Active filter techniques in data processing systems
Active filter techniques in data processing systems
This thesis describes work carried out over the period October 1970 to June 1975. The work described concentrates on the definition and solution of the filtering problems which are raised in two processing systems. These are, a real-time channel estimation system for improving the efficiency of high frequency (3-30MHs) radio links, and a compatible data modem. The generation and demodulation of signals in the modem is considered in detail with a full error performance analysis. Particular consideration is given to the choice of optimum filter parameters in a practical system. Variation of these parameters to obtain the best compatibility between the modem and estimation system is also considered with a presentation of the corresponding error mapping results. Methods of obtaining the required filter characteristics are outlined with a detailed examination of a non-minimum phase approximation technique and the corresponding transfer function, synthesis alternatives. Two different types of practical filters based on this design procedure are described. The first uses filter sections based on a modified Sallen and Key arrangement and is analysed with regard to non-ideal components and temperature stability. Results are reported for two representative data modem filters using this arrangement. A more stable configuration is described using ladder filters where the inductive elements are replaced by their gyrator equivalents. The development of a suitable gyrator, using a single operational amplifier is described. The design of a narrow band-width filter suitable for the estimation system is considered, using minimum-phase approximations. A numerical design procedure for a specific output-noise autocovariance is described and to the selection of a suitable m+n+m++m-phase approximation. The design and construction of the filter is considered and practical results reported.
University of Southampton
1978
Cook, S. J
(1978)
Active filter techniques in data processing systems.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
This thesis describes work carried out over the period October 1970 to June 1975. The work described concentrates on the definition and solution of the filtering problems which are raised in two processing systems. These are, a real-time channel estimation system for improving the efficiency of high frequency (3-30MHs) radio links, and a compatible data modem. The generation and demodulation of signals in the modem is considered in detail with a full error performance analysis. Particular consideration is given to the choice of optimum filter parameters in a practical system. Variation of these parameters to obtain the best compatibility between the modem and estimation system is also considered with a presentation of the corresponding error mapping results. Methods of obtaining the required filter characteristics are outlined with a detailed examination of a non-minimum phase approximation technique and the corresponding transfer function, synthesis alternatives. Two different types of practical filters based on this design procedure are described. The first uses filter sections based on a modified Sallen and Key arrangement and is analysed with regard to non-ideal components and temperature stability. Results are reported for two representative data modem filters using this arrangement. A more stable configuration is described using ladder filters where the inductive elements are replaced by their gyrator equivalents. The development of a suitable gyrator, using a single operational amplifier is described. The design of a narrow band-width filter suitable for the estimation system is considered, using minimum-phase approximations. A numerical design procedure for a specific output-noise autocovariance is described and to the selection of a suitable m+n+m++m-phase approximation. The design and construction of the filter is considered and practical results reported.
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Published date: 1978
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Local EPrints ID: 459989
URI: http://eprints.soton.ac.uk/id/eprint/459989
PURE UUID: a6e0998e-a86b-44b7-9fcd-80a33d234c41
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Date deposited: 04 Jul 2022 17:32
Last modified: 04 Jul 2022 17:32
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Author:
S. J Cook
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