| Summary: | 博士 === 中原大學 === 電子工程研究所 === 95 === For years, the realization of analog signal processing systems in the current domain provides advantages of wider signal bandwidth, higher slew-rate, better linearity, less circuit complexity, wider dynamic range and lower power consumption. Thus, current-mode approaches can be considered as an alternative choice aside from the traditional voltage-mode circuits. They play important roles in the development of many new high-performance circuits for signal processing applications. In addition, current-mode active devices, which comprise voltage and current variables in their port relations of input and output ports, have been proved to possess favorite balance of operational flexibility and simplicity over those conventional op-amp counterparts. They are suitable to operate with signals in current-mode and/or in voltage-mode, thus rapidly getting the acceptance of researchers as building blocks in high-performance circuit designs.
Moreover, the minimum passive component count and the active element performances have received wide attention in the circuit designs and applications. In this work, the oscillator circuits not only have minimum passive component count properties but also utilize all terminals of a unique active component CDBA (current differencing buffered amplifier).
In addition to the design with the minimum components, the signal flow graph representation is used to simplify the cumbersome analysis of a multi-loop circuit rather than the familiar nodal analysis method. This paper also presents a criterion from the well-known Mason’s formula for multi-loop oscillator in terms of signal flow graphs.
Finally, a synthetic network using second-generation current conveyors (CCIIs), third-generation current conveyors (CCIIIs) and differential difference current conveyors (DDCCs) is proposed here, with each transfer impedance parameter being either minimum- or nonminimum-phase.
All the new techniques presented in this dissertation have been verified through computer simulations or experimental measurements. It is believed that the proposed techniques provide promising approaches and new scope for the design of analog signal processing circuits. Certainly, one can design it automatically with computer since the current conveyor circuits, the transfer functions and numerical methods are available. Further research on high-performance implementations of the current-mode active devices and circuits in monolithic technology is the subject of the future study.
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