Novel dual-mode electronically tunable all-pass filter using voltage gain-controlled MCFOA

In this paper, a new bipolar junction transistor (BJT) voltage gain-controlled modified current feedback amplifier (VGC-MCFOA) is presented. As application example using the presented new active building block a novel first-order allpass filter employing single VGC-MCFOA and four grounded passive elements is proposed. Reported filter structure provides both current- and transimpedance-mode transfer functions at the same configuration simultaneously. The pole frequency of the circuit can be easily tuned by means of bias currents. The theoretical results are verified by SPICE simulations based on bipolar transistor arrays AT&T ALA400-CBIC-R process parameters.