Bilingual edition: English is preserved and Chinese follows each unit. Terminology uses the confirmed v20260916 glossary; automated semantic review remains traceable.
中英双语版：英文原文完整保留，中文紧随对应单元；术语采用 v20260916 确认表，自动语义审校结果可追溯。

Analog-to-Digital Conversion

模拟-数字转换

This is a sample of the large number of analog-to-digital conversion methods. The basic principle of operation is to use the comparator principle to determine whether or not to turn on a particular bit of the binary number output. It is typical for an ADC to use a digital-to-analog converter (DAC) to determine one of the inputs to the comparator.

这是一些模拟-数字转换方法的示例。其基本原理是利用比较器原理来确定是否要开启二进制数输出中的某一位。通常，ADC会使用数字-模拟转换器（DAC）来确定比较器的一个输入。
Digital-Ramp ADC
数字斜坡ADC
Successive Approximation ADC
逐次逼近型ADC
Flash ADC
闪速ADC
 Index

Electronics concepts

Digital Circuits
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Digital Ramp ADC

数字梯形ADC

Conversion from analog to digital form inherently involves comparator action where the value of the analog voltage at some point in time is compared with some standard. A common way to do that is to apply the analog voltage to one terminal of a comparator and trigger a binary counter which drives a DAC. The output of the DAC is applied to the other terminal of the comparator. Since the output of the DAC is increasing with the counter, it will trigger the comparator at some point when its voltage exceeds the analog input. The transition of the comparator stops the binary counter, which at that point holds the digital value corresponding to the analog voltage.

将模拟信号转换为数字形式本质上涉及比较器的作用，其中在某个时间点的模拟电压值与某个标准进行比较。一种常见的方法是将模拟电压施加到比较器的一个端口，并触发一个二进制计数器，该计数器驱动一个数模转换器（DAC）。DAC的输出被施加到比较器的另一个端口。由于DAC的输出随计数器增加而增加，它会在其电压超过模拟输入时触发比较器。比较器的转换会停止二进制计数器，此时计数器保持的数字值对应于模拟电压。
Analog-to-Digital Converters
模拟-数字转换器
 Index

Electronics concepts

Digital Circuits

Reference
Tocci
Digital Systems, Sec 10-8.
索引 电子概念 数字电路 参考 Tocci 数字系统，第10-8节。
 
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Successive Approximation ADC

逐次逼近型ADC

Illustration of 4-bit SAC with 1 volt step size (after Tocci, Digital Systems).

4位SAC的示意图（步长为1伏，参考Tocci的数字系统）

The successive approximation ADC is much faster than the digital ramp ADC because it uses digital logic to converge on the value closest to the input voltage. A comparator and a DAC are used in the process.

successive approximation ADC 比 digital ramp ADC 更快，因为它使用数字逻辑来逼近输入电压最接近的值。该过程使用了比较器和 DAC。
Analog-to-Digital Converters
模拟-数字转换器
Digital-to-Analog Converters
数字-模拟转换器
Comparator
比较器
 Index

Electronics concepts

Digital Circuits

Reference
Tocci
Digital Systems, Sec 10-10.
索引 电子概念 数字电路 参考 Tocci 数字系统，第10-10节。
 
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Flash ADC

闪速ADC

Illustrated is a 3-bit flash ADC with resolution 1 volt (after Tocci). The resistor net and comparators provide an input to the combinational logic circuit, so the conversion time is just the propagation delay through the network - it is not limited by the clock rate or some convergence sequence. It is the fastest type of ADC available, but requires a comparator for each value of output (63 for 6-bit, 255 for 8-bit, etc.) Such ADCs are available in IC form up to 8-bit and 10-bit flash ADCs (1023 comparators) are planned. The encoder logic executes a truth table to convert the ladder of inputs to the binary number output.

如图所示是具有1伏分辨率的3位闪式ADC（参考Tocci）。电阻网络和比较器为组合逻辑电路提供输入，因此转换时间仅仅是网络的传播延迟——它不受到时钟速率或某种收敛序列的限制。这种ADC是最快的ADC类型，但需要为每个输出值配备一个比较器（6位需要63个，8位需要255个，依此类推）。这种ADC以IC形式可达到8位和10位闪式ADC（计划有1023个比较器）。编码逻辑通过真值表将输入梯级转换为二进制数输出。
Analog-to-Digital Converters
模拟-数字转换器
 Index

Electronics concepts

Digital Circuits

Reference
Tocci
Digital Systems, Sec 10-11.
索引 电子概念 数字电路 参考 Tocci 数字系统，第10-11节
 
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