New Voltage-Variable Immittance Functions: Linear Voltage-Controlled Quadrature Oscillator

A new voltage-variable immittance functions (VVIFs) implementation has been proposed. Here two types of grounded-immittances function have been realized viz., inductor (L) and Frequency-Dependent Negative Resistor (D) using a pair of ABBs i.e. Current Feedback Amplifier (CFA-AD844) amalgamated with analog voltage-multiplier (AD-835) devices. Thereafter, high-quality (Q) resonant filters and voltage-controlled quadrature oscillator (VCQO) implementation with linear tuning law are designed using the proposed VVIF. The analysis indicates that the filter/oscillator parameters are impervious to the effects of the CFA-device parasitic capacitors. A VCQO-linear tuning range of f(o)similar to 14 MHz with a satisfactory phase-noise margin of (-)103 dBc/Hz at 29 KHz for the LC-type linear QO has been experimentally observed.