Interactive digital filtering of gated cardiac studies during cine display

The use of a novel class of image processing hardware, the image computer, is illustrated by application to gated cardiac studies. Digital filtering of a nine-view study consisting of 144 frames, each 64x64 pixels in size, is performed using the Wiener filter. During image display the operator can change the filter parameters. Refiltering is then performed essentially instantaneously, permitting truly interactive filter selection. Comparable digital filtering using a fast conventional computer and display hardware is shown to be too slow to permit interactive filter modification. Image computers incorporate very large image memories with very tightly coupled, fast arithmetic processors and video display devices and allow very computation-intensive calculations to be performed interactively.     

用MicroTCA机箱构建高性价比的硬件平台

作为当今业界流行的模块化硬件平台标准——AdvanedTCA标准的补充,MicroTCA硬件技术标准主要针对的是网络通信、医疗影像处理、嵌入式控制、军工等市场的中低端应用。其高带宽、模块化、灵活性、高性价比等优势使其能够被运用到较为广泛的应用领域,成为当今构建高性价比模块化标准硬件平台的优选标准。众所周知,MicroTCA平台中承载的是Advanced-MC（AMC）模块。     

A low-jitter 125-1250-MHz process-independent and ripple-poleless0.18-μm CMOS PLL based on a sample-reset loop filter

This paper describes a low-jitter phase-locked loop (PLL) implemented in a 0.18-μm CMOS process. A sample-reset loop filter architecture is used that averages the oscillator proportional control current which provides the feedforward zero over an entire update period and hence leads to a ripple-free control signal. The ripple-free control current eliminates the need for an additional filtering pole, leading to a nearly 90° phase margin which minimizes input jitter peaking and transient locking overshoot. The PLL damping factor is made insensitive to process variations by making it dependent only upon a bandgap voltage and ratios of circuit elements. This ensures tracking between the natural frequency and the stabilizing zero. The PLL has a frequency range of 125-1250 MHz, frequency resolution better than 500 kHz, and rms jitter less than 0.9% of the oscillator period