| 摘要 |
PURPOSE:To obtain non-linear amplifying operation from the area of extremely fine amplitude in an input signal by adding an input signal to an input signal passed through a low frequency removing filter and a logarithmic amplifier or an output signal under prescribed polarity relation and outputting the inputted signal as an output signal. CONSTITUTION:After removing a low band component such as a DC component from an input signal X(s) by the low frequency removing filter 12, the processed signal is inputted to the logarithmic amplifier 16 and added to the input signal X(s) by an adder 17 under the prescribed polarity relation. In the case of using a non-linear amplifier circuit as a non-linear emphasis circuit, the output signal of the amplifier 16 is added to the input signal X(s) by the adder 17 under the same polarity. In the case of using the circuit as a non-linear deemphasis circuit, the output signal of the amplifier 16 is added to the input signal X(s) by the adder 17 under reverse polarity. Consequently, non-linear emphasis characteristic increasing gain at the small amplitude of the input signal and reducing the gain at the large amplitude in a high frequency level can be obtained. |
