电子工程术语和定义,以字母A打头

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A 请参考:安培
A to D 请参考:A/D转换器
A-D 请参考:A/D转换器
A-h 请参考:mAh
A-weighted dB levels 请参考:A加权
A-Weighting A加权是一种用于音频测量的标准权重曲线,用于反映人耳的响应特性。

声压电平源于A加权,用“dBA”表示,或A加权dB电平。
A/D 请参考:A/D转换器
A/D Converter 模/数转换器,也称为A/D转换器,是将模拟信号转换成数字数据流(数字信号)的电路。
A/D Mux 请参考:ADM
Accelerometer

An accelerometer is a sensor used to measure acceleration. Acceleration is defined as the rate of change of velocity i.e. how quickly a body is speeding up or slowing down while travelling in a given direction.

Physically, an accelerometer is a microelectromechanical (MEMS) device which is machined using microfabrication technology. Accelerometers are fabricated in a multilayer wafer process, measuring acceleration forces by detecting the displacement of a mass relative to fixed electrodes.

Capacitance is commonly used as a sensing approach in accelerometers. This works on the principle that acceleration is related to the change in the capacitance of a moving mass (Figure 1). This accelerometer sensing technique is known for its high accuracy, stability, low power dissipation and simpler construction. It is not prone to noise and variation with temperature. The bandwidth of a capacitive accelerometer is only a few hundred Hertz because of its physical geometry (spring and air trapped inside the IC which acts as a damper).

moving mass creating variable capacitance

Figure 1. A moving mass creating variable capacitance

The capacitance sensing structure can be either single-sided or a differential pair (a movable mass on either side of the fixed electrode).

Since the change in capacitance for a single mass/electrode pair is tiny, multiple movable and fixed electrodes are connected together in a parallel configuration. This creates a much greater change in capacitance, which is detected more easily and increases accuracy of measurement.

The signal from the capacitance sensing structure then undergoes charge amplification, signal conditioning, demodulation, and lowpass filtering before being converted into a digital domain using a sigma-delta ADC. The serial digital bit stream from the ADC is then sent to a host controller (using an appropriate protocol like SPI or I2C) for further processing.

A shock sensor is a type of accelerometer that can detect high acceleration and deceleration.

Learn More:

Access Point Base Station 请参考:femto基站
ACPI 高级配置与电源接口:一项行业标准规范(由Hewlett-Packard、Intel、Microsoft、Phoenix及Toshiba公司)共同开发,面向笔记本电脑、台式机及服务器,由操作系统直接实现电源管理,是APM的替代标准。
ACPR 邻(交替)信道功率比。
ACR 累积电流寄存器。
ADAS

What does ADAS stand for?

ADAS stands for Advanced Driver Assistance Systems.

What is ADAS?

The list of ADAS features is extensive and includes driver monitoring systems (DMS) to monitor a driver’s attention level, autonomous driving, adaptive front lighting control, automatic parking, traffic sign recognition and more. New ADAS technologies have the potential to improve driver safety and comfort, and even more importantly, to reduce automobile accidents and casualties. However, the adoption of ADAS technologies introduces new issues for automotive design especially in electronic solution size, safety, and reliability.

Why is ADAS important?

ADAS is a key disruptive technology ushering in a new age of smart mobility in transportation. Automakers increasingly see themselves as both product manufacturers and mobility service companies. In addition to developing next-generation connected and autonomous vehicles that will improve traffic flow and safety, automakers are investing in a wide swath of new mobility services. Urban planners will use the mobility ecosystem to reduce congestion, while generating related benefits such as fewer traffic accidents, better air quality, and a smaller urban footprint for parking. ADAS, with its emphasis on safety, is even expected to disrupt the automobile insurance industry to the benefit of consumers.

What are the key enablers for ADAS?

ADAS capabilities are enabled by a plethora of sensors deployed across the car which are networked to I/O modules, actuators, and controllers throughout the automobile. Ultimately, the on-board sensors connected to cloud support functions will provide external data from other vehicles and from cloud infrastructure for connected safety, advanced driver assistance support, and autonomous driving software and functions.

Learn MoreAdvanced Driver Assistance Systems (ADAS)

ADC

An analog-to-digital converter (also known as an ADC or an A/D converter) is an electronic circuit that measures a real-world signal (such as temperature, pressure, acceleration, and speed) and converts it to a digital representation of the signal.

How does an ADC work?

