Figure 3-4: AsCll and Extended Ascll ASCll Code to Represent Text ASCll is the traditional binary code to represent text data Seven bits per character 2(128 characters possible Sufficient for all keyboard characters(including shifted values Capital letters(a is 1000001) Lowercase letters(a is 1100001) Each character is stored in a byte The 8tn bit in a byte normally is not used 16
16 Figure 3-4: ASCII and Extended ASCII • ASCII Code to Represent Text – ASCII is the traditional binary code to represent text data – Seven bits per character • 2 7 (128) characters possible – Sufficient for all keyboard characters (including shifted values) • Capital letters (A is 1000001) • Lowercase letters (a is 1100001) – Each character is stored in a byte • The 8th bit in a byte normally is not used
Figure 3-4: ASCII and Extended ASCll, Continued Extended Ascll Used on Pcs Uses a full 8 bits per character 28(256)characters possible Extra characters can represent formatting in word processing, etc Converters Text-to-ASCll and Text-to-Extended ascll Converters are readily available on the Internet 17
17 Figure 3-4: ASCII and Extended ASCII, Continued • Extended ASCII – Used on PCs – Uses a full 8 bits per character – 2 8 (256) characters possible – Extra characters can represent formatting in word processing, etc. • Converters – Text-to-ASCII and Text-to-Extended ASCII Converters are Readily Available on the Internet
Figure 3-5: Binary Coding for Graphics Image Pixels Screen is divided into small squares called pixels(picture elements) 3. JPEG Stores one 2. Each pixel has three byte per color dots-red, green, and (24 bits total) blue. Sometimes a black dot too This gives 256 intensity levels for each color or 16.8 million colors overall(256) 18
18 Figure 3-5: Binary Coding for Graphics Image • Pixels – 1. Screen is divided into small squares called pixels (picture elements) – 2. Each pixel has three dots—red, green, and blue. Sometimes a black dot too 3. JPEG stores one byte per color (24 bits total) This gives 256 intensity levels for each color or 16.8 million colors overall (2563 )
Test Your Understanding ·P146 3 C 19
19 • Test Your Understanding • P 146 • 3 c
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