# Pulse Modulation, Encoding Techniques, and Transmission Codes Sept 19, 2002.

## Presentation on theme: "Pulse Modulation, Encoding Techniques, and Transmission Codes Sept 19, 2002."— Presentation transcript:

Pulse Modulation, Encoding Techniques, and Transmission Codes Sept 19, 2002

Announcement Test #1 next week, from 7:30-8:30 PM. There will be a lecture after the test. Free Grammar Workshops for non-native speakers of English sponsored by the University Writing Center and the English Language Institute. All workshops meet on Wednesdays from 12:30-1:20 PM. Please review WAV files in our class web page that illustrate some quantizing effects.

Homework Homework: –Chapter 5: 2, 4, 5 (use 3100 Hz), 11, 13 (use 10010111) –Chapter 6: Convert the following binary numbers to octal, decimal, and hexadecimal A) 010101101011 B) 110100001111

Class Objectives Quantization –How do we go from continuous to discrete signal? Encoding –How do we prepare the discrete data for serial transmission? Serial Transmission –How do we get the data from point A to B?

Quantization What is Quantization? –We are sampling a signal and forcing the samples to “fit” into a predetermined set of values. Two Key Factors in Quantizing –Sample Rate –Predefined Levels It is the fundamental technique of all digital telecommunications systems.

Why Quantize? Disadvantages –The resulting signal has less resolution. Sampling gives us just a portion of the original signal We introduce errors in the amplitude of the quantized signal –Therefore, a quantized signal is always of inferior quality than the original signal. If that is so, Then why do we market digital systems as being of superior performance?

Why Quantize? (cont) Advantages –Consistency Signal quality and/or degradation can be “controlled” better than continuous/analog –Data Storage –Signal Processing DSP techniques provide powerful mathematical processes. For example, amplification and filtering can be duplicated reliably over a wide variety of equipment.

FIGURE 5-7 (b) reconstructed voice pattern with compression, which is much closer to the original signal. Warren Hioki Telecommunications, Fourth Edition Copyright ©2001 by Prentice-Hall, Inc. Upper Saddle River, New Jersey 07458 All rights reserved.

Chapter 6

FIGURE 6-1 Electrical impulses for the Baudot character F, transmitted by a Teletype terminal: (a) voltage impulses. Warren Hioki Telecommunications, Fourth Edition Copyright ©2001 by Prentice-Hall, Inc. Upper Saddle River, New Jersey 07458 All rights reserved.

FIGURE 6-1 Electrical impulses for the Baudot character F, transmitted by a Teletype terminal: (b) current impulses. Warren Hioki Telecommunications, Fourth Edition Copyright ©2001 by Prentice-Hall, Inc. Upper Saddle River, New Jersey 07458 All rights reserved.