An ADC compares samples of the analog input voltage (produced using a Sample and Hold circuit) to a known reference voltage and then produces a digital representation of this analog input. The output of an ADC is a digital binary code. By its nature, an ADC introduces a quantization error, which is simply the information that is lost. This error occurs because there are an infinite number of voltages for a continuous analog signal, but only a finite number of ADC digital codes. Therefore, the more digital codes that the ADC can resolve, the more resolution it has, and the less information lost to quantization error. In A/D conversion, the Nyquist principle (derived from the Nyquist-Shannon sampling theorem) states that the sampling must be at least twice the maximum bandwidth of the analog signal being converted, in order to allow the signal to be accurately reproduced. The maximum bandwidth of the signal (half the sampling rate) is commonly called the Nyquist frequency (or Shannon sampling frequency). In real life, sampling rate must be higher than that (because filters used to re-produce the original signal are not perfect). As an example, the bandwidth of a standard audio CD is a bit less than the theoretical maximum of 22.05kHz (based on the sample rate of 44.1kHz).

Related Pages:

Add-Drop Mux 请参考:ADM
ADM 添加/卸载多路复用器:一种可承载多个信道的同步传输网络(SDH或Sonet)。添加/卸载多路复用器是一种可从高数据速率汇聚信道上增加(插入)或减少(撤下)低数据速率信道的设备。
ADMs 请参考:ADM
ADPCM 自适应差分脉冲编码调制:一种只对顺序采样之差进行编码的压缩技术。
ADS 模拟设计系统。
ADSL 非对称数字用户线:一种借助普通电话线传输数据的方法。ADSL电路通过编码可在常规电话线上承载比普通调制解调器更多的数据量。ADSL利用普通电话线(双绞铜线)与用户端设备连接。
Advanced Configuration And Power Interface 请参考:ACPI
Advanced Mobile Phone System 请参考:AMPS
Advanced Power Management 请参考:APM
Advanced Product Quality Planning 请参考:APQP
AEC-Q100 由AIAG汽车组织开发的用于集成电路的资格认证测试流程。
AECQ100 请参考:AEC-Q100
AFE 模拟前端:A/D转换前的模拟电路部分。
AGC 自动增益控制:一种根据输入信号强度调节放大器增益,以保持恒定输出功率的电路。
Ah 安培小时(安时):电池容量单位。例如一节4Ah (安时)电池可提供4小时、1安培电流,或8小时的0.5安培电流。
Air Discharge 一种用于测试ESD (静电放电)保护结构的方法,其中ESD发生器通过它与被测设备(DUT)之间的空气间隙来放电。
Air Gap Discharge 请参考:空气放电
Air-Gap Discharge Method 请参考:空气放电
AIS 报警指示系统。
AISG 天线接口标准组织(AISG)为3G系统创建开放式的天线控制和监测规范。

来源:AISG网站 (English only)
alias 请参考:重叠
Aliasing 在A/D转换器中,根据奈奎斯特定律,采样速率必须至少是模拟信号最大带宽的两倍。如果采样速率不满足这一条件,较高的频率成份将被“欠采样”,并被搬移到较低的频段,被搬移的频率成份即所谓的混叠。

所搬移的频率也称为“混叠频率”,因为从频谱图上看,高频成分与频带的欠采样部分重叠在一起。

另请参考:
Alternator 将机械能转化成交流电能的机电设备。

通常,线圈内部的磁场旋转在绕组内产生交流电。磁场可以是由铁芯产生的永久磁场,或者是由外部施加电流产生的电磁场。

AM 幅度调制(或调幅):载波幅度随输入信号幅度变化的调制方法。
Ambient Sensor 请参考:环境温度传感器
Ambient Temperature 元件周围的温度。
Ambient Temperature Sensor 用于检测元件周围温度(环境温度)的传感器。
American National Standards Institute 请参考:ANSI
American Wire Gauge 请参考:AWG
AMLCD 有源矩阵液晶显示器。
Amp 1. 安培

2. 放大器

amp-hour 请参考:mAh
Ampacity 导体在不超出其指定温度的条件下所能承载的电流,用安培表示。
Ampere 安培,电流单位。电流定义为单位时间内流过指定节点的电荷量。

用符号I表示电流,A是安培英文单词的缩写。
Ampere-hour 一种电荷(或电流流动时间)的测量方法。

  • 1安培-小时(或者是1安-时或1Ah)表示以1安培电流供电1个小时,所传输的电荷量为3,600库仑(安培-秒)。
  • 1毫安-小时(mAh或毫安-时)表示千分之一安-时。
  • 1安培-秒(As或安培-秒)表示以1安培电流供电1秒钟。

该参数通常用来计量设备的储能,特别是可充电电池。例如:报警系统中的一个12V、7Ah的可充电电池能够在额定电压下,以1安培电流支持七个小时的供电,能够以2安培电流支持3.5小时的系统供电。如果我的报警器耗电只有250mA,电池将能够支撑28小时的工作时间。

