First-Order All-Pass Filters Comprising One Modified DDCC-

Abstract

In this paper, two new first-order voltage-mode all-pass filters (APFs) are proposed. Each of the proposed APFs comprises a single modified DDCC-, and has high input impedance. The first and second APFs can provide first-order noninverting and inverting APF responses, respectively. As passive elements, the first APF comprises two grounded capacitors, and a floating resistor while the second one uses a grounded resistor, a floating resistor and a grounded capacitor. However, both of the APFs suffer from a matching problem. Two quadrature oscillators (QOs) obtained from the APFs are presented. Simulations of the APF and QO circuits are fulfilled via the SPICE program. Besides, diverse experiments for the APFs are made to verify the performances.