采用TPS40170的高精度恒流源设计

采用TI同步降压控制芯片TPS40170、超低内阻MOS管IPP075N15N3G和低失真、高共模抑制比、单电源运算放大器OPA2365为核心,设计一款具有宽输入电压35～55 V,输出电流3 A的降压型高精度恒流源。样机经测试满载效率为95.8%、负载调整率Si≤0.1%、电压调整率Sv≤0.2%,可应用在电镀、热处理炉、照明等行业。

应用于薄膜透光均匀性检测的锁相电路设计

鉴于薄膜透光均匀性检测系统抗干扰能力差、检测信号微弱、输出电压值与输入光信号强度成正比等原因,设计了一款FPGA双通道锁相电路。阐述该设计的组成,在FPGA内部设计的DDS电路和只有3阶的IIR滤波器分别简化了设计,减少了FPGA逻辑资源的使用,最终整个设计能在只有4608个逻辑单元EP2C5T144C8芯片上完成锁相功能。实验结果表明,电路输出与理论分析相吻合,输入输出及幅频特性满足薄膜均匀性检测系统要求。

Spatial Correlation Properties of Tightly Focused J0-Correlated Azimuthally Polarized Vortex Beams

Based on vectorial Debye diffraction theory, the spatial correlation properties in the focal region of a J0 -correlated azimuthally polarized vortex beam through a high numerical aperture (NA) are analyzed. The expressions for a pair of points on the axis of symmetry and for a pair of points in the focal plane are derived. It is found that the longitudinal and transverse coherence lengths in the focal region change with the variation in the topological charge and coherence parameter of the vortex field, together with the NA values. In addition, the degree of coherence is shown to possess phase singularities.

利用STM32单片机的大功率智能渔探仪的设计

研究了一款能够探测水下鱼群和智能分析鱼群大小的渔探仪。该渔探仪系统由74HC4024芯片和中频变压器构成的超声波发射及接收模块、LM2596电源芯片构成的开关电源模块、STM32单片机模块、液晶显示模块和报警模块组成,实现了鱼群探测、判断鱼群大小和显示功能。该渔探仪具有探测精度高、体积小的特点,具有一定的实用性。