| 摘要 |
Automatic gain control circuit for setting the gain of a signal amplifier (8) having a peak value detector (16) for measuring signal amplitudes of the analogue signal which is amplified by the signal amplifier (8), a comparator circuit (20) which compares the measured signal amplitudes with an upper threshold value and a lower threshold value and generates digital range display data items which in each case indicate whether the measured signal amplitudes lie below the lower threshold value, between the two threshold values or above the upper threshold value, and having a digital control circuit (26) which incrementally changes the gain of the signal amplifier (8) as a function of the generated digital range display data until the digital range display data indicate that the measured signal amplitudes between the two threshold values (Vsw1, Vsw2) lie in a lock-in amplitude range.
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