A low-power ROM-less Direct Digital Frequency Synthesis (DDFS) system that exceeds the spectral purity of existing low-power DDFS systems by approximately is presented. The design applies an analogue voltage to the CMOS differential current switch in one cell of a non-linear DAC to interpolate between the output values which would be available from a conventional non-linear DAC.

statement of problem: digital measurement of rvg may improve diagnostic interpretation of radiographs in terms of accuracy, although it has been shown that validity of linear measurements of interproximal bone loss could not be improved by basic digital manipulations. purpose: the aim of this study was to evaluate the accuracy of radiovisiography (rvg) in the linear measurement of interproximal...

Direct digital synthesis (DDS) is a method to generate waveforms directly in the digital domain. In this method,the target waveforms are the sine and cosine ones. The Co-ordinate Rotational Digital Computer (CORDIC) algorithm configured in Rotation Mode (RM) can behave as a quadrature phase-to-amplitude converter that directly generates sine and cosine waveforms. The main advantage of using COR...

background and aims. in periapical radiographic technique, the changes will be visible only after considerable deposition or resorption while digital subtraction technique visualizes slight density changes. this study was aimed to compare visualization of density changes in conventional periapical radiographs and digital subtraction technique with or without image enhancement. materials and met...

Thomas Jefferson National Accelerator Facility Newport News, VA Abstract. The technologies of direct digital down converters, digital frequency synthesis, and digital signal processing are being used in many commercial applications. Because of this commercialization, the component costs are being reduced to the point where they are economically viable for large scale accelerator applications. T...