Search

Design and implementation of recursive digital filters with f'ixed point arithmetic using special hardware are considered in detail and applied to a mechanization of a second order filter structure with variable coefficients. Two new methods of performing quantization after arithmetic operations within a digital filter are presented: quantization after addition and quantization before multiplication. Both methods are shown applicable to hardware implementation of digital filters and offer advantages over the usual quantization after multiplication. Error bounds are derived for these two quantization schemes and compared with the results previously obtained by other authors. It is concluded that the quantization before multiplication is the most suitable for hardware filter implementation. A design modification of the presently available hardware chips in order to permit round-off or truncation before multiplication is presented, http://archive.org/details/hardwareimplemen1094517043, Lieutenant, Portuguese Navy, Approved for public release; distribution is unlimited.

http://archive.org/details/anadaptivekalmid1094520408, NA, NA, NA

The Rio Agrio in northern Patagonia is highly acidic due to inputs of the volcanic gases SO2, HCl and HF in the headwaters. The unique watershed has many geochemical and biological similarities to acid waters caused by mining. Geochemical similarities include the presence of highly acidic rivers and lakes with pH values of less than 0.5 to more than 6.0, highly elevated concentrations of rock-forming elements such as Fe and Al and precipitation of hydrous metal oxides over pH gradients that are similar to those typically observed in waters affected by acid mine drainage. Microbiological similarities include an abundance of acidiphilic algae, chemolithotrophic Fe- and S-oxidising bacteria and yeasts. An interesting difference is the presence of sulphate-reducing bacteria which have apparently adapted to the low pH conditions of the Lago Caviahue sediment pore water., The Rio Agrio in northern Patagonia is highly acidic due to inputs of the volcanic gases SO2, HCl and HF in the headwaters. The unique watershed has many geochemical and biological similarities to acid waters caused by mining. Geochemical similarities include the presence of highly acidic rivers and lakes with pH values of less than 0.5 to more than 6.0, highly elevated concentrations of rock-forming elements such as Fe and Al and precipitation of hydrous metal oxides over pH gradients that are similar to those typically observed in waters affected by acid mine drainage. Microbiological similarities include an abundance of acidiphilic algae, chemolithotrophic Fe- and S-oxidising bacteria and yeasts. An interesting difference is the presence of sulphate-reducing bacteria which have apparently adapted to the low pH conditions of the Lago Caviahue sediment pore water.

This thesis summarizes the theory of number theoretic transforms (NTT's), and presents original examples to illustrate the theory- Concepts have been studied and compared in order to present them in a cohesive and unified manner. Software and hardware implementation of Ferraat number transforms are discussed and compared with the Fourier Transform showing a substantial improvement in efficiency and accuracy. The main drawback of Fermat Number Transforms is a rigid relationship between the allowed sequence length and word length. Methods and other NTT's, for overcoming this problem are discussed. The theory has also been extended to two dimensions.

The efficient use of a search-surface radar or sonar, in which one or more targets appear on the screen intermittently usually demands a device for tracking the targets automatically. Such a device, called a "track while scan system", must make an estimate of each target's instantaneous position from the sampled-data information provided by the radar. For this purpose, an a-8 filter and an optimal Kalman filter, that must track maneuvering targets, are analyzed here and compared in terms of tracking accuracy for tactical applications.

Design and implementation of recursive digital filters with f'ixed point arithmetic using special hardware are considered in detail and applied to a mechanization of a second order filter structure with variable coefficients. Two new methods of performing quantization after arithmetic operations within a digital filter are presented: quantization after addition and quantization before multiplication. Both methods are shown applicable to hardware implementation of digital filters and offer advantages over the usual quantization after multiplication. Error bounds are derived for these two quantization schemes and compared with the results previously obtained by other authors. It is concluded that the quantization before multiplication is the most suitable for hardware filter implementation. A design modification of the presently available hardware chips in order to permit round-off or truncation before multiplication is presented

A deterministic analysis of the limit cycle oscillations which occur in fixed-point implementations of recursive digital filters due to roundoff and truncation quantization after multiplication operations, is performed. Amplitude bounds, based upon a correlated nonstochastic signal approach and Lyapunov's direct method, as well as an approximate expression for the frequency of zero-input limit cycles, are derived and tested for the two-pole filter. The limit cycles are represented on a successive value phase-plane diagram from which certain symmetry properties are derived. Similar results are developed for other second-order digital filter configurations, and the' parallel and cascade forms. The results are extended to include limit cycles under in-put signal conditions. A basic design relationship between the number of significant digits required for the realization of a filter algorithm with a desired signal-to-noise (limit cycle) ratio is stated.

A deterministic analysis of the limit cycle oscillations which occur in fixed-point implementations of recursive digital filters due to roundoff and truncation quantization after multiplication operations, is performed. Amplitude bounds, based upon a correlated nonstochastic signal approach and Lyapunov's direct method, as well as an approximate expression for the frequency of zero-input limit cycles, are derived and tested for the two-pole filter. The limit cycles are represented on a successive value phase-plane diagram from which certain symmetry properties are derived. Similar results are developed for other second-order digital filter configurations, and the' parallel and cascade forms. The results are extended to include limit cycles under in-put signal conditions. A basic design relationship between the number of significant digits required for the realization of a filter algorithm with a desired signal-to-noise (limit cycle) ratio is stated., http://archive.org/details/adeterministicna1094514952, Kapitänleutnant, Deutsche Marine, Approved for public release; distribution is unlimited.

This thesis summarizes the theory of number theoretic transforms (NTT's), and presents original examples to illustrate the theory- Concepts have been studied and compared in order to present them in a cohesive and unified manner. Software and hardware implementation of Ferraat number transforms are discussed and compared with the Fourier Transform showing a substantial improvement in efficiency and accuracy. The main drawback of Fermat Number Transforms is a rigid relationship between the allowed sequence length and word length. Methods and other NTT's, for overcoming this problem are discussed. The theory has also been extended to two dimensions., http://archive.org/details/descriptionndimp1094518394, Lieutenant, Portuguese Navy, Approved for public release; distribution is unlimited.

The efficient use of a search-surface radar or sonar, in which one or more targets appear on the screen intermittently usually demands a device for tracking the targets automatically. Such a device, called a "track while scan system", must make an estimate of each target's instantaneous position from the sampled-data information provided by the radar. For this purpose, an a-8 filter and an optimal Kalman filter, that must track maneuvering targets, are analyzed here and compared in terms of tracking accuracy for tactical applications., http://archive.org/details/comparisonofnalp1094518639, Lieutenant Commander, Hellenic Navy, Approved for public release; distribution is unlimited.