIONAL CODE WCn=1 BAND MULTITONE Eb/Nj, dB Figure 2.77. Same as Figure 2.76, but for worst case n = 1 band multitone jamming. For sufficiently small Pb's, performance improves with K. Non-Coherent Frequency-Hopped Systems DUAL - K, RATE 1/2 CONVOLUTIONAL CODE WC PARTIAL-BAND NOISE Eb/N, dB Figure 2.78. Same as Figure 2.76, but for dual-K, rate 1/2 convolutional coding. Performance improves with K for moderate to small Pb's, but improvement is minor for K V 4. DUAL - K, RATE 1/2 CONVOLUTIONAL CODE WC n = I BAND MULTITONE Eb/Nj, dB Figure 2.79. Same as Figure 2.78, but for multitone jamming. Performance is opti- mized over range of interest of Pb at K = 2. For K 2, performance degrades with K (similar effect was observed for uncoded FH/MFSK signals with optimum diver- sity in Figure 1.51). Coding Countermeasures DUAL - K, RATE 1/3 CONVOLUTIONAL CODE WC PARTIAL-BAND NOISE E /N, , dB Figure 2.80. Same as Figure 2.78, but for rate 1/3, dual-K convolutional coding. Performance improves with K. DUAL - K, RATE 1/3 CONVOLUTIONAL CODE WC n = I BAND MULTITONE Eb/N,,dB Figure 2.81. Same as Figure 2.79, but for rate 1/3, dual-K convolutional coding. Variation with K is qualitatively identical to rate 1/2 code in Figure 2.79. Non-Coherent Frequency-Hopped Systems sity, we wou