数字频率计的说明书

6th International Conference on Machinery, Materials, Environment, Biotechnology and Computer (MMEBC 2016)Design and Implementation of FPGA-Based Digital Frequency MeterHUANG rui1,a1Chongqing college of electronic engineering， Chongqing， 401331,China）a*****************Keywords: FPGA, Digital Frequency Meter, Design and ImplementationAbstract. Development of EDA technology has changed the traditional electronic design methods. Widely used in large-scale FPGA and other programmable logic devices, electronic design and software programming becomes as easy and quick. Advances in electronic design technology, but also changed the traditional frequency meter design. It exists conventional frequency measurement method using an analog circuit frequency characteristic measurement frequency, but also the use of a digital pulse counting frequency measurement method. With the development of digital circuit technology to pulse count based on the law derived from a variety of improved digital frequency measurement method, measurement accuracy, fast response measurement and other aspects have been greatly improved. This paper analyzes the direct frequency measurement method and measurement principle cycle frequency measurement method, which are explained in frequency measurement method of producing ± 1 count error reasons.IntroductionFrequency meter design technology with the development of electronic circuit technology and gradually move forward, the early frequency meter design using discrete components, long design cycles, poor stability, and the finished product volume, high power consumption. Development of digital electronic technology and integrated circuits, so that the digital frequency meter wide applications, digital frequency meter circuit and microcontroller unit can be used to design and implementation. Compared to a discrete piece of frequency meter, a digital frequency meter to improve the stability, reducing the volume, but there is still a digital frequency meter circuit complex, long design cycles and other shortcomings, digital frequency meter measuring range is limited, to measure signals of different frequencies are designed to be a part of the circuit, poor flexibility. 20th century, with the development of microelectronics technology advances and computer technology, both in the mutual promotion to FPGA family, represented by application of programmable logic devices becoming more common. Programmable logic device programmed by the universal integrated circuit integrated onto a single silicon chip the size of a small, exponentially reducing the size of the circuit, and because traces short, reduce interference and increase system reliability. Because such devices can be reconstructed through software programming and its structure and working methods of the hardware, such as hardware design software design as convenient, it brings a great deal of flexibility in the design of digital circuit system. With the integration of programmable logic devices have been expanding, continuously improve and enhance their own computer-aided design technology capabilities, EDA in modern electronic system design field was born.Study of Frequency Measurement TechniqueCurrently, many methods for measuring the frequency accuracy of the measurement depends on the frequency characteristics of the frequency range of the measurement and the measured object. The measurement accuracy can be achieved, as the clock frequency depends not only on the accuracy of the criteria used, but also on measuring apparatus and methods used. Next, several types of commonly is used frequency measurement methods briefly. Direct Reading frequency measurement using the frequency characteristics of the circuit is the frequency interpretation. Direct Reading measured frequency of the bridge frequency measurement method, resonance frequency measurement method, frequency - voltage conversion frequency measurement method.Comparison of frequency measurement method is to use standard frequency fc and compare the measured frequency fx, when the standard frequency is adjusted to the measured frequency equal means zero meter (zero indicator) it means zero, and the value that is measured frequency standard frequency value. Comparison of measured frequency can be divided into the beat frequency measured and difference frequencies measured frequency models. The former is to be measured frequency signal and standard frequency signal superimposed on the linear element to generate a beat frequency. The latter is to be measured frequency signal and standard frequency signal in the non-linear mixing element. Currently beat frequency absolute error measurement frequency of about a few tenths of hertz, the frequency of the difference frequency measurement error can be orders of magnitude better than 10-5, the minimum detectable signal level of 0.1μV ~ 1μV. Beat frequency and differential frequency method in routine situations rarely used.Measurement frequency counting method is commonly used in digital frequency meter, the basic frequency measurement method. Count is the number per unit time of the periodic signal is counted. The accuracy of counting frequency measurement depends on the accuracy and error counts the reference time. The design uses a counting frequency measurements, the following notation for frequency measurement and frequency measurement principle based on several methods of counting method for detailed analysis.FPGA Structure and Working PrincipleFPGA is a field programmable logic array (Field Programmable Gate Array) abbreviation. It CPLD (Complex Programmable Logic Device, complex programmable logic devices), is currently used for a class of large-scale programmable logic devices.For combinational logic circuit, the current output is always a function of the current input, and when the fixed circuit configuration, the same amount of input, output does not change. The combinational logic circuits are shown in Fig.1.Fig.1 Combinational logic circuit examplesTruth table determines the logical relationship between input and output. The truth table and random access memory link, we will see if the input A, B, C as random access memory address input A2, A1, A0, the output P, Q can be seen as corresponding to the address memory the data stored in the storage unit D1, D0. . The memory cells each store different data, data (output) Address (input) and the storage unit may be constituted of a combination of different logic. This basic principle is implemented with random access memory (RAM) programmable combinational logic. FPGA programmable logic forming method is based on this principle programmable lookup tables (LookUp Table, LUT) structure. LUT is programmable logic constitutes the smallest unit. Most of the structure is formed using FPGA-based SRAM (static random access memory) look-up table logic, SRAM is used to form the logic function generator. Currently FPGA Multi-use 4-input LUT, so every LUT can be viewed as a 4-bit address lines 16 × 1 of RAM. All possible outcomes when the user development environment by the EDA schematic or HDL language to describe a logic circuit, the development of EDA software will automatically calculate the logic circuit, and the results pre-write RAM, so that each input signal logic operation is equivalent to input an address look-up table to find the address of the corresponding content, then the output can.FPGA-Based Frequency Meter