信号发生器中英文翻译-毕业论文.doc

毕业设计(论文)外文资料翻译系 别： 电子信息系 专 业： 通信工程 班 级： B090310 姓 名： 王海涛 学 号： B09031018 外文出处： annul reviews 附 件： 1. 原文； 2. 译文 2013年06月 Signal generatorSignal generator is refers to produce the parameters of electric testing signal equipment. According to the signal waveform, the function can be divided into sine signal (waveform) signal, pulse signal and random signal generator and so on four categories. Signal generator also called source or oscillator, in production practice and science and technology has been widely used in the field. Various waveform curve can be represented with trigonometric function equation. Can produce various waveform, such as triangle wave, sawtooth wave, rectangle wave (including square wave), sine wave of the circuit is called a function signal generator. Also known as the signal generator, which is used to produce specific parameters required for the circuit being measured electric testing signal. In testing, research, or adjust the electronic circuits and devices, measurement circuit of some electric parameters, such as measuring the frequency response, noise coefficient, for voltmeter, etc, are required to conform to the conditions set by the technology of electrical signals, to simulate a used in the actual work of excitation signal of the device under test. When the requirement of system steady state characteristics of the measurement, need to use sine signal source of known amplitude and frequency. When the transient characteristics of the testing system, and to use front time, pulse width and repetition period known rectangular pulse source. And the parameters of the signal source output signal, such as frequency, waveform, the output voltage, or power, can under certain ?Working principle of the signal generatorSignal generator is used to produce frequency of 20 hz 200 KHZ sine signal (low frequency). Besides has the voltage output, and power output. So the usage is very wide, can be used for testing or repair a variety of electronic instruments and equipment in the frequency characteristic of the low frequency amplifier, gain, passband, also can be used for outer modulation signal of high frequency signal generator. In addition, electronic voltmeter in calibration, it can provide ac voltage signal. Low-frequency signal generator: the principle of the system including the main vibration level, the main vibration output adjustment potentiometer, voltage amplifier, attenuator, power amplifier and output impedance converter (output transformer) and instructs the voltmeter.Main vibration level low frequency sinusoidal oscillation signals, the voltage amplifier amplification, to achieve the requirement of the output voltage amplitude, the attenuator can be directly output voltage output, with the main vibration output adjustment potentiometer to adjust the size of the output voltage.Signal generator is introducedSine signal generator: sine signal is mainly used in the measuring circuit and frequency characteristic of the system, the nonlinear distortion, gain and sensitivity, etc. According to the frequency range can be divided into low-frequency signal generator, high-frequency signal generator and the microwave signal generator; According to the output level can be adjusted the scope and degree of stability can be divided into simple signal generator (signal) and standard signal generator (attenuation to the output power can be accurately - 100 decibels below milliwatts) and power signal generator (output power up to tens of milliwatts); Way frequency