An explanation of PTT course levels is given at the end of this document

Transcription

1 Online course specification SRB: Transmission fundamentals Target audience: Those joining or planning to join the telecommunications sector in a technical role. This course is one of the StarTel suite of courses which are suitable for those preparing for the BTEC level 3 Communications Technology national certificate or diploma qualification. Course aim: To describe the characteristics, capabilities and applications of copper, optical fibre and wireless transmission media and explain the techniques used to maximise the traffic carrying capacity of those media. Course level: Introductory An explanation of PTT course levels is given at the end of this document Pre-requisites: An understanding of the basic properties of analogue and digital signals and passive electronic components. It is recommended that the PTT course SRA: Analogue and digital signals is studied before attempting this course. Course access requirements: To access the course, a PC running a browser such as Internet Explorer 6 or above, Firefox 2 or above, Google Chrome or Safari is required. The PC should have Internet access and be running Flash version 8 or above. A screen resolution of at least 1024x768 is necessary. Learning facilities This online course employs interactive simulations, hypertext links to an online glossary and multiple choice question sessions to fully involve the trainee in the learning experience. Each module provides revision links to previously studied, relevant topics. A record of progress and level of achievement is recorded for each trainee. Once studied as a structured, assessed course, the content can be browsed for revision or reference. Course structure: The course consists of the following eight modules: 1. Course introduction 2. Power transfer 3. Line transmission 4. Optical transmission 5. Wireless communications 6. Modulation 7. Time Division Multiplexing 8. Line and block codes Page 1 of 5

2 Objective syllabus SRB: Transmission fundamentals Module 1: Introduction Module Aim: To summarise the aims of each module and introduce the navigation and learning facilities provided by the course. Module 2: Power transfer. Module aim: To explain the conditions for maximum power transfer over a copper cable with reference to its characteristic impedance and describe the use of logarithmic units to express power loss and level. describe the equivalent circuit model of a transmission line in terms of resistance, capacitance and inductance. explain the concept of characteristic impedance. state the conditions for maximum power transfer between a source and a load. list typical values of characteristic impedance for various types of cable including co-axial cable and twisted pairs. explain the terms power level, loss, and gain. define the units decibel (db) and dbm and compare their relevance and use. calculate the output power of a circuit in dbm units from the individual losses in the circuit (in db) and a given input power (in dbm). Module 3: Line transmission Module aim: To describe and compare the characteristics and applications of twisted pair and coaxial copper cable. compare the configuration of an unbalanced pair of wires to a balanced pair. explain how a balanced pair of wires provides a higher immunity to interference with reference to the common mode rejection (CMR) of induced signals. explain that the twists in a twisted pair of wires enhance CMR. define, and explain the relevance of, nominal velocity of propagation (NVP) and delay skew. describe and compare the basic construction of unshielded and shielded twisted pair cables, compare their capabilities and give typical applications. describe the basic construction of coaxial cable and give typical applications. describe the role of baluns. Page 2 of 5

3 Module 4: Optical transmission Module aim: To explain the principles of the transmission of information over optical fibres. describe the basic structure of an optical fibre in terms of its core and cladding and explain how optical energy propagates down a fibre. define the term acceptance angle and explain its relevance to the choice of optical source. describe the capabilities of optical fibre compared with copper wires and give typical applications of optical fibre. describe and compare the structure and characteristics of singlemode and multimode fibre. explain the causes of loss in optical fibre in terms of scattering and absorption and describe how the choice of operating wavelength depends on the loss characteristics of a fibre. explain the basic principles of Wave Division Multiplexing (WDM). describe how WDM allows bi-directional operation over a single fibre and the sharing of a fibre by several traffic streams. Module 5: Wireless communications. Module aim: To describe the characteristics and applications of transmissions in the various frequency bands of the electro-magnetic spectrum. describe applications of the various electro-magnetic spectrum frequency bands from low frequency (LF) band to near infrared (NIR) band including reference to broadcast radio and television, mobile communications, microwave radio links, satellite communications and broadcasting and optical fibre transmission. describe the various propagation modes of electromagnetic radiation (EMR) with reference to line of sight and groundwave propagation, ionospheric refraction, tropospheric scattering, reflection and diffraction. explain that each type of radio system depends on a particular EMR propagation mode or a combination of modes. Module 6: Modulation. Module aim: To describe the principles, capabilities and applications of various types of modulation technique. explain the role of modulation in the transmission of data over both wired and wireless links. explain the principles of amplitude modulation (AM) and describe the characteristics of an AM wave in terms of the occupied bandwidth and effects of noise. explain the principles of Frequency Shift Keying (FSK) and describe the characteristics of an FSK wave in terms of the occupied bandwidth and effects of noise. explain the principles of Phase Shift Keying (PSK) with reference to the relationship between the number of permitted states, the maximum achievable data transfer rate and immunity to noise. Page 3 of 5

