A mixed-mode KHN-biquad using DVCC and grounded passive elements suitable for direct cascading

In this paper a mixed-mode (input and output signals can be current or voltage) Kerwin-Huelsman-Newcomb (KHN) biquad with low/high input impedance and high/low output impedance depending on the type of the corresponding signal (current/voltage) is presented. The circuit is constructed using three differential voltage current conveyors (DVCCs), two grounded capacitors and three grounded resistors. The circuit simultaneously provides bandpass (BP), highpass (HP) and lowpass (LP) responses when the output is current and notch, BP and LP responses when the output is voltage. The notch and allpass responses can be obtained by connecting appropriate output currents directly without using additional active elements. Because of the low input and high output impedance of the circuit for current signals and the high input and low output impedance for voltage signals, it can be used in cascade for realizing higher-order filters. SPICE simulation results are given to verify the theoretical analysis. Copyright (C) 2008 John Wiley & Sons, Ltd.