Reflection perceptibility threshold on NTSC signals and its measurement technique in a CATV system

The subjective effects of reflection impairment on NTSC pictures are established. Reflections in a CATV system can be analyzed using a broadband technique. The proposed RF model formulates a simple representation to describe the impairment caused by reflections. In the RF domain, reflections manifest themselves as ripple in the amplitude vs. frequency response curve. As the reflection gets closer in time to the transmitted signal, the number of voltage ripples in a given bandwidth decreases. By incorporating adequate computing and processing power in a CATV sweep system receiver, reflections can be characterized on site. Though such an instrument does not exist in the market, the author believes that this instrument, if available, would assist the CATV operator in carrying out preventive maintenance, such as locating mediocre cable connections/splices or devices with poor return loss more efficiently.<
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