Description: 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。文章综述了CMOS集成可变增益放大器的研究情况 给出了可变增益放大器的定义、应用、分类和主要指标,描述了多种开环和闭环放大器的结构,分析了相应的增益控制方法及其优缺点 说明了在CMOS工艺下实现放大器增益按指数变化的几种途径。最后,介绍了用于无线数字通信,具有宽带、高线性、低电源电压等高性能可变增益放大器的设计实例。-Variable gain amplifier circuit of the analog unit, a change is the gain, adjust the signal dynamic range, stability and the role of signal power. This paper reviews the CMOS integrated variable gain amplifier of the situation given the definition of a variable gain amplifier, application, classification and key indicators, describes a variety of open and closed loop amplifier structure, analysis methods and the corresponding gain control The advantages and disadvantages illustrates the CMOS process to achieve changes in amplifier gain in several ways according to index. Finally, introduced for wireless digital communications, with broadband high linearity and low supply voltage high-performance variable-gain amplifier design examples. Platform: |
Size: 328704 |
Author:bird |
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Description: 摘要
电能表作为用电量的测量工具广泛的应用于各种场合。在电能表校表系统中,需要的最基本的输入信号源是高精度双路正弦信号源,并要求可对其频率、相位、幅值进行调节,来对电能表进行校准。
基于单片机的程控信号源设计，运用数字调相、数字调幅和数字调频等技术，要求实现相位、幅度、频率的高精度程控调节。本文设计了一种利用锁相环频率合成技术和数字波形合成技术组成的程控低频正弦波信号发生器，并给出了调幅、调频、调相的实用电路，频率调节通过改变8253计数器的分频系数来实现；相位调节由51单片机预置计数器的计数初值来完成，幅度的调整通过改变DAC1210II的参考电压来实现，使频率分辨率达0.01Hz,相位调节精度达0.1°，并介绍电路中的主要芯的功能及使用。输出正弦波频率和幅值的精度高，稳定性好，失真度低，电路简单、可靠、便于程控。
关键词：数字合成信号源；程控；调幅；调频；移相；
-Abstract
Meter consumption as the size of the measurement tool is widely used in various occasions. In single-phase power meter verify system, the most basic needs of the input signal is the source of two-way high-precision sine signal source, and may request its frequency, phase, amplitude in a certain step to adjust to the imitate of the actual electricity load with a right meter calibration.
Design of the programmable signal supply controlled source，which based on the MCU，including digital phase adjustment，distal amplitude adjustment，digital frequency adjustment etc．The system should achieve high quality digital adjustment of phase, amplitude and frequency. This paper describes the use of a PLL frequency synthesizer technology, and digital wave form synthesis technology consisting of program-controlled low-frequency sine wave signal issued devices, and applies the amplitude， frequency， phase of practical circuit. Frequency can be adjusted through a change in the 8253 counter-frequ Platform: |
Size: 381952 |
Author:张谦 |
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Description: Bitcoin是点对点(peer-to-peer)基于网络的匿名数字货币。点对点(peer-to-peer)的意思是指没有中央权威控制货币 的汇款通道。相反，这些货币转帐的任务是由网络节点进行的集体管理。匿名就意味着交易各方可以隐藏自己的真实身份。优势：
无需信托中间人，能够方便的进行互联网上的汇款。
第三方不能够控制或者阻止您的交易。
Bitcoin 交易几乎免费, 而信用卡的网上在线支付系统通常收取 1-5 的交易费用，加上其他各种费用高达数百美元。
避免了中央储备银行的不良政策和不稳定性所造成的安全隐患. Bitcoin系统的有限货币通胀是均匀分布(由CPU决定)于整个网络, 而不是由银行垄断.
Bitcoin 是一个由Satoshi Nakamoto 制作的开源项目, 目前处于开发测试阶段. Bitcoin 研发网址位于SourceForge.
-Bitcoin P2P Cryptocurrency
Bitcoin is a peer-to-peer network based digital currency. Peer-to-peer (P2P) means that there is no central authority to issue new money or keep track of transactions. Instead, these tasks are managed collectively by the nodes of the network. Advantages:
Transfer money easily through the Internet, without having to trust middlemen.
