According to the feature of signal and noise, a signal processing circuit including lock-in amplifier is designed.
依据系统信号及噪声特征，基于相关检测原理，设计了以锁相放大器为核心的信号检测电路。
Because there are large-capacity power supply filter capacitor, which has led to the power amplifier circuit for a high voltage, one will be lower, there is obviously the strength of the voice of change; At the same time, because the moment will break off the flow of electricity 窜入 interference signal amplifier, can also lead to other noise.
因为电源内部有大容量的滤波电容，就导致功放电路的供电电压一会高，一会低，声音的强弱就有明显变化；同时，因为在通断的瞬间会有电流通断的干扰信号窜入放大电路，也会导致其他噪音。
In intelligent peripheral subsystem, Radio Frequency Front Modules include linear power amplifier, low noise amplifier and detection control circuit.
智能天线子系统中，射频前端模块包括线性功率放大器，低噪放大器，检测控制电路。
Based on the advanced thin-film hybrid integrated circuit technology, using Al2O3 fine ceramic substrates with high finish, good heat-conductivity and better mechanical strength, a C-band low noise amplifier is designed in this paper applying the eutectic technology and advanced stick techniques of Seekon Company.
本文中设计的C波段低噪声放大器是在国内先进的薄膜混合集成电路制作工艺基础上，采用光洁度高，导热率好，机械度强的氧化铝精细陶瓷基片，利用西科公司共晶微组装工艺和先进的粘接技术研制而成的。
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。
In the first year of the project, we will first design the front-end radio frequency circuit, including the low noise amplifier, image reject mixer, and multibit bandpass Sigma-Delta modulator.
本计划之第一年已分别设计无线区域网路接收机之前端电路---包含高频低杂讯放大器、镜像消除混波器、多位元带通三角积分类比/数位调变器等功能方块。
In view of the detection for the feeble signal in the progress of measuring the parameter of laser holo- graphic anti-counterfeiting production, a practical and low-noise prime amplifier circuit of photoelectric detection is designed. It is based on ICL7650 chopper-stabilized operational amplifier.
中文摘要：针对防伪全息产品参数检测中弱光强信号的探测，设计了一种实用化的基于ICL7650斩波自动稳零运算放大器的低噪声前级放大电路。
This paper discusses some kinds of function circuits to receiver for moblie telephone, incuding antenna circuit、low noise amplifier circuit and mixing circuit, the emaphsis are put on their performance indexes、characteristics and applications.
本文讨论了移动电话接收机功能电路中常见的几种天线电路、低噪声放大电路及混频电路，重点放在它们的性能指标、特性及应用方面。
First it chooses the ultrasonic sensor in accordance with the mechanism of partial discharge and the ultrasonic character and its propagation rules. In order to ensure the safety and reliability of the detector, it designs the photoelectric isolation circuit module, which realizes the strong and weak electricity power isolation with the optical transmission method. In the analog signal pre-processing unit and sampling trigger circuit design part, it completes the design of amplifier, band-pass filter circuit, sampling trigger circuit. In the high-speed data acquisition modules part, it mainly completes high-speed data collection and its storage. Because the speed of single-chip can not keep up with the sampling rate of ADC, it designs 20-bit address generator with the hardware to complete the storage of high-speed data. At the same time it completes the design of the discharge display circuit, alarm and reset circuit. RS485 inte***ce realizes the communication with the host computer and ensures the communication distance and the noise immunity. In order to analyze the relationship between the ultrasonic signal and the discharge, eliminate noise interference and accurately extract the partial discharge pulse signal, it introduces the extraction method of discharge signal using the wavelet transform. Finally, it makes prospects at the partial discharge detector and proposes some methods of thinking from several aspects to do further research and improvement of the system.
