Patent ID: 8354880

Claim:
A filter comprising: a voltage source having a first connection point coupled to ground; a first resistor having a first end coupled to a second connection point of said voltage source; a first operational amplifier having an inverting input coupled to a second end of said first resistor; said first operational amplifier having a non-inverting input coupled to ground; a second resistor having a first end coupled to the inverting input of said first operational amplifier, said second resistor having a second end coupled to an output of said first operational amplifier; a second operational amplifier having a non-inverting input coupled to the second end of said first resistor; a third resistor having a first end connected to the non-inverting input of said second operational amplifier; said third resistor having a second end connected to an inverting input of said second operational amplifier; said second operational amplifier having an output coupled to the second end of said third resistor.