Broadband microwave waveguide window Patent

Broadband microwave waveguide window to compensate dielectric material fillin

Waveguide physical modeling of vocal tract acoustics: flexible formant bandwidth control from increased model dimensionality

Digital waveguide physical modeling is often used as an efficient representation of acoustical resonators such as the human vocal tract. Building on the basic one-dimensional (1-D) Kelly-Lochbaum tract model, various speech synthesis techniques demonstrate improvements to the wave scattering mechanisms in order to better approximate wave propagation in the complex vocal system. Some of these techniques are discussed in this paper, with particular reference to an alternative approach in the form of a two-dimensional waveguide mesh model. Emphasis is placed on its ability to produce vowel spectra similar to that which would be present in natural speech, and how it improves upon the 1-D model. Tract area function is accommodated as model width, rather than translated into acoustic impedance, and as such offers extra control as an additional bounding limit to the model. Results show that the two-dimensional (2-D) model introduces approximately linear control over formant bandwidths leading to attainable realistic values across a range of vowels. Similarly, the 2-D model allows for application of theoretical reflection values within the tract, which when applied to the 1-D model result in small formant bandwidths, and, hence, unnatural sounding synthesized vowels

Research and Extension Capabilities: Program Economists in New South Wales Agriculture

In 1997 the economists in NSW Agriculture conducting applied economics research at its larger research stations were assigned to the Department's major programs of the Department. This report reviews some of their achievements since that time. The report begins with a section describing the role of Program Economists and their management. Then follows a brief review of the main areas of interest of each of the twelve economists. A large section of the report is devoted to outlining major areas of research and extension where program economists, often working cooperatively, have made a significant contribution. These areas include: Analyses of market conditions for agricultural products; Field crop economics; Grazing and pasture economics; Integrated weed and pest management economics; Farming systems economics; Provision of farm management information; Research and extension evaluation and policy. Aspects reviewed in these areas included the key findings from research, research objectives, future directions of research and for each area, a selection of the most significant publications produced by program economists. The final section of the report is a listing of publications by program economists since 1997. Since then they have written 9 book chapters, 57 refereed journal papers, 23 refereed research bulletins, 40 papers in conference proceedings, 94 invited and contributed conference papers, 56 miscellaneous reports and work papers; and 43 farm management papers.Research and Development/Tech Change/Emerging Technologies, Teaching/Communication/Extension/Profession,

Real-time dynamic articulations in the 2-D waveguide mesh vocal tract model

Time domain articulatory vocal tract modeling in one-dimensional (1-D) is well established. Previous studies into two-dimensional (2-D) simulation of wave propagation in the vocal tract have shown it to present accurate static vowel synthesis. However, little has been done to demonstrate how such a model might accommodate the dynamic tract shape changes necessary in modeling speech. Two methods of applying the area function to the 2-D digital waveguide mesh vocal tract model are presented here. First, a method based on mapping the cross-sectional area onto the number of waveguides across the mesh, termed a widthwise mapping approach is detailed. Discontinuity problems associated with the dynamic manipulation of the model are highlighted. Second, a new method is examined that uses a static-shaped rectangular mesh with the area function translated into an impedance map which is then applied to each waveguide. Two approaches for constructing such a map are demonstrated; one using a linear impedance increase to model a constriction to the tract and another using a raised cosine function. Recommendations are made towards the use of the cosine method as it allows for a wider central propagational channel. It is also shown that this impedance mapping approach allows for stable dynamic shape changes and also permits a reduction in sampling frequency leading to real-time interaction with the model

Mm-wave power meter mount

E-band thermistor mount and a technique for adjusting a temperature compensating thermistor to provide an electrically balanced bridge are used for measuring RF power in the mm-wavelength. The mount is relatively insensitive to temperature effects that cause measurement errors in single ended circuits

Matched Thermistors for Microwave Power Meters-Patent

Matched thermistors for microwave power meters with compensation for temperature change

The Collaborative Development of New CFD Methods Adapted for Tilt Rotor Aircraft in the HiPerTilt Project

No abstract available