COMMUNICATIONS INTERFERENCE REDUCTION TECHNIQUES.
GEORGIA INST OF TECH ATLANTA ENGINEERING EXPERIMENT STATION
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A discussion is presented on several techniques for controlling the interference susceptibility of receivers. Lossy dielectric filters are described which, when combined with conventional reactive filters, exhibit superior stop-band performance as well as high attenuation slopes in their cutoff regions. An active cancellation filter is discussed which can greatly reduce the level of co-channel or adjacent channel interfering signals before they enter the input of a receiver. The effects of mixer parameters on mixer spurious responses are studied and three unconventional modes of mixer operation which showed considerably reduced levels of spurious responses are pointed out. A description is given of the high frequency impedance characteristics of typical bonding structures. Methods of rapidly evaluating bonding impedances in field installations are developed and methods for lowering bonding impedances are considered. Measurement techniques are detailed which permit the frequencies of interfering signals to be accurately determined. The construction of a wide dynamic range loss measurement system to aid in the rapid evaluation of the stop-band performance of interference filters is also described. Author
- Radio Communications