Dynamic range

About: Dynamic range is a research topic. Over the lifetime, 7576 publications have been published within this topic receiving 101739 citations. The topic is also known as: DNR & DR.

Parallel-detection microwave spectroscopy system for breast imaging

Abstract: A liquid-coupled, noncontacting, broadband microwave imaging system has been designed and fabricated. Extension of the operating bandwidth allows us to exploit the potential of new clinical information for breast cancer diagnosis at frequencies higher than previously achieved. The new system design implements a parallel-detection scheme that allows signals to be simultaneously sampled at multiple receiving antenna sites (in 8 s for a single tomographic slice at a single frequency). It also has important features such as high cross-channel isolation (>120 dB), smooth broad bandwidth receiver response, and adjustable intermediate frequency signal amplification factors of 1 to 2000 to ensure successful realization of a large linear dynamic range which is especially important to counteract the increased signal loss at the higher operating frequencies. The new system is capable of recovering dielectric properties of breastlike phantoms with tumor inclusions over the frequency range from 0.5 to 2.1 GHz when embedded in an 87%/13% glycerin/water background. Errors in the measurement data are less than 0.5% in signal amplitude and 1° in phase, on average.

Region-based information compaction as for digital images

Abstract: A method and apparatus for preserving the dynamic range of a relatively high dynamic range information stream (S1), illustratively a high resolution video signal, subjected to a relatively low dynamic range encoding (230, 15) and/or transport (235, 30) process(es). The invention subjects the relatively high dynamic range information stream to a segmentation and remapping process (215-225, 10) whereby each segment is remapped to the relatively low dynamic range appropriate to the encoding and/or transport process(es) utilized. An auxiliary information stream (S4) includes segment and associated remapping information such that the initial, relatively high dynamic range information stream (S1) may be recovered in a post-encoding (i.e. decoding) or post-transport (i.e., receiving) process.

Wavelength conversion by optimized monolithic integrated Mach-Zehnder interferometer

Abstract: Semiconductor optical amplifiers have been monolithic integrated in a passive symmetric Mach-Zehnder interferometer to form a compact polarization insensitive all-optical wavelength converter operating at up to 10 Gb/s. A simple method for reducing the impact of input power variations is proposed that increases the input power dynamic range from 4-8 dB.

A low-power stereo 16-bit CMOS D/A converter for digital audio

Abstract: A low-power 16-bit CMOS D/A (digital/analog) converter for portable digital audio is described. The converter is based on current division. To guarantee monotonicity and a good small-signal reproduction, a dynamic segmentation technique is used. A geometric averaging technique is used to minimize the harmonic distortion of the converter at high signal levels. The dynamic range is 95 dB. The circuit operates in a time-multiplex mode at a sample frequency of 44 kHz in a power supply range of 2.5-5 V and has a power consumption of 15 mW. A 2- mu m CMOS technology is used and the active chip area is 5 mm/sup 2/. >

Dual-Polarized and Polarization-Flexible Reflective Cells With Dynamic Phase Control

Abstract: A reflecting cell allowing the dynamic and independent control of the reflection phase of two perpendicular linearly-polarized waves is presented. This capability is useful for the implementation of dual-polarized beam-reconfigurable reflectarrays, as well as for new reflector functionalities such as linear/circular polarization-flexibility and polarization-twisting with simultaneous phase control. The concept is demonstrated on a unit cell operating at 8 GHz, using surface-mounted diodes. In addition to its polarization capability, the cell implements a new concept to overcome the usual tradeoff between phase range and loss in monolayer reflective cells, using a combination of PIN and varactor diodes. For each linearly-polarized component, a dynamic phase range over 360° is achieved at 8 GHz under normal incidence, with 4 dB and 2 dB of maximum and average loss, respectively. The modeling of the cell in a general periodic environment, along with measurements in a waveguide simulator, show that similar performance is preserved within a 5% bandwidth and under TE and TM oblique incidences up to 45°. The cell size is only 0.42? at 8 GHz.