OTRA BASED MULTIPLE INPUT SINGLE OUTPUT SHADOW FILTER

Abstract

A shadow filter is a second order filter with an external amplifier in the feedback path, & the characteristics of filters are regulated by adjusting the gain(G) of external amplifier. Authors propose new voltage-mode electronically tunable Low-pass controlled low pass , Low-pass controlled Band-pass filter, Low-pass controlled High- pass filter, Low-pass controlled notch filter, Band-pass controlled Low-pass filter, Band-pass controlled Band-pass filter, Band-pass controlled High- pass filter, Band-pass controlled notch filter, High- pass controlled Low-pass filter, High- pass controlled Band-pass filter, High- pass controlled High- pass filter, High- pass controlled notch filter, notch controlled Low-pass filter, Notch controlled Band-passfilter, Notch controlled High- pass filter and Notch controlled notch filter shadow filters. The operational transconductance amplifier is built into the filters (OTRA). OTRA uses CMOS technology to provide an electronic tuning capability for its transresistance gain by adjusting its bias current or voltage. The OTRA-implemented circuits do not require a resistor, making them ideal for any integrated circuit implementation. In every case, the gain of an external amplifier built around the operational transresistance amplifier can be adjusted electronically to control one or more filter parameters. The shadow filter is implemented using the MISO configuration, which eliminates the need for an external summing amplifier. Component matching conditions are not required to implement filter functions. To verify the presented theory, the proposed shadow filter is simulated using the LTspice simulator with a 180nm CMOS process.