A closed form transfer function of low delay bandpass FIR filters with maximally flat characteristics in the passband and the transmission zeros in the stopband

The large group delay of the high order FIR fillers is unacceptable in some applications. So, recently, how to reduce the group delay of FIR filters has been studied intensively. To reduce the ringing in the time domain and to maximize the stopband attenuation, it is useful to design FIR filters with maximally flat characteristics in the passband and transmission zeros in the stop band. We present a mathematically closed form transfer function of low delay bandpass FIR filters with maximally fiat amplitude in the passband and the transmission zeros in the stopband. Therefore, the designing filters are very simple.