SYSTEM FOR CONFIGURING ACTIVE INDUCTOR SIMULATOR AND MULTIPLIER CIRCUIT
20240405754 ยท 2024-12-05
Assignee
Inventors
Cpc classification
International classification
Abstract
A tunable grounded positive and negative active inductor simulator and impedance multiplier circuit and a method for implementing the tunable grounded positive and negative active inductor simulator and impedance multiplier circuit are described. The circuit includes one second generation voltage-mode conveyor circuit (VCII+), a voltage source configured to generate an output current, a first impedance, a second impedance and an operational transconductance amplifier OTA. The first impedance is connected between the voltage source and the positive VCII+ input terminal, Y. The second impedance is connected between the second output terminal and a ground terminal. The OTA is configured to have a transconductance gain. The circuit is configured to be tuned by a selection of values for the first and second impedances.
Claims
1-19. (canceled)
20. A system for configuring a tunable grounded positive and negative active inductor simulator and impedance multiplier circuit, comprising: one second generation voltage-mode conveyor circuit, (VCII+), configured with a positive VCII+ input terminal, Y, a first output terminal, Z, and a second output terminal, X, wherein the VCII+ has a current gain ; and a voltage gain ; a voltage source V.sub.s configured to generate an output current at a frequency, s; a first impedance Z.sub.1 connected between the voltage source and the positive VCII+ input terminal Y, wherein an internal circuit of the first impedance Z.sub.1, comprises a resistor R.sub.1, in parallel with a capacitor C.sub.1; a second impedance Z.sub.2, connected between the second output terminal X and a ground terminal, wherein an internal circuit of the second impedance Z.sub.2 comprises a resistor R.sub.2 in parallel with a capacitor C.sub.2; and an operational transconductance amplifier OTA, configured to have a transconductance gain g.sub.m, wherein the OTA includes a positive OTA input terminal, a negative OTA input terminal, an OTA output terminal, and a current bias I.sub.B input terminal, wherein: the positive OTA input terminal is connected to one of the first output terminal Z and the ground terminal; the negative OTA input terminal is connected to one of the first output terminal Z and the ground terminal; and the OTA output terminal is connected to the first impedance Z.sub.1, wherein the grounded positive and negative active inductor simulator and impedance multiplier circuit is configured to be tunable by a selection of a value for R.sub.1, a value for C.sub.1, a value for R.sub.2 and a value for C.sub.2; wherein: the OTA is configured to generate an output current, I.sub.o; the positive VCII+ input terminal is configured to receive an input current I.sub.y, equal to the difference between I.sub.s and I.sub.0; the first output terminal Z is configured to generate a voltage, V.sub.z; the second output terminal X is configured to generate a voltage V.sub.x, across the second impedance Z.sub.2 and a current i.sub.x through the second impedance Z.sub.2, wherein i.sub.x=I.sub.y and V.sub.z=V.sub.x; the output current I.sub.o is given by I.sub.o=I.sub.x Z.sub.2 g.sub.m=I.sub.y Z.sub.2 g.sub.m; and a voltage at the positive VCII+ input terminal Y is given by V.sub.y, where V.sub.y=0; when the positive OTA input terminal is connected to the first output terminal Z and the negative OTA input terminal is connected to the ground terminal, an input impedance Z.sub.in of the VCII+ is given by
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] A more complete appreciation of this disclosure and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
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DETAILED DESCRIPTION
[0030] In the drawings, like reference numerals designate identical or corresponding parts throughout the several views. Further, as used herein, the words a, an and the like generally carry a meaning of one or more, unless stated otherwise.
[0031] Furthermore, the terms approximately, approximate, about, and similar terms generally refer to ranges that include the identified value within a margin of 20%, 10%, or preferably 5%, and any values therebetween.
