Title: Accuracy improvement of real-poles allpass-based digital Hilbert transformers

Authors: Kamelia S. Nikolova; Georgi K. Stoyanov

Addresses: Department of Communication Networks, Faculty of Telecommunications, Technical University of Sofia, 8 Kl. Ohridski Blvd., Sofia 1000, Bulgaria ' Department of Communication Networks, Faculty of Telecommunications, Technical University of Sofia, 8 Kl. Ohridski Blvd., Sofia 1000, Bulgaria

Abstract: In this work a very efficient approach to extend the frequency range over which the real-poles allpass-based digital Hilbert transformers (HT) phase difference is kept near constant and to reduce the deviation of the phase from 90° in a limited word-length environment is proposed. This approach is based on minimisation of the phase sensitivity of each individual first- and second-order allpass section in the cascade realisation of the two branches of the structure used, depending on their transfer function pole positions, including replacements of second-order-sections by two first-order low-sensitivity allpass sections. The effectiveness of the proposed design is experimentally verified and the HTs so obtained are very suitable for different telecommunication applications.

Keywords: digital filters; allpass filters; Hilbert transformers; sensitivity minimisation; telecommunications.

DOI: 10.1504/IJRIS.2014.063947

International Journal of Reasoning-based Intelligent Systems, 2014 Vol.6 No.1/2, pp.2 - 11

Received: 08 May 2021
Accepted: 12 May 2021

Published online: 27 Jul 2014 *

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