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Information and Communications
Technology Qualifications
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| Prescription: MW600 Mobile Wireless Principles |
| Aim of Module | Students will gain an understanding of the principles utilised in the transmission of signals by mobile wireless systems.
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| Credits | 14
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| Student Learning hours | 140
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| Prescription Expiry Date | Nov 2005
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LEARNING OUTCOMES
The Student Will
| | | | | A | 1. | Describe the Electromagnetic spectrum, the allocation of frequencies to the various services and use logarithmic units to measure system gains and losses. | | | A | 2. | Investigate and explain encoding techniques used for analogue signals and techniques for modulating radio carrier frequencies. | | | A | 3. | Describe H.F. transmission lines, and their properties, as they apply to radio frequency transmission and measure signal levels on a H.F. transmission line. | | | C | 4. | Describe the various signal propagation modes and explain how they are affected by the ionosphere and terrestrial conditions. | | | A | 5. | Investigate and describe the construction of basic aerials and explain their radiation patterns. | | | C | 6. | Describe and explain the concept of Spread Spectrum techniques. | | | C | 7. | Explain error detection and correction techniques used in mobile wireless applications. | | | C | 8. | Describe Infrared transmission techniques and how these are applied to LAN’s | | |
CONTENT
| | | | > | A description of the electromagnetic spectrum and the allocation of frequencies to various services will include; | | | -frequency bands and their typical application | | | -services that are suited to higher frequency bands | | | | | An explanation of the application of logarithmic units for the measurement of R.F. systems gains and losses will include; | | | -describing the advantages of the system of logarithmic-based units | | | -defining a decibel as a logarithmic power ratio and expressing the levels in decibels relative to 1 mW | | | -calculating losses and gains in a system using measured power, voltage and current | | |
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| | | | > | An explanation of signal encoding techniques will include; | | | a)Continuous wave modulation: | | | -amplitude, frequency and phase modulated carrier | | | -pulse and sine-wave AM waveforms | | | -"modulation index" as applied to a DSB AM waveform | | | -the production of single-sideband and double side-band AM signals | | | -the comparison of single and double sideband systems with specific reference to power and bandwidth | | | -the investigation of the operation of simple modulators, demodulators and detectors | | | -FM waveforms, frequency deviation and modulation index | | | -A comparison of AM with FM in relation to bandwidth (use of Carson’s rule), power, and signal-to-noise ratio | | | | | b)Digital Modulation: | | | -transmitting an analogue signal as a series of pulses without loss of information | | | -the minimum sampling rate needed in order to accurately reconstruct an analogue signal | | | -PAM, PPM, PWM and PCM signal waveforms | | | -the process of analogue to PAM to PCM conversion | | | -the process of delta modulation | | | -compare delta modulation with PCM | | | | | c)Digital Radio Modulation: | | | Digital Modulation techniques, BPSK, QPSK, QAM, p/4 DQPSK, MSK and GMSK | | | -choice of modulation technique in terms of quality, power, efficiency and bandwidth utilisation | | |
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| | | | > | A description of H.F. transmission lines and their properties, as they apply to radio frequency transmission, will include; | | | -a uniform transmission line represented by a Pi or T-Network showing the primary constants | | | -the characteristic impedance (Zo) of a uniform transmission line | | | -characteristic impedance expressed as the product of the open circuit and the short circuit impedances and calculated from the primary line constants | | | -the secondary line coefficients | | | -primary and secondary line constants as they relate to frequency | | | -definition of the phase change constant ( ) of a uniform transmission line | | | -definition of phase velocity (v) of propagation of a wave along a line | | | -"skin effect" | | | -the stucture of a co-axial cable and the relationship of its dimensions to Zo and | | | -the reasons for matching a transmission line to its load | | | -choosing a particular transmission line for a particular application | | | -measurement of maximum and minimum voltage values of a HF transmission line under various operating conditions | | |
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| | | | > | A description of the various propagation modes and an explanation of how they are affected by the ionosphere and terrestrial conditions will include | | | -ground waves and sky waves | | | -the effect of refraction in the ionosphere | | | -skip distance, maximum useable frequency and optimum traffic frequency in non-mathematical terms | | | -the phenomenon of, and reasons for, fading | | | -the choice of transmission frequencies in the H.F. band | | | -the use of the various frequency band allocations (VLF- SHF) | | |
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| | | | > | A description of the construction of aerials and an explanation of their radiation patterns will include; | | | -concepts of radiation | | | -half wave dipole (opened out quarter wave open circuit line (equivalent)) and its electric and magnetic field patterns | | | -polarisation of an electromagnetic (em) wave and the pictorial representation of an em wave detaching from the local field | | | -frequencies necessary for efficient radiation | | | -induction and radiation fields | | | -transmitting and receiving aerials operating at given frequencies | | | -the Radiation Resistance of an aerial | | | -measurement of a half-wave dipole polar diagram with and without the addition of a reflector and director | | | -aerial gain in terms of an isotropic radiator | | | -effective radiated power | | | -the derivation of the Marconi unipole (from the dipole) and measurement of its polar diagram | | | -the effect of aerial height above ground (graphically illustrated) | | | -measurement of the forward and reverse power of an aerial feed as the aerial length is varied | | |
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| | | | > | A description of the concept of Spread Spectrum and an explanation of the different techniques that are used will include; | | | -frequency hopping and Direct Sequence Spread Spectrum | | | -Code-Division Multiple Access (CDMA) | | | -the use of pseudo noise sequences or orthogonal codes for generating spreading sequences | | |
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| | | | > | An explanation of error detection and correction techniques used in mobile wireless applications will include; | | | -parity check and cyclic redundancy check CRC | | | -forward error correction (FEC), e.g. Hamming Code | | | -automatic repeat request (ARQ) | | |
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| | | | > | A description of Infrared transmission techniques, as applied to LAN’s, will include; | | | -limitations of Infrared (IR) transmissions | | | -wavelengths, light sources and receivers | | | -Omni-directional and Diffused systems | | |
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| | | | Note | | LEARNING RESOURCES | | | Required textbooks: | | | Stallings, W. (2001) Wireless Communications and Networks: Prentice Hall | | |
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