4 explain the principles of Quadrature Amplitude Modulation (QAM) with reference to the relationship between the number of permitted states, the maximum achievable data transfer rate and immunity to noise. describe the benefits of Gaussian Minimum Shift Keying (GMSK) compared with FSK. give examples of the applications of AM, FSK, PSK, QAM and GMSK. Module 7: Time Division Multiplexing. Module aim: To explain the principles of Time Division Multiplexing (TDM) and describe the capabilities of TDM signals as used in modern telecommunications networks. explain the principles of TDM with reference to timeslots and the role of a Frame Alignment Word (FAW). describe the benefits of TDM with reference to sharing link resources while offering a guaranteed bandwidth and minimum delay for individual circuits. describe the structure and payload capability of an E1 primary multiplex frame. explain the benefits of the Synchronous Digital Hierarchy (SDH) in terms of the multiplexing flexibility and the availability of a comprehensive set of ITU recommendations. explain that TDM-based networks are synchronous in operation and depend on the distribution of timing signals from a centralised clock. list and compare the bit rates and payload capabilities of European SDH and North American SONET aggregate signals. Module 8: Line and block codes. Module aim: To describe the role, characteristics and format of the various types of signal transmitted over copper and optical cable systems. explain the purpose of a line code with reference to the bandwidth efficiency and dc component of a transmitted signal, and the requirement for timing extraction and error checking. describe methods of improving timing extraction including the use of zero (RZ) signals. explain the advantages of bipolar line codes with reference to error checking and the reduction in the DC component of a signal. explain that a multi-level line code reduces the bandwidth requirement of a signal but also reduces its noise immunity. give examples and applications of line codes including Manchester encoding, CMI, AMI, HDB3 and 2B1Q. explain the basic principles of block coding with reference to error checking, bandwidth requirement and use with optical signals. Page 4 of 5

5 PTT course levels PTT online courses are categorised by one of three levels according to the depth of treatment they provide: 1. Introductory: PTT Introductory courses are designed for those with no previous experience or knowledge of telecommunications. These courses provide an overview of telecommunications or discuss the fundamentals of electronic communications. The study of general science at secondary (high) school is a typical pre-requisite for PTT Introductory courses. PTT Introductory courses are suitable for those joining the telecommunications sector particularly those in an apprenticeship programme. 2. Intermediate PTT Intermediate courses are designed for technicians and engineers requiring an understanding of a certain aspect of telecommunications. Those planning to study an Intermediate course should have an understanding of the basic principles of electronic communications. The depth of treatment provided by Intermediate courses is typically equivalent to level 3 of a UK national vocational qualification (NVQ). PTT Intermediate courses can be used to support the attainment of a Communications Technology NVQ at level Advanced PTT Advanced courses are designed for those who require an in-depth treatment of a certain aspect of telecommunications. Such courses are suitable for system designers as well as those who will be responsible for the maintenance of the system described in the course. Those planning to study a PTT Advanced course should have a background in telecommunications, and an understanding of telecommunications fundamentals and the principles of the type of telecommunications system described in the course. PTT July 2013 Page 5 of 5