DesignFrequency measurement and display the entire frequency meter control module is the core module for the fully digital circuit, using FPGA devices using VHDL programming to achieve. Frequency measurement part of multi-period synchronous frequency measurement method which achieve equal precision frequency measurement, measurement accuracy only and the reference frequency signal frequency, accuracy and relevant gate opening time, and frequency of the signal is independent, enabling a wide range of equal precision frequency measurement. The signal frequency measurement portion from the signal shaping module, as all pulse counting frequency measurement can only receive pulse signal, the signal must be shaped to form a pulse signal and the signal with the frequency. Reference frequency measurement part (clock) signal generated by the "reference frequency (clock) signal modules." Gate signal generator preset gate signal, because it is programmed, long can be programmed to modify all open gate signal. Operator by the formula fx = (Nx / Nc) • fc calculate the frequency value of the measured signal, the operator of multiplication and division operations include two operations. The display control section includes a BCD code converter, decoder latch two sub-modules. Frequency operator is obtained in binary form, to be displayed in decimal form and it must be BCD code converter, in the form of BCD code to decimal. Frequency meter display portion using 7-segment, so the decoder, the latch complete display decoder BCD code, and also has stored decoding function.The module generates a reference frequency signal frequency measurement using the standard clock pulse signal, also known as the clock signal module. The module uses a crystal oscillator and the corresponding hardware circuit to generate the standard clock signal, in addition to providing a reference clock signal frequency signal frequency measurement section 1 of the counter, but also provides the timing clock signal to the gate signal generator.The form of the signal is varied, based on the pulse count after the frequency measurement can only accept pulse frequency signal, the signal must be shaped to form the measured signal with the pulse signal frequency to frequency values measuring. Frequency response characteristic of the signal shaping module also determines the frequency measurement frequency range of the upper frequency.To simplify the design, frequency meter to display only the integer portion of the measured signal frequency value. Display module uses six seven-segment LED display. Because the seven-segment decoder, the latch circuit has the frequency measurement display module design is completed, the six digital tube directly to the FPGA pins to the corresponding output, but also consider the issue of digital drive tube.Power modules provide the required standard for the entire voltage frequency meter modules. After the power module 220V AC power input, transformer rectifier, regulator device through the output DC voltage required by the system stable.Frequency Meter Design and Implementation of the Functional ModulesFrequency measurement and display control module design using top-down design approach. First, the module is according to the functions are divided into several sub-modules, and then were using VHDL, and finally through the top-level design file to each sub-module assembled together to complete frequency measurement and display control functions.A reference frequency signal is measured based on the frequency, and in the design of the reference frequency signal is also used as a timing clock signal multiplier, divider, BCD code converters, etc. Cyclone series FPGA devices contained in the present design uses high-performance embedded analog phase-locked loop (DPLL performance is far superior), the phase-locked loop (PLL) can be synchronized with the clock signal input, and the input clock as PLL reference implementation, and the input clock frequency multiplier or do 1 to 32 division. Compared with the clock directly from the external, internal clock this chip can reduce the clock delay and clock distortion, reduce chip interference, but also can improve the set-up time and holdtime clock.Although the measured signal is a periodic signal, its form may be varied. But the frequency measurement signal module can only be measured in the form of pulses, so before the measurement to the measured signal shaping, the different forms of signals organized into periodic pulse signal.Frequency measurement system consists of different chips, each chip required supply voltage have different requirements, so the requirements of the power supply module to provide multiple voltage value. FPGA devices are used in this design Altera's EP1C3T144C8, core voltage of the device is 1.5V, I / O voltage of 3.3V, FPGA need to provide + 1.5V and + 3.3V dual voltage; inverting oscillator circuit 74LS04 devices require + 5V voltage; LM361 the standard voltage Vcc is + 5V, V + and V- voltage range is wide, V + requires 5V ~ 15V, V- between -6V ~ -15V.The design of frequency values are measured by the six seven-segment LED display. Since the latch function display decoder and decoding of digital values in the FPGA design has been completed, so the FPGA output can directly access input digital tube display frequency value. However, due to limited FPGA drive capability, it said only a theoretical point of view, the actual application, but also to access the digital front tube drive circuit, here we use ULN2003 as digital tube driver.ConclusionFrequency meter is one of the commonly used electronic measuring equipment. With the development of electronic technology, design methodology frequency meter are gradually moving forward. Discrete pieces from the early to the integrated circuit, LSI, this process must have the appropriate design features components to complete. When the development of electronic design EDA technology, the emergence of large-scale, ultra-large-scale programmable logic device, the electronic circuit includes a frequency meter design becomes more simple and convenient, and without changing the hardware structure on the basis and may be changed according to design requirements design, different functions and even complete systems with the same hardware circuit design. Based on the analysis and comparison of several commonly used based on the frequency measurement method, synchronous frequency measurement method according to the design need to use a multi-cycle frequency meter design. As a result of EDA design technology, most of the design work is done on the computer and logic simulation is completed by the middle of the computer. References[1] W. Zhou. Systematic Reseach on High-Accuracy Frequency Measurements and Control.Shizuoka University.Doctor Dissertation, 2000:15-24,90-96[2] M.A.A .Sour, H.I.Saleh. An FPGA Inplem Entation Guide for Some Different TypesOfserial-Parallel Multiplier Structures. Microelectronics Fournal, 2000, 31(3):161-168[3] W.Zhou. Some New Method for Precision Time Interval Measurement. Proceedings Of The1977Ieee International Frequency Control Symposium, 1997,418-421[4] R.A.James, F. Gallgray. Vhdl Design Expression and Synthesis of Vhdl. Cambridge: HarvardUniversity Press, 2001[5] C.Altera. Configuration Devices For Sram-Based Lut Devices. 2002.[6] F.W.John. Digital Design Principles And Practices,2001.[7] M.M.Mano. Digital Design, 3rd Ed. Prentice Hall Usa,2002.。

