| 摘要 |
<p>The low pass filter in the feedback loop has a certain time constant. A comparator compares the amplified signal amplitude with a reference threshold, and operates a switch which interrupts the feedback loop when the output signal amplitude exceeds the threshold. An amplifier is provided in the feedback loop, to which is allocated a passive integrator. The integrated operates a second switch in the negative feedback loop. A differential amplifier may be provided, whose one input is connected directly to the main amplifier output, and the other one is connected to this output through a low pass filter whose time constant is greater than the signal rise time, and through a switch. The comparator one input is connected to this differential amplifier output, and its output controls the switches.</p> |
