| 摘要 |
PURPOSE:To prevent the generation of distortion by controlling attenuation in accordance with the output value of a peak holding circuit. CONSTITUTION:A signal inputted to input terminal 11 is supplied to logarithmic amplifier 14 while output after being amplified by amplifier 13. After logarithmic amplifier 14 amplifies the input signal, rectifier 15 converts the input into a direct current, which is integrated by integrator 16. Consequently, the input signal, even when in a burst shape, is averaged to a proper level. This averaged input signal is peak-held by peak holding circuit 18. The peak-held signal is converted by A/D converter 19 into a signal of a digital value, which is used to control programmable attenuator 20. Gain control is exercised by varying the input resistance of amplifier 13. The peak holding is carried on until a reset signal is supplied to terminal 21. |
