Digital-electronics 简明教程
Digital Electronics - Encoders
编码器是一种组合逻辑电路，用于将普通信息或熟悉信息转换为编码格式。换句话说，编码器是一种数字设备，它将以十进制数字和字母字符形式表示的信息转换为编码形式，如二进制表示。编码器执行的操作称为（ encoding ）。
An encoder is a combinational logic circuit that is used to convert a normal or familiar information into a coded format. In other words, an encoder is a digital device that coverts a piece of information represented in the form of decimal digits and alphabetic characters into a coded form like binary representation. The operation that the encoder performs is termed as encoding.
在本章中，我们将解释编码器的基础知识和常用类型的编码器。
In this chapter, we will explain the basics of encoder and commonly used types of encoders.
What is an Encoder?
encoder 是一个数字组合电路，它将人类友好的信息转换为编码格式，以便机器处理。简单来说，编码器将一条以正常形式存在的信息转换为编码形式。这个过程被称为编码。
An encoder is a digital combinational circuit that converts a human friendly information into a coded format for processing using machines. In simple words, an encoder converts a piece of information normal form to coded form. This process is called encoding.
编码器是在数据传输、控制与自动化、通信、信号处理等各种数字电子应用程序中至关重要的组件。
Encoders are crucial components in various digital electronics applications such as data transmission, controlling and automation, communication, signal processing, etc.
编码器由一定数量的输入和输出线路组成。其中，编码器最多可具有“2n”条输入线路和“n”条输出线路。因此，编码器通过“n”位对由“2n”条输入线路表示的信息进行编码。
An encoder consists of a certain number of input and output lines. Where, an encoder can have maximum of "2n" input lines whereas "n" output lines. Hence, an encoder encodes information represented by "2n" input lines with "n" bits.
block diagram of an encoder 如以下数字所示 -
The block diagram of an encoder is shown in the following figure −
现在让我们讨论数字电子应用程序中常用的不同类型的编码器。
Let us now discuss different types of encoders commonly used in digital electronic applications.
Types of Encoders
数字电子中一些常用的编码器类型 -
Some of the commonly used types of encoders in digital electronics −
-
4 to 2 Encoder
-
8 to 3 Encoder (Octal Encoder)
-
Decimal to BCD Encoder
现在让我们详细讨论这三种最常用的编码器类型。
Let us now discuss these three types of most commonly used encoders in detail.
4 to 2 Encoder
4 到 2 编码器是一种编码器，具有 4 个（22）输入线路和 2 个输出线路。它根据输入线路的组合生成输出代码（即，以 2 位格式转换输入信息）。
A 4 to 2 Encoder is a type of encoder which has 4 (22) input lines and 2 output lines. It produces an output code (i.e., convert input information in a 2-bit format) depending on the combination of input lines.
4 到 2 编码器的框图如下图所示。
The block diagram of a 4 to 2 Encoder is shown in the following figure.
4 到 2 编码器针对不同输入组合的工作在以下真值表中予以描述 -
The working of a 4 to 2 Encoder for different input combinations is described in the following truth table −
Inputs |
Outputs |
I3 |
I2 |
I1 |
I0 |
Y1 |
Y0 |
0 |
0 |
0 |
1 |
0 |
0 |
0 |
0 |
1 |
0 |
0 |
1 |
0 |
1 |
0 |
0 |
1 |
0 |
1 |
0 |
0 |
0 |
1 |
1 |
从这个真值表中，我们可以得出 4 到 2 编码器的每个输出的布尔表达式，如下所示 -
From this truth table, we can derive the Boolean expression for each output of the 4 to 2 Encoder as follows −
\mathrm{Y_{0} \: = \: I_{1} \: + \: I_{3}}
\mathrm{Y_{1} \: = \: I_{2} \: + \: I_{3}}
显然，我们可以使用两个或门实现 4 到 2 编码器的逻辑电路。下图描绘了 4 到 2 编码器的逻辑框图。
It is clear that we can implement the logic circuit of the 4 to 2 Encoder using two OR gates. The following figure depicts the logic diagram of the 4 to 2 Encoder.