目录页数1. 产品介绍.................................................................................1-1.简述……….……………………………………………….1-2.特性…...…………………………………………………... 1 1 12. 技术规格 (2)3. 使用前之注意事项……………………………….…………...3-1.拆开包装…………………..………………….…………...3-2.使用电源…………………...…………………..………….3-3.设备安装和操作………………………...………………...3-4.预备工作………………………………………………….. 3 3 3 4 44. 面板介绍 (5)5. 应用…………………………………………………………….5-1.灵敏度………..……………………………………………5-2.输入灵敏度特性………………...………………………...5-3.最大输入电压…………..………………………………...5-4.典型应用…………………………………………………..7 71011 116. 电路描述…………………..……………………………...…...6-1.工作原理……………………………..…………………....6-2.频率测量精度 (13)13147. 维护……………..……………………………………………..7-1.标准的校准方法………………….………………………7-2.清洁…..…………………………………………………... 18 18 181. 产品介绍1-1.简述GFC-8010H是一台高输入灵敏度20mVrms, 测量范围0.1Hz~120MHz的综合计频器.最新半导体技术的应用使仪器具备简洁,高性能,高分辨率和高稳定性的特点.1-2. 特性另外,此计频器还具备以下特性:●分辨率高达1μHz.●线性滤波器被密封在静电噪声区以扺制噪声的影响.●低通滤波器保证了低频的精确测量.●结构简洁,重量轻.●低功率消耗.●高质量的晶体保证了精确的频率测量.12. 技术规格灵敏度(rms) 10Hz~10MHz 10mV 10MHz~40MHz 20mV 40MHz~80MHz 35mV 80MHz~120MHz 50mV输入阻抗1MΩ35pF.最大输入电压150Vrms.耦合系统交流耦合时基晶振频率: 10MHz.老化率: ±1×10-6/月.温漂: 25℃±5℃±5×10-6.0℃~50℃±2×10-5. 精度1Hz + 1位数+时基误差计数容量8个十进制位显示系统数字发光二极管显示闸门时间0.1 s, 1 s, 10 s 开关可选最大分辨率1μHz (10Hz 范围,10s门时间) 0.1Hz (100MHz范围,10s门时间)工作温度范围0℃~40℃储存温度范围-10℃~+70℃功率消耗大约5W.电源要求100V, 120V/220V/230V±10%, 50/60Hz. 尺寸大约245(W) × 95(H) × 280(D) m/m.重量大约1.7kgs.附件操作手册……………………× 1 测试线GTL-101 …………..× 1233.使用前之注意事项 3-1. 拆开包装仪器在出厂前已被检测过.收到仪器后,请打开包装检查是否有运输过程中造成的损坏.若有,请及时与运货商或供货商联系.3-2. 使用电源仪器的使用电源可以是以下表格中任一种.请检查后面板上所标示的电源并替换相应的保险丝.警告: 为避免电击, 请务必将电源线保护接地端子接地.当使用电源改变,请按以下表格所示替换保险丝:使用电源 范围 保险丝 使用电源 范围保险丝100V 120V 90-110V 108-132V T160mA 250V 220V 230V 198-242V 207-253V T100mA 250V警告: 为避免人身伤害,换保险丝前请不要连接电源线.3-3.设备安装和操作请确保该仪器在适当的环境下使用.如果该仪器的使用未遵循规定,可能会造成对仪器的损坏.3-4.预备工作1)当阻抗是1MΩ,最大输入电压取决于频率和SENSITIVITY开关的位置,其相互关系如图６所示,此图表中的值须严格对应.初始时将SENSITIVITY开关打到1/10,如果此计频器不计数,将SENSITIVITY开关打到1/1范围并进行测量.此步骤可以降低损坏输入电路的危险性.2)选择交流电源100V, 120V, 220V, 或230V±10%.3)在0~40℃的环境温度下使用该计数器. 不要将仪器放在高温设备的顶上, 并保证仪器周围环境的通风.4)不要让水渗进仪器,也不要剧烈振动仪器.5)若仪器在特别嘈杂的环境中使用,在电源里加入噪声滤波器.6)测量低频时,按下低通滤波器开关,可以削弱高频成分,以防止可能出现错误触发.44. 面板介绍(1). Counter Input BNC 型接口(2). ATT, 1/1, 1/10 输入灵敏度(衰减)按钮.1/1 : 输入信号被直接连接到输入放大器.1/10: 输入信号衰减率为10.(3). LPF ON/OFF 低频测量时,将此键打到ON位置,插入输入信道一个100KHz低通滤波器.(4). FREQ/PRID 用此键选择频率测量或周期测量.(5). Gate TimeSelector用此按钮选择10s,1s或0.1s的门时间.(6). Power ON/OFF 电源开或关用此按钮.(7). Gate Time(LED) 显示设定的闸门时间10s,1s或0.1s(8). Over (LED) Over 指示灯亮表示一个或多个有效数字无法显示.(9). Displayed (LED) 频率值以８位数字显示.(10) Exponent andunits(LED) LED指示灯显示单位S和Hz,指示测量值指数如下:k=1000 M=1,000,000G=1,000,000,000 m=1/1000 μ=1/1,000,000 n=1/1,000,000,0005前面板图１. 前面板65. 应用5-1. 