为了精确获取分幅摄影机的拍摄频率和条纹摄影机的扫描速度，必须精确测量转镜在拍摄期间的速度。提出一种基于数字信号处理器（DSP）与现场可编程门阵列（FPGA）相结合的高精度数字测量方法。DSP与FPGA采用高速串行外设接口（SPI）通信，DSP根据转镜转速的变化，自动对FPGA预置适当的时间闸门，FPGA计数缓冲后将测速数据发送给DSP处理，再经DSP串行口发送给计算机进行实时显示。FPGA的逻辑单元采用32位而且预置时间闸门可变，有效防止了数据的溢出，提高了转速的范围和精度；高速DSP提高了数据处理的速度，保证了实时性。系统仿真结果和实际工程使用情况表明此设计是可行的，测速精度可达0.0001%，测速范围为3～3×108 r/min。

The speed of rotating mirror must be measured in shooting period precisely in order to obtain the shooting frequency of framing cameras or scanning speed of steak cameras. A high precision digital measurement method based on digital signal processing (DSP) and field programmable gate array (FPGA) is put forward. DSP and FPGA are communicated by high-speed serial peripheral interface (SPI). Time gate for FPGA is preset by DSP according to the change of rotating mirror′s speed. The measured data is transmitted to DSP for disposing after FPGA′s counting and buffering and to computer for showing in real time. It prevents the overflow of the data and improves the range of rotating speed by adopting 32 bit logic unit for FPGA. High-speed DSP improves the process speed of the data and ensures the real time. The design is feasible by the simulated result of the system and the engineering practice. The precision of speed measurement is up to 0.0001%, and the range is from 3 to 3×108 r/min.