The Shadow Negative Group Delay Filter

In this work, the shadow negative group delay filter has been proposed. It has been found that the proposed filter retains the bandpass negative group delay filtering function of its core. Therefore, it is a shadow bandpass negative group delay filter. Owing to the virtue of the shadow circuit design concept, the characteristics and key parameters of the proposed shadow negative group delay filter can be adjusted by simply altering the gain of the feedback amplifier stage without the necessity to change any parameter of the core negative group delay filter. This is the major advantage of our shadow negative group delay filter. To the best of our knowledge, this is the first time that the shadow circuit design concept has been applied to the negative group delay filter. In addition, the basis block diagram has been found to be the simplest one of all shadow circuits ever proposed. Since the magnitude frequency response resembles that of the band-stop filter, this shadow negative group delay filter can be applied for signal quality improvement by simultaneously suppressing the noise and cancelling the delay.