Breathing Stabilization System is a new idea and method. The purpose of this system is to produce a device to control a patient's breathing for gated radiotherapy. This thesis focuses on building a simple Breathing Stabilization System that includes five solenoids, a power supply and five force sensors to build up the whole system. Significantly, this thesis will introduce the modeling of solenoids in detail that include how to build a mathematical model of the solenoids. The simulation of the electromagnetic in professional multi-physics software COMSOL will also be explained. To drive the solenoid system, a voltage-to-current converter is used. This part will be introduced as well as the operational amplifier circuit used by the force sensors.

Frequency reference oscillator is a critical component of modern radio transceivers. Currently, most reference oscillators are based on low-frequency quartz crystals that are inherently bulky and incompatible with standard micro-fabrication processes. Moreover, their frequency limitation (<200MHz) requires large up-conversion ratio in multigigahertz frequency synthesizers, which in turn, degrades the phase-noise. Recent advances in MEMS technology have made realization of high-frequency on-chip low phase-noise MEMS oscillators possible. Although significant research has been directed toward replacing quartz crystal oscillators with integrated micromechanical oscillators, their phase-noise performance is not well modeled. In addition, little attention has been paid to developing electronic frequency tuning techniques to compensate for temperature/process variation and improve the absolute frequency accuracy. The objective of this dissertation was to realize high-frequency temperature-compensated high-frequency (>100MHz) micromechanical oscillators and study their phase-noise performance. To this end, low-power low-noise CMOS transimpedance amplifiers (TIA) that employ novel gain and bandwidth enhancement techniques are interfaced with high frequency (>100MHz) micromechanical resonators. The oscillation frequency is varied by a tuning network that uses frequency tuning enhancement techniques to increase the tuning range with minimal effect on the phase-noise performance. Taking advantage of extended frequency tuning range, and on-chip temperature-compensation circuitry is embedded with the sustaining circuitry to electronically temperature-compensate the oscillator. Finally, detailed study of the phase-noise in micromechanical oscillators is performed and analytical phase-noise models are derived.

Increased awareness concerning our energy consumption and its environmentaleffects, has led to a high demand for renewable energies. Hydropower providesaround 40 percent of the electric energy consumed in Sweden today. If energyefficiency and production time were to increase only by some percent in thehydropower plants, vast amounts of additional renewable energy could besupplied to the electric grid. The Hydropower group at Uppsala University usesa hydropower generator to localize and decrease some of the power losses andthe wearing in the generator. New equipment is being tested and evaluated onthe generator. By measuring static and dynamic forces in the generator broaderinsight can be reached during these tests. This thesis describes the development of a system measuring forces on ahydropower generator using strain gages. Each sensor node is equipped withfour strain gages and a signal conditioning circuit. The system measures strain inthe generator, converts it to a voltage signal, amplifies it, filters and transmits it.After calibration of the nodes, forces can be extracted indirectly. This thesisdescribes considerations made during design of the system as well as its differentparts and configurations.