另请参考:
ampere-second 请参考:mAh
Amplifier 在输出端还原输入信号的电路。输出信号可能发生比例变化或增强了驱动能力,有时也可能提供隔离(以确保输出发生变化时不影响输入或其它输出)。输出信号也可能产生其它变化(例如:滤波或对数驱动)。
Amplifier Class 放大器电路被划分成几“类”,用来区分放大器工作在线性模式或开关模式,以及用来恢复线性输出信号的技术。
Amplitude Modulation 请参考:AM
AMPS 高级移动电话系统:工作于800MHz至900MHz频段的第一代模拟移动通信标准,仍在美国广泛使用。
AMR 自动读表:用来读取远端公用表的系统。
Analog 一种用电量(通常为电压或电流,有时为频率、相位等)来描述物理世界某些事物的系统。电信号可被处理、传输、放大并最终转换回物理世界。

例如:麦克风产生与声压成正比的电流,经过放大、处理、调制等不同的处理过程,最后再用扬声器将其转换为声波。

相反,数字系统则将信号作为一种数字流来处理。
Analog Fan Controller 请参考:风扇控制器 - 线性
Analog Front End 请参考:AFE
Analog Switch 模拟开关(有时简称为“开关”)是根据数字控制信号的电平切换或路由模拟信号(信号可以是规定范围内的任何电平)的开关器件。通常由“传输门电路”构成,模拟开关的功能类似于继电器。

例如:模拟开关可以在MUTE信号的控制下接通或断开音频信号,模拟开关也可以将两路信号中的一路送入耳机放大器。

通常采用CMOS集成电路实现开关功能,Maxim提供数百种模拟开关。请参考模拟开关和多路复用器产品线网页。

另请参考What is a Transmission Gate (Analog Switch)?
Analog Temperature Sensor 具有连续模拟电压或电流输出(通常与被测温度成线性关系)的温度传感器。
Analog to Digital 请参考:A/D转换器
analogue 请参考:模拟
AND 组合了两个信号,当两个信号都存在时输出导通。这个功能可以通过“与”逻辑门电路实现(两路输入,一路输出,当两路输入均为高电平时输出为高电平)。
ANSI 美国国家标准化组织。
Antenna Interface Standards Group 请参考:AISG
anti-alias 请参考:抗重叠
Anti-Aliasing 抗混叠滤波器,用在A/D转换器的前端。可消除高于奈奎斯特频率成分的低通滤波器,因此可以消除带内的信号重叠(混叠)。

另请参考:
APC 自动功率控制:激光驱动器(例如MAX3669)中利用激光器反馈调节驱动器,使激光输出保持恒定的特性。
APD 雪崩光电二极管:利用光电流的雪崩倍增效应提供增益的特性而设计的光电二极管。当反偏电压接近击穿电压时,吸收光子产生的空穴-电子对与离子碰撞时获得足够的能量。产生额外的空穴-电子对,达到倍增效果或信号增益。
API 应用编程接口:允许通过一组经过定义的指令对系统进行编程的软件层。
APM 高级电源管理:计算机电源管理标准,可提供五种电源状态:就绪、待机、挂起、休眠及关机。
APON 基于ATM的无源光网络。
APQP 先期产品质量策划,该体系由AIAG汽车组织创建,用于协调汽车工业供应商的通用产品的质量管理和控制规范。
Arrhenius 请参考:FIT
Arrhenius/FIT Rate 请参考:FIT
ASCII 美国信息交换标准码。
ASIC 专用集成电路。

请参考:Maxim ASIC services

Asymmetric Digital Subscriber Line 请参考:ADSL
ATE 自动测试设备。请参考:Maxim ATE方案
ATM 异步传输模式。
Audio Taper 请参考:抽头
Auto Shutdown EIA-232接口器件的特性,当EIA-232总线上没有信号时使IC进入低功耗关断模式。
Auto Shutdown + 请参考:AutoShutdown Plus
Autoclave Test 请参考:高压炉测试
Automatic Gain Control 请参考:AGC
Automatic Meter Reading 请参考:AMR
Automatic Power Control 请参考:APC
AutoShutdown 请参考:Auto Shutdown
Autoshutdown Plus EIA-232接口器件的特性,当总线或发送器输入端没有信号时使IC进入低功耗关断模式。
AutoShutdown+ 请参考:AutoShutdown Plus
Autotransformer 一种主、次级使用同一线圈的变压器,电感都带有中心抽头。常在电源升压转换器中使用,以获得较高的输出电压,同时限制由电源开关所产生的峰值反馈电压。
Avalanche Photo Diode 请参考:APD
Avalanche Photodiode 请参考:APD
AWG 1. 任意波形发生器。

2. 美国线规(AWG):一种计量线径(也用横截面积表示,并指定材料、安培容量等)规格的标准。例如:24 AWG线缆的标称直径是0.0201英寸或0.511mm,也称为Brown和Sharpe线规。

值得注意的是:钢缆采用不同的规格定义,AWG仅用来表示导电线缆。