Agricultural engineering; measuring and controlling system of constant temperature constant wet box; design; surface circuit; frequency modulation technique; PID regulate
农业工程；恒温恒湿箱测控系统；设计；接口电路；调频技术； PID调节
The chaotic Chua's circuit is controlled to its fixed point as well as nP periodic orbits by using switching modulation on one of its capacitor parameters.
不仅给出了数值模拟结果，而且设计了电路实验仿真电路。
Fittings series lasers have: a dedicated optical laser lens (spherical and non-spherical), laser diode driver circuit boards and with TTL modulation drive plate, laser-specific power supply (with a soft-start and reverse polarity protection).
激光器配件系列有：激光专用光学透镜、激光二极管驱动电路板及带TTL调制驱动板、激光器专用电源（具有软启动及极性反接保护）。
Numerical simulation results show that under the modulation of different amplitude of the sinusoidal signals, the modified chua's circuit can be driven to its equilibrium point or 2〓p periodic orbits from its chaotic state.
数值模拟结果表明：如果调制信号的频率大于系统变量的最高频率，则在不同幅度的正弦信号调制下，可使变型蔡氏电路由混沌状态转变到稳定的平衡点和2〓P周期轨道。
The approach uses the parasitic inductance of the antenna to implement ASK modulation by adjusting the capacitive reactance of the matching network, which changes with the backscatter circuit.
该阻抗匹配方法利用天线的寄生电感，通过调整反向散射电路的电容来改变匹配网络的容抗，从而实现ASK调制。
Laser medium for Nd∶YAG, 300W LDAend-pumped continuous surface and micro-lens and lens catheter optical coupling efficiency of 75% transmission, for the electro-optic crystal KDP, Ping-cavity structure, dielectric cavity placed polarizer, cavity length 11cm, the withdrawal pressure-Q-switched, a practical design of the retreat pressure Q-switched circuit, Q-switch along the trigger, improved low-light silicon photodiode measurement circuit, the output pulse modulation, the output pulse width 11ns, light-light conversion efficiency of 10.8%, the output-4 mJ pulse energy, the experimental results are analyzed and discussed.
激光介质为Nd∶YAG，采用300W准连续LDA端面泵浦，表面加微柱透镜和透镜导管进行光耦合，传输效率75%，电光晶体为KDP，平-凹腔结构，腔内放置介质膜起偏器，腔长11cm，退压式调Q，设计了实用的退压调Q电路，Q开关后沿触发，改进了硅光电二极管弱光测量电路，输出脉冲被调制，输出脉宽11ns，光-光转换效率10.8%，输出单脉冲能量4mJ，对实验结果进行了分析讨论。
Including acoustic pickup, signal modulation and enlargement electric circuit, signal projector, signal receiver, signal return to original state and enlargement electric circuit.
包括拾音器、信号调制及放大电路、信号发射器、信号接收器、信号还原及放大电路。
Based on mixed-signal ISP flash MCU C8051F005 and full-bridge pulse width modulation integrated circuit 3955, a microstepping driver with high performance, simple structure and ultra small size was designed for two-phases hybrid stepping motors.
以高性能单片机C8051F005和全桥脉宽调制(PWM，Pulse Width Modulation)驱动电路3955为核心实现了一种结构简单的高性能、多细分、微型化两相混合式步进电动机驱动器。
The timers can be used in various combinations of astable or monostable circuit connections, with or without modulation, for extremely flexible waveform control.
定时器可用于各种非稳和单稳电路的组合中，无论调节与否，都可实现高度灵活的波形控制。
Repairs the positive wave invertor to use the chip control, the pulse-duration modulation, the constant voltage output, has the completely automatic to protect the function reliably, the job safety stable, has the undervoltage, the overload, to press, the short circuit warm and so on many kinds of protection functions, the economy to be practical, practical in the user community.
修正波逆变器采用芯片控制，脉宽调制，稳压输出，有全自动保护功能，工作安全可靠稳定，具有欠压、过载、过压、过温、短路等多种保护功能，经济实用，实用于广大用户。
This paper will first study the theory and method for the pulse width modulation of the dc-dc converter, and then use the method of digital logic circuit to design a pure digital PWM controller, and implement it with FPGA. At last, it will control the duty cycle of the digital PWM controller by combining an 8-bit A/D converter, and apply it to the buck dc-dc converter.
