第一章 单元测试

1、判断题：
Digital signals are a type of signal that contains a limited number of discrete values, typically used in digital circuits for data transmission and processing. According to this definition, the characteristics of digital signals include continuity and infinite values.
选项：
A:错误
B:正确
答案: 【错误】

2、单选题：
Which of the following statements best describes a key difference between analog signals and digital signals?
选项：
A:Digital signals are used exclusively in audio applications, while analog signals are used in visual applications.
B:Analog signals can represent a continuous range of values, while digital signals can only represent discrete values.
C:Analog signals are always more accurate than digital signals.
D:Digital signals can represent a continuous range of values, while analog signals can only represent discrete values.
答案: 【Analog signals can represent a continuous range of values, while digital signals can only represent discrete values.】

3、单选题：
Which of the following is a characteristic of the binary number system?
选项：
A:It uses the digits 0, 1, 2, 3, 4, 5, 6, 7, 8, 9.
B:It is primarily used for human calculations.
C:It uses the digits 0 to 9.
D:It is a base-2 number system.
答案: 【It is a base-2 number system.】

4、单选题：
Which of the following is the correct conversion of the decimal number 10 to binary?
选项：
A:1100
B:1110
C:1001
D:1010
答案: 【1010】

5、判断题：
In digital circuits, encoding is the process of converting information into a specific format, which can enhance the efficiency and reliability of the system. Based on the importance of encoding and its basic rules, is the following statement correct: When designing digital circuits, the choice of an appropriate encoding method can be ignored because the final result is the same regardless of the encoding used.
选项：
A:正确
B:错误
答案: 【错误】

6、单选题：
In the context of the "8421 BCD" code, which of the following statements accurately describes the weight of each bit in the BCD representation?
选项：
A:The weights are determined by the hexadecimal representation of the digits.
B:The weight of each bit is represented as 8, 4, 2, and 1 respectively, corresponding to the binary values of each position.
C:The bits are weighted in reverse order, with the least significant bit assigned the highest value.
D:The weight of the bits is based on the decimal values of the numbers 1, 2, 3, and 4.
答案: 【The weight of each bit is represented as 8, 4, 2, and 1 respectively, corresponding to the binary values of each position.】

7、单选题：
Given a binary number represented in its original form, what is the correct representation of its two's complement?
选项：
A:Leave the number unchanged
B:Invert all bits
C:Add 1 to the least significant bit only
D:Invert all bits and add 1 to the least significant bit
答案: 【Invert all bits and add 1 to the least significant bit】

8、单选题：
Which of the following statements best describes the characteristics of the 2421 code?
选项：
A:2421 code uses four bits to represent decimal digits.
B:2421 code is a binary-coded decimal (BCD) representation.
C:2421 code allows for easy conversion to decimal without complex calculations.
D:2421 code is primarily used in digital communication systems.
答案: 【2421 code uses four bits to represent decimal digits.】

第二章 单元测试

1、单选题：
In a digital circuit, an AND gate is used to control the power supply to a device. If the input conditions are such that one input is true and the other is false, which of the following statements is true regarding the output of the AND gate?
选项：
A:The output will be false if at least one input is false.
B:The output will depend on the voltage level of the inputs.
C:The output will be true if both inputs are true.
D:The output will be true if both inputs are false.
答案: 【The output will be false if at least one input is false.】

2、单选题：
Which of the following best defines a logical function?
选项：
A:A logical function is a type of function that can only take numerical inputs.
B:A logical function is a function that only performs arithmetic operations.
C:A logical function is a function that does not depend on any variables.
D:A logical function is a mathematical function that outputs logical values based on logical variables.
答案: 【A logical function is a mathematical function that outputs logical values based on logical variables.】

3、单选题：
When constructing a truth table, assume there are two input variables and . How many rows will the truth table contain when listing all possible input combinations?
选项：
A:2
B:4
C:8
D:3
答案: 【4】

4、判断题：
The simplification of logical functions can help reduce the number of logic gates in a circuit, thereby lowering costs and improving efficiency. Therefore, the simplification of logical functions is not important in circuit design.
选项：
A:正确
B:错误
答案: 【错误】

5、单选题：
Which of the following best describes the basic structure of a Karnaugh Map?
选项：
A:It is a three-dimensional model for visualizing logic circuits.
B:It is a graphical representation of truth tables only.
C:It is a grid-like representation used to simplify Boolean functions.
D:It consists of only two variables for simplification.
答案: 【It is a grid-like representation used to simplify Boolean functions.】

6、判断题：
In the simplification process of logical functions, irrelevant terms refer to those input variables that do not affect the output results of the logical function. In Karnaugh maps, irrelevant terms can be identified as those areas that do not change the function output. Therefore, irrelevant terms can be ignored during the simplification of logical functions.
选项：
A:正确
B:错误
答案: 【正确】

7、单选题：
In a Karnaugh map, how is the relationship between the input variables and the output variables represented?
选项：
A:By the boundary of the entire Karnaugh map to represent the value of the output variable.
B:By writing the value of the input variables in each cell of the Karnaugh map.
C:By the intersection of rows and columns to represent the value of the output variable.
D:By using different colors to distinguish between input and output variables.
答案: 【By the intersection of rows and columns to represent the value of the output variable.】

8、单选题：
In logic circuit design, using Karnaugh maps (K-maps) to simplify logical expressions is a common practice. Suppose there is a four-variable logical function, and its corresponding K-map has multiple groups. The combination of these groups can reflect the simplification of the logical expression. According to the principle of expanding Karnaugh groups and reducing the number of groups, which of the following descriptions best reflects the effectiveness of simplifying logical expressions through the combination of groups?
选项：
A:Only using the minimum number of groups can yield a complete logical expression.
B:Expanding Karnaugh groups will increase the complexity of the logical expression.
C:Expanding Karnaugh groups can cover more 1s, reducing the number of terms in the logical expression.
D:Reducing the number of groups will always lead to misunderstanding the true representation of the logical function.
答案: 【Expanding Karnaugh groups can cover more 1s, reducing the number of terms in the logical expression.】