首先根据局部放电的发声机理和超声波的特点及其传播规律选择了合适的超声波传感器；为保证检测仪使用的安全可靠，设计了光电隔离模块电路，用光纤传输的方法实现了强弱电的电气隔离；模拟信号预处理单元中设计了放大电路、带通滤波电路、采样触发电路；高速数据采集模块中设计了高速数据采集和存储电路，由于单片机速度远远赶不上AD采样的速度，用硬件设计了20位地址发生器，来完成对高速数据的存储；同时系统中还设计了放电显示、报警电路以及复位电路；系统与上位机的通讯采用RS485通讯接口形式，保证了上位机与下位机之间的通讯间隔和抗干扰性；为了分析超声波信号与放电之间的关系，消除噪声干扰，正确提取局部放电脉冲信号，文中先容了利用小波变换提取放电信号的方法；最后本文对局部放电检测仪的研究提出了一些展看，从几个方面提出了对系统做进一步的研究和改进的方法思路。
Design Of Front- End Circuit Of K - Band Satellite Receiver Key words: waveguide-to-microstrip transition, low noise amplifier, image reject band- pass filter sub-harmonic mixer, low- pass filter Abstract The front-end circuit is important in satellite communication systems. In this paper, the design of the K-band front-end circuit of satellite receiver, is presented. It has many distinct advantages such as high gain, low noise, low cost and simple structure, making it promising in future application.
K 波段卫星接收系统前端电路设计关键字波导-同轴-微带转换器，低噪声放大器，镜象抑制带通滤波器，分谐波混频器，低通滤波器摘要卫星接收系统前端电路是卫星通信系统中的一个重要部件，本文主要介绍了一种K波段卫星接收系统前端电路的设计方法，其特点是高增益，低噪声，低成本，结构简单，有望提高整个接收系统的性能。
In contrast, if a standard op amp amplifier circuit were used in this application, it would simply amplify both the signal voltage and any dc, noise, or other common-mode voltages.
相反，如果在此应用中采用一只标准的运算放大器，它仅仅能放大两端的信号电压和任何 DC 信号、噪声或其它共模电压。
In order to improve signal to noise ratio (SNR) of the differential absorption gas sensor system, based on the correlation detection principle, a faint signal processing circuit is designed centering around lock-in amplifier.
为了提高气体差分传感系统的信噪比，基于微弱信号的相关检测原理，设计了以锁相放大器为核心的微弱信号处理电路。
The one step linear modulation was realized by the use of calculation amplifier of precedent phase on three steps with two differential circuit, which can bate the disturbance effectively and advance the signal to noise ratio.
对强干扰下的声波信号采用两级差动放大，采用相位超前型三运放二阶电路，实现一级增益线性调节。
In addition, as steady-state accuracy and current ripple of dynamic shim amplifier is very demanding, this thesis uses noise analysis method to analyze the feedback circuit and designs output filter for the power stage, in order to achieve performance requirements.
另外，由于动态匀场放大器对稳态精度和纹波要求非常苛刻，本论文还采用噪声分析的方法对反馈电路进行分析设计，并为功率级输出设计滤波器，以便达到性能的要求。
Signal amplification system designed partly based on the differential op amp amplifier circuit to improve the signal to noise ratio, increasing the signal common mode rejection ratio.
系统的信号放大设计部分采用了差分运放放大电路，以提高信号的信噪比，并增大信号的共模抑制比。
The power amplifier module is to enhance the launch of the main signal power to increase the effective transmission distance and lower noise; low-noise amplifier circuit module to receive weak signals from the channel, improve system sensitivity.
发射端的功放模块主要是增强发射信号的功率以增加有效的传输距离和降低噪声的干扰；低噪声功放电路模块接收来自信道中微弱的信号，提高系统的灵敏度。
This paper discusses the input matching circuit and the effect of the amplifier structure on noise performances.
本文从低噪声FET放大器的实际设计出发，分析了输入匹配电路对噪声性能的影响。
Design, simulation and realization of power amplifier and low noise amplifier are discussed in this article, including RF amplifiers circuit and DC feed circuit.
基于工程开发的需要，本文讨论了功率放大器和低噪声放大器的设计、仿真及整个电路的实现方法，包括射频放大电路和直流馈电电路，并提供了相关的仿真结果和测试结果。
Circuit Model of a Semiconductor Laser Amplifier and Its Noise Characteristics Analysis
半导体激光放大器的电路模型及噪声特性分析
The remote control circuit adopts power amplifier circuit and low noise amplifier circuit to improve transmission power.
遥控电路中还设计了功率放大电路与低噪声放大电路来提高数据发送功率以增加数据传输距离。