Analysis of single-tone spurious effects in nondesensitized radio communication systems

An investigation and analysis of STS (single-tone spurious) interferences are presented. The analysis provides a new semiempirical computational method of obtaining a list of forbidden, potentially disturbing STS frequencies for each nonsensitized receiver operating channel. A newly developed UHF/FM or FSK modulated radio communication system using two frequency converter stages is used as an example to illustrate the method´s validity for improving the radio system´s performance. The preliminary results of the computational program and the STS products and measurements on two engineering models of receivers are used contribute to improve the computational method. The improved computational method takes into account the effects of the STS harmonic components and input power level variations on the frequency converter stages attenuation characteristics and on the receiver´s system rejection ratio. The final computed and measured results are very similar to each other