Band pass filter allows only signals within a certain frequency range pass through rather than the pass band lower frequency than the upper limit of the low and high frequency
signals are to be attenuated or suppressed. A typical voltage-controlled voltage source second order band-pass filter as shown in FIG. The advantage of this circuit is to change the ratio of wind RF bandwidth can be changed without affecting the center frequency. FIG integrated operational amplifier AJ dual op amp vA747.