Radio frequency detector for cable television distribution systems

Abstract

A distribution amplifier (210) for a cable television system (100) includes an output gain stage section (215) for receiving an input signal from a cable head end section (105). The output gain stage section (215) includes multiple active amplifier circuits (225, 230) for amplifying the input signal to generate main and auxiliary outputs that are processed by a radio frequency (RF) detector (255) having at least a first detector circuit (300) for processing the main output to generate a first voltage and a second detector circuit (305) for processing the auxiliary output to generate a second voltage. Further included in the distribution amplifier (210) is a status monitor (260) coupled to the RF detector (255) for converting the first and second outputs to first and second digital values and transmitting the first and second digital values. In this manner, an indication of a system or amplifier malfunction can be provided. Other advantages of the RF detector (255) are that the main and auxiliary outputs can be either simultaneously or sequentially processed, as desired, to provide multiple indications of system problems and that the RF stages of the detector circuits (300,305) are connected in series to reduce current drain, thereby reducing power consumption. Additionally, the RF detector (255) includes a differential amplifier stage (325) that compensates for temperature variations introduced by the diode etector stage (320) to provide a thermally stable RF detector (255).