A groundbased instrument to measure the Atmospheric airglow of the molecular oxygen infrared atmospheric band emission was designed, built, tested and operated. The two channel photometer constructed was based on the original design by Evans (1967) that had been used in balloon experiments. The two channel photometer system specifications are presented. The major difference between the presented design and the earlier two channel photometers is the detector. An Indium Gallium Arsenide (InGaAs) photodiode provided better signal to noise in the conversion of the infrared light signal to an electronic signal than the previously used Lead Sulphide (PbS) detectors. The completed instrument was tested to determine its performance characteristics. Through these tests it was found that the photometer output offset is sensitive to ambient temperature fluctuations. An analysis of the instrument noise was done in an attempt to explain this sensitivity. The output noise performance was characterized and is presented together with the absolute brightness and wavelength calibrations. Data was collected with the instrument in Saskatoon, SK and Eureka, NU. After an initial observation campaign in the high arctic (Eureka, NU) modifications were made to the environmental housing of the instrument in order to improve the scientific value of the data collected. The collected data was processed and a simple analysis performed to demonstrate the capability of the photometer to measure the infrared atmospheric airglow. The collected data can be used to determine the mesospheric ozone height profile. The required data analysis to do so is beyond the scope of this presentation. However, the presented data does demonstrate that the designed and constructed two channel photometer can make the necessary measurements.

A groundbased instrument to measure the Atmospheric airglow of the molecular oxygen infrared atmospheric band emission was designed, built, tested and operated. The two channel photometer constructed was based on the original design by Evans (1967) that had been used in balloon experiments. The two channel photometer system specifications are presented. The major difference between the presented design and the earlier two channel photometers is the detector. An Indium Gallium Arsenide (InGaAs) photodiode provided better signal to noise in the conversion of the infrared light signal to an electronic signal than the previously used Lead Sulphide (PbS) detectors. The completed instrument was tested to determine its performance characteristics. Through these tests it was found that the photometer output offset is sensitive to ambient temperature fluctuations. An analysis of the instrument noise was done in an attempt to explain this sensitivity. The output noise performance was characterized and is presented together with the absolute brightness and wavelength calibrations. Data was collected with the instrument in Saskatoon, SK and Eureka, NU. After an initial observation campaign in the high arctic (Eureka, NU) modifications were made to the environmental housing of the instrument in order to improve the scientific value of the data collected. The collected data was processed and a simple analysis performed to demonstrate the capability of the photometer to measure the infrared atmospheric airglow. The collected data can be used to determine the mesospheric ozone height profile. The required data analysis to do so is beyond the scope of this presentation. However, the presented data does demonstrate that the designed and constructed two channel photometer can make the necessary measurements.

The aim of the master thesis is on lock-in amplifiers. Amplifier's basic parts and lock-in circuits description is listed in introductory chapters. The thesis offers overview of parameters of chosen devices available on the market and their possible usage. We describe HF2LI device functions and usage of ziControl software. With the aim to verify properties of the device and ziControl software, one of the last chapters focuses on manipulation with HF2LI device. The conducted experiments and achieved results are presented in the last chapter.

No description available.

As the number of people with diabetes continues to increase, research efforts improving glucose testing methods and devices are under way to improve outcomes and quality of life for diabetic patients. This dissertation describes the design and testing of a Data Acquisition Unit (DAU) providing low noise photocurrent spectra for use in a continuous glucose monitoring system. The goal of this research is to improve the signal to noise ratio (SNR) of photocurrent measurements to increase glucose concentration measurement accuracy. The glucose monitoring system consists of a portable monitoring device and base station. The monitoring device measures near infrared (IR) absorption spectra from interstitial fluid obtained by microdialysis or ultrafiltration probe and transmits the spectra to a base station via USB or a ZigBee radio link. The base station utilizes chemometric calibration methods to calculate glucose concentration from the photocurrent spectra. Future efforts envisage credit card-sized monitoring devices. The glucose monitor system measures the optical absorbance spectrum of an interstitial fluid (ISF) sample pumped through a fluid chamber inside a glucose sensor. Infrared LEDs in the glucose sensor illuminate the ISF sample with IR light covering the 2.2 to 2.4 micron wavelength region where glucose has unique features in its absorption spectrum. Light that passes through the sample propagates through a linearly variable bandpass filter and impinges on a photodiode array. The center frequency of the variable filter is graded along its length such that the filter and photodiode array form a spectrometer. The data acquisition unit (DAU) conditions and samples photocurrent from each photodiode channel and sends the resulting photocurrent spectra to the Main Controller Unit (MCU). The MCU filters photocurrent samples providing low noise photocurrent spectra to a base station via USB or Zigbee radio link. The glucose monitoring system limit of detection (LOD) from a single glucose sensor wavelength is 5.8 mM with a system bandwidth of 0.00108 Hz. Further analysis utilizing multivariate calibration methods such as the net analyte signal method promise to reduce the glucose monitoring system LOD approaching a clinically useful level of approximately 2 mM.

