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.

A third-order /spl Sigma//spl Delta/ modulator in 0.18-/spl mu/m CMOS with calibrated mixed-mode integrators

Abstract: This paper describes a third-order sigma-delta (/spl Sigma//spl Delta/) modulator that is designed and implemented in 0.18-/spl mu/m CMOS process. In order to increase the dynamic range, this modulator takes advantage of mixed-mode integrators that consist of analog and digital integrators. A calibration technique is applied to the digital integrator to mitigate mismatch between analog and digital paths. It is shown that the presented modulator architecture can achieve a 12-dB better dynamic range than conventional structures with the same oversampling ratio (OSR). The experimental prototype chip achieves a 76-dB dynamic range for a 200-kHz signal bandwidth and a 55-dB dynamic range for a 5-MHz signal bandwidth. It dissipates 4 mW from 1.8-V supply voltages and occupies 0.7-mm/sup 2/ silicon area.

A 0.6-V Dynamic Biasing Filter With 89-dB Dynamic Range in 0.18- $\mu$ m CMOS

Abstract: This paper presents a 100-kHz fifth-order Chebychev low-pass filter (LPF) using the proposed dynamic biasing (DB) technique which enables wide dynamic range under a low-supply voltage. The change of state variables in the internal nodes of the filter can be corrected by using a novel simplified scheme, avoiding the output transient owing to dynamic biasing. The filter, including an automatic frequency tuning system based on the voltage-controlled-filter (VCF) architecture and voltage reference circuit, is fabricated in a 0.18-mum standard CMOS technology with a 0.5-V threshold voltage and consumes 443 muW from a power supply of 0.6 V. The output noise and the in-band IIP3 are 575 pArms and 219 muA, respectively. The filter achieves a dynamic range of 89 dB.

Ultrafast and Doppler-free femtosecond optical ranging based on dispersive frequency-modulated interferometry

Abstract: An ultrafast and Doppler-free optical ranging system based on dispersive frequency-modulated interferometry is demonstrated. The principle is similar to the conventional frequency-modulated continuous-wave interferometry where the range information is derived from the beat frequency between the object signal and the reference signal. However, a passive and static frequency scanning is performed based on the chromatic dispersion of a transform-limited femtosecond pulse in the time domain. We point out that the unbalanced dispersion introduced in the Mach-Zehnder interferometer can be optimized to eliminate the frequency chirp in the temporal interferograms pertaining to the third order dispersion of the all-fiber system, if the dynamic range being considered is small. Some negative factors, such as the polarization instability of the femtosecond pulse, the power fluctuation of the optical signal and the nonuniform gain spectrum of the erbium-doped fiber amplifier lead to an obvious envelope deformation of the temporal interferograms from the Gaussian shape. Thus a new data processing method is proposed to guarantee the range resolution. In the experiment, the vibration of a speaker is measured. A range resolution of 1.59 microm is achieved with an exposure time of 394 fs at a sampling rate of 48.6 MHz.

Wide dynamic range vision sensor for vehicles

Abstract: The dynamic range of brightness on road scenes is very wide, because the lighting condition dynamically varies with various weather and road conditions. Therefore, the dynamic range of conventional TV cameras is insufficient to input the images of road scenes. The authors have developed a method for expanding the dynamic range of TV cameras. Also, they have developed an experimental vision sensor system with a wide dynamic range based on the method applicable to the vision systems for vehicles. The effectiveness of the sensor in comparison with conventional TV cameras was confirmed from the experiments on highways under various lighting conditions. >

High Dynamic Range, Heterogeneous, Terahertz Quantum Cascade Lasers Featuring Thermally Tunable Frequency Comb Operation over a Broad Current Range

Abstract: We report on the engineering of broadband quantum cascade lasers (QCLs) emitting at Terahertz (THz) frequencies, which exploit a heterogeneous active region scheme and have a current density dynamic range (Jdr) of 3.2, significantly larger than the state-of-the-art, over a 1.3 THz bandwidth. We demonstrate that the devised broadband lasers operate as THz optical frequency comb synthesizers, in continuous-wave, with a maximum optical output power of 4 mW (0.73 mW in the comb regime). Measurement of the intermode beatnote map reveals a clear dispersion-compensated frequency comb regime extending over a continuous 106 mA current range (current density dynamic range of 1.24), significantly broader than the state-of-the-art at similar geometries, with a corresponding emission bandwidth of ≈1.05 THz and a stable and narrow (4.15 kHz) beatnote detected with a signal-to-noise ratio of 34 dB. Analysis of the electrical and thermal beatnote tuning reveals a current-tuning coefficient ranging between 5 and 2.1 MHz/m...