4 到 2 编码器广泛用于以下应用：数据多路复用、生成数字控制信号、地址解码应用、对数字系统中的数据进行编码等。
The 4 to 2 Encoder is widely used in the following applications: Data multiplexing, Generating digital control signals, Address decoding applications, Encoding data in digital systems, etc.
Octal to Binary Encoder
八进制到二进制编码器是一种将八进制代码转换成二进制代码的编码器类型。它接受 8 条输入线路，并根据输入线路的组合生成一个 3 位输出。因此，它也被称为 8 to 3 Encoder 。
The octal to binary encoder is a type of encoder that converts an octal code into binary code. It accepts 8 input lines and produces a 3-bit output depending on the combination of input lines. Therefore, it is also known as 8 to 3 Encoder.
block diagram of an octal to binary encoder 如以下数字所示 -
The block diagram of an octal to binary encoder is shown in the following figure −
以下真值表描述了八进制到二进制编码器的作用 -
The following truth table describes the working of an octal to binary encoder −
Inputs |
Outputs |
I7 |
I6 |
I5 |
I4 |
I3 |
I2 |
I1 |
I0 |
Y2 |
Y1 |
Y0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
1 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
1 |
0 |
0 |
0 |
1 |
0 |
0 |
0 |
0 |
0 |
1 |
0 |
0 |
0 |
1 |
0 |
0 |
0 |
0 |
0 |
1 |
0 |
0 |
0 |
0 |
1 |
1 |
0 |
0 |
0 |
1 |
0 |
0 |
0 |
0 |
1 |
0 |
0 |
0 |
0 |
1 |
0 |
0 |
0 |
0 |
0 |
1 |
0 |
1 |
0 |
1 |
0 |
0 |
0 |
0 |
0 |
0 |
1 |
1 |
0 |
1 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
1 |
1 |
从这个真值表中，我们可以写出八进制到二进制编码器输出的布尔表达式，如下所示。
From this truth table, we can write the Boolean expression for the outputs of the octal to binary encoder as follows.
Y0 = I1 + I3 + I5 + I7
\mathrm{Y_{0} \: = \: I_{1} \: + \: I_{3} \: + \: I_{5} \: + \: I_{7}}
Y1 = I2 + I3 + I6 + I7
\mathrm{Y_{1} \: = \: I_{2} \: + \: I_{3} \: + \: I_{6} \: + \: I_{7}}
Y2 = I4 + I5 + I6 + I7
\mathrm{Y_{2} \: = \: I_{4} \: + \: I_{5} \: + \: I_{6} \: + \: I_{7}}
从这些表达式中，可以清楚地看出八进制到二进制编码器的实现需要 3 个或门。
From these expressions, it is clear that the implementation of an octal to binary encoder requires 3 OR gates.
八进制到二进制编码器的逻辑电路图如下图所示：
The logic circuit diagram of the octal to binary encoder is shown in the following figure −
八进制到二进制编码器用于以下应用：
The octal to binary encoder is used in the following applications −
-
Data conversion in digital systems.
-
Conversion of octal memory addresses into binary memory addresses.
-
In microprocessors and microcontrollers, to convert octal instructions into binary format.
-
In communication systems, to encode octal data into binary form for transmission, etc.
Decimal to BCD Encoder
一种可以将十进制数字或使用十进制数字表示的信息转换成其等效二进制编码十进制 (BCD) 格式的编码器称为十进制到 BCD 编码器。
A type of encoder that can convert a decimal number or information represented using decimal number into its equivalent binary-coded decimal (BCD) format is known as a decimal to BCD encoder.
在 BCD 编码方案中，每个十进制数字都可以转换成 4 位二进制表示。下表显示了十进制数字 0 到 9 的 BCD 等价物。
In the BCD encoding scheme, each decimal digit can be converted into a 4-bit binary representation. The following table shows the BCD equivalents of decimal digital from 0 to 9.
