| 摘要 |
PURPOSE:To reduce high frequency components and to reduce the distortion of an output by connecting a diode between the collector and the emitter of a transistor in parallel, varying the amplification degree of a second amplifier circuit and varying the amplification limitter level of an output signal. CONSTITUTION:When the signal amplification of connection capacitors 8 and 9 in a connection point A exceeds +0.7V, the diode 20 is turned on and the signal is shunted to the ground. Consequently, an amplification is limited at 0.7V on a + side. When the signal amplification at the point A drops below -0.7V, the base potential of the transistor 16 becomes larger more than 0.7V. Thus, the point A is shunt by the earth and the amplification of the point A does not drop less than -0.7V. Consequently, the amplification is limited by the limitter voltage of 0.7X2=1.4V by the diode 20 and the transistor 16 at the point A. Wide band distortion components which occur when the amplification is clipped in a limitter circuit is reduced by the operation of a low pass filter in the amplifier of a second stage. |
