Electronically Tunable Mixed Mode Universal Filter Employing Grounded Passive Components

This research paper contains a new electronically tunable current-mode biquadratic universal filter using a new active building block; current controlled differential difference current conveyor transconductance amplifier (CCDDCCTA). The proposed filter provides the following important and desirable features: (i) One can use only one CCDDCCTA and two capacitors; (ii) One can get low pass (LP), band pass (BP), high pass (HP), notch (NF) and all pass (AP) current responses from the same configuration without any alteration; (iii) Passive components are grounded, which ease the integrated circuit implementation; (iv) Responses are electronically tunable; and (v) Sensitivity is low. Moreover, the non-ideality analysis shows that the parasitic passive components can be compensated for the proposed circuit. The functionality of the design is verified through SPICE simulations using 0.25 μm CMOS TSMC technology process parameters. Simulation result agrees well with the theoretical analysis.

This paper presents the second-order current-mode filter with 4 input currents and single output current. Five filter responses, namely High-pass (HP), Low-pass (LP), Band-pass (BP), Band-reject (BR) and All-pass (AP) filters are achieved. The pole frequency and quality factor are tuned by input bias current called electronic control. It has high output impedance which is able cascading in the current-mode filter and driving load without buffering devices. The filter uses only single active element namely current controlled current differencing transconductance amplifier (CCCDTA) and 2 grounded capacitors which is ideal for monolithic integrated circuit implementation. The filter was proved by Pspice simulation using BJT technology. The results are agreed with theoretical prediction.

In this paper, a new low-voltage low-power dual-mode universal filter is presented. The proposed circuit is implemented using inverting current buffer (I-CB) and second-generation voltage conveyors (VCIIs) as active building blocks and five resistors and three capacitors as passive elements. The circuit is in single-input multiple-output (SIMO) structure and can produce second-order high-pass (HP), band-pass (BP), low-pass (LP), all-pass (AP), and band-stop (BS) transfer functions. The outputs are available as voltage signals at low impedance Z ports of the VCII. The HP, BP, AP, and BS outputs are also produced in the form of current signals at high impedance X ports of the VCIIs. In addition, the AP and BS outputs are also available in inverting type. The proposed circuit enjoys a dual-mode operation and, based on the application, the input signal can be either current or voltage. It is worth mentioning that the proposed filter does not require any component matching constraint and all sensitivities are low, moreover it can be easily cascadable. The simulation results using 0.18 μm CMOS technology parameters at a supply voltage of ±0.9 V are provided to support the presented theory.

This paper presents two transadmittance mode universal filters having single voltage input and multiple current outputs. The filter employs three multiple output current controlled conveyors (MOCCCII) and two grounded capacitors. It can realize low pass, high pass, band pass, notch and all pass responses. As desired, the input voltage signal is inserted at high impedance input terminal and the output currents are obtained at high impedance output terminals and hence eases cascadability. The filter enjoys low sensitivity performance and low component spread; and exhibits electronic and orthogonal tunability of filter parameters via bias currents of MOCCCII. SPICE simulation results confirm the workability of the proposed structure.

This paper proposes a current mode universal filter circuit, employing two active elements along with four grounded passive components only. The derived circuit realizes all five filtering responses, i.e., low pass (LP), band pass (BP), high pass (HP), band reject (BR) and all pass (AP), simultaneously from high-impedance ports along with the input being fed to low-impedance port, thus making it a fully cascadable filter. In addition, the designed circuit exhibits independent tunability of its quality factor. With the idea of making the proposed filter fully integrable, a resistor-less approach of the configuration has also been discussed. By making slight modifications in the filter configuration, a current mode single-resistance-controlled quadrature oscillator circuit has also been derived. The ideal, nonideal, sensitivity and parasitic analysis have been conducted for the designed configurations. The functionality of the proposed structures is verified by PSPICE simulations using 0.18[Formula: see text][Formula: see text]m CMOS technology. The designs have also been verified using PSPICE macro-model of the commercially available IC, i.e., OPA860.