[0032] Aspects of this disclosure are directed to a grounded positive and negative active inductor simulator (AIS) and impedance multiplier circuit. The grounded positive and negative active inductor simulator and impedance multiplier circuit can be configured as any one of an active inductor simulator, a capacitance multiplier, a positive resistance multiplier, a negative resistance multiplier, a negative active inductor simulator, and a negative capacitance multiplier by choosing the values of Z.sub.1 and Z.sub.2. The described circuit includes only one second-generation voltage-mode conveyor (VCII+), one transconductance amplifier, OTA, and two passive elements.
[0033] In various aspects of the disclosure, non-limiting definitions of one or more terms that are used in the document are provided below.
[0034] The term second-generation voltage-mode conveyor (VCII) is defined as a dual circuit of a second-generation current conveyor (CCII), which provides the possibility of processing signals in the current domain while providing output signals in the voltage form. The VCII includes Y and X ports (input terminals) and Z port (output terminal). Y is a low-impedance current input port and X is a high-impedance current output port. For VCII, B is a current gain between the Y and X ports and a is a voltage gain between the X and Z ports. V.sub.x and V.sub.z are the voltages at the X and Z ports, respectively. I.sub.Y and I.sub.X are the input current to the Y port and output current at the X port, respectively.
[0035] The term plus type VCII (VCII+) is defined as a second-generation voltage-mode conveyor (VCII) in which current in the X terminal flows in the same direction with respect to that related to the Y terminal. The VCII+ has + (positive current gain).
[0036] The term negative type VCII (VCII) is defined as a second-generation voltage-mode conveyor (VCII) in which current in the X terminal. The VCII has (positive current gain).
[0037] The term impedance simulator is defined as a circuit that simulates an input impedance that may be one of inductive, capacitive and active (resistance). The impedance simulator is used for simulating the impedance of an electronic equipment under different power consumption platforms.
[0038] The term capacitance multiplier is defined as an electronic circuit that increases the value of a reference capacitor by a predefined multiplication factor, achieving a higher equivalent capacitance level in an IC form. The capacitor multipliers support design of complex integrated circuits possible that otherwise would be challenging with actual capacitors.
[0039] The term impedance multiplier is defined as a circuit that effectively magnifies the impedance presented by an external load. An example of impedance multiplier is an impedance doubler, which doubles the effective impedance of the external load. The impedance multiplier circuit includes an input impedance having a defined value of impedance and a circuit coupled to this input impedance for multiplying its value by a multiplication factor.
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[0041] The second generation voltage-mode conveyor circuit (VCII+) 110 includes a positive VCII+ input terminal Y, a first output terminal Z, and a second output terminal X. In an aspect, the VCII+110 has a current gain , and a voltage gain . The voltage source V.sub.s is configured to generate an output current I.sub.s at a frequency s.
[0042] The first impedance Z.sub.1 is electrically connected between the voltage source V.sub.s and the positive VCII+ input terminal Y. An internal circuit of the first impedance Z.sub.1 includes a resistor R.sub.1 and a capacitor C.sub.1, where the resistor R.sub.1 is connected in parallel to the capacitor C.sub.1.
[0043] The second impedance Z.sub.2 is electrically connected between the second output terminal X, and a ground terminal. An internal circuit of the second impedance Z.sub.2 has a resistor R.sub.2 and a capacitor C.sub.2, where the resistor R.sub.2 is connected in parallel to the capacitor C.sub.2.
[0044] The operational transconductance amplifier (OTA) 120 is an amplifier whose differential input voltage produces an output current. For example, the OTA 120 is a voltage controlled current source (VCCS). In an aspect, the OTA 120 includes an additional input for a current to control a transconductance of the OTA 120. In an example, the OTA 120 has a transconductance gain g.sub.m. The OTA 120 includes a positive OTA input terminal 125, a negative OTA input terminal 130, an OTA output terminal 135, and a current bias I.sub.B input terminal. In an aspect, the positive OTA input terminal 125 is connected to one of the first output terminal Z and the ground terminal. The negative OTA input terminal 130 is connected to one of the first output terminal Z and the ground terminal. The OTA output terminal 135 is connected to the first impedance Z.sub.1.