change into tuner type signal generator, frequency sweep signal generator, program-controlled signal generator and frequency synthesis type signal generator, etc.Low frequency signal generator: this includes audio (200 20000 hz) and video (1 hz 10 MHz) range of sine wave generator. Main vibration level generally use RC oscillator, difference frequency oscillator is also available. For ease of testing system frequency characteristic and asked for peace amplitude-frequency characteristic waveform distortion.High frequency signal generator, frequency of 100 KHZ to 30 MHZ frequency, VHF signal generator of 30 300 MHZ. General use LC tuned oscillator, frequency can be read by tuning capacitor dial scale. Main purpose is to measure all the receiver technology indicators. Output signal is available internally or with the low-frequency sine amplitude modulation or frequency modulation signal, the output frequency voltage can decay to microvolt under 1.The output signal level can accurate readings, adjustable amplitude or frequency can also be used for electricity meter reading. In addition, the instrument and to prevent leakage signal of good shielding.Standard signal generatorMicrowave signal generator: from decimeter wave to millimeter wave band of the signal generator. Signal is usually by uhf triode with distribution parameters of the resonator and the reflex klystron, but has gradually be microwave transistor, field effect tube and gunn diode solid-state devices to replace the trend. Instruments generally rely on mechanical tuning cavity to change frequency, each covering one octave, signal power is general by cavity coupling can be up to 10 milliwatts. Simple signal source requires only can add 1000 HeFang wave amplitude modulation, while standard signal generator will output a benchmark level adjustment to one milliwatt, again from the back with the attenuator db milliwatts of the readout signal value; Must also have internal or with rectangular pulse amplitude modulation, in order to test the radar receiver.Frequency sweep and program-controlled signal generator, frequency sweep signal generator can produce constant amplitude, frequency, in limited within the scope of linear change signal. In hf and VHF frequency scanning voltage or current control oscillation circuit components (such as a varactor tube or core coil) to implement the frequency sweep oscillator; In microwave paragraph early use voltage tuning frequency sweep, use change the backward wave pipe spiral electrode of the dc voltage to change the oscillation frequency, then widely used magnetic tuning frequency sweep, YIG ferrite ball for microwave solid oscillator tuning circuit, by scanning current control dc magnetic field changes the resonance frequency of the ball. Frequency sweep signal generator with automatic sweep, hand control, process control and remote control, etc.Frequency synthesis type signal generator: this signal generator is not produced by the oscillator directly, but rather serve as standard frequency source with high stability crystal oscillator, frequency synthesis technology is used to form the arbitrary frequency of the signal, is the same as the standard frequency source frequency accuracy and stability. Output signal frequency according to decimal Numbers often go, highest can reach 11 digital high resolution. Frequency except by manual selection can also be programmed control and remote control, also can be carried out step magnitude frequency sweep, is suitable for automatic test system. Direct frequency