I det här examensarbetet har jag tittat närmare på hur man med hjälp av en transformator kan höja Signal/brus-förhållandet för en mikrofonSignal som förstärks av en förstärkarkrets. Arbetet baseras sig på en psykoakustisk brusmätning enligt standarden ITU-468-4.Ett bra förhållande mellan Signal och brus är alltid eftersträvat i en krets. När Signalen i kretsen är svag kan Signalen i värsta fall försvinna i bruset. Arbetet kommer att titta på hur man definierar och mäter Signal/brus-förhållanden på en förstärkare samt vad som påverkar Signal/brus-förhållandet. Arbetet kommer visa att med hjälp av en spänningstransformering av en in-Signal så kan ett bättre Signal/brus- förhållande ut från en serie förstärkare erhållas..

We have different kinds of Signal processing everywhere around us in our everyday life, in our cellphones, when we are listening to music, watching TV etc. This makes Signal processing a very interesting and important technical area, where the demand of skilled engineers sets the limit of what is possible.Working with Signal processing requires in-depth knowledge in areas such as mathematics, physics, electronics, and other related areas. For this, it has traditionally been demanded by a talented developer to also master the advanced programming languages such as C / C + + and Assembler.This has begun to change; today there are several companies that offer graphical development environments for Signal processing, environments where programming skills are not needed anymore, and the focus can be on Signal processing instead.The goal with this project is to build a corresponding graphical development environment to reach an understanding of what is required of these systems, and also to grasp what opportunities that are available within graphic programming. Inspiration for the work has partly arise from some of the tools available on the market, and partly from previous theses that have been written about graphic programming.The challenge lies in creating a program that can execute Signal diagrams in real time from given Signal blocks, and be able to handle feedback loops in an efficient way and to do so at the lowest "cost" in terms of clock cycles as possible. This should also be compared against to code, compile and run a complete Signal diagram directly.To increase the usability it should also be possibility to externally manage in real time the parameters of the Signal diagram during execution.The interface is a separate program, which is to some extent similar to Matlab Simulink, where a Signal diagram is drawn up graphically by connecting wires between different Signal blocks.

The data acquisition system COMET developed by Saab AB contains a unit for Signal conditioning and A/D conversion, called KSM. The varieties in Signal conditioning constitutes of a number of specific PBAs and maintenance as well as reconfiguration of these are complicated not to mention costly. This thesis has aimed to investigating whether the Signal conditioning circuits can be replaced by a general purpose, programmable solution. If so, how can this be done? The development has been carried out by evaluating ideas through the use of a laboratory environment and has resulted in an analog design for laboratory purpose.

The purpose with the report is to show that it is possible to design a class-D amplifier, using a programmable FPGA mounted on a developing card from Xess and a H-bridge. The FPGA was programmed in VHDL which is the language the software from Xilinx use to implement a logical function into the FPGA The logical function corresponds to a modeling of the music Signal and the modeling can be described as a comparator which compare the music Signal with a triangle wave and as a out Signal produce a pulse width modulated (PWM) Signal. The report is also a review and evaluating of two different modulating technologies, AD- modeling and BD-modeling. A detailed part about how the H-bridge was designed and how it works. The result of this project is a working audio amplifier to a significant lower price than the products in todays market..

To be able to evaluate different radio waveforms in a laboratory environment FOI in Linköping has developed an experimental system for radio communication called Rasmus. The system consists of a transmitter, a channel emulator and a receiver. The transmitter modulates a digital Signal to a desired analogue waveform. The channel emulator is used to simulate a real radio channel. The channel emulator distorts the Signal by splitting it up in several propagation paths.

The purpose of this project was to produce Signal relay stations that could receive information via 2.4 GHz radio and relay the information to a designated target station. If a relay station was located outside of Signal range for the target station it was supposed to utilize other relay stations to transfer the information to the target station, so called multi-hop.The would-be application of the relay stations was orienteering. When an orienteer punches a checkpoint the Signal stations would relay information of who punched the control, when it was punched and the checkpoint that was punched to the speaker tower in the goal area.The work resulted in prototypes which fulfilled the statement of purpose and was tested at an orienteering competition with satisfactory results. The performance of the prototypes was tested and found adequate for the would-be application..