[0045] In an aspect, the grounded positive and negative active inductor simulator and impedance multiplier circuit 100 is configured to be tuned by a selection of a value for R.sub.1, a value for C.sub.1, a value for R.sub.2 and a value for C.sub.2.
[0046] In an aspect, the OTA 120 is configured to generate an output current I.sub.0. In an example, the output current I.sub.0 is given by I.sub.o=I.sub.x Z.sub.2 g.sub.m=I.sub.y Z.sub.2 g.sub.m. The positive VCII+ input terminal Y is configured to receive an input current I.sub.y. In an example, the I.sub.y is equal to the difference between I.sub.s and I.sub.0. A voltage at the positive VCII+ input terminal Y is given by V.sub.y, where V.sub.y=0. The first output terminal Z is configured to generate a voltage V.sub.z. The second output terminal X is configured to generate a voltage V.sub.x across the second impedance Z.sub.2. The second output terminal X is configured to generate a current i.sub.x through the second impedance, Z.sub.2, wherein i.sub.x=I.sub.y and V.sub.z=V.sub.x.
[0047] In one example configuration, the positive OTA input terminal 125 is electrically connected to the first output terminal Z, and the negative OTA input terminal 130 is connected to the ground terminal. In such configuration, an input impedance Zin of the VCII+ 110 is given by
where z.sub.2g.sub.m is 1.
[0048] In an aspect, the circuit 100 is configured to operate as a tunable positive active inductor simulator by setting Z.sub.1=R.sub.1, C.sub.1=0, R.sub.2=0 and Z.sub.2=1/sC.sub.2, such that the input impedance is given by
In an aspect, a value of the inductor L can be tuned by the selection of the value of C.sub.2 and the value of R.sub.1.
[0049] In an aspect, the circuit 100 is configured to operate as a tunable positive capacitance multiplier by setting Z.sub.1=1/sC.sub.1, R.sub.1=0, Z.sub.2=R.sub.2, and C.sub.2=0, such that the input impedance is given by
in which the capacitance C.sub.1 is multiplied by (1+20 R.sub.2I.sub.B). In an aspect, an amount of multiplication of C.sub.1 is tuned by the selection of the value of R.sub.2.
[0050] In an aspect, the circuit 100 is configured to operate as a tunable positive resistance multiplier by setting Z.sub.1=R.sub.1, C.sub.1=0, Z.sub.2=R.sub.2, C.sub.2=0, such that the input impedance is given by
in which R.sub.1 is multiplied
where 020R.sub.2I.sub.B<1. In an aspect, an amount of multiplication of R.sub.1 is tuned by the selection of the value of R.sub.2.
[0051] In one example configuration, the positive OTA input terminal 125 is connected to the ground terminal. The negative OTA input terminal 130 is connected to the first output terminal Z. The input impedance Zin of the VCII+ is given by
where Z.sub.2g.sub.m>1.
[0052] In an aspect, the circuit 100 is configured to operate as a tunable negative active inductor simulator by setting Z.sub.1=R.sub.1, C.sub.1=0, R.sub.2=0 and Z.sub.2=1/sC.sub.2, such that the input impedance is
In an aspect, a value of the inductor L given by is tuned by the selection of the value of C.sub.2 and the value of R.sub.1.
[0053] In an aspect, the circuit 100 is configured to operate as a tunable negative active capacitance multiplier is configured by setting Z.sub.1=1/sC.sub.1, R.sub.1=0, Z.sub.2=R.sub.2, and C.sub.2=0, such that the input impedance is given by
in which the capacitance, C.sub.1, is multiplied by (20R.sub.2I.sub.B). In an aspect, an amount of multiplication of C.sub.1 is tuned by the selection of the value of R.sub.2.
[0054] In an aspect, the circuit 100 is configured to operate as a tunable negative resistance multiplier by setting Z.sub.1=R.sub.1, C.sub.1=0, Z.sub.2=R.sub.2, and C.sub.2=0, such that the input impedance is given by
in which R.sub.1 is multiplied by
where 020R.sub.2I.sub.B<1. In an aspect, an amount of multiplication of R.sub.1 is tuned by the selection of the value of R.sub.2.
