<p>The thesis project consists on developing an interface for a Nios II processor integrated in a board of Altera (UP3- 2C35F672C6 Cyclone II).</p><p>The main goal is show how the Nios II processor can interact with the other components of the board.The Quartus II software has been used to create to vhdl code of the interfaces, compile it and download it into the board. The Nios II IDE tool is used to build the C/C++ files and download them into the processor.</p><p>It has been prepared an application for the audio codec integrated in the board (Wolfson WM8731 24-bit sigma-delta audio CODEC). The line input of the audio codec receives an analog signal from a laptop, this signal is managed by the control interface of the audio codec. The converters ADCs and DACs are stereo 24-bit sigma delta and they are used with oversampling digital interpolation and decimation filters.</p><p>The digital interface of the audio codec sends the digital signal to the Nios II processor and receives the data from the processor. After building the interfaces for the audio codec and the processor, it has been prepared an application in C++ language for the processor that modifies the volume of the signal.</p><p>The signal come back to the audio codec and it is possible to check the results with headphones or speakers at the line output of the audio codec.</p>

The thesis project consists on developing an interface for a Nios II processor integrated in a board of Altera (UP3- 2C35F672C6 Cyclone II). The main goal is show how the Nios II processor can interact with the other components of the board.The Quartus II software has been used to create to vhdl code of the interfaces, compile it and download it into the board. The Nios II IDE tool is used to build the C/C++ files and download them into the processor. It has been prepared an application for the audio codec integrated in the board (Wolfson WM8731 24-bit sigma-delta audio CODEC). The line input of the audio codec receives an analog signal from a laptop, this signal is managed by the control interface of the audio codec. The converters ADCs and DACs are stereo 24-bit sigma delta and they are used with oversampling digital interpolation and decimation filters. The digital interface of the audio codec sends the digital signal to the Nios II processor and receives the data from the processor. After building the interfaces for the audio codec and the processor, it has been prepared an application in C++ language for the processor that modifies the volume of the signal. The signal come back to the audio codec and it is possible to check the results with headphones or speakers at the line output of the audio codec.

The main focus in this diploma thesis is to analyse ARM microcontroller ATSAM3X8E, audio codec TLV320DAC3203 and CAN / RS485 bus for communication possibly used in device design. This device's purpose is to establish communicatio between elevator cabin and central control unit. Finally, there is design made for this communication device and measurement of CAN bus speed on H05VVH6 cable.

This thesis is focused on the design of secured audio codec for Asterisk PBX. The first chapter is focused on the basic division of traditional PBX producers and the open source PBX. The second chapter explains the structure of Asterisk PBX and its fundamental difference from a traditional PBX. Asterisk is based on components called modules, therefore the work also deals with the most important modules for operation of exchanges and their division of terms of support and dividing by the type of application and their properties. In this chapter there are described in more detail audio codec A-law and u-law. The third chapter contains simple instructions to get your orientation in the construction of the module for Asterisk PBX and this guide is accompanied by a simple example of creating a module demonstration of his method of translation, commissioning and loaded into Asterisk. Simulation of voice security is in the fourth chapter which provides a description of the proposed security solutions with subsequent implementation in Simulink. This simulation verifies the functionality of the solution proposed security phone call. In the fifth chapter outlines the historical use of encryption techniques primarily mirroring the spectrum and time division signal and comparing them with current modern digital technics. In the last sixth chapter is the actual implementation audio codec module with encryption.

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This work deals with the creation of electronically controlled audio system for the language classroom. Possible solutions compares analog and digital form. Furthermore, describes the final system that was designed. The resulting system is implemented by analog amplifiers and analog crosspoint matrix. Hardware control is realized by microcontroller and that is controlled from the computer.

This paper deals with development and construction of an electronic drum module. The purpose of the device is to capture signals from an electronic drumkit and to produce sound accordingly. Firstly, a protoype with no sound output is constructed to demonstrate an ability to capture input signals. Based on its function, parameters for a final device are determined. Then, electronic component selection and design of printed circuit boards is described with an aim to maximalize polyphony and minimize latency of the sound generator. After that, firmware with software mixing algorithm is designed. Lastly, testing and measurement of real device parameters is performed.

The emergence of Bluetooth Low Energy in combination with optimized coders has made it possible to transfer digital audio at very low bitrates, paving the way for small devices with longlasting batteries. The aim of this study is to compare the audio codecs LC3 and aptX, as well as peoples’ attitude towards audio quality in different contexts. Two open source implementations of the codecs are evaluated in terms of time for execution. Furthermore, the perceived audio quality of low bitrates are subjectively compared in a listening test in combination with a questionnaire regarding peoples’ attitude towards audio quality. The results show that LC3 is capable of delivering satisfying audio quality at very low bitrates, whilst also outperforming aptX. It will be interesting to see how LC3 will affect transmission latency, battery life and overall QoS once it is established in everyday products