In this paper, Current Differencing Transconductance Amplifier (CDTA) based multimode single input multiple output (SIMO) biquadratic filter is presented. The developed circuit uses three CDTAs, two grounded capacitors, one grounded resistor, and one virtually grounded resistor. The realized filter has one input and three outputs, which are lowpass (LP), high-pass (HP), and band-pass (BP) responses. It can be arranged as current mode (CM), voltage mode (VM), transadmittance mode (TAM), and transimpedance mode (TIM) using appropriate input choices. The performance of the developed biquadratic arrangement is demonstrated through PSPICE simulation with $0.18 \mu \mathrm{m}$ TSMC CMOS technology parameters.

The design of transconductance-mode multifunction biquad filter containing three input voltage nodes and single-output current node is proposed. Its circuit principle is emphasized on employing Voltage Differencing Current Conveyor (VDCC) to be an active building block. The proposed filter description uses three VDCCs co-working with two grounded capacitors and three grounded resistors. The synthesis of the proposed multifunction filter is based on avoidance of using multiple-output active elements to achieve commercially available integrated circuits for practical implementation. Additionally, without multiple-output active element, it can alleviate current tracking error from the current mirrors used in output ports. It also decreases the amounts of the transistors inside the active elements. The proposed multifunction filter offers all 5 filter functions, which are non-inverting Low-Pass (LP), non-inverting High-Pass (HP), non-inverting Band-Pass (BP), non-inverting Band-Reject (BR) and also non-inverting All-Pass (AP) functions from same circuit topology under different circuit condition for input signals. Furthermore, the natural frequency for all filtering responses is independently achieved from the bandwidth or the quality factor of the proposed filter. For cascade-able connectivity, the output current port indeed provides a high impedance. In addition, the magnitude of the output current for all filtering functions can be resistively adjusted. The consideration for non-ideal case of the presented multifunction filter is also analyzed. The simulation and experimental results of the presented transconductance multifunction biquad filter based on VDCC practically implemented by the commercially available ICs, LM13700 and AD844 can validate the theoretical anticipation.

In this paper two new voltage-mode (VM) universal filters employing three plus-type differential voltage current conveyors (DVCC+s) and grounded passive elements are presented. The first proposed filter is a single-input five-output (SIFO) circuit which can realize simultaneously all of the standard responses, i.e. low-pass (LP), band-pass (BP), high-pass (HP), all-pass (AP) and notch (NH) from the same configuration. The second proposed circuit is a three-input single-output (TISO) universal filter for realizing standard responses depending on the selection of the input signal from the same topology. Both of the proposed filters have the advantage of a high input impedance, which enables easy cascading to obtain higher order filters. The proposed filters are simulated using the SPICE program to verify the theoretical analysis.

Synthesis of biquad filters using two VD-DIBAs with independent control of quality factor and natural frequency

A current mode universal filter using current controlled differential difference current conveyor transconductance amplifier (CCDDCCTA) is discussed. The filter provides important and desirable features : (i) Uses only one CCDDCCTA and two capacitors, (ii) One can get low pass (LP), band pass (BP), high pass (HP), notch (NF) and all pass (AP) current responses using the same configuration without any alteration, (iii) Passive components are grounded, which eases the integrated circuit implementation, (iv) Responses are electronically tunable, and (v) Sensitivity is low. Simulation results agree well with theory.

In this paper a new realization of electronically tunable current-mode Active-C biquad filter is presented. In the proposed current-mode biquad filter, only a single modified current conveyor transconductance amplifier (MCCTA) as active building block and two grounded capacitors as passive elements are used. The proposed filter can realize three filtering functions namely, low pass (LP), band pass (BP) and high pass (HP), simultaneously. It is also capable of realizing band reject (BR) and all pass (AP) responses. The pole frequency and quality factor of the proposed circuit can be electronically and orthogonally tuned via only biasing currents of the MCCTA. The theoretical results of the filter are verified by P-SPICE simulation where standard 0.25um CMOS process parameters from TSMC were used.

