Examensarbeten för masterexamen // Master Theses
Länka till denna samling:
Browse
Browsar Examensarbeten för masterexamen // Master Theses efter Program "Embedded electronic system design (MPEES), MSc"
Visar 1 - 5 av 5
Sökresultat per sida
Sortera efter
- PostDigital Linearization of a Receiver Optimized for Radar(2022) Laurenius, Rickard; Chalmers tekniska högskola / Institutionen för elektroteknik; Eriksson, ThomasLinearity is an important property of radio frequency amplifiers that has implications for performance in a wide range of applications, from communications to radar. As digital hardware grows ever cheaper and more power efficient, digital techniques for improving the linearity of amplifiers have emerged as an effective replacement for older more power-hungry analogue methods. This thesis seeks to investigate the effectiveness of digital linearization techniques for post-distortion on the receiver side, and in the context of digital radar systems. The investigation has been performed by testing linearization algorithms on recorded signals using hardware typical of modern radio receiver systems. Triangular chirp signals and combined two-tone signals using frequency pairs based on coprime integers are shown to be effective calibration signals. Post-distortion techniques using either memoryless polynomials, memory polynomials or generalized memory polynomials are shown to suppress intermodulation distortion by up to 20dB, and to remain stable for a temperature drift of about 10C. The coefficient estimation algorithm is shown to find inverse models that can improve linearity using only a small number of samples, indicating the possibility of implementations using a low amount of digital resources and model complexities. Ways of compensating for temperature drift have been investigated but to inconclusive results.
- PostMap representation and LIDAR-based vehicle localization(2016) Hägg, Eiliv; Ning, Yingzhi; Chalmers tekniska högskola / Institutionen för signaler och system; Chalmers University of Technology / Department of Signals and Systems
- PostRobotized test setup for autonomous driving - Virtual objects injection(2019) Bodduluri, Preethi; Jagadeepan, Shiva Ajay; Chalmers tekniska högskola / Institutionen för elektroteknik; Chalmers University of Technology / Department of Electrical Engineering
- PostSignal processing unit for bone conduction microphone and speaker An implementation of delay, pitch shifting and echo cancellation(2024) Eliasson, Daniel; Stauffer-Kee, Lucien; Chalmers tekniska högskola / Institutionen för elektroteknik; Reinfeldt, Sabine; Fredén Jansson, Karl-JohanAbstract This paper introduces the development of a signal processing unit for bone conduction microphone and speaker generating real-time adjustable delayed auditory feedback (DAF) and frequency altered feedback (FAF). These types of feedbacks are known to effectively increase fluency in people who stutter. The incidence of stuttering is about 1% of the world population. The effects of DAF have been noted since the 1950s. The user’s voice is captured by a microphone, processed, and then relayed back through a speaker. DAF introduces a delay of 50 to 200 milliseconds, while FAF alters the pitch by a quarter to a full octave. A notable challenge for bone conduction devices is the potential for strong feedback paths between speaker and microphone, which can result in echo or oscillation. The signal processing algorithms, including DAF, FAF, and echo cancellation, were developed and tested using MATLAB®. Additionally, an analog chain was constructed and evaluated on a breadboard, featuring variable amplification and power amplifier to directly drive a passive speaker. To achieve a standalone device, the algorithms were ported to a microcontroller, which was further enhanced with a user-friendly interface, including a rotary encoder and LCD, allowing adjustments of the algorithms without programming expertise. The entire system was then integrated onto a custom-designed printed circuit board (PCB), combining both analog and digital circuitry. The MATLAB® script successfully implements all algorithms; DAF, FAF and echo cancellation. It can be used either with sound files like wav or mp3, or through the use of a audio interface the MATLAB® script can be used in real-time for live application such as a test with a real person. The hardware implemented design on PCB has a working and tested DAF, and a untested implementation of echo-cancellation. Due to limitation in floating point performance of the microcontroller a pitch shifting algorithm remains incomplete. The hardware device has sufficient audio quality with a total harmonic distortion of about 3% adhering to IEC 60645-1. This work lays the groundwork for future enhancements, particularly in refining the pitch-shifting capability.
- PostTorque estimation algorithms for stepper motor(2018) Jansson, Julia; Rådahl, Charlotte; Chalmers tekniska högskola / Institutionen för elektroteknik; Chalmers University of Technology / Department of Electrical Engineering