Improved Nyquist Filters with Piece-Wise Parabolic Frequency Characteristics

This paper presents and investigates a novel approach for constructing a family of ISI-free pulses having an asymptotic decay rate of t^-2, and comparable or better ISI performance as compared to several recently proposed pulses. The proposed solution for the design of Nyquist pulses is based on a piece-wise parabolic frequency characteristic. This can be considered as a piece-wise polynomial frequency characteristic with second degree polynomials. It is shown that a lower bit error rate (BER) can be achieved for same values of the roll-off factor, timing jitter, signal to noise ratio and number of interfering pulses, as compared to recently reported pulses.