The paper deals with the preparation and measurement of an experimental polymer graphite cathode that
seems to be a promising and cheap source of electrons utilizing cold field-emission in high- and ultra-high
vacuum. Polymer graphite seems to be a proper material as it contains a large amount of hybridized carbon
with a low degree of surface oxidation and silicon monoxide (SiO). Within the frame of this work, a special
experimental method of tip preparation has been designed and tuned. This method is based on ion milling
inside a dual-beam electron microscope enabling to obtain ultra-sharp tips of a diameter smaller than 100 nm
with a predefined opening angle. The charge transport within experimental samples is evaluated based on
results provided by the noise spectroscopy of the total emission current in the time and frequency domains.
In the paper, a general topology of continuous-time Active-RC filter is presented. The model includes all possible Active-RC filter
structures as particular cases and allows us to analyze them using a unified algebraic formalism. This makes it suitable for use in computeraided analysis and design of Active-RC filters. By its construction, the model takes into account the finite DC gain and the finite bandwidth as well as non-zero output resistance of operational amplifiers. Filters with ideal OPAMPs can be treated as particular cases. Sensitivity and noise analysis of Active-RC filters is also performed in the proposed general setting. The correctness of the model is verified by comparison with SPICE simulation.