用Filter solutions 设计滤波器笔记 要求:分别设计5 阶切比雪夫1 型带通滤波器、切比雪夫2 型带通滤波器,中心频率 500MHz,带宽 50MHz。尝试选用不同的电路结构,观察所用元器件的值有何变化。 切比雪夫1 型滤波器:通带中等纹波,阻带是单调的 切比雪夫2 型滤波器:通带中单调,阻带等纹波,即阻带中有零点(陷波点)。 (1)5 阶切比雪夫1 型带通滤波器:通带中等纹波,阻带是单调的 图 1:参数设置 注释:Asymmetrical 非对称的,只有带通滤波器才有此选项,用于设计非对称结构的滤波器。 Delay Equalize 延迟补偿,低通和带通滤波器才有此选项,用于低通滤波器或者带通滤波器的通带群延迟补偿。延迟补偿的概念: Tx Line:Transmission Line 传输线滤波器 Sw Cap:Switched Capacitor 开关电容滤波器, Active:有源滤波器, Passive:无源滤波器, Digital:数字滤波器, 1st Ele Shunt:滤波器电路结构的第一个元件是并联电感。 1st Ele Series:滤波器电路的第一个元件是串联电容。 Incl Source Bias:Check to include the bias due to the source resistance to appear in the transfer function, frequency response, impedance response, and time response of your filter. For example, if the source resistance is equal to the load resistance, checking this box will cause a -6dB offset will appear in the frequency response, and a factor of .5 will appear in the transfer function and time response. This offset goes away when this box is left unchecked. This box should be left unchecked when using the transfer function for any purpose other than passive filters applications. Complex Terminations:创建滤波器复杂的驱动终端,即自定义滤波器的源终端。 Add Stop Band Zeros:添加阻带零点,Butterworth and Chebyshev I 才有添加阻带零点的选项,这种滤波器已经不再是严格意义上的 Butterworth and Chebyshev 滤波器。 图2:电路图 注释:Resonator 谐振器:仅在设计没有阻带的带通滤波器时才有此选项,即Gaussian, Bessel, Butterworth, and Chebyshev I。 Balance :电路中没有全通级存在的时候才有此选项,选择此选项将显示均衡...