灵敏度灵敏度(或衰减器)开关对一般仪器的作用是保护输入电路和防止仪表超出量程.对计频器,灵敏度仍然起着这个重要的作用.迟滞一般发生在计数器的信号整形电路中.为了增强计频器对噪声的抵制,即使噪声低于迟滞(hysteresis),此电路也将不工作.这个信号整形电路是施密特电路(Schmitt Circuit),其作用图如下:图. 2 施密特电路作用图7根据图2,当输入电压为V+,输出为相对高的电压;当输入电压为V-, 输出为相对低的电压,电压差V H=(V+)-(V-)叫作迟滞电压. 若输入电压为图3中任一种情况,施密特电路将不工作,也无输出.图. 3 施密特电路不工作的状态从以上的描述中可以看出施密特电路是否工作取决于决定输入电压幅值大小的灵敏度.图4是合适选择灵敏度以防止错误计频的例子:(a)通过选择合适的灵敏度以正确对一个失真信号进行计频.当输入信号太大时,杂波也会被计频,所显示的实际上是未知频率的两倍.(b)若高频噪音信号迭加到未知信号并且输入施密特电路的电压过高,计频会发生错误.但选择合适的灵敏度可以获得正确的计频.8图. 4 9满足以下两点可以防止错误的计频:a)使噪音电压的峰峰值小于ＶH.b)当未知信号的峰峰值大于ＶH,测量时先将灵敏度设在1/10,然后再将其设在1/1以保护输入电路并避免错误的计频.5-2. 输入灵敏度(Sensitivity)特性这台仪器的输入灵敏度如图5所示.图. 5 输入灵敏度特性105-3. 最大输入电压最大输入电压(Input Voltage) V s频率特性如图6所示.图. 6. 最大输入电压-频率5-4. 典型应用下面是典型的几个应用:1).对于发射器或接受器的输出频率测量(输出功率在1W左右),仅仅需要将一圈带夹的导线接到天线以外几十厘米处,具体距离取决于输出的幅值.2).当进行振荡器阶段,乘法器阶段,及输出阶段的频率跟踪测量,则利用一个2-3圈的细线,将信号耦合到每一个线圈.(输入电容与多圈导线在谐振频率时可能引起谐振.)注意: 因为此产品有很高的灵敏度,当测试人员触到带夹线的红端(非接地端),感应现象可能会引起错误的计频.因此,11按以上方法进行测量时请把持住黑色夹和与之同轴的电缆.3).测量一般都可通过将带夹线黑的一端连到地,红的一端接到测试点进行.4).若电缆电容对测试电路有影响(当测量圈状的电路或高阻抗电路),测量前将一个高阻与带夹线串联插入.进行4)和5)的测量时,确保带夹线黑的一端连到地.如果可能的话,将此电缆接地到测试电路的地端.这个步骤可降低噪音的影响.除了(1-5), 利用计频器的特性还可进行其它不同的测量.126. 电路描述6-1. 工作原理为了更好地利用此频率计数器,充分理解电路是有用的.我们尽可能利用最新的集成电路技术以降低该产品的价格同时减小电路的复杂性,提高稳定性.假设输入信号到达10MHz~100MHz并输入到主板上标明的CHA.此信号首先由Q201~Q202放大.电路中的三级放大器标识为U202,是ECL逻辑电路.在线性误差范围内,每一级放大器在反馈之前的增益为5.Q203和Q204将ECL电平转变成TTL 电平.此信号直接被传送到计数器IC U301.IC U301提供此计频器的所有功能,通过LED显示结果.使用电源经变压器成为9V输入信号,U201调节此9V电压以纠正电路.当电源开关打在“on”位置,大约5.0V电压输入电路.136-2. 频率测量精度测量精度频率测量精度由以下两点决定:1)±1计频.2)时基精度.±1 计频的误差由数字表的特性和闸门信号(Gate Signal)与输入信号的相位差关系所决定.如图7,计频结果多1或少1取决于相位差.图. 7 ±1 计频误差14高精度测量振荡器的时基精度几乎完全由晶振特性所决定.时基规格如下: 振荡频率10MHz老化率1×10-6/月温漂5×10-6(25±5℃)±2×10-5 (校准环境温度0~40℃) 这台仪器中的晶振温度特性如图8所示.从中可看出温度系数最大为2×10-5.图. 8 晶振温度特性15晶振的温漂: 2×10-5(温度0~60℃) 25℃为参考. 选择0~60℃的温度范围是因为仪器内部的温升约20℃,而适合晶振的环境温度范围为:0~40℃.假设晶振的环境温度为25℃,频率为10MHz,则根据最大温漂和晶振频率,可能产生的误差为(10x10６)x(2x10-5)=2x102Hz.在实际应用中,以下两种情况会产生最糟的情况:1)在0℃的环境温度(Ambient temperature)下一打开仪器电源开关(Switch ON)即进行频率校准;在40℃的环境温度下打开仪器电源开关长时间后(Time elapsed after switch ON)进行测量.2)在40℃的环境温度下打开仪器电源开关长时间后进行校准;在0℃的环境温度下一打开仪器即进行测量.在这些最糟的情况下,保证精度4×10-5(校准温度:0~40℃) 即0.004%.图. 9 晶振上升特性范例16在实际应用中,上述最坏的情况几乎从未踫到过而且一直保持着高精度状态.图9为上升特性的一个范例,精度随着温度的变化而变化.如图所示,打开开关后50分钟,此仪器的晶振到达热平衡状态.发货前,此仪器在25℃的环境下校准了60分钟.如果仪器在打开开关1小时后开始工作且是在20~30℃的环境下校准,则即使用最糟的晶振也可保证精度5x10-6.5x10-6(25±5℃)用百分比表示为0.0005%.老化率1×10-6/月表示在恒定常温下一月后,变化为0.0001%.177.维护以下指示步骤仅可由合格人员执行﹒为避免电击﹐请不要进行操作手册上未指明的操作.7-1.校准的标准方法50分钟的预热后,将一标准的或精度高达1x10-7的STD OUT信号输入计频器.调整调节器SVC301以显示10.000000MHz.经过这个步骤可能会获得超过1x10-7的精度.用一个螺丝起子(非铁头)来调整调节器.7-2.清洁清洁仪器时﹐请用沾有水和温和溶剂的软布﹒不要将清洁剂直接喷到仪器上﹐以防止其渗透到外壳内造成损坏﹒不要用含有汽油﹐苯﹐甲苯﹐二甲苯﹐丙酮等相似的溶剂﹒不要将研磨剂用于仪器的任何部分﹒18。

