Importance

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Abstract

Improved gain control for a digital signal processing (DSP) repeater, such as a bi-directional repeater, is disclosed. A repeater includes a back-end subsystem which comprises, for each channel in a set of wanted frequency channels that are amplified by the repeater, a coupler (314) arranged to provide a monitor signal corresponding with an output channel power level. A feedback loop (306) receives the monitoring signal, and incorporates a power control circuit (308) that compares the monitored output channel power level with a predetermined maximum output signal level (310). A corresponding control signal is generated, and provided to a variable attenuator (304) in order to maintain the individual output channel power level at or below the maximum output signal level (310). Advantageously, a DSP output level control function (404) is also provided, which maintains the output signal level of each digital channel below a maximum rated value for a digital-to -analogue converter (402). It is also advantageous to provide a front-end subsystem (420) including a variable gain attenuator (424) that is controlled by a signal (430) generated by a digital processing element (428) that monitors an output of an analogue-to-digital converter (426), in order to maintain an IF signal level at the analogue-to-digital converter input below a predetermined threshold value. An improved frequency stability control apparatus (600) and method (800) are also disclosed.

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First Claim