An all fiber pulsed coherent Doppler lidar （CDL） system at 1.54 μm wavelength is developed for wind profiles measurements. This lidar affords 43.0-μJ pulse energy at 10-kHz pulse repetition frequency with 500-ns p...An all fiber pulsed coherent Doppler lidar （CDL） system at 1.54 μm wavelength is developed for wind profiles measurements. This lidar affords 43.0-μJ pulse energy at 10-kHz pulse repetition frequency with 500-ns pulse width. The lidar is operated in monostatic mode with 50-mm diameter telescope. The heterodyne mixing signals are acquired with 500 M/s analog to digital converter and 2048 points fast Fourier transform （FFT） is implemented. Line of sight wind speeds are measured with more than 3.0-km range in a horizontal direction and about 1.9 km in the vertical direction with 75-m range resolution. Systematic error of speed measurement of 0.2 m/s is validated.展开更多
An improved two-stage model of colorimetric characterization for liquid crystal display （LCD） was proposed. The model included an S-shape nonlinear function with four coefficients for each channel to fit the Tone re...An improved two-stage model of colorimetric characterization for liquid crystal display （LCD） was proposed. The model included an S-shape nonlinear function with four coefficients for each channel to fit the Tone reproduction curve （TRC）, and a linear transfer matrix with black-level correction. To compare with the simple model （SM）, gain-offset-gain （GOG）, S-curve and three-one-dimensional look-up tables （3-1D LUTs） models, an identical LCD was characterized and the color differences were calculated and summarized using the set of 7 × 7 × 7 digital-to-analog converter （DAC） triplets as test data. The experimental results showed that the model was outperformed in comparison with the GOG and SM ones, and near to that of the S-curve model and 3-1D LUTs method.展开更多
A newΣΔmodulator architecture for thermal vacuum sensor ASICs is proposed.The micro-hotplate thermal vacuum sensor fabricated by surface-micrornachining technology can detect the gas pressure from 1 to 10;Pa. The am...A newΣΔmodulator architecture for thermal vacuum sensor ASICs is proposed.The micro-hotplate thermal vacuum sensor fabricated by surface-micrornachining technology can detect the gas pressure from 1 to 10;Pa. The amplified differential output voltage signal of the sensor feeds to theΣΔmodulator to be converted into digital domain.The presentedΣΔmodulator makes use of a feed-forward path to suppress the harmonic distortions and attain high linearity.Compared with other feed-forward architectures presented before,the circuit complexity,chip area and power dissipation of the proposed architecture are significantly decreased.The correlated double sampling technique is introduced in the 1st integrator to reduce the flicker noise.The measurement results demonstrate that the modulator achieves an SNDR of 79.7 dB and a DR of 80 dB over a bandwidth of 7.8 kHz at a sampling rate of 4 MHz.The circuit has been fabricated in a 0.5μm 2P3M standard CMOS technology.It occupies an area of 5 mm;and dissipates 9 mW from a single 3 V power supply.The performance of the modulator meets the requirements of the considered application.展开更多
基金supported by the National Natural Science Foundation of China under Grant No.60908036
文摘An all fiber pulsed coherent Doppler lidar （CDL） system at 1.54 μm wavelength is developed for wind profiles measurements. This lidar affords 43.0-μJ pulse energy at 10-kHz pulse repetition frequency with 500-ns pulse width. The lidar is operated in monostatic mode with 50-mm diameter telescope. The heterodyne mixing signals are acquired with 500 M/s analog to digital converter and 2048 points fast Fourier transform （FFT） is implemented. Line of sight wind speeds are measured with more than 3.0-km range in a horizontal direction and about 1.9 km in the vertical direction with 75-m range resolution. Systematic error of speed measurement of 0.2 m/s is validated.
基金This work was supported by the National Nature Science Foundation of China under Grant No. 60578011.
文摘An improved two-stage model of colorimetric characterization for liquid crystal display （LCD） was proposed. The model included an S-shape nonlinear function with four coefficients for each channel to fit the Tone reproduction curve （TRC）, and a linear transfer matrix with black-level correction. To compare with the simple model （SM）, gain-offset-gain （GOG）, S-curve and three-one-dimensional look-up tables （3-1D LUTs） models, an identical LCD was characterized and the color differences were calculated and summarized using the set of 7 × 7 × 7 digital-to-analog converter （DAC） triplets as test data. The experimental results showed that the model was outperformed in comparison with the GOG and SM ones, and near to that of the S-curve model and 3-1D LUTs method.
基金Project supported by the National Natural Science Foundation of China(No.90607003).
文摘A newΣΔmodulator architecture for thermal vacuum sensor ASICs is proposed.The micro-hotplate thermal vacuum sensor fabricated by surface-micrornachining technology can detect the gas pressure from 1 to 10;Pa. The amplified differential output voltage signal of the sensor feeds to theΣΔmodulator to be converted into digital domain.The presentedΣΔmodulator makes use of a feed-forward path to suppress the harmonic distortions and attain high linearity.Compared with other feed-forward architectures presented before,the circuit complexity,chip area and power dissipation of the proposed architecture are significantly decreased.The correlated double sampling technique is introduced in the 1st integrator to reduce the flicker noise.The measurement results demonstrate that the modulator achieves an SNDR of 79.7 dB and a DR of 80 dB over a bandwidth of 7.8 kHz at a sampling rate of 4 MHz.The circuit has been fabricated in a 0.5μm 2P3M standard CMOS technology.It occupies an area of 5 mm;and dissipates 9 mW from a single 3 V power supply.The performance of the modulator meets the requirements of the considered application.
