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This thesis focuses on the analysis of frequency-hopped spread-spectrum communication systems in the presence of worst-case jamming interference. Multi-level quantization is employed to improve the performance at the receiver in both coherent and noncoherent systems over hard decision systems. The channel capacity is the performance measure. The worst-case jamming strategies (from the communicator's perspective) are discussed with various types of noise in coherent/noncoherent systems. For coherent systems, the types of jamming noise considered are tone jamming, phase mismatched tone jamming and partial-b and Gaussian jamming. In noncoherent systems, one-dimensional tone jamming and partial-b and Gaussian jamming are considered. For both coherent and noncoherent systems two, three or four level quantization detectors are used. The jamming strategies we consider allow the jammer to pulse between several power values subject to an average power constraint. It is found that four level tone jamming makes the performance significantly worse than two level tone jamming, whereas with Gaussian jamming, four level jamming does not significantly degrade the channel capacity compared with two level jamming.