A Low-Voltage Electronically Tunable MOSFET-C Voltage-Mode First-Order All-Pass Filter Design

This paper presents a simple electronically tunable voltage-mode first-order all-pass filter realization with MOSFET-C technique. In comparison to the classical MOSFET-C filter circuits that employ active elements including large number of transistors the proposed circuit is only composed of a single two n-channel MOSFET-based inverting voltage buffer, three passive components, and one NMOS-based voltage-controlled resistor, which is with advantage used to electronically control the pole frequency of the filter in range 103 kHz to 18.3 MHz. The proposed filter is also very suitable for low-voltage operation, since between its supply rails it uses only two MOSFETs. In the paper the effect of load is investigated. In addition, in order to suppress the effect of non-zero output resistance of the inverting voltage buffer, two compensation techniques are also introduced. The theoretical results are verified by SPICE simulations using PTM 90 nm level-7 CMOS process BSIM3v3 parameters, where +/- 0.45 V supply voltages are used. Moreover, the behavior of the proposed filter was also experimentally measured using readily available array transistors CD4007UB by Texas Instruments

DCCII-Based Novel Lossless Grounded Inductance Simulators With No Element Matching Constrains

In 1996, the differential current conveyor (DCCII) was introduced as a versatile active element with current differencing capability. Therefore, in this study, the usefulness of the DCCII is shown on six novel lossless grounded inductance simulator circuits. Proposed circuits simultaneously employ minimum number of elements, i.e. single DCCII, one capacitor, and two resistors. No passive element matching restriction is needed and all solutions are electronically tunable in case that one of resistors is replaced by MOSFET-based voltage-controlled resistor. The internal structure of the active element has been implemented using the TSMC 0.25 um SCN025 CMOS process BSIM3v3.1 parameters. Firstly, the performance of the selected inductor simulator is evaluated and subsequently verified in the design of 5th-order high-pass ladder and 2nd-order frequency filters. In addition, experimental results using commercially available AD844/ADs are given to verify the theoretical analysis and SPICE simulations

Current and Voltage Mode Multiphase Sinusoidal Oscillators Using CBTAs

Current-mode (CM) and voltage-mode (VM) multiphase sinusoidal oscillator (MSO) structures using current backward transconductance amplifier (CBTA) are proposed. The proposed oscillators can generate n current or voltage signals (n being even or odd) equally spaced in phase. n+1 CBTAs, n grounded capacitors and a grounded resistor are used for nth-state oscillator. The oscillation frequency can be independently controlled through transconductance (gm) of the CBTAs which are adjustable via their bias currents. The effects caused by the non-ideality of the CBTA on the oscillation frequency and condition have been analyzed. The performance of the proposed circuits is demonstrated on third-stage and fifth-stage MSOs by using PSPICE simulations based on the 0.25 µm TSMC level-7 CMOS technology parameters

Novel Floating General Element Simulators Using CBTA

In this study, a novel floating frequency dependent negative resistor (FDNR), floating inductor, floating capacitor and floating resistor simulator circuit employing two CBTAs and three passive components is proposed. The presented circuit can realize floating FDNR, inductor, capacitor or resistor depending on the passive component selection. Since the passive elements are all grounded, this circuit is suitable for fully integrated circuit design. The circuit does not require any component matching conditions, and it has a good sensitivity performance with respect to tracking errors. Moreover, the proposed FDNR, inductance, capacitor and resistor simulator can be tuned electronically by changing the biasing current of the CBTA or can be controlled through the grounded resistor or capacitor. The high-order frequency dependent element simulator circuit is also presented. Depending on the passive component selection, it realizes high-order floating circuit defining as V(s) = snAI(s) or V(s) = s-nBI(s). The proposed floating FDNR simulator circuit and floating high-order frequency dependent element simulator circuit are demonstrated by using PSPICE simulation for 0.25 μm, level 7, TSMC CMOS technology parameters

Lossy/Lossless Floating/Grounded Inductance Simulation Using One DDCC

In this work, we present new topologies for realizing one lossless grounded inductor and two floating, one lossless and one lossy, inductors employing a single differential difference current conveyor (DDCC) and a minimum number of passive components, two resistors, and one grounded capacitor. The floating inductors are based on ordinary dual-output differential difference current conveyor (DO-DDCC) while the grounded lossless inductor is based one a modified dual-output differential difference current conveyor (MDO-DDCC). The proposed lossless floating inductor is obtained from the lossy one by employing a negative impedance converter (NIC). The non-ideality effects of the active element on the simulated inductors are investigated. To demonstrate the performance of the proposed grounded inductance simulator as an example, it is used to construct a parallel resonant circuit. SPICE simulation results are given to confirm the theoretical analysis

Realization of Resistorless Lossless Positive and Negative Grounded Inductor Simulators Using Single ZC-CCCITA

This paper is in continuation with the very recent work of Prasad et al. [14], wherein new realizations of grounded and floating positive inductor simulator using current differencing transconductance amplifier (CDTA) are reported. The focus of the paper is to provide alternate realizations of lossless, both positive and negative inductor simulators (PIS and NIS) in grounded form using z-copy current-controlled current inverting transconductance amplifier (ZC-CCCITA), which can be considered as a derivative of CDTA, wherein the current differencing unit (CDU) is reduced to a current-controlled current inverting unit. We demonstrate that only a single ZC-CCCITA and one grounded capacitor are sufficient to realize grounded lossless PIS or NIS. The proposed circuits are resistorless whose parameters can be controlled through the bias currents. The workability of the proposed PIS is validated by SPICE simulations on three RLC prototypes

Study of Adjustable Gains for Control of Oscillation Frequency and Oscillation Condition in 3R-2C Oscillator

An idea of adjustable gain in order to obtain controllable features is very useful for design of tuneable oscillators. Several active elements with adjustable properties (current and voltage gain) are discussed in this paper. Three modified oscillator conceptions that are quite simple, directly electronically adjustable, providing independent control of oscillation condition and frequency were designed. Positive and negative aspects of presented method of control are discussed. Expected assumptions of adjustability are verified experimentally on one of the presented solution

Supplementary First-Order All-Pass Filters with Two Grounded Passive Elements Using FDCCII

In this study, two novel first-order all-pass filters are proposed using only one grounded resistor and one grounded capacitor along with a fully differential current conveyor (FDCCII). There is no element-matching restriction. The presented all-pass filter circuits can be made electronically tunable due to the electronic resistors. Furthermore, the presented circuits enjoy high-input impedance for easy cascadability. The theoretical results are verified with SPICE simulations

Guest editorial: special issue on signal processing

It affords us great pleasure to introduce you to a collection of the best 10 invited papers focusing on different areas of signal processing that were originally mainly submitted by young scientists and Ph.D. students and, on a limited scale, presented at the 2011 34th International Conference on Telecommunications and Signal Processing (TSP) held on 18-20 August, 2011, in Budapest, Hungary. Here you can find their extended versions, in which the authors present their research results in more depth and detail. [...