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RECOMMENDED BOOKS

ITM1010 COMPUTER AND COMMUNICATION TECHNOLOGIES Prof. C.S. Choy, room 412 Prof. H.K. Tsang, room 306 Tutors: CY Poon ZJ Zhang CW Lee SK Cheung Assignments Mid-term Final.

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RECOMMENDED BOOKS

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  1. ITM1010 COMPUTER AND COMMUNICATION TECHNOLOGIESProf. C.S. Choy, room 412Prof. H.K. Tsang, room 306Tutors: CY Poon ZJ Zhang CW Lee SK CheungAssignmentsMid-termFinal C.S. Choy

  2. FIRST-HALF TERM SCHEDULEWeek (Monday) 8/1 Introduction and Number System 15/1 Logic Gates and Boolean Algebra 22/1 Chinese New Year 29/1 Conference Leave 5/2 Digital Design 12/2 Sequential Logic Design 19/2 Computer Organization 21/3 Mid-term Examination C.S. Choy

  3. RECOMMENDED BOOKS • Digital Electronics – A Simplified Approach by R.D. Thompson Prentice Hall • The Digital Information Age by R. Kuc PWS Publishing C.S. Choy

  4. INFORMATION SYSTEMS • Process – amplifier, scanner, MP3 player • Transmit – telephone network • Store – tape and harddisk C.S. Choy

  5. Why Digital (Binary System)? • Information Integrity Better noise immunity • Information Manipulation Computer is a binary system and its programmable characteristics offer the greatest flexibility C.S. Choy

  6. SOURCES OF DIGITAL INFORMATION • Analog Signal • Representation of Number Values C.S. Choy

  7. BINARY NUMBER SYSTEM e.g. (1011.11)2= C.S. Choy

  8. BINARY NOTATION Digit is called BIT. Possible representations: 1 0 high low true false LSB – Least Significant Bit Bit change with the least effect HSB – Most Significant Bit Bit change with the most effect C.S. Choy

  9. BINARY MATHEMATICS • Addition 1101 + 1001 = 1310 + 910 = • Subtraction • Rules 0 – 0 = 0 1 – 0 = 0 1 – 1 = 0 10 – 1 = 1 C.S. Choy

  10. BINARY MATHEMATICS • Multiplication 1101 x 101 = 1310 x 510 = • Division 110111 ÷ 101 = 5510 ÷ 510 = C.S. Choy

  11. SIGNED BINARY NUMBER Ones (1s) Complement The 1s complement of a binary number of a binary number is derived by subtracting each bit in the number to be complemented from 1. e.g. 1s complement of 1100 C.S. Choy

  12. SIGNED BINARY NUMBER The use of complementary representation allows the subtraction process to be accomplished using addition. Positive result – high end-round carry Negative result – low end-round carry C.S. Choy

  13. SIGNED BINARY NUMBER Twos (2s) Complement The 2s complement of a binary number is the 1s complement plus 1. Positive result – high carry Negative result – low carry C.S. Choy

  14. SIGN BIT The use of a single bit, usually the leftmost bit to indicate the sign of a number. The meaning of the sign bit can be fixed arbitrarily. But normally, sign bit 0 - positive number 1 - negative number e.g. -510 = 1101 +510 = 0101 Note: the magnitude of a number is represented by the lower three bits C.S. Choy

  15. SIGN BIT 1s Complement 2s Complement range: -7 – +7 range: -8 – +7 The leftmost bit still indicates sign. In complement representation, two numbers can be added or subtracted as usual. e.g. 6 + (-2) C.S. Choy

  16. OVERFLOW CONDITIONS Overflow occurs whenever the sum of two positive numbers yields a negative result or when two negative numbers are summed and the result is positive. Overflow can be detected by the difference in the carry-in and carry-out of the sign bit. C.S. Choy

  17. HEXADECIMAL C.S. Choy

  18. BINARY-CODED DECIMAL BCD C.S. Choy

  19. GRAY CODE C.S. Choy

  20. AMERICAN STANDARD CODE FOR INFORMATION INTERCHANGE, ASCII The ASCII encodes the letters in the alphabet as well as numbers, it is an alphanumeric code. It is a 7-bit code so allows representation of 128 different characters and commands. upper-case and lower-case letters decimal numbers punctuation marks special symbols command codes for formatting text Extended ASCII 8-bit code allows for 128 additional graphics characters. C.S. Choy

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