This thesis studies the negative impact that control Signal saturation may have on a controlled system. Different methods that are used to compensate for this problem are also studied and evaluated. Both sensitivity to disturbances and the effect the method has on the systems'ability to follow a reference Signal will be examined. Stability will be discussed, but no conclusions whether the systems are stabilized or not can be drawn. Control Signal saturation will lead to a slower behavior in general.

This report tested the possibility of using induction as a mean for transferring data and power so that it can be implemented as a communication medium between a terminal and measuring head mounted in a measuring frame. This would eliminate the need for the cable bunches that are used today. For testing, Signal generators were used to generateFSK-Signals and were transferred with the help of inductors to the oscilloscope for Signal detection, this to see how the coils used in the tests behaved. Simulations of a PLL were performed to see how good it could handle FSK-demodulation. With the help of a PLL IC and the simulations a working FSK-demodulator could be assembled.

SAAB Aerotech division FGR in Arboga builds and develops equipment and components used in both military and civilian applications. To build a test system for a specific project that SAAB is responsible for requires a simple Signal generator that can provide a pulse modulated Signal. The need to buy a new advanced Signal generator for example from Agilent is not as profitable as the instrument is expensive and contains features that SAAB does not require in their applications and test systems. That was the reason why SAAB offers two students a thesis where the goal is to construct a Signal generator in accordance with what SAAB requests.This thesis contains several different phases. The first step was a meeting with our supervisor Mats Bergman and by reading the data sheets for components to be used in the project, with these information and specifications that we have received from SAAB we started to construct the Signal generator.What we did during the construction work was to simulate and draw a schematic to be able to design the circuit board.

This work is an experimental study where knock sensor placements are investigated using engine tests. The aim is to studythe quality of the Signal from knock sensors and how the Signal for engine control is affected at different sensor locations on Scanias, engine DC13. To find out at witch position on the engine youcan get a usable Signal for engine control, the engine is running while the knock sensors with advanced measurement equipment is connected to the engine. Evaluation of Signals from the knock sensors are made in the computer program Matlab. The program is producing a seriesof plots, from these plots it is visually possible to draw conclusions and find connections.

This work aims to evaluate the possibility of using a graphical programming language to develop software for a digital Signal processor. A fixed-point digital Signal processor called Blackfin BF-537 is used for this. Instead of using conventional programming languages, like C or assembler, for software development the possibilities to use a graphical environment to fill the same purpose are examined. The development environment primarily used is NI LabVIEW, but also the use of Mathworks Matlab Simulink is investigated. A variety of programs consisting of various Signal processing operations and utilities are developed using these development environments.

This bachelor thesis is about an ultrasonic sensor, implemented in a bubble chamber in Artis. The sensor consists of the piezoelectric sensor and an electronic control circuit. The control circuit consists of a programmable microprocessor, PIC18F2420 and a circuit, which sends the excitation Signal to the piezoelectric sensor, and later receives the echo. This bachelor thesis consists also of a theoretical study, which examines different techniques of liquid level sensing in a chamber. The study discusses which factors are important in liquid level sensing and examine accepted methods.

In many clinical applications, it is desirable to transmit sensor information wireless. In earlier research, investigation transmit ECG Signal using Bluetooth, was performed. However, when Bluetooth has some drawbacks it is of interest to investigate alternative methods, one such method is ZigBee. Bluetooth has higher data rate speed (1Mbps) than ZigBee (250kbps). However, Bluetooth consumes more power.

At the Department of Technology and Built environment at the University of Gävle there was an interest to study GNU Radio, which is an "open source radio project. The project is based on that most of the radio Signal processing is made in an ordinary PC. The idea behind this degree project was that in a laptop there are several radio transmitters/receivers that takes space, generates heat and transmit in varied frequency band etcetera. All these radio transmitters/receivers could be replaced with a Software Defined Radio system. It means that one common, general radio hardware is used to different communications such as: WLAN, Bluetooth, GPRS, 3G etcetera. The waveform is generated in the software, which makes the system very flexible.

In this thesis a prototype board for data aqcusition is designed and manufactured. The board is compliant with Compact PCI Express and it can sample an analog Signal with two time interleaved ADC:s. Furthermore, the board is also equiped with one FPGA for the possibility of Signal processing. The thesis also include a study for investigation what is needed for a total solution for data aqcusition, represention and managing the sampled data with LabView..