VC3165智能频率计使用说明书第一章概述（一）概述：VC3165频率计是一种以微处理器为基础而设计的高分辨率、多功能数字式智能化仪器。

具有：频率测量，周期测量以及等精度测量等功能，并有3档功能选择、工作状态显示、单位显示及8位LED高亮度显示。

本仪器是智能数字化仪器，全部功能是用一个单片微控制器（CPU）来完成的。

晶体有恒温控制线路,降低了温度漂移造成的测量误差；输入回路设有衰减器（X1、X20）和AC/DC耦合转换器。

整机性能稳定, 功能齐全，是一种高性能，低价位的理想智能数字化仪器。

本仪器测量频率范围极宽，可从0.01Hz到2.4GHz。

闸门时间从100ms到10s连续可调。

使用本机前请仔细阅读本仪器的资料和操作方法，以便取得最好的使用效果。

（二）技术条件及说明1、测量〈1〉.输入端口本机有两个输入通道端口①.A端口为0.01Hz—50MHz的低频通道端口②.B端口为50MHz—2.4GHz的高频通道端口〈2〉.频率测量①量程第1档： 50MHz— 2.4GHz，由B端口输入第2档： 2MHz—50MHz，由A端口输入第3档： 0.01Hz—2MHz，由A端口输入②分辨率:档位状态频率范围分辨率闸门时间最小闸门时间最大100Hz1GHz—2.4GHz 1kHz 第一档 AC50MHz—1GHz(不含1GHz) 1kHz 10Hz 第二档 AC 2MHz—50MHz 1kHz10Hz0.1HzAC 100Hz—2MHz 10Hz 第三档DC 0.01Hz—100Hz(不含100Hz) 0.001Hz 0.001Hz③闸门时间连续可调：可调范围：100ms—10s④精度:基准时间误差×频率±1个字。

<3>.周期测量：可从A、B两端口中的任何一个端口输入，其中A端口测量范围为 0.2us—10s，B端口测量范围为0.2us—0.5ns。

2．输入特性通道A输入灵敏度：“AC”: ≤80mVrms，“DC”: 0.01Hz—1Hz≤500mVrms，1Hz—100Hz≤80mVrms。

数显频率计设计任务书⑴硬件设计：根据任务要求，完成单片机最小系统及其扩展设计。

⑵软件设计：根据硬件设计完成显示功能要求，完成控制软件的编写与调试；⑶功能要求：用89C51单片机的定时器/计数器的定时和计数功能，外部扩展6 位LED数码管，要求累计每秒进入单片机的外部脉冲个数，用LED数码管显示出来。