[0055] A relationship between voltage and currents terminals of VCII+110 is represented as:
where is a current gain and a is a voltage gain.
[0056] The terminal characteristics of the VCII+110 are high impedance at X node (input terminal) and low impedance at Y and Z nodes (output terminals).
[0057] With reference to
[0058] As, i.sub.y=V.sub.s/Z.sub.1, the input impedance is given as:
where, g.sub.m=20I.sub.B is the OTA transconductance and I.sub.B is the OTA bias current.
[0059] From equation (4), the circuit 100 can be used to implement the tunable grounded active inductor and capacitance multiplier as follows:
I. Implementation as the Active Inductor Simulator (AIS)
[0060] If Z.sub.1=R.sub.1, and
the input impedance is given by:
[0061] Equation (5) implements the tunable AIS, and the value of the inductance is controlled using R.sub.1 and I.sub.B.
II. Implementation as the Capacitance Multiplier
[0062] If
and Z.sub.2=R.sub.2, then the input impedance is given by:
[0063] The original capacitance (C.sub.1) is multiplied by (1+20 R.sub.2I.sub.B) and can be tuned using R.sub.2 and I.sub.B.
[0064]
where VCII+ and VCII are identified by + and , respectively (where should be close to 1). For example, a VCII can act as a positive VCII+ and a negative VCII. The function of the VCII is either positive or negative based on whether a current in the X terminal flows in the same direction (positive, VCII+) or in the opposite direction (negative, VCII) with respect to that related to the Y terminal.
[0065] The voltage gain of the voltage buffer 220 is (AV=). In an example, the value of is unity. As the Y terminal has an extremely low input impedance, the Y terminal can be considered as a virtual ground node. The main features of VCII 200 can be summarized as firstly, unlike other active blocks, a current summing operation can be easily performed at the current input low impedance Y port. Secondly, having a low impedance voltage output Z port allows the employment of the VCII 200 in a voltage mode workflow, giving the flexibility to easily perform current mode operations to the designer. Thirdly, positive and negative voltage gains are simply obtained by employing a VCII+ and a VCII, respectively.
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[0067] With reference to
I. Implementation as a Positive Resistance Multiplier
[0068] From Equation 8, if Z.sub.2g.sub.m<1, then Z.sub.1 will be scaled up and if Z.sub.1=R.sub.1 (the resistance to be scaled up), Z.sub.2=R.sub.2, then the input impedance is given by:
[0069] In an aspect, a value of the 20R.sub.2I.sub.B lies between 0 and 1.
II. Implementation as a Negative Resistance Multiplier
[0070] From Equation 8, if Z.sub.2g.sub.m>1, then a negative tunable resistance multiplier is obtained.
[0071] If Z.sub.1=R.sub.1 (the resistance to be scaled up), Z.sub.2=R.sub.2, then the input impedance is given by:
III. Implementation as a Negative Active Inductor Simulator
[0072] If Z.sub.1=R.sub.1 and,
Z.sub.2g.sub.m>1, then a negative active inductor is obtained and is given by:
IV. Implementation as the Negative Capacitance Multiplier
[0073] If
and Z.sub.2=R.sub.2, Z.sub.2g.sub.m>1, then the input impedance is given by:
[0074] The following examples are provided to illustrate further and to facilitate the understanding of the present disclosure.
Experimental Data and Analysis
[0075] First Experiment: Determining the functionality of the tunable grounded positive and negative active inductor simulator and impedance multiplier circuit 100.
[0076] To confirm the functionality of the circuit 100, the active inductor simulator (AIS) and the capacitor multiplier were used in the design of a high pass filter (HPF) and a low pass filter (LPF) respectively. The resistance multiplier was also used in the designing of the HPF.
