Delay circuit employing active bandpass filter

摘要

A signal to be delayed is applied to a frequency selective path including an inverting active bandpass filter and to a non-frequency selective path including a voltage-to-current converter. The paths are coupled to a signal combiner which produces an output current having a first component proportional to the output current of the converter and a second component directly proportional to the filter output voltage and inversely proportional to the value of a gain control resistor. The resistor is selected to provide a predetermined ratio of the output current components to provide an overall allpass characteristic for the delay circuit and biased to conduct no current under quiescent signal conditions thereby reducing power dissipation. Several circuits may be cascaded for such purposes as peaking and delay equalization in television receivers, video disc players or the like.