Ivo Lattenberg

The conception of differential-input buffered and transconductance amplifier (DBTA) and its application

In this paper, a novel versatile active building block the differential-input buffered and transconductance amplifier (DBTA) is proposed. The application of the newly defined active function block is shown on the design of voltage-mode (VM), multi-input and single-output (MISO)-type multifunction biquad, employing single DBTA and five passive elements. Proposed VM filter structure can realize four filter functions i.e., low- (LP), band- (BP), high-pass (HP) and band-stop (BS) without changing the circuit topology and enables independent control of the quality factor Q using single passive element. Theoretical results are verified by PSPICE simulations using a BJT realization of DBTA.

New voltage-mode universal filter and sinusoidal oscillator using only single DBTA

In this article, a new voltage-mode second-order universal frequency filter and sinusoidal oscillator using only single differential-input buffered and transconductance amplifier (DBTA) is presented. The proposed voltage-mode filter structure using single DBTA and four passive elements can provide all standard filter functions, i.e. low-, band-, high-pass, band-stop, and all-pass without changing the circuit topology and enables independent control of the quality factor Q using single passive element. The circuit requires the minimal number of active and passive elements with no conditions for component matching. By slight modification of the proposed filter structure, the new DBTA-based sinusoidal oscillator is easily obtained. The oscillation condition and the oscillation frequency are independently adjustable by different virtually grounded passive elements. The proposed sinusoidal oscillator employs only grounded capacitors. The passive and active sensitivities of all the proposed circuit configurations are low. PSPICE simulations using a BJT realisation of DBTA and experimental results based on commercially available amplifiers OPA860 and MAX436 are included, which prove the workability of the proposed circuits.

Bipolar CCIII+ and CCIII- conveyors and their current mode-filter application

The internal bipolar structure of the third-generation current conveyor and the multifunctional filter with CCIII in the current mode are presented. Some results of PSpice simulation on the CCIII+ and CCIII- presented and of a simulation on a filter with CCIII are included.

Filters with Current Amplifiers for High-speed Communication

The paper deals with the novel filtration techniques for analog high-speed data signal preprocessing working on the base of a pure current mode filters. Because of better current-mode properties and frequency features, and due to the tendency to lower supply voltages, which is given by the possibilities of the technology used, where the dynamic range in the voltage area goes down due to the use of the voltage mode, a fast development in the field of current-mode application design can be witnessed. The paper shows possibilities of current-mode filter realizations using only current amplifiers. The paper shows also various possibilities of current amplifier realization such as basic building blocks for circuits working in the current-mode. Current amplifier realization possibilities are presented using both the existing elements, e.g. current conveyors and OTA elements, and those based on the transistor level. The currentmode filter with only current amplifier, without any active element with voltage terminal is designed.

Signal processing for high-speed data communication using pure current mode filters

The paper deals with the novel filtration techniques for analog high-speed data signal preprocessing working on the base of a pure current mode filters. The paper describes a novel structure of the universal multifunction filter working in the pure current mode. Due to better frequency features of the current mode and a tendency to reduce the supply voltage because of the technology used (where in the voltage mode the dynamic range goes down in the voltage domain), we decided to design a universal filter working in exactly the pure current mode. It is a circuit where the active elements are only the current-controlled current sources. The current buffer with one input and one positive and one negative output appears to be the optimum element. The bipolar structure of such a current buffer is designed and the basic simulations are carried out.

Low Input-Impedance Current-Mirror for High-Speed Data Communication

The paper deals with a novel low input impedance current mirror for analog high-speed data signal preprocessing as the basic building block of pure current mode filters. The principle of reducing the input impedance of current mirror is shown. A comparison of the features of the proposed current mirror with low input impedance and the other types of current mirror using both the symbolic and the numerical method is performed.

Filters Eliminating Input Impedance of Input Current Terminal for High-Speed Analog Signal Processing

The paper describes a field of filters for high-speed analog signal processing, whose transfer function is affected by the existence of real input impedances of current active elements. The influence of this input impedance is analyzed in detail. This is indicated by both the additive error and the multiplicative error. Novel filter circuits, which partially eliminate the influence of this input impedance, are designed.

Novel filter design using synthetic elements with immittance converters

The principles of the design of filters with a synthetic element of higher-order immittance function are given. Also, the design of a higher-order synthetic immittance element with gyrator is described. The block diagram of a gyrator with higher-order gyration admittance is shown. Lowpass, bandpass, highpass and notch filters with gyrators with higher-order gyration admittance are designed. PSpice simulation of the second-order Butterworth filters is included.

Conveyor-based Cauer filters

The paper deals with continuous-time active RC biquadratic filters with transmission zeros, based on difference voltage current conveyors (DVCC) and theirs application in Cauer filters. These sharp filters are very suitable for high frequency (MHz) applications.

Novel immitance inverters

The design procedure of general immittance inverters is described. Three types of such an inverter were derived using general current or general voltage conveyors. Realizations of grounded inductors employing DVCC (differential-voltage current conveyor) elements and their simulated frequency characteristics are shown.