[0077] Experiments were performed using a multisim professional tool (developed by National Instruments, located at NI. 11500 N Mopac Expwy, Austin, TX 78759-3504, USA). The multisim tool is an industry standard SPICE simulation and circuit design software for analog, digital, and power electronics in education and research. The multisim tool integrates industry standard SPICE simulation with an interactive schematic environment to instantly visualize and analyze electronic circuit behavior. The circuit 100 was experimentally tested by using an AD844 as the VCII+110. The AD844 is fabricated by Analog Devices, located at One Analog Way Wilmington, MA 01887, USA. In an example, an LM13700 is used as OTA 120. The LM13700 is fabricated by Texas Instruments, located at 12500 TI Blvd., Dallas, Texas 75243, USA. In an example, the circuit 100 is powered with V.sub.CC=V.sub.SS=5V.
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[0091] The HPF circuit 410 using AIS was simulated for total harmonic distortion (THD) using different bias currents (For example, I.sub.B=0.2 mA, 1 mA, and 2 mA). The observed THD was 0.484%, 0.019%, and 0.005% respectively which is within the acceptable range. The frequency response was also carried out for the bias current of 0.2 mA.
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[0093] The performance of the present circuit 100 is compared with the existing circuits and is summarized in Table 1. It can be observed from the comparison table that the present circuit 100 is efficient in comparison to all cited existing circuits.
TABLE-US-00001 TABLE 1 Summary of performance comparison No. of Number of passive active elements # of R # of C building Grounded Frequency Impedance/Simulated block (Floating) elements Power Technology range (AIS, R & C Circuits used: (ABB) G(F) G(F) supply m (Hz) multiplier) Conventional 1 VCII 0.9 0.18 (2) 1 1 KHz-10 MHz +AIS only simulated inductor with reduced series resistors using a single VCII+ Conventional 3 CFOA NA NA 2(1) 1(0) 1 Hz-1 MHz +AIS only simulated inductors with reduced parasitic impedance effects Conventional 1 CFOA 15 NA 1(1) 0(1) NA +AIS only lossless and lossy grounded inductor simulators Conventional 2CFOA 5 NA active device based grounded inductor simulator and universal filter Conventional 1 E-VCII 0.3 0.18 0 (1) 80 Hz-40 KHz C extremely multiplier Low power only temperature insensitive electronically tunable VCII- Based Grounded Capacitance Multiplier Conventional 1 INIC, 0.75 0.13 0(2) 1(0) 100 Hz-50 MHz +AIS simulated 1 VNIC grounded inductor based on two NICs, two resistors and a grounded capacitor Conventional 1 MD 0.75 0.13 0(2) 1(0) +AIS Inverting VCC Voltage Buffer Based Lossless Grounded Inductor Simulators Present circuit 1 VCII 5 NA 1(1) 1 100 Hz-10 MHz All 100 and 1 OTA
[0094] The first embodiment is illustrated with respect to
[0095] In an aspect, the OTA 120 is configured to generate an output current I.sub.0. The positive VCII+ input terminal Y is configured to receive an input current I.sub.y, equal to the difference between I.sub.s and I.sub.0. The first output terminal Z is configured to generate a voltage, V.sub.z. The second output terminal X is configured to generate a voltage V.sub.x, across the second impedance Z.sub.2, and a current i.sub.x, through the second impedance Z.sub.2, wherein i.sub.x=I.sub.y and V.sub.z=V.sub.x. The output current I.sub.0 is given by I.sub.o=I.sub.x Z.sub.2 g.sub.m=I.sub.y Z.sub.2 g.sub.m, and a voltage at the positive VCII+ input terminal Y, is given by V.sub.y, where V.sub.y=0.
[0096] In an aspect, the positive OTA input terminal 125 is connected to the first output terminal Z. The negative OTA input terminal 130 is connected to the ground terminal, such that an input impedance Zin, of the VCII+ is given by
where Z.sub.2 g.sub.m is 1.
