ANALYSIS OF SINGLE-TONE SPURIOUS EFFECTS IN NONDESENSITIZED RADIO-COMMUNICATION SYSTEMS

Single-tone spurious (STS) interferences are one of the principal causes of radio system disturbances due to their high probability of occurrence. An investigation and analysis of STS interferences are presented. The resulting analysis provides a new semi-empirical computational method to obtain a list of forbidden, potentially disturbing STS frequencies for each non-desensitized 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 followed by the STS products and measurements on two receiver's engineering model's contribute to improve the computational method. The improved computational method considers 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. Applying this improved STS frequencies list method to the initial design stages of a radio communication system can help to optimize the system performances and frequency allocation policy.