Third parties can’t prevent or control your transactions.
Bitcoin transactions are practically free, whereas credit cards and online payment systems typically cost 1-5 per transaction plus various other merchant fees up to hundreds of dollars.
Be safe from the instability caused by fractional reserve banking and bad policies of central banks. The limited inflation of the Bitcoin system’s money supply is distributed evenly (by CPU power) throughout the network, not monopolized by the banks.
Bitcoin is an open source project created by Satoshi Nakamoto, and is currently in beta development stage. Bitcoin development is h Platform: |
Size: 5025792 |
Author:lijun |
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Description: The TLC5620C and TLC5620I are quadruple 8-bit voltage output digital-to-analog converters (DACs) with
buffered reference inputs (high impedance). The DACs produce an output voltage that ranges between either
one or two times the reference voltages and GND, and the DACs are monotonic. The device is simple to use,
running from a single supply of 5 V. A power-on reset function is incorporated to ensure repeatable start-up
conditions. Platform: |
Size: 179200 |
Author:Ma |
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Description: 本调频收音机主要由FM/AM收音机芯片CXA1019、PLL且频率合成器BU2614和单片机AT98C51组成。收音机以单片机AT98C51为控制核心, 实现全频搜索、指定频率范围搜索和手动搜索电台 本收音机还使用了数字电位器(X9511)控制音量。采用液晶显示器显示载频和时钟等信息, 大幅度降低了系统的功耗。整机实现3V 电源工作, 采用E2PROM(AT24C04)存储电台, 还增加了立体声解码功能。-Mainly by the FM radio FM/AM radio IC CXA1019, PLL and frequency synthesizer BU2614 and SCM AT98C51 composition. AT98C51 microcontroller for the control of the radio to the core, to achieve full frequency search, specify the frequency range of search and manual search radio station the radio also uses a digital potentiometer (X9511) to control the volume. Carrier frequency with LCD display and clock and other information, significantly reducing system power consumption. Machine to achieve 3V supply, the use of E2PROM (AT24C04) storage station, also increased the stereo decoding. Platform: |
Size: 320512 |
Author:梁蛟龙 |
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Description: TLC5615C, TLC5615I
10-BIT DIGITAL-TO-ANALOG CONVERTERS
-10-Bit CMOS Voltage Output DAC in an
8-Terminal Package
5-V Single Supply Operation
3-Wire Serial Interface
High-Impedance Reference Inputs
Voltage Output Range . . . 2 Times the
Reference Input Voltage
Internal Power-On Reset
Low Power Consumption . . . 1.75 mW Max
Update Rate of 1.21 MHz
Settling Time to 0.5 LSB . . . 12.5 µ s Typ
Monotonic Over Temperature
Pin Compatible with the Maxim MAX515
ications
Battery-Powered Test Instruments
Digital Offset and Gain Adjustment
Battery Operated/Remote Industrial
Controls
Machine and Motion Control Devices
Cellular Telephones
Platform: |
Size: 305152 |
Author:li |
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Description: 本单相正弦波逆变电源的设计，以12V蓄电池作为输入，输出为36V、50Hz的标准正弦波交流电。该电源采用推挽升压和全桥逆变两级变换，在控制电路上，前级推挽升压电路采用SG3525芯片控制，闭环反馈；逆变部分采用驱动芯片IR2110进行全桥逆变，采用U3990F6完成SPWM的调制，后级输出采用电流互感器进行采样反馈，形成双重反馈环节，增加了电源的稳定性；在保护上，具有输出过载、短路保护、过流保护、空载保护等多重保护功能电路，增强了该电源的可靠性和安全性；输出交流电压通过AD637的真有效值转换后，再由STC89C52单片机的控制进行模数转换，最终将电压值显示到液晶12864上，形成了良好的人机界面。该电源很好的完成了各项指标，输入功率为46.9W，输出功率为43.6W，效率达到了93 ，输出标准的50Hz正弦波。-The single-phase sine wave inverter is designed to 12V battery as input sine wave AC output to the standard 36V, 50Hz' s. The push-pull power boost and full-bridge inverter levels change in the control circuit, the first-stage booster circuit using SG3525 chip push-pull control, closed loop feedback inverter part of the driver chip IR2110 full bridge inverter, using U3990F6 completed SPWM modulation, the output stage is sampled using a current transformer feedback, forming a double feedback loop, increasing the stability of the power in the protection, with multiple output overload protection, short circuit protection, over-load protection functional circuits, and enhance the reliability and security of supply the output AC voltage through AD637 rms converter, and then analog to digital conversion is controlled by the microcontroller STC89C52 final voltage value is displayed on the LCD 12864, forming a good The man-machine interface. The completion of the power good indicators, i Platform: |
