Since the poor performance of orthogonal binary Pulse Position Modulation (PPM) compared with binary Pulse Amplitude Modulation (PAM), this paper presents a new modulation scheme named Pulse Width Modulation (PWM) for...Since the poor performance of orthogonal binary Pulse Position Modulation (PPM) compared with binary Pulse Amplitude Modulation (PAM), this paper presents a new modulation scheme named Pulse Width Modulation (PWM) for Impulse Radio Ultra-WideBand (IR-UWB) communication systems. This modulation scheme uses pulses with equal amplitude and different widths to carry different information. The receiver employs differences between similarity coefficients among these pulses to distinguish different information. Both theoretical analysis and simulation results verify that this novel scheme has a Signal to Noise Ratio (SNR) gain of about 1.75 dB compared with or- thogonal binary PPM, and has an SNR loss of about 1.4 dB compared with binary PAM. Although both the theoretical analysis and simulations are based on time-hopping multiple access, this modulation scheme can also be applied to other accessing techniques of UWB communication systems.展开更多
在分析有源电力滤波器APF(Active Power Filter)数学模型的基础上,提出了改进的三角波脉宽调制电流控制方法。与传统方法相比,通过在输出指令电压中增加一个与电源电压瞬时值成正比的量,抵消了电源电压对输出指令电压的干扰作用,提高了...在分析有源电力滤波器APF(Active Power Filter)数学模型的基础上,提出了改进的三角波脉宽调制电流控制方法。与传统方法相比,通过在输出指令电压中增加一个与电源电压瞬时值成正比的量,抵消了电源电压对输出指令电压的干扰作用,提高了APF输出电压的准确性,使APF的实际输出电流能够更加精确地跟踪指令电流的变化,从而有效地减小了输出电流误差的脉动范围,这也有利于减小有源电力滤波器的工作损耗和整机容量。仿真结果对比验证了采用改进控制方法的APF比采用传统控制方法的APF的输出电流误差范围小。展开更多
文摘Since the poor performance of orthogonal binary Pulse Position Modulation (PPM) compared with binary Pulse Amplitude Modulation (PAM), this paper presents a new modulation scheme named Pulse Width Modulation (PWM) for Impulse Radio Ultra-WideBand (IR-UWB) communication systems. This modulation scheme uses pulses with equal amplitude and different widths to carry different information. The receiver employs differences between similarity coefficients among these pulses to distinguish different information. Both theoretical analysis and simulation results verify that this novel scheme has a Signal to Noise Ratio (SNR) gain of about 1.75 dB compared with or- thogonal binary PPM, and has an SNR loss of about 1.4 dB compared with binary PAM. Although both the theoretical analysis and simulations are based on time-hopping multiple access, this modulation scheme can also be applied to other accessing techniques of UWB communication systems.
文摘在分析有源电力滤波器APF(Active Power Filter)数学模型的基础上,提出了改进的三角波脉宽调制电流控制方法。与传统方法相比,通过在输出指令电压中增加一个与电源电压瞬时值成正比的量,抵消了电源电压对输出指令电压的干扰作用,提高了APF输出电压的准确性,使APF的实际输出电流能够更加精确地跟踪指令电流的变化,从而有效地减小了输出电流误差的脉动范围,这也有利于减小有源电力滤波器的工作损耗和整机容量。仿真结果对比验证了采用改进控制方法的APF比采用传统控制方法的APF的输出电流误差范围小。
