【正文】 C rate than plastic filter circuit posed of the input links of the reference voltage 1/2Vcc parison with the wind speed is proportional to the plastic rectangular wave signal period varies with the detection signal. Ultrasonic wind speed measuring instrument software design mainly by the main program, ultrasonic receiving procedures and display, keyboard subroutine, temperature pensation know the assembly language program is a high efficient and easy to run precise calculation of the time, and ultrasonic velocity 基于單片機(jī)的風(fēng)速測量儀的設(shè)計(jì) VI measurement instrument procedures require precise calculations (per unit time to plete the ultrasonic plastic rectangle when the number of square wave), the control programMixed programming using assembly language. Ultrasonic Range Finder Algorithm Ultrasonic wind sensor is the use of ultrasound through the air by the vortex modulation, has been transferred from the vortex frequency waves were detected to determine wind , S is a pair of the same resonant frequency ultrasonic transducer, F for the launching transducer, emission 145 kHz ultrasonic amplitude。 S transducer for the receiver to receive sound waves modulated by the vortex. When no vortex, the receiving transducer receives the amplitude S wave signal。 a vortex, because of the pressure gradient within the vortex and the vortex rotation, leading to ultrasonic refraction, reflection and absorption effects, so that the received signal through the beam, the received signal is back to , the ultrasonic frequency and amplitude changes in the frequency of vortex line, from the receiving transducer to detect changes in frequency ultrasonic beam amplitude can be measured wind speed values. Basic formula is: f = St * v / d f vortex frequency, Hz。 v flow velocity, m / s。 d bluff body diameter, mm。 St coefficient (Reynolds number in the range of 200 to 50 000, St is a constant). Ultrasonic vortex wind speed sensor and pared to other forms of wind speed sensor has the following advantages: (1) no moving parts, no mechanical wear, stable performance, long life。 (2) The output itself is a linear relationship between wind velocity and pulse frequency signals, no zero drift, and the sensor sensitivity change would not directly affect output, high accuracy。 (3) The output signal from fluid properties (temperature, humidity, pressure, 華北科技學(xué)院畢業(yè)設(shè)計(jì)（論文） VII position, density, viscosity, mineral dust, etc.) sensors in coal mine safety monitoring system has wide application prospects. Key words: wind speed measurement。 Karman vortex street。 SCM AT89C52。 temperature pensation華北科技學(xué)院畢業(yè)設(shè)計(jì)（論文） 目錄 綜述 ...........................................................................................................................................I Summary...................................................................................................................................IV 第一章 緒論 .............................................................................................................................1 課題的背景和意義及任務(wù) .......................................................................................1 課題的背景意義 ...........................................................................................1 課題的任務(wù) ...................................................................................................1 國內(nèi)外超聲波風(fēng)速儀的現(xiàn)狀 ..................................................................................1 國外風(fēng)速儀的現(xiàn)狀 .......................................................................................1 國內(nèi)測距儀的現(xiàn)狀 .......................................................................................2 超聲波風(fēng)速儀的研究內(nèi)容 ......................................................................................3 第二章 超聲波風(fēng)速儀測量原理及其總體設(shè)計(jì) .....................................................................4 超聲波風(fēng)速儀原理 ..................................................................................................4 風(fēng)速測量原理 ...............................................................................................4 超聲波風(fēng)速測量的理論分析 .......................................................................5 超聲波傳感器工作原理 ..........................................................................................6 超聲波傳感器基本結(jié)構(gòu)及工作原理 ...........................................................6 超聲波傳感器的基本特性 ...........................................................................7 超聲波測距的總體設(shè)計(jì) ..........................................................................................9 總體設(shè)計(jì)思想 ................................................................................................9 工作過程 ........................................................................................................10 第三章 系統(tǒng)結(jié)構(gòu)及其硬件設(shè)計(jì) .............................................................................................11 單片機(jī)系統(tǒng)及復(fù)位電路設(shè)計(jì) ..................................................................................11 單片機(jī) AT89S52 的結(jié)構(gòu) ............................................................................11 單片機(jī)系統(tǒng)及復(fù)位電路設(shè)計(jì) .....................................................................16 報(bào)警電路 ..................................................................................................................17 顯示電路設(shè)計(jì) ..........................................................................................................18 超聲波發(fā)射電路設(shè)計(jì) ..............................................................................................18 LM555 定時(shí)器 .............................................................................................19 基于單片機(jī)的風(fēng)速測量儀的設(shè)計(jì) 74LS123 單穩(wěn)態(tài)觸發(fā)電路 .................