All-Pass Sections with High Gain Opportunity

In this paper, two new circuits for realizing first-order voltage-mode (VM) all-pass section (APS) with variable gain are presented. The first proposed filter uses a single differential difference current conveyor one grounded capacitor and three resistors. The second proposed filter consists of two DDCCs, three grounded resistor; and one grounded capacitor. It provides high-input and low-output impedances and can provide high gain. Both of the proposed circuits do not require any element matching condition. Moreover, oscillator circuits with minimum number of active and passive elements are derived from the proposed APSs. The proposed circuits are tested experimentally or by simulation using SPICE program to confirm the theory