Multifunctional current-mode filter with dual-parameter control of the pole frequency

Abstract

This paper presents a multifunctional current-mode filter with dual-parameter control of the pole frequency. The filter is of the second order, of single-input triple-output (SITO) type and a required type of the response (low pass, inverting band pass, high pass, band reject and all pass) is obtained by proper selection of one or more outputs. The filter employs two capacitors, two operational transconductance amplifiers (OTAs), each of them with controllable transconductance, and two digitally adjustable current amplifiers (DACAs), providing controllable current gain. Both these controllable parameters directly influence pole frequency of the filter. The theoretical presumptions were confirmed by laboratory measurements.

Keywords

• active filters
• circuit analysis
• circuit synthesis
• current-mode circuits
• tunable circuits and devices