| 摘要 |
PURPOSE:To optionally and highly accurately set a clipping level from the outside, by setting a clipping voltage on the basis of a set reference voltage and clipping an input signal by outputting the clipping voltage through a buffer circuit. CONSTITUTION:When a control voltage VC is applied across controlling input terminals 6 and 8, a reference voltage Vref is formed in such a way that a differential output corresponding to the voltage VC is applied to the base of a transistor (Tr)9 and an electric current corresponding to the voltage VC is made to flow to the Tr9. The voltage Vref is applied across a differential amplifier 16 and its output voltage V0 becomes the mid-point level of a clipping level. When a constant current is made to flow from a constant-current source 20 to another constant-current source 22 through resistances 24 and 26, clipping voltages +VD and -VD are formed at each terminal of the resistances 24 and 26. The voltages + or -VD are generated at emitters of Trs36 and 38 through differ ential amplifiers 32 and 34 and Trs36 and 38 and a clipping output VOCL is given in the form of VOCL=V0+ or -VD. Therefore, the clipping output VOCL is generated at an output terminal 40 when an inputvoltage VIN is given to an input terminal 44.
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