Deterministic signals and interference in FM reception: The "Instantaneous" approach, with undistorted inputs

The purposes of this study are several: 1) to extend earlier models of the FM reception process, to include as much "realism"-i.e., nonideality of both the linear and nonlinear elements of the typical FM receiver-as possible, and still retain analytical and computational feasibility; 2) to examine explicit cases of interference produced by one or more deterministic signals; and 3) with such specific examples, both to provide insights into the distortion effects generated by the nonlinar interactions of the various (desired and undesired) signals in the receiver and to present the analytical framework of the instantaneous outputs required in any (subsequent) fully statistical treatment, where now the interference (e.g., "noise") is noticeably non-Gaussian. In addition, these deterministic models may also provide useful structures for simulation studies. The instantaneous receiver outputs are obtained for the following receiver models (A) and interference "scenarios" (B). For (A), (I) "superclipping" and an ideal discriminator; (II) no limiting and ideal discriminator; (III) "superclipping" and a nonideal discriminator; (IV) no limiting and a nonideal discriminator. For (B), with each (A), we consider explicitly the cases of: (i)one cochannel interfering signal; (ii) one adjacent channel interferer, and (iii) M symmetrical interferers (M = 1, 5). All the above are obtained here for idealized (i.e., sufficiently wide-band) RF-IF receiver stages, which are essentially linear under this condition. The results are illustrated with cases for selected, typical parameters of the combination of the interference-receiver structure.