Abstract:
An application of the nano-electronic quantum device single electron transistor (SET)
is presented in this thesis work. With the operating principle described, a circuit is
proposed with the name of 'rate controlled oscillator'. The proposed circuit takes any
small signal voltage wave as input variable and produces a pulse train of square wave
with low duty cycle. The frequency of the pulses occurring at the output node is
directly proportional to the slope (dv/dt) of the input voltage signal. The circuit thus
generates a pulse with frequency proportional to the rate of change of the input signal
and hence the name is given 'rate controlled oscillator'. This circuit is expected to
find its application in many daily life applications as well as in many high end
research projects.
A proposed adaptive sample and hold circuit which uses SET based rate controlled
oscillator as its sampling frequency generator is also presented which is named
'adaptive sample and hold circuit'. The adaptive sample and hold circuit is capable of
detecting the slope of the incoming signal and thereby generates proportional (to
slope) sampling frequency - thus making it an intelligent circuit which is capable of
employing variable sampling frequency depending on the slope of the input signal.
This circuit maximizes performance and minimizes bit rate as compared to
conventional sample and hold circuit whose sampling frequency has a preset value
and is not capable of changing the sampling firequency when in operation. Simulation
based comparison among adaptive sample and hold circuit and conventional sample
and hold circuit is presented which reveals that adaptive sampler offers better
performance regarding the sampling of signal with unpredictable composite frequency
component and it also requires lower bit rate than conventional sample and hold
circuit.
