| 摘要 |
<p>Gain-controlled amplifier arrangement comprising a cascade arrangement of first (1-8) and second (19-28) gain-controlled amplifier stages, an AM-detection circuit and an integrating arrangement (36-38) for generating a control voltage for the two stages (1-8; 19-28), also comprising a threshold arrangement (½VB; 39, 40) for generating first and second threshold voltages, for delaying at an increasing input level the start of the control of the first stage (1-8) relative to that of the second stage (19-28). So as to prevent the gain control of the first stage (1-8) from starting, for example because of an unwanted variation of the threshold voltages, before the gain control of the second stage (19-28) has ended, the control ranges of the two stages are separated from each other by a so-called separation area in which no gain control is effected. In order to prevent an unwanted deviation of the output level in that separation area the control voltage is generated by integration of a current in a capacitor (37), which current varies with the input level, so that this control does not only depend on the actual input level but also on the duration of occurrence of this input level.</p> |