Size: 1252352 |
Author:qikaiyi |
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Description: AD7606是16位，8通道同步采样模数数据采集系统。AD7606完全满足电力系统的要求，具有灵活的数字滤波器、2.5V基准电压源、基准电压缓冲以及高速串行和并行接口。它采用5V单电源供电，可以处理±10V和±5V真双极性输入信号、同时所有通道均能以高达200kSPS的吞吐率采样。-AD7606 16-bit, 8-channel simultaneous sampling analog-digital data acquisition system. AD7606 fully meet the requirements of the power system with flexible digital filter, 2.5V reference, reference buffer and high speed serial and parallel interfaces. It uses a single 5V supply and can handle ± 10V and ± 5V true bipolar input signals while all channels up 200kSPS throughput sampling. Platform: |
Size: 894976 |
Author:zdy |
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Description: Variable speed drives with Pulse Width Modulation are increasingly applied in many new industrial
applications for more efficient performance. Recently, developments in power electronics and semiconductor
technology have lead to widespread use of power electronic converters in the power electronic systems. A number of
Pulse width modulation (PWM) schemes are used to obtain variable voltage and frequency supply from a three-phase
voltage source inverter. Among the different PWM techniques proposed for voltage fed inverters, the sinusoidal PWM
technique has been popularly accepted. But there is an increasing trend of using space vector PWM (SVPWM) because
of their easier digital realization, reduced harmonics, reduced switching losses and better dc bus utilization. This paper
focuses on step by step development of SVPWM implemented on a PMBLDC motor. Simulation results are obtained
using MATLAB/Simulink environment for effectiveness of the stud Platform: |
Size: 1032192 |
Author:hmod |
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Description: The ADS5500 is a high-performance, 14-bit, 125 Msps analog-to-digital converter (ADC). To provide a complete converter solution, it includes a high-bandwidth linear sample-and-hold stage (S&H) and internal reference. Designed for applications demanding the highest speed and highest dynamic performance in little space, the ADS5500 has excellent power consumption of 578 mW at 3.3-V single-supply voltage. This allows an even higher system integration density. The provided internal reference simplifies system design requirements. Parallel CMOS-compatible output ensures seamless interfacing with common logic. Platform: |
Size: 1739776 |
Author:kadomcevvn86 |
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Description: General Description
The GN25L95 is a combined burst mode laser driver and limiting post amplifier designed for fiber optic transceiver modules.
The GN25L95 features on-chip digital diagnostic monitoring and digital set-up. This enables a complete solution for SFP/SFF optical transceiver modules.
A fully compliant SFF-8472 digital diagnostic monitoring solution can be realised by connecting an external 8k EEPROM.
The GN25L95 features automatic mean power and automatic extinction ratio control functions for robust and reliable control of laser operating conditions over temperature.
Auto-ranging A/D converters with digitized monitoring, an internal temperature sensor and an on-chip DAC for controlling an external APD bias circuit are also included.
Consuming 90 mA from a 3.3 V supply the GN25L95 is packaged in a 4x4 mm QFN 28 pin RoHS package rated from -40 to +95 °C. Platform: |
Size: 1564790 |
Author:Clayray |
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Search - digital power supply