Patent ID: 7138873

Claim:
A filter circuit processing an input signal to provide a variable gain amplification (VGA), said filter circuit comprising: an operational amplifier having an input terminal and an output terminal; a first resistor and a second resistor connected in series at a first node, a second terminal of said second resistor being connected to said input terminal of said operational amplifier, said first resistor being coupled to receive said input signal at an input node; a first capacitor connected between said first node and a first constant bias; a second capacitor connected between said input terminal and said output terminal; a third resistor and a fourth resistor connected in series between said input terminal and said output terminal, said third resistor and said fourth resistor being connected at a second node; and a third capacitor connected between said second node and a second constant bias, wherein at least some of said first resistor, said second resistor, said third resistor, said fourth resistor, said second capacitor, said first capacitor, and said third capacitor are programmable to corresponding desired values to achieve said desired VGA, and wherein said input signal amplified by said VGA is provided as an amplified signal to said output terminal.