SITO current-mode multifunction biquad using readily available IC LT1228s

This paper focuses on the practical realization of current-mode multifunction biquadratic filter with single input and triple outputs (SITO), implementing from two readily available IC LT1228s. Only three grounded passive elements have been used for the realization. Highpass (HP), bandpass (BP) and lowpass (LP) biquadratic filtering functions are simultaneously generated without modifying the circuit structure. The tuning laws of the natural angular frequency (ωo) and the quality factor (Q) are non-interactive electronic control by changing the external bias current of LT1228s. The critical circuit sensitivities are considered to be low. Computer simulations with PSPICE program are also confirmed with theoretical ones and used to demonstrate the circuit performance.