[0097] In an aspect, a tunable positive active inductor simulator is configured by setting Z.sub.1=R.sub.1, C.sub.1=0, R.sub.2=0 and Z.sub.2=1/sC.sub.2, such that the input impedance is given by
and a value of the inductor, L, is tuned by the selection of the value of C.sub.2 and the value of R.sub.1.
[0098] In an aspect, a tunable positive capacitance multiplier is configured by setting Z.sub.1=1/sC.sub.1, R.sub.1=0, Z.sub.2=R.sub.2, and C.sub.2=0, such that the input impedance is given by
in which the capacitance, C.sub.1, is multiplied by (1+20R.sub.2I.sub.B), and an amount of multiplication of C.sub.1 is tuned by the selection of the value of R.sub.2.
[0099] In an aspect, a tunable positive resistance multiplier is configured by setting Z.sub.1=R.sub.1, C.sub.1=0, Z.sub.2=R.sub.2, C.sub.2=0, such that the input impedance is given by
in which R.sub.1 is multiplied by
where 020R.sub.2I.sub.B<1, and an amount of multiplication of R.sub.1 is tuned by the selection of the value of R.sub.2.
[0100] In an aspect, the positive OTA input terminal 125 is connected to the ground terminal, the negative OTA input terminal 130 is connected to the first output terminal Z, and an input impedance Z.sub.in, of the VCII+ is given by
where Z.sub.2 g.sub.m>1.
[0101] In an aspect, a tunable negative active inductor simulator is configured by setting Z.sub.1=R.sub.1, C.sub.1=0, R.sub.2=0 and Z.sub.2=1/sC.sub.2, such that the input impedance is given by
and a value of the inductor, L, is tuned by the selection of the value of C.sub.2 and the value of R.sub.1.
[0102] In an aspect, a tunable negative active capacitance multiplier is configured by setting Z.sub.1=1/sC.sub.1, R.sub.1=0, Z.sub.2=R.sub.2, and C.sub.2=0, such that the input impedance is given by
in which the capacitance C.sub.1 is multiplied by (20R.sub.2I.sub.B), and an amount of multiplication of C.sub.1 is tuned by the selection of the value of R.sub.2.
[0103] In an aspect, a tunable negative resistance multiplier is configured by setting Z.sub.1=R.sub.1, C.sub.1=0, Z.sub.2=R.sub.2, C.sub.2=0, such that the input impedance is given by
in which R.sub.1 is multiplied by
where 020R.sub.2I.sub.B<1, and an amount of multiplication of R.sub.1 is tuned by the selection of the value of R.sub.2.
[0104] The second embodiment is illustrated with respect to
[0105] The method further includes connecting the positive OTA input terminal 125 to the first output terminal Z, and connecting the negative OTA input terminal 130 to the ground terminal, such that an input impedance, Z.sub.in, of the VCII+ is given by
where Z.sub.2 g.sub.m is 1.
[0106] The method further includes configuring a tunable positive active inductor simulator by setting Z.sub.1=R.sub.1, C.sub.1=0, R.sub.2=0 and Z.sub.2=1/sC.sub.2, such that the input impedance is given by
and tuning a value of the inductor, L, by selecting the value of C.sub.2 and the value of R.sub.1.
[0107] The method further includes configuring a tunable positive capacitance multiplier by setting Z.sub.1=1/sC.sub.1, R.sub.1=0, Z.sub.2=R.sub.2, and C.sub.2=0, such that the input impedance is given by
in which the capacitance, C.sub.1, is multiplied by (1+20 R.sub.2I.sub.B), and tuning an amount of multiplication of C.sub.1 by selecting the value of R.sub.2.
[0108] The method further includes configuring a tunable positive resistance multiplier by setting Z.sub.1=R.sub.1, C.sub.1=0, Z.sub.2=R.sub.2, C.sub.2=0, such that the input impedance is given
in which R.sub.1 is multiplied by
where 020R.sub.2I.sub.B<1, and tuning an amount of multiplication of R.sub.1 by selecting the value of R.sub.2.
