Reconnection-less Electronically Reconfigurable Filter with Adjustable Gain Using Voltage Differencing Current Conveyor

Abstract

This paper presents a novel reconnection-less and electronically reconfigurable analogue filter. It employs two active elements, Voltage-Differencing Current Conveyor (VDCC) and Dual-Output Current Amplifier (DO-CA) with two independently tunable gains. Filter has the single input and single output topology (SISO). The current-mode transfer function of the filter can be tuned electronically from the lowpass (LP) response to the high-pass (HP) response, via the band-stop (BS) response, without reconnection of the input or output terminal. It is designed in order to provide tuning of both the stop-band gain and also pass-band gain of all the transfer functions, because also transfer functions with additional and intended zero in transfer function are available. The theoretical presumptions are confirmed by both simulations and lab measurements with available devices.

Electronically reconfigurable universal filter based on VDTAs

“…The proposed structure, thanks to its realization, also offers the ability to obtain low-pass and high-pass response with intended zero in transfer function (LPZ, HPZ). These types of functions can be used in special cases due to their feature to provide steeper transition from passband to stopband area [19]. The behavior of the LPZ and HPZ function can be observed in Fig.…”

Reconnection–less reconfigurable low–pass filtering topology suitable for higher–order fractional–order design

“…Such solution can have rather complex control logic and more importantly does not offer a feature of a fine tuning of the transfer function as the switches are either on or off in comparison to a continuous control when employing a suitable amplifier similarly to [21] and this paper. The feature of the reconnection-less reconfiguration is a beneficial ability of so–called reconnection–less reconfigurable filters [21] , [37] , [38] , [39] , [40] . These filters can change the resulting output response by adjusting electronically controllable parameters of various active elements such as transconductance g m in case of an operational transconductance amplifier (OTA) or voltage or current gain A , B in case of a variable gain amplifier (VGA) and adjustable current amplifier (ACA), etc.…”

Single VDCC-Based Electronically Tunable Voltage-Mode Second Order Universal Filter

“…Literature review shows that, a number of the analog circuits using VDCC as active element have been found for examples, inductance simulator [10][11], capacitance multiplier [12][13], versatile passive element simulator [14][15], square and triangular wave generator [16], sinusoidal oscillator [6,13,[17][18][19][20], first order allpass filter [21], ladder filter [22] etc. The VDCC based universal filters have been proposed in [23][24][25][26]. The three-inputs single-output currentmode universal filter with five filter responses was proposed in [23].…”

“…Also, for all-pass response, the double gain amplifier is required. The current-mode reconnection-less reconfigurable filter was proposed in [24]. It consists of single VDCC, single dual output current amplifier, single resister and two grounded capacitors.…”