Direct Digital Frequency Synthesizer Pentomics’ first DDS patent concerns a method and apparatus for DDS which, unlike the traditional table-lookup methods, uses a simplified “angle-rotation” algorithm implemented as a multiplierless feedforward datapath, allowing easy pipelining and limiting the accumulation of roundoff errors. Our DDS’s modular architecture permits outputs of arbitrary precis...

A digital height field is an array of height values assigned to the vertices of a regular grid in the two-dimensional domain over which an explicit function (landscape) is defined. A new direct rendering algorithm for digital height fields is described. “Direct rendering” means that the image is calculated without an intermediate step of conversion to a polygonal mesh. It is shown that direct h...

This paper reviews spur reduction techniques used in direct digital synthesizers (DDSs) or numerically controlled oscillators (NCOs). First, the classification and operation of conventional DDSs are reviewed. Covered are the pulse output DDS, sine output DDS, fractional divider, and phase interpolation DDS. It is shown that DDSs produce spurs as well as the desired output frequency due to the a...

An optimized Direct Digital Frequency Synthesizer (DDFS) design in terms of reduced ROM, high throughput and speed is designed in this paper. DDFS is designed with 200 MHz reference clock frequency and 32 bit FTW for the generation of sine and cosine signal with 16 bit output frequency having frequency resolution of 0.0466 Hz and Phase resolution of 0.0055°. DDFS design is simulated using VHDL ...

Memristors have become interesting to many research areas within the last years. This paper discusses memristors in the context of digital logic synthesis. Giving a brief overview about memristor characteristics it is explained how they can be used in digital logic. It will be explained how memristors map to digital logic operations and how this can be used with common synthesis methods to turn...

BACKGROUND The number of rejected images is an indicator of image quality and unnecessary imaging at a radiology department. Image reject analysis was frequent in the film era, but comparably few and small studies have been published after converting to digital radiography. One reason may be a belief that rejects have been eliminated with digitalization. PURPOSE To measure the extension of de...