[0109] The method further includes connecting the positive OTA input terminal 125 is connected to the ground terminal, connecting the negative OTA input terminal 130 is connected to the first output terminal, Z, such that an input impedance, Z.sub.in, of the VCII+ is given by
where Z.sub.2 g.sub.m>1.
[0110] The method further includes a tunable negative active inductor simulator is configured by setting Z.sub.1=R.sub.1, C.sub.1=0, R.sub.2=0 and Z.sub.2=1/sC.sub.2, such that the input impedance is given by
and a value of the inductor, L, is tuned by the selection of the value of C.sub.2 and the value of R.sub.1.
[0111] The method further includes a tunable negative active capacitance multiplier is configured by setting Z.sub.1=1/sC.sub.1, R.sub.1=0, Z.sub.2=R.sub.2, and C.sub.2=0, such that the input impedance is given by
in which capacitance, C.sub.1, is multiplied by (20R.sub.2I.sub.B), and an amount of multiplication of C.sub.1 is tuned by the selection of the value of R.sub.2.
[0112] The method further includes a tunable negative resistance multiplier is configured by setting Z.sub.1=R.sub.1, C.sub.1=0, Z.sub.2=R.sub.2, C.sub.2=0, such that the input impedance is given
in which R.sub.1 is multiplied by
where 020R.sub.2I.sub.B<1, and an amount of multiplication of R.sub.1 is tuned by the selection of the value of R.sub.2.
[0113] The third embodiment is illustrated with respect to
where Z.sub.2 g.sub.m is 1. The system is configured to implement any one of: a tunable positive active inductor simulator by setting Z.sub.1=R.sub.1, C.sub.1=0, R.sub.2=0 and Z.sub.2=1/sC.sub.2, such that the input impedance is given by
and a value of the inductor, L, is tuned by the selection of the value of C.sub.2 and the value of R.sub.1, a tunable positive capacitance multiplier by setting Z.sub.1=1/sC.sub.1, R.sub.1=0, Z.sub.2=R.sub.2, and C.sub.2=0, such that the input impedance is given by
in which the capacitance, C.sub.1, is multiplied by (1+20R.sub.2I.sub.B), wherein an amount of multiplication of C.sub.1 is tuned by the selection of the value of R.sub.2, and a tunable positive resistance multiplier by setting Z.sub.1=R.sub.1, C.sub.1=0, Z.sub.2=R.sub.2, C.sub.2=0, such that the input impedance is given by
in which R.sub.1 is multiplied by
where 020R.sub.2I.sub.B<1, wherein an amount of multiplication of R.sub.1 is tuned by the selection of the value of R.sub.2; and when the positive OTA input terminal is connected to the ground terminal, the negative OTA input terminal is connected to the first output terminal, Z, such that an input impedance, Z.sub.in, of the VCII+ is given by
where Z.sub.2g.sub.m>1, the system is configured to implement any one of: a tunable negative active inductor simulator by setting Z.sub.1=R.sub.1, C.sub.1=0, R.sub.2=0 and Z.sub.2=1/sC.sub.2, such that the input impedance is given by
wherein a value of the inductor, L, is tuned by the selection of the value of C.sub.2 and the value of R.sub.1, a tunable negative active capacitance multiplier by setting Z.sub.1=1/sC.sub.1, R.sub.1=0, Z.sub.2=R.sub.2, and C.sub.2=0, such that the input impedance is given by
in which the capacitance, C.sub.1, is multiplied by (20R.sub.2I.sub.B), wherein an amount of multiplication of C.sub.1 is tuned by the selection of the value of R.sub.2, and a tunable negative resistance multiplier by setting Z.sub.1=R.sub.1, C.sub.1=0, Z.sub.2=R.sub.2, C.sub.2=0, such that the input impedance is given by
in which R.sub.1 is multiplied by
where 020R.sub.2I.sub.B<1, wherein an amount of multiplication of R.sub.1 is tuned by the selection of the value of R.sub.2.
[0114] Obviously, numerous modifications and variations of the present disclosure are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the disclosure may be practiced otherwise than as specifically described herein.