degree compared to the baseline jammer. At bit error probability of 10-6 there is approximately a 40 dB degradation due to pulse jamming. These jam- mers, however, can be effectively neutralized with coding and interleaving. 1.5 STANDARD CODES AND CUTOFF RATES In Chapter 3, Part 1, the point was made that the use of coding wit spread- spectrum systems does not require any reduction in data rate or increase in the spread-spectrum signal bandwidth. Even with simple repeat codes, the large degradation due to pulse jamming in DS/BPSK systems can be neu- tralized. With more powerful codes the pulse jammer neutralization plus additional coding gain can be achieved. Recall that in the general coding analysis in Chapter 4, Part 1, the coded bit error bound was given in the form (1.91) where G() and B() are functions specified by the particular code, while D and R are parameters of the channel. For the DS/BPSK systems, D and R have the relationship bits/symbol (1.92) where Figure 1.6 shows the general system block diagram. The system enclosed in dotted lines represents an equivalent binary input channel for which D and R0 can be evaluated. In this case, a symbol entering the equiv- alent channel is a coded bit and the energy per coded bit (channel symbol) Es is related to the energy per bit Eb by Es=REb (1.93) where R is the code rate in bits per channel symbol. Parameter D, and hence parameter R, depend on EN, the symbol energy to equivalent jammer noise ratio. 1.5.1 The Additive White Gaussian Noise Channel This section summarizes well-known results for standard coherent BPSK and QPSK modulations with some binary codes and the additive white Gaussian noise channel model. These results will serve as a reference for the DS/BPSK system with jamming. For the additive white Gaussian noise channel R0 is given by (1.92) where D=e-Es/No (1.94) and No is the single-sided noise spectral density. Coded bit error bounds of the form given by (1.91) are shown in Figure 1.7 for several binary codes. CODING CHANNEL Standard Codes ENCOD