Telephone networks use circuit switching. The telephone network had its beginnings in the late 1800s. The entire network, which is referred to as the plain old telephone system (POTS), was originally an analog system using analog signals to transmit voice.
Today’s control system designers face an ever-increasing “need for speed” and accuracy in their system measurements and computations. New design approaches using microcontrollers and DSP are emerging, and designers must understand these new approaches, the tools available, and how best to apply them.
This practical text covers the latest techniques in microcontroller-based control system design, making use of the popular MSP430 microcontroller from Texas Instruments.
• Analog voice data must be translated into a series of binary digits before they can be transmitted in
digital transmission system. One means of doing this is called pulse amplitude modulation (PAM).
• The process of converting analog signal to digital is also known as A_to_D conversion or A/D
conversion. The circuit does the conversion known as A/D converter.
In analog modulation (continuous wave modulation), some parameter of a sinusoidal carrier wave is
varied continuously in accordance with the message signal.
.This page intentionally left blank
.Power Transmission and Distribution
Anthony J. Pansini, E.E., P.E.
THE FAIRMONT PRESS, INC.
.Library of Congress Cataloging-in-Publication Data
Pansini, Anthony J. Power transmission and distribution/Anthony J. Pansini.--2nd ed. p. cm. Includes index. ISBN: 0-88173-503-5 (print) — 0-88173-504-3 (electronic) 1. Electric power transmission. 2. Electric power distribution. I. Title. TK3001.P29 2005 621.319--dc22 2004056439
Power transmission and distribution, second edition/Anthony J.
Communication systems consist of an input device, transmitter, transmission medium,
receiver and output device, as shown in Fig. 1.1. The input device may be a computer,
sensor or oscillator, depending on the application of the system, while the output device
could be a speaker or computer. Irrespective of whether a data communications or
telecommunications system is used, these elements are necessary.
In almost all areas of daily life the demands on the communications infrastructure
increased dramatically. With regard to the volume of data that has to be transmitted,
no matter whether we are dealing with public or private networks, industrial
fields or automobiles, needs will continue to rise. Consequently, the demands
on the bandwidth of communications systems will continue to increase since more
and more video data streams with high picture quality (IP TV), in addition to telephone
and data circuits, will be transmitted.
Today’s transmission methods and equipment are robust and reliable and feature integrated network
monitoring, troubleshooting, maintenance, and provisioning systems. However, public carriers and
most major private networks have historically engineered their network’s physical plant to include
access points at which they can gain quick and organized “hard-contact” access to any particular
Typically, these access points were comprised of analog jackfields with “line-drop-monitor” access
Long distance transmission is typically done over a network of switched nodes
Nodes not concerned with content of data
End devices are stations
Computer, terminal, phone, etc.
A collection of nodes and connections is a communications network
Data routed by being switched from node to node
A circuit-switched network consists of a set of switches connected by physical links. A connection between two stations is a dedicated path made of one or more links. However, each connection uses only one dedicated channel on each link. Each link is normally divided into n channels by using FDM or TDM.
Although the previous chapters in this part are issues related to the physical layer or transmission media, Chapter 8 discusses switching, a topic that can be related to several layers. We have included this topic in this part of the book to avoid repeating the discussion for each layer.
GSM (Global System for Mobile Communications, originally Groupe Spécial Mobile), is a standard set developed by the European Telecommunications Standards Institute (ETSI) to describe technologies for second generation (2G) digital cellular networks. Developed as a replacement for first generation (1G) analog cellular networks, the GSM standard originally described a digital, circuit switched network optimized for full duplex voice telephony.
Synchronous systems negotiate the connection at the data-link level before communication begins Basic synchronous systems will begins. synchronize two clocks before transmission.
Asynchronous systems do not send separate information to indicate the encoding or clocking information. The receiver must decide the clocking of the signal on it's own. This means that the receiver must decide where to look in the signal stream to find ones and zeroes.
Classification a. Means of transmission b. Service c. Circuit switched network d. Method of signalling e. Electronic system f. Light sources g. Remote part of an exchange Characteristics /Function A. It provides a means of asynchronous data transmission. B. It uses one pair for performing all signalling functions of one route. C. It involves the sampling and coding of analogue signals. D. They enable PCM transmission to be used further out in the local network.
General Packet Radio Service (GPRS)
Packet data transmission has already been standardized in GSM phase 2, offering access to the Packet Switched Public Data Network (PSPDN); see Sections 9.5.3 and 9.6.2. However, on the air interface such access occupies a complete circuit switched traf®c channel for the entire call period. In case of bursty traf®c (e.g. Internet traf®c), such access leads to a highly inef®cient resource utilization. It is obvious that in this case, packet switched bearer services result in a much better utilization of the traf®c channels.
In chapter 3:
Circuits and techniques can be employed to transmit a frame of information between 2 DTEs
Error detection schemes which allow the receiving DTE to determine the presence of any errors in the transmitted bit stream.
The Internet Protocol (IP) is a routed protocol that is used to transmit data in
packets. It uses the best-effort delivery for individual packets without any flow
control. Transmission Control Protocol (TCP) is used with IP to provide a
Asynchronous Transfer Mode (ATM), on the other hand, provides connections
between endpoints in the ATM network. The connections are called virtual circuits
IP’s default best effort service can be supplemented by differentiated quality of
service based on IP precedence or DSCP marking.
Signals represent information about data, voice, audio, image, video… There are many ways to
classify signals but here we categorize signals as either analog (continuous-time) or digital (discretetime).
Signal processing is to use circuits and systems (hardware and software) to act on input signal
to give output signal which differs from the input, the way we would like to.
The Soneplex® management access point (MAP) chassis
dapts and concentrates telemetry byte oriented serial
TBOS) alarm and control signals into simplified network
management protocol (SNMP) messages. Equipment
ormerly monitored by TBOS can now be added to SNMP
management systems used by other data or transmission
products, eliminating the TBOS overlay network. The MAP
nables centralized end-to-end circuit visibility, reduces
overall costs of the management network and provides a
unified SNMP presentation to the operations personnel....
Coding and Modulation
The block diagram in Figure 6.1 describes a digital communication system. Similarly, data transfer between reader and transponder in an RFID system requires three main functional blocks. From the reader to the transponder — the direction of data transfer — these are: signal coding (signal processing) and the modulator (carrier circuit) in the reader (transmitter), the transmission medium (channel ), and the demodulator (carrier circuit) and signal decoding (signal processing) in the transponder (receiver)....