synthesizer by addition, multiplication, crystal oscillator, filter and amplification circuit, frequency transformation rapidly but complicated circuits, high output frequency can reach around 1000 MHZ. Use morer indirect frequency .Function generator, also called waveform generator. It can produce certain cyclical time function waveform (mainly sine wave, square wave, triangle wave, sawtooth wave and pulse wave, etc.). Frequency range can be from a few hz JiWei hz ultra-low frequency until even tens of megahertz. Except for communications, instrumentation and automatic control system test, also widely used in other non-electric measurement field. One method of figure 2 to generate the waveform, the integral circuit and a certain threshold switching circuit with hysteresis characteristics, such as Schmitt trigger is connected into a loop, integrator can square integral into triangle wave. Schmitt circuit and can make a triangle wave rises to a certain threshold or fall into another threshold jump to form a square wave, frequency division can along with the integrator of the RC value of the variable .Pulse signal generator: width, amplitude and repetition frequency adjustable rectangular pulse generator, can be used to test the transient response of linear systems, or use the analog signal to test the radar, road and other performance of the pulse number system. Pulse generator is mainly composed of master oscillator, delay, pulse forming stage, output stage and attenuator etc. Master oscillator circuit for harmonic oscillator, usually in addition to outside the self-excited oscillation, the main work according to the trigger mode. Usually after additional trigger signal output a front-facing first trigger pulse, in order to trigger the oscilloscope observation instrument, in advance and then after a period of delay time is adjustable to output the signal pulse, the width can be adjusted. Some can output pairs of main pulse, ?Random signal generator: random noise signal generator and the pseudo random signal generator can be divided into two kinds of signal generator.Noise signal generator: completely random signal is within the working frequency band with uniform white noise spectrum. Commonly used white noise generator are: working at 1000 MHz saturated diode type of coaxial system under white noise generator; Microwave gas discharge tube waveguide system used in white noise generator; Using the noise of the crystal diode reverse current solid-state (can work under 18 GHz) across the spectrum, etc. The intensity of the noise generator output must be known, usually with the output noise power over the resistor thermal noise decibels (referred to as the s/n ratio) or by their noise temperature. With white noise as input signals, for example, and measure the output of the network signal and the input signal of the cross-correlation function, you can get the impulse response function of the networkSignal generator applicationsSignal generator also called source or oscillator, in production practice and science and technology has been widely used in the field. Various waveform curve can be represented with trigonometric function equation. Can produce various waveform, such as triangle wave, sawtooth wave, rectangle wave (including square wave), sine wave of the circuit is called a function signal generator.Function signal generator in circuit experiment and test equipment has the very wide range of USES. In communications, broadcasting and television system, for example, require rf (radio frequency), the radio frequency wave is the carrier, the audio frequency (low frequency), to carry out or pulse signal, video signal needs to be able to produce high-frequency oscillator.In industry, agriculture, biomedical and other fields, such as the high frequency induction heating, melting, quenching, ultrasonic diagnosis, nuclear magnetic resonance (NMR) imaging, etc., all need power or big or small, frequency or high or low of the oscillator.