This thesis presented the research, design and fabrication associated with a unique application of rectenna technology combined with lock-in amplification. An extremely low-power harmonic transponder is conjoined with an interrogator base-station, and utilizing coherent demodulation the Remote Lock-In Amplifier (RLIA) concept is realized. Utilizing harmonic re-radiation with very low-power input, the 1st generation transponder detects a transmitted interrogation signal and responds by retransmitting the second harmonic of the signal. The 1st generation transponder performs this task while using no additional power besides that which accompanies the wireless signal. Demonstration of the first complete configuration provided proof of concept for the RLIA and feasibility of processing relevant information under "zero" power operating conditions with a remote transponder. Design and fabrication of a new transponder where the existing zero-bias transponder was modified to include a DC bias to the diode-based frequency doubler is presented. Applied bias voltage directly changed the impedance match between the receiving 1.3 GHz antenna and the diode causing a change in conversion loss. Testing demonstrated that a change in conversion loss induces an amplitude modulation on the retransmission of the signal from the transponder. A test of bias sweep at the optimal operating frequency was performed on the 2nd generation transponder and it was seen that a change of ~ 0.1 V in either a positive or negative bias configuration induced an approximate 15 dB change in transponder output power. A diode-integrated radar detector is designed to sense microwaves occurring at a certain frequency within its local environment and transform the microwave energy to a DC voltage proportional the strength of the signal impinging on its receiving antenna. The output of the radar detector could then be redirected to the bias input of the 2nd generation transponder, where this DC voltage input would cause a change in conversion loss and modulate the retransmitted interrogation signal from the transponder to the base station. When the base station receives the modulated interrogation signal the information sensed by the radar detector is extracted. Simulations and testing results of the fabricated radar detector demonstrate capability of sensing a signal of approximately -53.3 dBm, and accordingly producing a rectified DC voltage output of 0.05 mV. A comparison is made between these findings and the transponder measurements to demonstrate feasibility of pairing the radar detector and the 2nd generation transponder together at the remote sensor node to perform modulation of interrogation signals.

No description available.

I characterize the behavior of microcantilever arrays which utilize the in-plane photonic transduction that I've previously developed and evaluate the performance of the microcantilever arrays in simple sensing scenarios with integrated microfluidics. First the thermal responses of microcantilevers with a variety of patterns of deposited gold films are compared. Using a scanning electron microscope, I observe the deflection thermal sensitivities of 300 µm long microcantilevers to be -170.82 nm/K for a full gold coating and -1.93 nm/K for no gold coating. Using the photonic transduction method I measure a thermal sensitivity of -1.46 nm/K for a microcantilever array with no gold. A microcantilever array integrated with microfluidics is exposed to a solution of bovine serum albumin (BSA) followed by solutions of various pH's. In all cases I observe a previously unreported transient deflection response. We find that the transient response is due to temporary nonuniform concentration distributions. In response to nonspecific binding of BSA, I observe a transient surface stress of -0.23 mN/m that agrees well with the -0.225 mN/m predicted by simulations. We hypothesize that the deflection response to pH changes is due to stress generated by conformational changes of bound BSA.The deflection response of an integrated microcantilever array to different types of flow and different flow rates is observed. Simulations of the deflection response match well with experimental results but disagree at higher flow rates. For flow rates greater than 200 µL/min, the limitation of the differential signal's dynamic range becomes apparent. We then investigate flow driven by an on-chip reciprocating reservoir pump. We demonstrate that it is possible to use the reciprocating pump to achieve high flow rates while making deflection measurements in-between reservoir actuations. Investigations of the microcantilever array noise show that flicker noise dominates below 10 Hz, while above 10 Hz, readout noise dominates. A minimum deflection noise density of 15 pW/√Hz is achieved. To improve the signal-to-noise ratio I develop algorithms for a digital lock-in amplifier with a digital phase-lock loop. In simulation the lock-in amplifier is able to improve the SNR by up to a factor of 6000, and self-lock to a noisy carrier signal without an external reference signal.