本论文首先研究直流对直流转换器之脉波宽度调变的理论与方法后，再利用数位逻辑电路之方法，设计一个纯数位式PWM控制器，并使用FPGA来实现，最后配合一个8 bit A/D转换器，以控制数位PWM控制器输出之责任周期，并应用於降压式直流对直流转换器。
When the modulation in the IF signal from the oscillator is not inverted, the cancellation means may comprise a subtraction circuit for subtracting the modulating signal from the modulated IF signal.
当调制的中频信号从振荡器不倒，取消手段可能包括减法减去电路调制信号的调制中频信号。
In the second place, this paper presents the operation principles of multiple-frequency circuits and analyzes the electrical variants operated in different modes, which is fulfilled by simulations and theoretic calculations. A conclusion is also drawn: the optimum method of power modulation is to make the circuit work under discontinuous mode.
其次，对倍频电路的工作原理作了详尽的阐述，并从仿真和理论推导的角度分析了电路的不同工作状况下的电气变量，提出电路工作在断态下更适合电路功率调节的方法。
Sensor module is composed of sensor circuit, modulation circuit and analog signal switch.
传感模块由传感器电路、调制电路和模拟信号开关组成。
The main contents is:This paper analyzes interferometry and modulation of LD. It makes a theoretical analysis of heterodyne interference and linear frequency modulation. By analyzing LD characteristics of modulation and temperature, the range of current (.5μA) and temperature(±0.1℃) is obtained. Some circuits such as temperature control, power control and zigzag driving circuit are given in this paper.
主要内容如下：分析了半导体激光器干涉测量方法和调制方法，对外差干涉测量和注入电流调谐做了理论分析，通过对半导体激光器的调谐特性和温度特性的分析，提出了半导体激光器光源系统的实验设计指标：注入电流的波动必须小于0.5μA，温度变化应在±0.1℃的范围内。
The synchronized detection mainly uses for to demodulate the single side band and the double sideband modulation signal, uses the MC1496 integrated circuit constitution demodulator in the article.
同步检波主要用来解调单边带和双边带调制信号，在本文中采用MC1496集成电路构成解调器。
In some of these circuit configurations, the modulation occurring in the IF output will not be inverted with respect to the modulating signal 40, and so a subtraction circuit is then used (instead of the summation circuit 6 to 9) to subtract the modulating signal 40 from the modulated IF output 41 and thereby to produce a substantially demodulated IF output signal I.
在其中一些电路配置，调制发生在中频输出将不会倒对调制信号40 ，所以减法电路然后用（不是求和电路6日至9日）减去40的调制信号从调制中频输出41 ，从而产生一个大大解调中频输出信号一
The sending end when the use of pulse modulation approach will be a binary digital signal into a frequency modulation of the pulse sequence, and driver fired infrared tube to the form of light pulses sent receiver will receive the pulse of light conversion to electrical signals, and then, after amplification, filtering and other treatment to the demodulation circuit after demodulation, reduced to a binary digital signal after the output.
发送端采用脉时调制方式，将二进制数字信号调制成某一频率的脉冲序列，并驱动红外发射管以光脉冲的形式发送出去；接收端将接收到的光脉转换成电信号，再经过放大、滤波等处理后送给解调电路进行解调，还原为二进制数字信号后输出。
One is auto-zero and the other is chopping. The chopping amplifier with its many parts of modulation switches, pre-amplifier, band-pass selective amplifier, and voltage follower and demodulation switches is designed. The circuit is simulated with HSPICE to optimize. The residual offset of microvolt and the equivalent input noise PSD of 70 nV /Hz were obtained.
zero和斩波Chopping 对失调和噪声的影响，具体针对传感器的信号要求进行了斩波放大电路的调制，预放，带通选择放大器，电压跟随和解调等各个部分的设计，电路使用Hspice进行了仿真优化，达到了微伏量级的残余失调和70 nV /Hz输入等效噪声PSD。
The traditional class D amplifier is composed of three parts: modulation circuit, driving circuit and power amplification circuit.
传统的D类放大器一般由三部分组成，即调制电路、驱动电路和功率输出电路。