信号发生器 信号发生器是指产生所需参数的电测试信号的仪器。按信号波形可分为正弦信号、函数(波形)信号、脉冲信号和随机信号发生器等四大类。信号发生器又称信号源或振荡器，在生产实践和科技领域中有着广泛的应用。各种波形曲线均可以用三角函数方程式来表示。能够产生多种波形，如三角波、锯齿波、矩形波(含方波)、正弦波的电路被称为函数信号发生器。也称为信号发生器，它用于产生被测电路所需特定参数的电测试信号。在测试、研究或调整电子电路及设备时，为测定电路的一些电参量，如测量频率响应、噪声系数，为电压表定度等，都要求提供符合所定技术条件的电信号，以模拟在实际工作中使用的待测设备的激励信号。当要求进行系统的稳态特性测量时，需使用振幅、频率已知的正弦信号源。当测试系统的瞬态特性时，又需使用前沿时间、脉冲宽度和重复周期已知的矩形脉冲源。并且要求信号源输出信号的参数，如频率、波形、输出电压或功率等，能在一定范围内进行精确调整，有很好的稳定性，有输出指示。 信号源可以根据输出波形的不同，划分为正弦波信号发生器、矩形脉冲信号发生器、函数信号发生器和随机信号发生器等四大类。正弦信号是使用最广泛的测试信号。这是因为产生正弦信号的方法比较简单，而且用正弦信号测量比较方便。正弦信号源又可以根据工作频率范围的不同划分为若干种。信号发生器工作原理信号发生器用来产生频率为20Hz200kHz的正弦信号(低频)。除具有电压输出外，有的还有功率输出。所以用途十分广泛，可用于测试或检修各种电子仪器设备中的低频放大器的频率特性、增益、通频带，也可用作高频信号发生器的外调制信号源。另外，在校准电子电压表时，它可提供交流信号电压。低频信号发生器的原理：系统包括主振级、主振输出调节电位器、电压放大器、输出衰减器、功率放大器、阻抗变换器(输出变压器)和指示电压表。主振级产生低频正弦振荡信号，经电压放大器放大，达到电压输出幅度的要求，经输出衰减器可直接输出电压，用主振输出调节电位器调节输出电压的大小。信号发生器分类介绍正弦信号发生器：正弦信号主要用于测量电路和系统的频率特性、非线性失真、增益及灵敏度等。按频率覆盖范围分为低频信号发生器、高频信号发生器和微波信号发生器;按输出电平可调节范围和稳定度分为简易信号发生器(即信号源)、标准信号发生器(输出功率能准确地衰减到-100分贝毫瓦以下)和功率信号发生器(输出功率达数十毫瓦以上);按频率改变的方式分为调谐式信号发生器、扫频式信号发生器、程控式信号发生器和频率合成式信号发生器等。低频信号发生器：包括音频(20020000赫)和视频 (1赫10兆赫)范围的正弦波发生器。主振级一般用RC式振荡器，也可用差频振荡器。为便于测试系统的频率特性，要求输出幅频特性平和波形失真小。高频信号发生器：频率为 100千赫30兆赫的高频、30300兆赫的甚高频信号发生器。一般采用 LC调谐式振荡器，频率可由调谐电容器的度盘刻度读出。主要用途是测量各种接收机的技术指标。输出信号可用内部或外加的低频正弦信号调幅或调频，使输出载频电压能够衰减到1微伏以下。输出信号电平能准确读数，所加的调幅度或频偏也能用电表读出。此外，仪器还有防止信号泄漏的良好屏蔽。标准信号发生器微波信号发生器：从分米波直到毫米波波段的信号发生器。信号通常由带分布参数谐振腔的超高频三极管和反射速调管产生，但有逐渐被微波晶体管、场效应管和耿氏二极管等固体器件取代的趋势。仪器一般靠机械调谐腔体来改变频率，每台可覆盖一个倍频程左右，由腔体耦合出的信号功率一般可达10毫瓦以上。简易信号源只要求能加1000赫方波调幅，而标准信号发生器则能将输出基准电平调节到1毫瓦，再从后随衰减器读出信号电平的分贝毫瓦值;还必须有内部或外加矩形脉冲调幅，以便测试雷达等接收机。扫频和程控信号发生器：扫频信号发生器能够产生幅度恒定、频率在限定范围内作线性变化的信号。在高频和甚高频段用低频扫描电压或电流控制振荡回路元件(如变容管或磁芯线圈)来实现扫频振荡;在微波段早期采用电压调谐扫频，用改变返波管螺旋线电极的直流电压来改变振荡频率，后来广泛采用磁调谐扫频，以YIG铁氧体小球作微波固体振荡器的调谐回路，用扫描电流控制直流磁场改变小球的谐振频率。扫频信号发生器有自动扫频、手控、程控和远控等工作方式。频率合成式信号发生器：这种发生器的信号不是由振荡器直接产生，而是以高稳定度石英振荡器作为标准频率源，利用频率合成技术形成所需之任意频率的信号，具有与标准频率源相同的频率准确度和稳定度。输出信号频率通常可按十进位数字选择，最高能达11位数字的极高分辨力。频率除用手动选择外还可程控和远控，也可进行步级式扫频，适用于自动测试系统。直接式频率合成器由晶体振荡、加法、乘法、滤波和放大等电路组成，变换频率迅速但电路复杂，最高输出频率只能达1000兆赫左右。用得较多的间接式频率合成器是利用标准频率源通过锁相环控制电调谐振荡器(在环路中同时能实现倍频、分频和混频)，使之产生并输出各种所需频率的信号。这种合成器的最高频率可达26.5吉赫。高稳定度和高分辨力的频率合成器，配上多种调制功能(调幅、调频和调相)，加上放大、稳幅和衰减等电路，便构成一种新型的高性能、可程控的合成式信号发生器，还可作为锁相式扫频发生器。函数发生器：又称波形发生器。它能产生某些特定的周期性时间函数波形(主要是正弦波、方波、三角波、锯齿波和脉冲波等)信号。频率范围可从几毫赫甚至几微赫的超低频直到几十兆赫。除供通信、仪表和自动控制系统测试用外，还广泛用于其他非电测量领域。图2为产生上述波形的方法之一，将积分电路与某种带有回滞特性的阈值开关电路(如施米特触发器)相连成环路，积分器能将方波积分成三角波。施米特电路又能使三角波上升到某一阈值或下降到另一阈值时发生跃变而形成方波，频率除能随积分器中的RC值的变化而改变外，还能用外加电压控制两个阈值而改变。将三角波另行加到由很多不同偏置二极管组成的整形网络，形成许多不同斜度的折线段，便可形成正弦波。另一种构成方式是用频率合成器产生正弦波，再对它多次放大、削波而形成方波，再将方波积分成三角波和正、负斜率的锯齿波等。对这些函数发生器的频率都可电控、程控、锁定和扫频，仪器除工作于连续波状态外，还能按键控、门控或触发等方式工作。脉冲信号发生器：产生宽度、幅度和重复频率可调的矩形脉冲的发生器，可用以测试线性系统的瞬态响应，或用模拟信号来测试雷达、多路通信和其他脉冲数字系统的性能。脉冲发生器主要由主控振荡器、延时级、脉冲形成级、输出级和衰减器等组成。主控振荡器通常为多谐振荡器之类的电路，除能自激振荡外，主要按触发方式工作。通常在外加触发信号之后首先输出一个前置触发脉冲，以便提前触发示波器等观测仪器，然后再经过一段可调节的延迟时间才输出主信号脉冲，其宽度可以调节。有的能输出成对的主脉冲，有的能分两路分别输出不同延迟的主脉冲。信号发生器应用信号发生器又称信号源或振荡器，在生产实践和科技领域中有着广泛的应用。各种波形曲线均可以用三角函数方程式来表示。能够产生多种波形，如三角波、锯齿波、矩形波(含方波)、正弦波的电路被称为函数信号发生器。函数信号发生器在电路实验和设备检测中具有十分广泛的用途。例如在通信、广播、电视系统中，都需要射频(高频)发射，这里的射频波就是载波，把音频(低频)、视频信号或脉冲信号运载出去，就需要能够产生高频的振荡器。在工业、农业、生物医学等领域内，如高频感应加热、熔炼、淬火、超声诊断、核磁共振成像等，都需要功率或大或小、频率或高或低的振荡器。8