| 摘要 |
PURPOSE:To attain continuous and linear change of a set clip voltage by applying the clip voltage changed by a constant current changed with a control voltage as a non-inverting input to an operational amplifier and adding an input signal as an inverting input. CONSTITUTION:A control voltage Vc is fed to the non-inverting input + of the operational amplifier 4 of a clip voltage source 2, its output is fed to the base of transistors (TRs) 8, 10 and the voltage generated in the emitter of the TR8 is fed back to the inverting input (-) of the amplifier 4. Further, resistors 22, 24 and a TR20 whose base is connected in common to the base and the collector of the TR18 are placed between the TR8 and the positive line, a prescribed operation reference voltage Vref is set to a middle connecting point and positive/negative clip voltages Vc1, Vc2 are set by using the voltage Vref as a center level. The voltages Vc1, Vc2 are fed to the non-inverting inputs of operational amplifiers 28, 30, each output is fed back to the inverting input, and after an input signal voltage Vin at a terminal 36 is clipped by the voltages Vc1, Vxc2, a clip output V0 is extracted from a terminal 32. |
