| 主权项 |
1. An analog filter, comprising:
a chain of filter stages including at least a first filter stage, a second filter stage, and a third filter stage, wherein:
the first filter stage includes a first negative-gain amplifier, a first capacitor, a first input node, and a first output node, wherein the first negative-gain amplifier and the first capacitor are positioned between the first input node and the first output node,
the second filter stage includes a second negative-gain amplifier, a second capacitor, a second filter stage resistor, a second input node, and a second output node, wherein the second negative-gain amplifier, the second filter stage resistor, and the second capacitor are positioned between the second input node and the second output node, and the first output node of the first filter stage is connected to the second input node of the second filter stage through a first resistor,
the third filter stage including a third negative-gain amplifier, a third capacitor, a third filter stage resistor, a third input node, and a third output node, wherein the third negative-gain amplifier, the third filter stage resistor, and the third capacitor are positioned between the third input node and the third output node, and the second output node of the second filter stage is connected to the third input node of the third filter stage through a second resistor; anda feedback resistor effective to provide a negative feedback, wherein the feedback resistor includes a first end and a second end, wherein the first end is connected to an output of the analog filter, and wherein the second end is connected to the first input node of the first filter stage; and a feedback capacitor effective to provide a positive feedback, wherein the feedback capacitor includes a third end and a fourth end, wherein the third end is connected to the third output of the third filter stage, the output node of one of the chain of filter stages and the fourth end is connected to the second input of the second filter stage. |
