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四、非线性失真 |
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信号经放大电路放大以后,输出波形与输入波形不完全一致称为波形失真。
由于晶体管特性曲线非线性引起的波形失真称为非线性失真。
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与静态工作点的位置和输入信号的幅值有关。 |
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(一)截止失真:静态工作点设置太低,靠近截止区。 |
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消除截止失真的方法: |
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提高静态工作点的位置,适当减小输入信号ui的幅值 |
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(二)饱和失真:静态工作点设置太高,靠近饱和区。 |
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消除饱和失真的方法: |
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降低静态工作点的位置,以及适当减少输入信号ui的幅值。
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五、最大输出电压幅值 |
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放大电路在电路参数已确定的条件下,输出端不发生饱和失真和截止失真时的最大输出信号电压的幅值称为最大输出电压幅值,记作Uomax |
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UF是受截止失真限制的交流信号分量的最大幅值;
UR是受饱和失真限制的交流信号分量的最大幅值。
UCES叫做晶体管的饱和压降
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输出动态范围UP-P,表示最大输出电压的峰-峰值,即:
UP-P=2Uomax |
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