High dynamic range

About: High dynamic range is a research topic. Over the lifetime, 4280 publications have been published within this topic receiving 76293 citations. The topic is also known as: HDR.

Folded multiple-capture: an architecture for high dynamic range disturbance-tolerant focal plane array

Abstract: Earlier studies have shown that multiple capture can achieve high SNR, but cannot satisfy the high dynamic range (HDR) and high speed requirements of the Vertically-Integrated-Sensor-Array (VISA) project. Synchronous self-reset, on the other hand, can achieve these requirements, but suffers from poor SNR. Extended counting can achieve high dynamic range at high frame rate and with good SNR, but at the expense of high power consumption. The paper proposes a new HDR focal plane array architecture, denoted by folded-multiple capture (FMC), which by combining features of the synchronous self-reset and multiple capture schemes, can satisfy the VISA requirements at a fraction of the power dissipation and with more robustness to device variations than extended counting. The architecture is also capable of detecting subframe disturbances, e.g., due to laser jamming, and correcting for it.

Low power high dynamic range sigma-delta modulator

Abstract: A low power, high dynamic range sigma-delta modulator comprises a quantizer followed by a digital integrator for generating an integrated digital signal from a quantized signal The output of the digital integrator is coupled to a digital-to-analog converter in the feedback loop of the sigma-delta modulator

High-dynamic-range, low-noise analog optical links using external modulators: analysis and demonstration

Abstract: Analog fiber-optic links using an integrated-optical intensity modulator have been demonstrated. These links operate at frequencies from 50 MHz to 22 GHz with electrical gain u to 1 1 dB noise figure as low as 6 dB and intermodulation-free dynamic range of up to 1 13 dBHz2/3. The design factors determining optical link performance are discussed briefly and the effect of adding electronic amplifiers is analyzed. SUMMARY Analog optical links are attractive for many applications ranging from cable television distribution to radar-signal transmission at microwave frequencies. These systems often require a link with a low noise figure low electrical insertion loss and high dynamic range. We have demonstrated several intensitymodulated optical links that use a diode-pumped Nd:YAG laser and an integrated-optical modulator to achieve high performance by all these measures. 13 We will first discuss these experimental links and then show how their performance could be improved further by adding electronic amplifiers. Figure 1 illustrates the optical link used in our experiments with an electronic preamplifier and postamplifier added. (The experimental results reported here refer to the electrical ports of the optical link Figure 1. Block diagram of the optical link with an electronic preamplifier (Al) and postamplifier (A3) added. (Experimental results in the paper refer to the optical link alone without the amplifiers. ) 252 / SPIE Vol 1371 High-Frequency Analog Fiber Optic Systems(1990) OPTICAL LINK 161 884-1 INTEGRATED-OPTICAL PIN

Small-Aperture Focusing Chirp Transducers vs. Diffraction-Compensated Beam Compressors in Elastic SAW Convolvers

Abstract: Abstmct-High performance has been achieved in SAW convolvers using diffraction-corrected multistrip beam compressors. However, two different levels of metalization are required for optimum performance. A significant simplification of device fabrication was achieved with the design of convolvers using small-aperture chirp transducers, which require only one metalization layer. A design procedure is described that makes the transducers focusing to minimize diffraction loss. Experimental results are presented, which show that performance of this new design surpasses conventional designs in several respects. I. INTRODUCTION M ONOLITHIC acoustic surface wave convolvers on YZ-LiNb03 combine high-speed signal processing capability with ruggedness, small size, and relatively low cost of the device-thanks to the simplicity of its construction. However, the intrinsic nonlinearity of the substrate material polarization, which is used to generate the mixing product of the two input signals, is low and limits the efficiency of the device. High efficiency is crucial to achieve high dynamic range and economize input power. Since the introduction of beamwidth compression [l] to boost device efficiency, the elastic convolver has been developed to high performance in several laboratories [2], [3], [4] by optimization of its various components. The aim of such optimization was to increase the device efficiency by eliminating sources of loss in the acoustic path and providing good match at all electrical ports, while tailoring the device characteristics to minimize signal distortion and suppress spurious signals [5]. This means that the convolution efficiency vs. frequency should be reasonably flat and smooth in magnitude and linear in phase over the desired bandwidth. Notably reflections of acoustic waves in the device have to be suppressed to avoid selfconvolution of one input signal. The distributed output signal has to be collected from the integrating electrode in such a way as to avoid electromagnetic propagation loss or destructive interference of various signal components due to long-line effects. By these considerations one arrives at a standard design scheme as shown in Fig. 1. Interdigital transducers, which convert the input signals, typically are unapodized to avoid

High dynamic range pixel architecture for advanced diagnostic medical x-ray imaging applications

Abstract: The most widely used architecture in large-area amorphous silicon (a-Si) flat panel imagers is a passive pixel sensor (PPS), which consists of a detector and a readout switch. While the PPS has the advantage of being compact and amenable toward high-resolution imaging, small PPS output signals are swamped by external column charge amplifier and data line thermal noise, which reduce the minimum readable sensor input signal. In contrast to PPS circuits, on-pixel amplifiers in a-Si technology reduce readout noise to levels that can meet even the stringent requirements for low noise digital x-ray fluoroscopy (<1000 noise electrons). However, larger voltages at the pixel input cause the output of the amplified pixel to become nonlinear thus reducing the dynamic range. We reported a hybrid amplified pixel architecture based on a combination of PPS and amplified pixel designs that, in addition to low noise performance, also resulted in large-signal linearity and consequently higher dynamic range [K. S. Karim et ...