目录摘要............................................................................................................ .. (4)1. 绪论............................................................................................................ . (4)2. 设计要求及方案选 (6)1.1 设计要求 (6)1.2 方案选择 (6)3．系统电路设计 (7)3.1 基于单片机的数字频率计的原理 (7)3.2 单片机的概述及引脚说明 (8)3.3 单片机的最小系统 (9)3.4 单片机的定时\计数 (9)3.5 定时器\计数器的四种工作方式 (10)3.6 主要程序段及软件流程图设计 (12)3.6.1 流程图 (12)3.6.2 源程序 (14)结论............................................................................................................ (16)致谢......................................................................................................... .. (17)参考文献................................................................................................................. . (18)附录........................................................................................................... .. (19)摘要频率是电子技术领域中最基本的参数之一，在许多测量方案以及测量结果中都会涉及到频率测量的相关问题，频率精确测量的重要性显而易见。

自适应数字频率计安装调试说明书负责人：组员：目录一、产品生产 (3)1.1产品特性 (3)二、生产材料清单及说明 (3)2.1 材料清单 (3)2.2 材料说明 (4)三、产品制作流程图 (4)四、调试工具 (4)五、安装顺序 (4)六、调试顺序 (5)七、注意事项 (5)八、产品保管 (6)九、验收标准 (6)十、附件 (6)一、产品生产1.1产品特性本产品名为自适应数字频率计。

数字频率计是直接用十进制数字来显示被测信号频率的一种测量装置。

它不仅可以测量正弦波、方波、三角波和尖脉冲信号的频率。

而且还可以测量它们的周期。

数字频率计在测量其他物理量如转速、振动频率等方面也获得广泛应用。

1.2 产品外观产品外观图如下：图1.2-1二、生产材料清单及说明2.1 材料清单原件名称及型号数量（均以最小单位计）STM12C5A60S2 1CD4051 1四位共阴数码管 174HC393 11K排阻 110K 电阻1 12M 晶振1 22pF 瓷片电容 22.2 材料说明本系统中所用的所有原件都为直插原件，系统中的数码管只能用共阴数码管，led 等的颜色没有限定，可根据实践场合或用户爱好选择；系统中用到的六角开关实际只用到其中的一个，所以在生产的时候可用拨码开关代替。

其余材料可根据实际灵活应用。

三、产品制作流程图四、调试工具学生电源、万用表，电烙铁，焊锡丝。

学生电源用于动态调试时使用，即通电后用，万用表在整个调试过程均能用到，电烙铁和焊锡丝用于调试发现错误修改时用。

五、安装顺序画好PCB 图后，一系列过程制作出板子并且打好焊孔后，按如下数序进行安装：（1）对照PCB 图，找到对应的所有电阻的位置，把电阻依次插上，焊接；（2）焊接好电阻后，剪去高出焊盘的管脚；（3）多有电阻焊接好后，依次重复（1）（2）步骤开始放置电容，然后是晶振、按键、 DIP-40底座、数码管、排针，最后放置六角开关，知道所有原件都放置好。

一、设计功能与要求设计数字频率计，满足如下功能：（1）用VHDL语言完成数字频率计的设计及仿真。

（2）频率测量范围：1∼10KHz，分成两个频段，即1∼999Hz，1KHz∼10KHz，用三位数码管显示测量频率，且用LED（发光二极管）来表示所显示单位，我们这里定义亮绿灯表示以Hz为单位，亮红灯表示以KHz为单位。

（3）具有自动校验和测量两种功能，即既能用于标准时钟的校验，同时也可以用于未知信号频率的测量。

（4）具有超量程报警功能，在超出目前所选量程档的测量范围时，会发出音响报警信号。

二、设计思路通过计算已知单位时间内待测信号的脉冲个数来计算被测信号的频率，同时通过动态扫描方式在三个数码管上显示出测得频率值。

如下图1的系统框图所示，计数器对CP信号进行计数，在1秒定时结束后，将计数器结果送锁存器锁存，并通过时钟下降沿将不再变化的测量值送至数码管显示。

在下一个计数时钟信号上升沿到来时，再次重新计数。

图1 系统设计框架图系统各个模块介绍如下:（1）测量/校验选择模块：输入信号：选择信号selin，被测信号measure，标准校验信号test；输出信号：CP；当selin=0时，为测量状态，CP=measure；当selin=1时，为校验状态，CP=test。

校验与测量共用一个电路，只是被测信号CP不同而已。

（2）测频控制信号发生器（二分频）：输入信号：1Hz时钟信号clk；输出信号：1秒钟高电平基准信号clk1（周期为2秒）；（3）四级十进制计数器模块（带进位C）：输入信号：clk1、CP，用于计数开始、清零、锁存。

输出信号：q4～q1设置超出量程档测量范围示警信号alert。

若被测信号频率小于1KHz（K=0），则计数器只进行三级十进制计数，最大显示值为999.Hz，如果被测信号频率超过此范围，示警信号扬声器报警；若被测信号为1KHz~10KHz （K=1），计数器进行四位十进制计数，取高三位显示，最大显示值为9.99KHz，如果被测信号频率超过此范围, 示警信号扬声器报警。

