Two New Third-Order Quadrature Sinusoidal Oscillators

This communication presents a systematic realization of two new third-order quadrature sinusoidal oscillators employing operational transconductance amplifiers (OTAs). These oscillators use canonical number of transconductors (four) and canonical number of grounded capacitors (three). The proposed oscillators enjoy independent electronic control of the condition of oscillation (CO) and frequency of oscillation (FO). The independent electronic adjustment of FO through two identical transconductances controlled by a single external voltage (without disturbing CO) is beneficial in designing voltage-controlled oscillators (VCOs). The presented oscillators have high-frequency stability factor and low power consumption. Circuit simulations employing CMOS OTAs and experimental results using off-the-shelf available OTA IC LM13700 have also been included to confirm the workability of the presented circuits.