AM调制

水声声线仿真，基于射线模型。文章包含仿真条件和说明。文章附件为程序。(Underwater acoustic line simulation, based on the ray model. The article contains simulation conditions and instructions. The article appendix is the procedure.)

说明：  VL53L0X英文原版操作手册，便于有一定编程基础的用户使用(VL53L0X English Original Manual)

中国电信CDMA终端需求规范 数据终端AT命令接口分册 (China Telecom CDMA terminal needs AT command interface specification data terminal branch)

Problems and their solutions

Multiple input multiple output techniques combined with orthogonal frequency division multiplexing (MIMO-OFDM) provide a promising approach for wireless systems. However, a serious drawback of the OFDM system is the high peak-toaverage power ratio (PAPR), which may severely affect the power efficiency of RF power amplifiers. In this paper, we propose a simple method to reduce the PAPR of MIMO-OFDM signals based on the use of unused subcarriers. Instead of processing the signals at each transmitter separately, a peak cancelling signal is generated at one antenna and is then applied to all the others with only simple modifications. Simulation has shown that a minimum 2 dB reduction in PAPR can be achieved for all transmit signals using this approach. As the signal processing is nearly all done at a single transmitter, repetition of the operations at each transmitter is avoided, and therefore the overall cost of the system can be significantly reduced.

说明：  ofdm qpsk 添加循环前缀 信道估计 补偿与均衡 信号星座图(OFDM QPSK add cyclic prefix channel estimation compensation and equalization signal constellation)

模拟圆形阵列天线方向图，画二维天线方向图；(Simulation circular array antenna direction map, drawing two-dimensional antenna direction pattern;)

用MATLAB产生线性跳频信号，中心频率和带宽可调(Using MATLAB to generate linear frequency hopping signal with adjustable center frequency and bandwidth)

OFDM通信系统的仿真代码，可用作数字通信的分析参考(The simulation code of OFDM communication system can be used as analysis reference of digital communication.)

这是一个将语音信号通过DPCM编码传输的仿真测试程序，内有详细注释，希望对大家有用。(This is a voice signal transmission through the DPCM code simulation testing procedures, with detailed notes, We hope that the right useful.)