Decimal Digit |
BCD Code |
0 |
0 |
0 |
0 |
0 |
1 |
0 |
0 |
0 |
1 |
2 |
0 |
0 |
1 |
0 |
3 |
0 |
0 |
1 |
1 |
4 |
0 |
1 |
0 |
0 |
5 |
0 |
1 |
0 |
1 |
6 |
0 |
1 |
1 |
0 |
7 |
0 |
1 |
1 |
1 |
8 |
1 |
0 |
0 |
0 |
9 |
1 |
0 |
0 |
1 |
十进制到 BCD 编码器接受 10 个输入线路并根据输入线路的组合生成一个 4 位 BCD 输出。因此，有时也称之为一个 10 到 4 编码器。
The decimal to BCD encoder accepts 10 input lines and produces a 4-bit BCD output depending on the combination of input lines. Therefore, sometimes it is also called a 10 to 4 encoder.
下图描述了十进制到 BCD 编码器的框图。
The following illustration depicts the block diagram of a decimal to BCD encoder.
描述十进制到 BCD 编码器工作原理的真值表如下所示：
The truth table describing the working of the decimal to BCD encoder is given blow −
Inputs |
Outputs |
D9 |
D8 |
D7 |
D6 |
D5 |
D4 |
D3 |
D2 |
D1 |
D0 |
Y3 |
Y2 |
Y1 |
Y0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
1 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
1 |
0 |
0 |
0 |
0 |
1 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
1 |
0 |
0 |
0 |
0 |
1 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
1 |
0 |
0 |
0 |
0 |
0 |
1 |
1 |
0 |
0 |
0 |
0 |
0 |
1 |
0 |
0 |
0 |
0 |
0 |
1 |
0 |
0 |
0 |
0 |
0 |
0 |
1 |
0 |
0 |
0 |
0 |
0 |
0 |
1 |
0 |
1 |
0 |
0 |
0 |
1 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
1 |
1 |
0 |
0 |
0 |
1 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
1 |
1 |
1 |
0 |
1 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
1 |
0 |
0 |
0 |
1 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
1 |
0 |
0 |
1 |
从这个真值表中，我们可以写出十进制到 BCD 编码器的布尔表达式，如下所示：
From this truth table, we can write the Boolean expression of the decimal to BCD encoder as follows.
Y0 = D1 + D3 + D5 + D7 + D9
\mathrm{Y_{0} \: = \: D_{1} \: + \: D_{3} \: + \: D_{5} \: + \: D_{7} \: + \: D_{9}}
Y1 = D2 + D3 + D6 + D7
\mathrm{Y_{1} \: = \: D_{2} \: + \: D_{3} \: + \: D_{6} \: + \: D_{7}}
Y2 = D4 + D5 + D6 + D7
\mathrm{Y_{2} \: = \: D_{4} \: + \: D_{5} \: + \: D_{6} \: + \: D_{7}}
\mathrm{Y_{3} \: = \: D_{8} \: + \: D_{9}}
logic circuit of the decimal to BCD encoder 能够利用四个 OR 门来实现，如下图所示 −
The logic circuit of the decimal to BCD encoder can be implemented using four OR gates which is shown in the following figure −
Applications of Decimal to BCD Encoder
十进制到 BCD 编码器在数字时钟和计时器、数据处理设备和存储系统、计算器、测量仪器、显示设备、微处理器、微控制器、嵌入式系统等中找到了它们的应用。
Decimal to BCD encoders find their application in digital clocks and timers, data processing devices and storage systems, calculators, measuring instruments, display devices, microprocessors, microcontrollers, embedded systems, etc.
Conclusion
编码器转换某些编码格式的信息块。编码器是各种数字系统（比如自动化和控制系统、通信系统和存储单元、计算和计算设备、测量仪器、数据转换器等）中的基本元素。
An encoder converts a piece of information in a certain coded format. Encoders are essential elements in various digital systems such as automation and control systems, communication systems and storage units, computing and calculating devices, measuring instruments, data converters, and more.
在本章中，我们阐述了应用最广泛的编码器类型，它们是 4 到 2 编码器、八进制到二进制编码器以及十进制到 BCD 编码器。
In this chapter, we covered the most widely used types of encoders, they are 4 to 2 Encoder, octal to binary encoder, and decimal to BCD encoder.