1,769 research outputs found

    Electronics: GCE AS and A level subject content: February 2016

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    The development and implementation of a single-line intelligent digital telephone answering unit on a personal computer

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    ThesisCommercial telephone answering machines are limited to some extent by one or more of the following factors: ā€¢ limited facilities ā€¢ difficult to upgrade ā€¢ nonstandard telephone interfacing ā€¢ expensive ā€¢ lack of user-friendliness ā€¢ lack of dialogue and intelligence The purpose of this study is to design an intelligent digital telephone system which will overcome as many of the above-mentioned problems as possible. The following features are proposed and will be discussed: The use of a commonly available, but powerful, personal computer processor and memory instead of the elementary and rigid processor and magnetic tape storage units of the commercial telephone answering machine . This allows the quick storage and retrieval of digitized messages, each with its individual name, time and date stamp. Using the personal computer's hardware and not duplicating the processor and memory units allows a more cost-effective system upgrade. Upgrades mainly consist of software changes and minor hardware changes. This means that an upgrade does not implicate a total hardware redesign. Standards as prescribed by the local switching network standards and the Department of Post and Telecommunications, apply to this design and are applicable for licensing of the product. It is evident that the cost of this project and design is kept minimal by not duplicating expensive components like the microprocessor and the memory units, although these are used in the design. In this respect upgrades are software orientated to further limit the costs. The personal computer is equipped with a display which allows the user to make easy selections in order to execute the required instructions or to obtain information by using the help functions. This real-time help function eliminates the need for a user manual. Dialogue between user and personal computer over the telephone network offers a simple method of delivering information without the need for any extra equipment such as modems, keyboards or display units. The software used on the personal computer is designed in such a way that the system is intelligent and capable of decision making. Communication from the public telephone network is possible by using the telephone keypad and Dual Tone Multifrequency (DTMF) signalling

    Narrative music: towards an understanding of musical narrative functions in multimedia

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    As the computer screen is replacing the book as the dominant medium for communication (Kress, 2003), questions about how meaning is constituted by the multimodal interaction of different media (including music) is becoming increasingly important in contemporary research of pedagogy, sociology and media studies. The overall aim with this licentiate thesis is to explore musical narrative functions as they appear in multimedia such as film and computer games. The thesis is based on three publications. Publication 1 proposes a classification of musical narrative functions, with 6 narrative classes(the Emotive, Informative, Descriptive, Guiding, Temporal and Rhetorical classes) and 11 categories. The relational interplay of music with contextual factors is emphasized. Publication 2 describes the design of a software tool, REMUPP (Relations Between Musical Parameters and Perceived Properties), to be used for experimental studies of musical expression. REMUPP is used for real time alteration of musical expression, by the manipulation of musical parameters such as tempo, harmony, rhythm, articulation, etc. Publication 3 describes a quasi-experiment using REMUPP, where a group of young participants (12-13 years old) were given the task of adapting musical expression ā€“ by manipulating 7 parameters ā€“ to make it fit 3 visual scenes shown on a computer screen. They also answered a questionnaire asking about their musical backgrounds and habits of listening to music, watching movies and playing computer games. Numerical data from the manipulations were analyzed statistically with regards to the preferred values of the musical parameters in relation to the different visual scenes. The results indicated awareness and knowledge about codes and conventions of musical narrative functions, and were to some degree affected by the participantsā€™ gender, musical backgrounds and media habits

    GCE subject level conditions and requirements for electronics

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    Apollo experience report: Electronic systems test program accomplishments and results

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    A chronological record is presented of the Electronic Systems Test Program from its conception in May 1963 to December 1969. The original concept of the program, which was primarily a spacecraft/Manned Space Flight Network communications system compatibility and performance evaluation, is described. The evolution of these concepts to include various levels of test detail, as well as systems level design verification testing, is discussed. Actual implementation of these concepts is presented, and the facility to support the program is described. Test results are given, and significant contributions to the lunar landing mission are underlined. Plans for modifying the facility and the concepts, based on Apollo experience, are proposed

    NASA Tech Briefs Index, 1977, volume 2, numbers 1-4

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    Announcements of new technology derived from the research and development activities of NASA are presented. Abstracts, and indexes for subject, personal author, originating center, and Tech Brief number are presented for 1977

    A study and experiment plan for digital mobile communication via satellite

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    The viability of mobile communications is examined within the context of a frequency division multiple access, single channel per carrier satellite system emphasizing digital techniques to serve a large population of users. The intent is to provide the mobile users with a grade of service consistant with the requirements for remote, rural (perhaps emergency) voice communications, but which approaches toll quality speech. A traffic model is derived on which to base the determination of the required maximum number of satellite channels to provide the anticipated level of service. Various voice digitalization and digital modulation schemes are reviewed along with a general link analysis of the mobile system. Demand assignment multiple access considerations and analysis tradeoffs are presented. Finally, a completed configuration is described

    Class D Audio Amplifier

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    The purpose of this project was to design and produce a 90% eļ¬ƒcient, 80W Class D audio ampliļ¬er, with less than 1% Total Harmonic Distortion (THD) for the NECAMSID Lab. The ampliļ¬er consisted of a second order, three-level āˆ†Ī£ modulator, an H-bridge power stage, and a second order, passive Butterworth ļ¬lter. Testing conļ¬rmed that the eļ¬ƒciency, THD, and power speciļ¬cations were met in the ļ¬nal revision of the design
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