This paper presents a single VDTA based Mixed Mode type Biquad filter. The proposed Transadmittance Mode (TAM) type Biquad filter configuration employed single voltage differencing transconductance amplifier (VDTA) as an active building block, three passive element namely one grounded resistor, one grounded capacitor and one floating capacitor. The proposed transadmittance Mode multifunction Biquad filter configuration is presenting transadmittance mode type four basic standard filter functions low pass, high pass, band pass, band reject or band stop or band eliminate filter responses. These four type filter responses are realizing simultaneously with the selection of single input voltage signal. The proposed Transadmittance Mode multifunction Biquad filter configuration has more advantageous features such as low active and passive sensitivities, low power supply voltage, low power consumption, low quality factor, very low power consumption, more electronic tunability, higher linearity and required small area of the chip. The performance of the proposed configuration has been verified through PSPICE simulation using 0.18μm CMOS Technology process parameters.

In this paper, a new first-order current-mode (CM) universal filter employing two dual output second-generation current conveyors (DO-CCIIs), one resistor and a grounded capacitor is proposed. The proposed filter has low input and high output impedances; thus, it can be easily connected with other CM circuits. It can simultaneously realize first-order low-pass (LP) and all-pass (AP) responses and can provide high-pass (HP) response with interconnection of LP and AP responses. It can be tuned electronically by replacing with dual output second-generation current controlled conveyors (DO-CCCIIs) instead of DO-CCIIs and removing the resistor. It has only a resistor but no capacitor connected in series to X terminal of DO-CCII; accordingly, it can be operated at high frequencies. Also, it does not need any critical passive component matching conditions and cancellation constraints. A number of simulation results based on SPICE program are included to exhibit performance, workability and effectiveness of the proposed filter configuration.

This paper presents a systematic methodology for designing a voltage-mode multifunction biquad filter employing the commercially available active element, LT1228. The proposed topology adopts a three-input single-output (TISO) configuration. The circuit comprises a single LT1228, two capacitors, and three resistors, offering a highly compact design. The TISO biquad filter is capable of providing five fundamental filtering responses: low-pass (LP), band-pass (BP), high-pass (HP), band-reject (BR), and all-pass (AP) responses, within the same circuit architecture. Notably, these responses are achieved without the need for additional inverting amplifiers or reconfigurations of passive components. The parameters of the proposed filter, encompassing the natural (ω0 ) and quality factor (Q), are determined by electronic adjustment. Furthermore, we can adapt the proposed biquad filter to function as a current-controlled sinusoidal oscillator. The oscillation frequency is adjustable independently of the oscillation condition. We verified the performance and validity of the proposed circuits through PSpice simulations and experimental implementations in a laboratory setting. The proposed circuits hold immense significance for applications requiring precise signal generation and filtering, such as communication systems, test instrumentation, audio processing, automation and control systems.

This paper presents a new voltage-mode (VM) universal biquadratic filter using differential difference current conveyor transconductance amplifier (DDCCTA) as an active element. The circuit employs one DDCCTA, two floating resistors and two floating capacitors which can realize five biquadratic filters, namely low-pass (LP), band-pass (BP), band-stop (BS), high-pass (HP) and all-pass (AP) into one single topology. For realizing these filtering functions, passive component-matching conditions, inverting-type and/or doubling-input signal requirements and changing circuit configuration are absent. The natural angular frequency and quality factor of the filter can be orthogonally controlled deliberately. The VM biquadratic filter using grounded passive components with high-input and low-output impedances can be obtained by adding an additional DDCCTA or differential difference current conveyor (DDCC). The simulation results with 0.5[Formula: see text][Formula: see text]m CMOS process from MIETEC are given to confirm the theoretical predictions and the experimental results are also included to verify the workability of the proposed structure.