南师大07级中英班数字电路期末试卷(英文无答案).doc

专业： 班级： 学号： 姓名： -装-订-线- - -南京师范大学2008-2009学年 第2学期 电气与自动化工程 学院 中英班 专业 2007 年级电子技术（Electronics)课程期终试卷 A Name： Class： Student ID： Score： No.123456789PointsPoints1. Choose the correct answer:（20 points）(1) A quantity having discrete(离散的) values is (a) a digital quantity(b) an analog quantity(c) a binary quantity(d) a natural quantity(2) The binary number 11011101 is equal to the decimal number (a) 121 (b) 221 (c) 441 (d) 256(3) Which of the following is an invalid（无效） BCD code (a) 0011 (b) 1001 (c) 0101 (d) 1101(4) Simplify the expression , using DeMorgans theorems (a) (b) (c) (d) (5) This is the timing diagram for a 2-input _ gate. (a) OR (b) NAND (c) NAND (d) Exclusive-OR(6) The inputs to a full-adder are A = 1, B = 1 and Cin = 0. The outputs are (a) Sum = 1, Cout = 1 (b) Sum = 1, Cout = 0 (c) Sum = 0, Cout = 1 (d) Sum = 0, Cout = 0(7) The device used to convert a binary number to a 7-segment display format is (a) multiplexer (b) encoder (c) decoder (d) register(8) A modulo-12 counter （12进制计数器）must have (a) 12 flip-flops (b)3 flip-flops (c) 4 flip-flops (d)synchronous clocking(9) A 4-bit binary up/down counter is in the binary state of zero. The next state in the DOWN mode is (a) 0001 (b) 1111 (c) 1000 (d) 1110(10) What is the resolution（分辨率）, in percent, of a 8-bit DAC (a) 0.1% (b) 0.392% (c) 1% (d) 3.92%Points2. Simplify the following expressions as much as possible.（10 points）(1) (2) Points3. Design the logic circuit to control the motor on a simple remote control car. There are two buttons on the remote control for the motor. If neither button is pressed, the car stops. If the top button is pressed, the car moves forward. If the bottom button is pressed, the car moves backwards. If both buttons are pressed, the car spins clockwise(顺时针旋转). There are two motors（left and right） in the car and each motor has two inputs F(forward) and B(backward). A high on F makes the car go forward. A high on B makes the car go backward. （10 points）(1) Make a truth table for this design.Top ButtonBottom ButtonFLBLFRBRStateStopBackwardForwardSpin(2) Implement the circuit by using only NAND gates.Points4. Show how the expression can be implemented using:（10 points） (1) A 3-8 decoder 74LS138 with some gates as needed. A0 Y0A1 Y1A2 Y274LS138 Y3 Y4E3 Y5E2 Y6E1 Y7 (2) A dual 4:1 multiplexer 74LS153 .Points5. The JK flip-flop is negative edge triggered. Assuming the initial state of A is 0 at t=0, give the expressions of J、K、A、B respectively，and sketch the waveforms of A and B.（10 points）QQJABABCKCPCPPoints6. Analysis the circuit below, draw the state diagram and determine the modulo of this counter. (10 points)&Q3 Q2 Q1 Q0CPCP74LS161CRD LD EP ET D3 D2 D1 D0“1”“1”“1”Points7. Design a modulo-7 counter using a 74163 IC, which will Show 1-7 in LED display. (10 points)D0LDD1D2D3Q0Q1Q2Q3CEPETCPRD74163Points8. Create an astable multivibrator(多谐振荡器) using a 555 timer. The output frequency is 20 kHz. If the external capacitor C is 0.002F and the duty cycle is 75%, determine the values of the external resistors. （10 points） 8 47 36 555 2 5 1Points9. The pin diagram of 74LS00 are given below. Construct the circuit to implement the logic function using a single 74LS00 IC. (10 points) Data Sheet: 74138InputsOutputsS1A2A1A01111111110111111110000000000001111001100110101010110111111111011111111101111111110111111111011111111101111111110111111111074153InputsOutputEnableAddressDataA1A0DiY10