f number

英 [ˈef nʌmbə(r)]

美 [ˈef nʌmbər]

焦距值；光圈数

英英释义

noun

• the ratio of the focal length to the diameter of a (camera) lens system
  Synonym:focal ratiostop numberspeed

双语例句

• This paper analyses colour subcarrier quantization noise in PCM coding of complete television singal. The relationship between quantization noise and sampling frequency ( f s) as well as quantizing bit number ( n) is discussed.
  分析了全电视信号PCM编码色度副载波量化噪声，并讨论了量化噪声与取样频率fs和量化比特数n的关系。
• The F is a number field or a infinite field.
  F是一个数域无限域。
• The optical performance of small F number diffractive microlens arrays little voice
  小F数衍射微透镜阵列光学性能研究
• Papers during the theoretical analysis, but also cited a number of companies in the procurement of F found in a number of practical issues and give the corresponding solution to the problem.
  论文在进行理论分析的同时，也列举了一些F公司在采购工作中发现的一些实际问题并给出相应解决问题的办法。
• The matric characteristics and convergences on F-number space
  F数空间的度量特征及收敛性
• In the past design, under the conditions of larger discharge and energy dissipation, flow cavitation number σ f larger than incipient cavitation number σ I of the flood tunnel must be satisfied to avoid cavitation in it.
  在以往的设计中，在满足较大的泄量和消能量条件下，通常泄洪洞还要满足σf＞σi，以免发生空化空蚀。
• The ray tracing method and vectorial Stratton Chu diffraction Integration are applied in the analysis of the imaging performance over the focal planes of hyperbolic lens and reverse microscope lens system with small F number.
  采用射线追迹结合StrattonChu矢量衍射积分公式的方法分析计算了小F数双曲透镜和倒置显微镜的焦面成像特性。
• Study of F Number of Microlenses for Collimation of Laser Diode Arrays
  阵列激光微透镜准直器透镜F数的研究
• The author presents a method of calculating the error of location and analyses the relationship between the error of location and the frequency difference of double-frequency grating ( or the amount of shear) and F number of the system.
  文中提出了计算定焦误差的方法，分析了定焦误差与双频光栅的频率差（或剪切量）及系统的F数之间的关系。
• A modified first-derivative based QRST detection algorithm as well as a proposed adaptive f wave number detection algorithm was utilized in the method, and new conditions was set for AF detection.
  该方法应用了改进的一阶差分QRST检测算法和提出的自适应f波波数检测算法，并设置了新的房颤检测条件。