| 摘要 |
<p>The subscriber module is based on a sequential state machine which loads frequency control words corresponding to the jammed channels from a frequency control memory (404) into each latch on the cyclic basis. The state machine is adapted to modify the sequence in which the frequency control words are read out memory to vary the jamming pattern of the subscriber. The addresses of the memory are read out in a pseudo-random sequence to produce varying jamming patterns but without changing a selected jamming factor for a selected group of channels. The pseudo-random pattern is generated by logically combining (403) a predetermined address sequence with a random number seed from a seed generator. The random number seed can be varied either programmably or addressably to generate other pseudo-random jamming patters. In another implementation the seed generator will evenly distribute the jamming energy of unused time slots to all the other active time slots.</p> |
