This thesis presents a novel current-controlled oscillator (CCO). It charges and discharges a source-coupled capacitor periodically with well-controlled current sources. Its current-to-frequency conversion relies on passive components, which are insensitive to the temperature and process variations. The proposed CCO is compact and area-efficient. Moreover, compared to ring-oscillator and LC-tank oscillator, it exhibits much wider tuning range and better linearity. Therefore, it suits the modern system-on-chip (SoC) design. / text

Parametric acoustic arrays are ultrasonic-based loudspeakers that produce highly directive audio. The audio must first be preprocessed and modulated into an ultrasonic carrier before being emitted into the air, where it will self-demodulate in the far field. The resulting audio wave is proportional to the double time-derivative of the square of the modulation envelope. This thesis presents a fully analog processor which encodes the audio into two Pulse Width Modulated (PWM) signals in quadrature phase and sums them together to produce a Single Sideband (SSB) spectrum around the fundamental frequency of the PWM signals. The two signals are modulated between 8% and 24% duty cycle to maintain a quasi-linear relationship between the duty cycle and the output signal level. This also allows the signals to sum without overlapping each other, maintaining a two-level output. The system drives a network of narrowband transducers with a center frequency equal to the PWM fundamental. Because the transducers are voltage driven, they have a bandpass frequency response which behaves as a first-order integrator on the SSB signal, eliminating the need for two integrators in the processor. Results show that the “SSB-PWM” output wave has a consistent 20-30dB difference in magnitude between the upper sideband and lower sideband. In simulation, a single tone test shows higher total harmonic distortion for lower frequencies and higher modulation depth. A two-tone test creates a 2nd order intermodulation term that increases with the frequencies of the input signals.

In recent years great advances in the field of biomedical engineering and organic electronics have been achieved. One promising application would be the regulation of blood glucose concentration in type 2 diabetes patients. This application would eliminate medication and would improve the standard of life. To achieve this goal a system is needed which receives information about the glucose concentration and reacts upon it. This output reaction could then be used to stimulate the body's own glucose regulation mechanisms. This thesis combined a glucose sensor with an artificial neuron to take the first step towards such a system. Two different artificial neurons, the Axon-Hillock neuron and the astable multivibrator, were characterized and examined upon their usability. The Axon-Hillock, build with organic electrochemical transistors, revealed that it could be applied for both regulating high and low blood glucose concentrations. The astable multivibrator, build with silicon-based transistors, was not as functional as the Axon-Hillock neuron but with more development it could become as good. The placement of the glucose sensor in the astable multivibrator circuit is essential parameter to consider. The results demonstrate that the examined system is functional and could become a part of a larger closed-loop system. Future tests on an animal model may demonstrate its viability as a treatment for type 2 diabetes.