Null-zone envelope detection in binary systems

The effects of applying the null-zone decision mechanism to two types of envelope-detection systems are investigated, and comparisons are made with previous results for synchronous-detection systems. It is demonstrated conclusively that, just as for the synchronous system, null-zone reception offers a means of improving the information rate of a unidirectional system. Moreover, the relative behavior is about the same in all three cases, except that the asymmetry of the on-off system may present some additional difficulties.