Method and apparatus for automatic control of the gain of an amplifier and the use of this method and this device in the gain control of a tuner, in particular of a tuner for a video communication network

摘要

This process, which is intended to maintain the level of the output signal of this amplifier is equal to a desired value, comprises: & br / - a previous calibration phase, comprising it - even establishing a relationship which gives the variations of the control signal of the amplifier gain or as a function of the variations of the level of the input signal, at the level of output constant and equal to the desired value, or as a function of the variations of the level of the output signal, at the level of the input signal constant, & br / - an operational phase comprising it - same repetition of the following operations: & br / . application of a determined value of the gain control signal to the amplifier, & br / measuring the level of the corresponding output, & br / detection of a possible difference between the result of this measurement and the desired value, & br / search, in the case of a deviation detected, the value of the corresponding control signal, by the relationship, and according to the establishment mode that - ci, or at a level of the input, the difference with respect to the corresponding input level, by the relation to the said determined value of the control signal, is opposite to the detected difference, or to an output level, the difference with respect to the desired value, is opposite to the detected difference, & br / . the updating of the said determined value, depending on whether a deviation has or has not been detected, the said determined value which, in the first case, equal to the value thus obtained by the search.