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 16
16 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) 17
17 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 )
Signaling
Signaling
Figure 3-6: Data Encoding and signaling me Data “ Now is the.” First. data must be Male or female converted to binary, as we have just seen Graphics Human∨oice Binary Encoding Binary- Encoded Data 1101010 Signaling Second, bits must be covered Into signals(voltage changes, etc. loltage change, etc 19
19 Figure 3-6: Data Encoding and Signaling Data “Now is the …” Male or Female Graphics Human Voice BinaryEncoded Data 1101010 Binary Encoding Signaling 1. First, data must be converted to binary, as we have just seen 2. Second, bits must be covered Into signals (voltage changes, etc.). Voltage change, etc
Figure 3-7: On/Off Binary Signaling Clock ycle Light Off=On= On= Off= On Off On= Source 0 0 0 Optical fiber During each clock cycle light is turned on for a one or off for a zero 20
20 Figure 3-7: On/Off Binary Signaling Off= 0 On= 1 On= 1 Off= 0 On= 1 Off= 0 On= 1 Light Source Optical Fiber Clock Cycle During each clock cycle, light is turned on for a one or off for a zero