A New Realization of Linear-Phase Magnitude Complementary Network for Digital Bi-Amplifier

D. Sookcharoenphol, C. Chakreeteekapakvisi
King’s Monkut Institute of Technology, Bangkok, Thailand

A new realization of real-time linear-phase magnitude complementary filter pair structure that is based on a combination of two parallel all-pass networks is proposed in this paper for divides wide audio spectral into low and high frequency bands before passing to digital switching amplifiers. Each all-pass network consists of a cascade of a noncausal and causal IIR filter to obtain the linear-phase characteristics. The advantage of the proposed network is that it does not introduce a self-distortion and can save power consumption. Since the magnitude responses of each network have only squared of sub all-pass filters. While the power complementary network has the cross product of sub all-pass filters that degrade an efficiency of amplification. Moreover, the power complementary network gives a high sensitivity to the phase difference of two filters around the transition band. The new structure can be reduced an implementation complexity of the noncausal and causal filters compared to the conventional structures. In addition, the proposed structure provides a low sensitivity to coefficients quantization thus bit rate can reduce, example of simulations is also given.

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