Fully controllable first order current mode universal filter composed of bjts and a grounded capacitor

Abstract

In this paper, a new BJT based configuration for providing first order current mode high-pass, low-pass and all-pass filter responses from the same configuration is suggested. The proposed circuit called as a universal filter possesses some important advantages such as consisting of low component count BJT and a grounded capacitor, having electronic tunability property of its pole frequency and having electronic controllability feature of filter types. The suggested circuit does not suffer from disadvantages of use of the resistors. Moreover, as an application, second order band-pass filter is also obtained by cascading two proposed filter structure. Simulations by means of PSpice program are accomplished to demonstrate the performance and effectiveness of the developed first-order universal filter. Approximately more than 1 decade tunability range is achieved. Ill. 7, bibl. 14, tabl. 3 (in English; abstracts in English and Lithuanian).