DUAL-OUTPUT CURRENT DIFFERENCING TRANSCONDUCTANCE AMPLIFIERS-BASED CURRENT-MODE SINUSOIDAL QUADRATURE OSCILLATORS

摘要

This paper presents three current-mode quadrature oscillator (QO) circuits based on dual-output current differencing transconductance amplifier (DO-CDTA) which is designed from block diagram. The proposed circuits consist of two DO-CDTAs and two grounded capacitors. The circuits can provide two sinusoidal output currents with 90° phase difference. The condition of oscillation (CO) can be adjusted independently from the frequency of oscillation (FO) by adjusting the bias currents of the DO-CDTA. The proposed circuits have high output impedance appropriate for cascade connection application in current mode which is capable to directly drive load. The circuits use only grounded capacitors without any external resistor which is very appropriate for further development into an integrated circuit. Moreover, the oscillator circuits can also adjust amplitude of the output signal. The results of PSPICE simulation program are corresponding to the theoretical analysis.