目录第一章概述1第二章工作特性 22.1 毫伏表 22.2 频率计 32.3 基准输出 32.4 远控功能 32.5 其它 4 第三章面板说明 53.1 前面板 53.2 后面板10 第四章使用说明114.1 测量前的工作114.2 电压输入通道测量124.3 系统设置14 第五章远程控制175.1 遥控操作前的准备工作175.2 命令格式说明185.3 命令简介195.4 命令详解20 第六章注意事项24 第七章附件清单26SP2271是一种新型的采用微处理器控制的智能化数字超高频毫伏表/频率计，该仪器采用检波放大工作原理，能测量10kHz~1000MHz 的正弦电压。

测量电压围800µVrms~10Vrms、分辨率1μV、准确度优于±2%。

本仪器采用高亮度VFD显示，读数清晰、亮度高、寿命长，该机具有频率响应良好、驻波系数小、灵敏度高、功耗低、体积小、重量轻等特点。

仪器能自动调零，测量电压时既可以选择自动量程也可以选择手动测量量程，仪器带有RS232接口，可进行远程测量控制。

该仪器是生产车间和实验室超高频电压计量测试的必备仪器（如超高频标准信号源输出电压频响的计量测试）。

该仪器测量的稳定性好、分辨率高、重复性好，可用于计量信号源输出电压的误差和稳定性，同时也能用于10kHz到1GHz超高频电压计量工作传递标准，也可用于自动测试系统中测试高频电压。

该仪器可选配10kHz~1000MHz频率插件，使该机一机两用，可作为10kHz~1000MHz频率计使用。

该仪器按GB6587.1-86“电子测量仪器环境试验总纲”的规定属于第Ⅱ组仪器。

（额定使用上限温度试验按SJ2314-83的3.15规定湿度为80%）。

2.1 毫伏表2.1.1测量电压的频率围：射频探头10kHz~1000MHz2.1.2测量电压的围：800ｕVrms~10Vrms，50Ω负载2.1.3电压测量方式：手动或自动2.1.4电压测量量程档为：4mVrms/40mVrms/400mVrms/4Vrms/10Vrms 2.1.5测量100kHz电压的工作误差：(0~40℃)注： 1 标准电压源的频率100kHz2 波形要求：正弦波，失真度≤0.3%，幅度误差≤±0.3%；2.1.6测量电压的频率响应误差（100kHz为基准，50Ω同轴终端精密负载）2.1.7射频探头插入50Ω同轴三通（50Ω负载）10kHz~200MHz ，VSWR ≤ 1.35。

