Patent ID: 7248103

Claim:
A circuit comprising: a band-pass filter coupled to a voltage source, wherein the voltage source is a phase locked loop (PLL) that outputs a control voltage, the band-pass filter comprising: a first plurality of transconductors that receives a first voltage, wherein the first voltage controls the center frequency of the band-pass filter; a second plurality of transconductors coupled to the first plurality of transconductors, wherein the second plurality of transconductors receives a second voltage, wherein the second voltage controls the bandwidth of the band-pass filter, a first buffer coupled between the PLL and the first plurality of transconductors; a second buffer coupled to the PLL and the second plurality of transconductors; and wherein the first and second voltages track the control voltage to provide automatic frequency tuning for the band-pass filter, wherein the first buffer controls the first voltage to control the center frequency of the band-pass filter, and wherein the second buffer controls the second voltage to control the bandwidth of the band-pass filter.