Practical design of the voltage controllable quadrature oscillator for operation in MHz bands employing new behavioral model of variable-voltage-gain current conveyor of second generation

This paper introduces a new simple behavioral model of variable-voltage-gain (inverting) current conveyor of second generation (VG-(I)CCII) intended for experimental verification of linearly controllable quadrature oscillator operating above 1 MHz. The proposed novel topology implements two models of VG-(I)CCII. Next, its precise design procedure is presented. Operation with constant amplitude levels is ensured from 2.69 to 20.18 MHz, whereas the highest available oscillation frequency achieves 30.1 MHz. The oscillator employs high-speed off-the-shelf active elements, which emulate behavior of current conveyor of second generation with a variable voltage gain between Y and X terminals. The influence of the real features of active elements and printed circuit boards is considered for the estimation (design equations) of the operational conditions of the circuit. Experimental measurements confirmed the validity of the expected results. Novel behavioral model of active device brings significant advantages (variable voltage gain and its polarity control) for its implementation in applications. Simple circuitry of the newly proposed quadrature oscillator and its wideband linear electronic tuning, constant amplitudes and phase shift with frequency tuning are the most notable benefits of our proposed concept, compared to current state-of-the-art solutions.