目录页数1. 产品介绍 (1)2. 技术规格 (2)3. 操作前注意事项 (4)3-1. 拆开包装 (4)3-2. 使用电源 (4)3-3. 设备装配及操作 (5)4. 面板介绍 (6)5. 应用 (10)6 维护 (12)6-1. 校准的标准方法 (12)6-2. 清洁 (13)计频器GFC-8131H/GFC-8270H 操作手册1.产品介绍计频器的通道A用以测量范围为0.01Hz到120MHz的频率和周期﹐通道B的测量范围为50MHz到1.3(2.7)GHz.为读值之便﹐此产品提供了高分辨率和灵敏度特性﹒1计频器GFC-8131H/GFC-8270H 操作手册2﹒技术规格2计频器GFC-8131H/GFC-8270H 操作手册3耦计频器GFC-8131H/GFC-8270H 操作手册3﹒操作前注意事项3-1. 拆开包装仪器在出厂前已被检测过﹒收到仪器后﹐请打开包装检查是否有运输过程中造成的损坏﹒若有﹐请与运输公司或经销商联系﹒3-2. 使用电源仪器的使用电源可以是以下表格中的任一种﹒请检查后面板上所标示的电源﹐并替换相应的保险丝﹒警告﹒为避免电击﹐请务必将电源线保护接地端子接地﹒当使用电源改变﹐请按以下表格所示替换保险丝﹒警告﹒为避免人身伤害﹐换保险丝前请不要连接电源线﹒4计频器GFC-8131H/GFC-8270H 操作手册3-3. 设备装配及操作请确保该仪器在适当的环境下使用﹒如果该仪器的使用未遵循规定﹐可能会造成对仪器的损坏﹒5计频器GFC-8131H/GFC-8270H 操作手册４﹒面板介绍(1). Power ON/OFF 电源开/关键﹒(2). Reset 使计频器回初始值零以重新开始计频﹒(3). FREQ A 选择通道A频率模式(4). PRID A 选择通道A周期模式(5). FREQ B 选择通道B频率模式(6). Gate Time(旋钮) 用以连续选择从10ms到10s的不同测量时间﹒(最小＝输入信号的一个周期)﹒拉出此旋钮﹐显示值可被锁定﹒(7). Gate Time(LED) 当Gate time 发光二极管亮﹐计频器的主闸门电路被开﹐测量在进行﹒(8). TRIG LEVEL 拔出此钮﹐触发电平在–2.5V x ATT 到（旋钮）＋2.5V x ATT 间变动﹒按下此纽﹐进行自动设置功能﹒(9). TRIG LEVEL 设置了触发电平﹐该显示灯显示输入(LED) 信号高于或低于触发电平﹒6计频器GFC-8131H/GFC-8270H 操作手册(10). LPF/ON 通道Ａ中加入一100kHz的低通滤波器(11). ATT x1/x20 选择通道Ａ的衰减x1 输入信号直接连到放大器x20 衰减率为20(12). COUP DC/AC 选择通道Ａ的直流或交流耦合﹒(13). INPUT A 通道Ａ的输入BNC(14). INPUT B 通道Ｂ的输入BNC(15). S 显示值的单位为秒(S)(16). Hz 显示值的单位为赫兹(Hz)(17). Exponent (LED) 指示测量值的指数﹐如下﹕k=1000 M=1,000,000G=1000,000,000 m=1/1000u=1/1,000,000 n=1/1,000,000,000 (18). DISPLAY(LED) 8位红色LED显示﹒7计频器GFC-8131H/GFC-8270H 操作手册(19). OVFL(LED) OVFL(overflow) 指示灯显示一个或多个最有效数字无法显示﹒8计频器GFC-8131H/GFC-8270H 操作手册前面板图１前面板9GFC-8131H/GFC-8270H 操作手册5. 应用(1)信号测量若频率范围为0.01Hz~120MHz,按FREQ A开关﹐将输入信号连到通道Ａ﹒若频率范围为50MHz~1.3(2.7)GHz,按FREQ B开关﹐将输入信号连到通道Ｂ输入BNC.按“PRID” 开关选择通道A的周期模式﹒(2)闸门时间设置此仪器可连续调整10ms~10s的闸门时间或一个周期输入﹐取决于时间较长者﹒闸门时间的调整会影响到取样率和读值分辨率﹒逆时针旋转此钮可加快读数﹐顺时针旋转此钮可提高显示分辨率﹒拉出此GATE TIME 钮可锁定当前读值以方便纪录﹒按回此钮则恢复计频器正常操作﹒(3)触发电平调整通过拉出并旋转TRIG LEVEL钮来调整通道Ａ输入信号的触发电平﹒触发电平可设在-2.5V x ATT到+2.5V x ATT之间﹒如果按下此纽﹐则被设定在自动触发状态（此钮只适用通道Ａ）(4)LP 滤波器通道Ａ的低频测量噪声会造成读值不稳定﹒LP滤波器可最小化高频噪声﹐使计频器仅测量需测的低频成分﹒若需要更稳定的读值﹐按下LP FILTER按键﹐在通道Ａ中内建一个100kHz的低通滤波器﹒10GFC-8131H/GFC-8270H 操作手册(5)衰减器通道Ａ输入电路中提供一衰减器﹐测量大信号时可提供额外过载保护﹒按下此钮可减小信号20倍﹒当测量信号的幅值未知﹐建议按下此键以提供保护﹒若幅值很低﹐则松开此键以求更高的灵敏度﹒11GFC-8131H/GFC-8270H 操作手册6. 维护以下指示步骤仅可由合格人员执行﹒为避免电击﹐请不要进行操作手册上未指明的操作﹒6-1 校准的标准方法(1) 直流位准调整按下TRIG LEVEL 钮并旋到中间位置﹒连接一个10MHz的正弦波到通道Ａ﹐调整SVR102,降低10MHz正弦波(标准20mVrms)的幅值到能维持稳定显示﹒(2)标准振荡器调整连接一标准参考频率(10MHz,温度系数＜0.2ppm)到通道Ａ﹒调整Gate time以获得８位数字显示﹒调整SVC201以获得参考频率的最精确显示﹒(3)迟滞偏压调整激活LP FILTER并设置COUP到DC位置﹒按下TRIG LEVEL 钮并旋转到中间位置﹒连接一个1Hz正弦波30mVrms到通道A﹒调整SVR103到最小能维持稳定显示﹒12GFC-8131H/GFC-8270H 操作手册6-2. 清洁清洁仪器时﹐请用沾有水和温和溶剂的软布﹒不要将清洁剂直接喷到仪器上﹐以防止其渗透到外壳内造成损坏﹒不要用含有汽油﹐苯﹐甲苯﹐二甲苯﹐丙酮等相似的溶剂﹒不要将研磨剂用于仪器的任何部分﹒13。

数显频率计设计任务书⑴硬件设计：根据任务要求，完成单片机最小系统及其扩展设计。

⑵软件设计：根据硬件设计完成显示功能要求，完成控制软件的编写与调试；⑶功能要求：用89C51单片机的定时器/计数器的定时和计数功能，外部扩展6 位LED数码管，要求累计每秒进入单片机的外部脉冲个数，用LED数码管显示出来。

目录摘要............................................................................................................ .. (4)1. 绪论............................................................................................................ . (4)2. 设计要求及方案选 (6)1.1 设计要求 (6)1.2 方案选择 (6)3．系统电路设计 (7)3.1 基于单片机的数字频率计的原理 (7)3.2 单片机的概述及引脚说明 (8)3.3 单片机的最小系统 (9)3.4 单片机的定时\计数 (9)3.5 定时器\计数器的四种工作方式 (10)3.6 主要程序段及软件流程图设计 (12)3.6.1 流程图 (12)3.6.2 源程序 (14)结论............................................................................................................ (16)致谢......................................................................................................... .. (17)参考文献................................................................................................................. . (18)附录........................................................................................................... .. (19)摘要频率是电子技术领域中最基本的参数之一，在许多测量方案以及测量结果中都会涉及到频率测量的相关问题，频率精确测量的重要性显而易见。