Os crescentes problemas relacionados à poluição do meio ambiente colocam desafios para o desenvolvimento de sistemas de sensores integrados e portáteis que permitam o monitoramento do ambiente em tempo real. Nesse sentido, no presente trabalho foi projetado e implementado um sistema de aquisição, processamento de sinais e geração de imagens químicas aplicado para a medição do nível de pH e detecção de metais pesados e elementos patogênicos totalmente integrado e construído na placa sbRIO-9631. O sistema foi desenvolvido e integrado um amplificador Lock-in digital para leitura de valores de mudança de fase e intensidade dos sinais provenientes de sensores optoeletrônicos LAPS, TAOS e FMOS. Foi também desenvolvido e integrado a um sistema automatizado de controle de mistura de gases para realizar ensaios de calibração do sensor e medições de tempo de resposta dos sensores. Também foi integrado um sistema automatizado de escaneamento XY de fonte de luz de excitação para os sensores ópticos utilizando um display OLED-128-G1. Este sistema ainda pode ser integrado a dispositivos móveis via Internet para transferência de dados a centros de pesquisa e monitoramento. O sistema integrado com todas as unidades acima descritas mostrou ser um sistema portátil, reconfigurável e eficiente para a aquisição e processamento de sinais de resposta de diversos tipos de sensores tais com LAPS, TAOS e FMOS. / The problems of environment pollution increasingly growing and pose challenges for the development of integrated and portable sensor systems that allow the monitoring of the environment in real time. In that sense in the present work was designed and implemented an acquisition system, signal processing and chemical Imaging generation to apply in the pH level measurement and the detection of heavy metals and pathogenic elements fully integrated and built on the sbRIO-9631 board. In the system was developed and integrated a digital Lock-in amplifier for reading values of phase shift and intensity of the signals coming from optoelectronic sensors LAPS, TAOS and FMOS. It was also developed and integrated on the sbRIO-9636 an automated gas mixture control system to perform tests for calibration of the sensor and measure the sensor response time. It was developed and integrated an automated XY scan system for light source to excited optical sensors using a OLED-128-G1 display. This system can be integrated into mobile devices via Internet for transferring data to research and monitoring centers. The integrated system with all the units described above proved to be a portable, reconfigurable and efficient system for data acquisition and signal processing from many types of sensors such as LAPS, TAOS and FMOS.

Os crescentes problemas relacionados à poluição do meio ambiente colocam desafios para o desenvolvimento de sistemas de sensores integrados e portáteis que permitam o monitoramento do ambiente em tempo real. Nesse sentido, no presente trabalho foi projetado e implementado um sistema de aquisição, processamento de sinais e geração de imagens químicas aplicado para a medição do nível de pH e detecção de metais pesados e elementos patogênicos totalmente integrado e construído na placa sbRIO-9631. O sistema foi desenvolvido e integrado um amplificador Lock-in digital para leitura de valores de mudança de fase e intensidade dos sinais provenientes de sensores optoeletrônicos LAPS, TAOS e FMOS. Foi também desenvolvido e integrado a um sistema automatizado de controle de mistura de gases para realizar ensaios de calibração do sensor e medições de tempo de resposta dos sensores. Também foi integrado um sistema automatizado de escaneamento XY de fonte de luz de excitação para os sensores ópticos utilizando um display OLED-128-G1. Este sistema ainda pode ser integrado a dispositivos móveis via Internet para transferência de dados a centros de pesquisa e monitoramento. O sistema integrado com todas as unidades acima descritas mostrou ser um sistema portátil, reconfigurável e eficiente para a aquisição e processamento de sinais de resposta de diversos tipos de sensores tais com LAPS, TAOS e FMOS. / The problems of environment pollution increasingly growing and pose challenges for the development of integrated and portable sensor systems that allow the monitoring of the environment in real time. In that sense in the present work was designed and implemented an acquisition system, signal processing and chemical Imaging generation to apply in the pH level measurement and the detection of heavy metals and pathogenic elements fully integrated and built on the sbRIO-9631 board. In the system was developed and integrated a digital Lock-in amplifier for reading values of phase shift and intensity of the signals coming from optoelectronic sensors LAPS, TAOS and FMOS. It was also developed and integrated on the sbRIO-9636 an automated gas mixture control system to perform tests for calibration of the sensor and measure the sensor response time. It was developed and integrated an automated XY scan system for light source to excited optical sensors using a OLED-128-G1 display. This system can be integrated into mobile devices via Internet for transferring data to research and monitoring centers. The integrated system with all the units described above proved to be a portable, reconfigurable and efficient system for data acquisition and signal processing from many types of sensors such as LAPS, TAOS and FMOS.