可变增益

The ADT7674 that MLS384 still used ADI firm is used at systematic monitoring and fan control, sensor of ADT75A number temperature is used at coming loose to heat up monitoring, amplifier of ADL5330 alterable gain is used at cable road drive, and DAC of AD5601 NanoDAC series is used at gain control.

MLS384还采用了ADI公司的ADT7674用于系统监控和风扇节制，ADT75A数字温度传感器用于散热监控，ADL5330可变增益放大器用于电缆线路驱动，以及AD5601 nanoDAC 系列DAC用于增益节制。

Especially, the technology of Automatic Gain Control and signal processing are studied which are key factors working on the performance of the receiver. Based on analyzing the theory of automatic Gain Control, operational amplifiers 0P37 and logarithmic D/Aconverter AD7111A are used to design variable gain amplifiers which can be controlled numerally, A/D convector LTC1405 is Used to test the echo, Complex Programmable Logic device is used for controller, and an arithmetic is designed for automatic Gain Control which is simulated and analyzed in order to test its feasibility.

本文在分析自动增益控制AGC原理的基础上，采用集成运放OP37和数控增益衰减器AD7111A设计可数字控制的可变增益运放模块；采用高速A／D转换器LTC1405作为回波信号检测模块；采用复杂可编程逻辑器件CPLD作为核心控制模块，构成数字自动增益控制电路，并设计粗调和细调步进控制相结合的算法，对回波信号的增益进行精确而快速的调节控制，使回波信号振幅快速稳定在设计指标范围内，利于接收机后续信号处理电路对回波信号作进一步的处理。

In order to achieve the optimum power consumption, the bandwidth of the VGAs can also be dynamically reconfigured and some Gm cells can be cut off in the given application.

更为重要的是，为了优化功耗，可变增益放大器的带宽可以动态调节，而且一些Gm单元在特定的应用下可以关断。

AD8348 is a broadband quadrature demodulator with an integrated intermediate frequency variable gain amplifier, and integrated baseband amplifiers.

AD8348是一个带集成中频可变增益和基带放大器的宽带正交解调器。

Simulation results show that the Filter and VGA system has gain of 6~48 dB, variable gain of 42 dB,6 dB/Step, THD54 dBc at 100 mV peak-to-peak input voltage, IIP3 of-6.35 dBV. The NF is less than 25 dB and current dissipation is 30 mA from 1.8 V voltage supply.

电路的仿真结果表明滤波器和VGA系统的增益为6~48 dB，可变增益为42 dB，6 dB/step，在输入电压峰峰值为100 mV时THD小于-54 dBc，线性度为-6.35 dBV，噪声系数在通带内小于25 dB，消耗电流为30 mA。

Variable gain amplifier is an analog circuit, which varies gain, adjusts signal dynamic range and stabilizes signal power.

可变增益放大器是模拟单元电路之一，起着变化增益、调整信号动态范围、稳定信号功率的作用。

This paper presents a low-voltage low-power variable gain amplifier,which is applied in the automatic gain control loop of a super heterodyne receiver.

针对超外差接收机的自动增益控制网络，设计了一种结构简单的低压、低功耗全差分可变增益放大器。

According to the comparison of the advantages and the disadvantages of four implementing methods of the variable gain amplifier,the digital potentiometer is selected for the laser receiving circuit and its action process is analyzed.

比较可变增益四种实现方法的优缺点，在激光接收电路中选择使用数字电位器的方法实现可变增益控制，并分析其作用过程。

Techniques to linearly adjust the gains of variable gain elements (i.e., variable gain amplifiers or VGAs) in a receiver of transmitter.

线性地调节发射机的接收机内的可变增益元件(即，可变增益放大器或VGA)的增益的技术。

The charge pump can output a step-up and a step-down voltage simultaneously with a high driving capability.The multiple gain pair technique was introduced to enhance its efficiency.The proposed co-use technology for capacitors and switch arrays reduced its cost.

该电荷泵能同时提供具有驱动能力的升压和降压模式电压输出，且可实现可变增益组合，以便根据检测到的输入电压自动调整增益组合以提高工作效率。

The absorption and distribution of chromium were studied in ryeusing nutrient culture technique and pot experiment.

采用不同浓度K2CrO4(0，0.4，0.8和1.2 mmol/L)的Hoagland营养液处理黑麦幼苗，测定铬在黑麦体内的亚细胞分布、铬化学形态及不同部位的积累。

By analyzing theory foundation of mathematical morphology in the digital image processing, researching morphology arithmetic of the binary Image, discussing two basic forms for the least structure element: dilation and erosion.

通过分析数学形态学在图像中的理论基础，研究二值图像的形态分析算法，探讨最小结构元素的两种基本形态：膨胀和腐蚀；分析了数学形态学复杂算法的基本原理，把数学形态学的部分并行处理理念引入到家实际应用中。