Compact Dual-Mode SITO Universal Filter and Quadrature Oscillator with Only Single VDGA

Abstract

This study describes the synthesis of a single-input three-output (SITO) universal filter and a sinusoidal quadrature oscillator employing only a single voltage differencing gain amplifier (VDGA). The proposed circuit can work either SITO universal filter or QO with the same circuit structure. Both of the realized circuits also produce both voltage and current output signals simultaneously. The dual-mode SITO filter can simultaneously synthesize the main principal filter types (i.e. LP, BP and HP) without altering circuit structure. In contrast, the proposed sinusoidal quadrature oscillator can produce two duplicate sinusoid waveforms with 90° phase shift. Additionally, all the proposed circuits provide the benefit property of separate controlling of the significant parameters.