What is the digital output code word for an input of 1.2V? What is the voltage range corresponding to 1 LSB? 1,2𝑉 0,0195𝑉 = 61 ; 61 = 001111012 Digital output code for an input of 1.2V is 001111012. Voltage range corresponding to 1 LSB is U= 0,0195V. Question 3 A 15 bit ADC has a reference voltage of 10V. What is the digital output code word for an input of 6.83V? 15 bit = 32768 10V/ 32768 = 0,0003 V 6,83V / 0,0003 = 22767 22767 = 01011000 111011112 Question 4 What is the value of the quantization error between an input voltage of 2.3V and quantized voltage with the output code word equal to 011101012 using an 8 bit ADC with 5V reference? 011101012 = 117 Correspond to 5V * 117/256 = 2.2852V Error = 2,3V – 2.2852 = 0,0148V Question 5 A digital multimeter is designed to have a readout with four decimal digits. How many bits will be required in its ADC? MAX = 9999 213 = 8192 214 = 16384 (too many digits)
Logic and arithmetic 4. Using two’s complement arithmetic, calculate the following (choose a suitable number of bits for the representation): a) 121 – 185 = -64 121 in 16-bit binary is 0000 0000 0111 1001 -185 in 16-bit binary is 1111 1111 1011 1001 -64 in 16-bit binary is 1111 1111 1100 0000 00000000 01111001 + 11111111 10111001 --------------------------- 11111111 11000000 b) -70 – 88 = -158 11111111 10111010 - 00000000 01011000 ------------------------- 11111111 01100010 5. Calculate the following without converting the number base. Show calculations. 3A916 + 24D16 = 5F616 3A9 + 24D --------- 5F6 9 + D = 16 A+4+1=F 3+2=5 6. Variable X contains the number of bytes to be read from an external device. Using a binary shift, write one line of pseudocode to calculate the number of bits to be read and store the result in Y. 1 byte = 8 bits
68 44 104 01000100 84 54 124 01010100 100 64 144 01100100 116 74 164 01110100 69 45 105 01000101 85 55 125 01010101 101 65 145 01100101 117 75 165 01110101 70 46 106 01000110 86 56 126 01010110 102 66 146 01100110 118 76 166 01110110 71 47 107 01000111 87 57 127 01010111 103 67 147 01100111 119 77 167 01110111 72 48 110 01001000 88 58 130 01011000 104 68 150 01101000 120 78 170 01111000 73 49 111 01001001 89 59 131 01011001 105 69 151 01101001 121 79 171 01111001 74 4A 112 01001010 90 5A 132 01011010 106 6A 152 01101010 122 7A 172 01111010 75 4B 113 01001011 91 5B 133 01011011 107 6B 153 01101011 123 7B 173 01111011 76 4C 114 01001100 92 5C 134 01011100 108 6C 154 01101100 124 7C 174 01111100
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