The Enhanced Variable Rate Codec (EVRC) is a standard for the Speech Service Option 3 for Wideband Spread Spectrum Digital System, which has been employed in both IS-95 cellular systems and ANSI J-STC-008 PCS (Persona...The Enhanced Variable Rate Codec (EVRC) is a standard for the Speech Service Option 3 for Wideband Spread Spectrum Digital System, which has been employed in both IS-95 cellular systems and ANSI J-STC-008 PCS (Personal Communications Systems). This paper investigated the combination of turbo codes with Unequal Error Protection (UEP) and 16-QAM modulation for EVRC codec of Rate 1 to get power and bandwidth efficient coding scheme. The results show that the UEP system outperforms the Equal Error Protection (EEP) one by 1.45 dB at BER of 10 -5.展开更多
Rate control plays an important role in video coding. An algorithm is proposed by Tsai et al in which macroblock’s coding order is rearranged to improve the coding quality. However, the complexity is very high due to...Rate control plays an important role in video coding. An algorithm is proposed by Tsai et al in which macroblock’s coding order is rearranged to improve the coding quality. However, the complexity is very high due to the change of macroblock’s coding order. In this paper, a macroblocl-level rate control algorithm is proposed which recalculates the quantization parameter of each macroblock based on its significance. Simulation results show that the proposed algorithm not only achieves 0.1-0.6 dB in peak signal-to-noise ratio (PSNR) but also reduces 33%-55% total encoding time compared to Tsai’s algorithm.展开更多
A novel design of a two-axis fast steering mirror(FSM) with piezoelectric actuators is proposed for incoherent laser beam combination. The mechanical performance of the FSM is tested. The results show that the tilting...A novel design of a two-axis fast steering mirror(FSM) with piezoelectric actuators is proposed for incoherent laser beam combination. The mechanical performance of the FSM is tested. The results show that the tilting range of the mirror is about 4 mrad, and the 1st-order resonance frequency is about 250 Hz. A self-designed grating encoder is taken as the sensor, which ensures the optimal precision of 10 μrad. The novel mechanical design can meet the requirement of engineering in incoherent laser beam combination.展开更多
基金National Natural Science Foundation ofChina( No.6972 5 0 0 1)
文摘The Enhanced Variable Rate Codec (EVRC) is a standard for the Speech Service Option 3 for Wideband Spread Spectrum Digital System, which has been employed in both IS-95 cellular systems and ANSI J-STC-008 PCS (Personal Communications Systems). This paper investigated the combination of turbo codes with Unequal Error Protection (UEP) and 16-QAM modulation for EVRC codec of Rate 1 to get power and bandwidth efficient coding scheme. The results show that the UEP system outperforms the Equal Error Protection (EEP) one by 1.45 dB at BER of 10 -5.
文摘Rate control plays an important role in video coding. An algorithm is proposed by Tsai et al in which macroblock’s coding order is rearranged to improve the coding quality. However, the complexity is very high due to the change of macroblock’s coding order. In this paper, a macroblocl-level rate control algorithm is proposed which recalculates the quantization parameter of each macroblock based on its significance. Simulation results show that the proposed algorithm not only achieves 0.1-0.6 dB in peak signal-to-noise ratio (PSNR) but also reduces 33%-55% total encoding time compared to Tsai’s algorithm.
基金supported by the Technology Project of Changchun City(No.2013270)
文摘A novel design of a two-axis fast steering mirror(FSM) with piezoelectric actuators is proposed for incoherent laser beam combination. The mechanical performance of the FSM is tested. The results show that the tilting range of the mirror is about 4 mrad, and the 1st-order resonance frequency is about 250 Hz. A self-designed grating encoder is taken as the sensor, which ensures the optimal precision of 10 μrad. The novel mechanical design can meet the requirement of engineering in incoherent laser beam combination.
