Gabor Csipkes

An OTA-C field programmable analog array for multi-mode filtering applications

This paper presents a reconfigurable analog array and its possible application in multi mode wireless communication equipments. The array is built around configurable analog blocks comprised of linearized, fully differential transconductance amplifiers. The circuit sacrifices a degree of generality in favor of specialized filtering operations at high frequencies, low consumption and good linearity, all required in modern communication devices. The programming of the filter frequency parameters is achieved through binary weighted transconductor arrays and a capacitance scaling circuit. The proposed analog array has been simulated at transistor level by using the Eldo simulation engine on a 90nm digital CMOS process.

On the Design of a Reconfigurable OTA-C Filter for Software Radio

This paper presents a novel approach in the design of integrated reconfigurable and programmable analog filters for commercial mobile applications. The method is described in the specific context of an analog filter which is capable of operating in both the complex and real domains; the filter is designed using the OTA-C technique, features a programmable order and transfer function and is envisioned as part of a combined low- IF/zero-IF receiver architecture for a software defined radio transceiver. The novel method is demonstrated by presenting the simulation results of the real low- pass/complex band-pass filter for a 0.5 dB Chebyshev approximation.

A Reconfigurable and Programmable Filter for Software Defined Radio Based on a Transconductor-Capacitor Analog Array

This paper presents a reconfigurable and programmable analog array intended to support the implementation of the filter stage in a software defined radio (SDR) wireless transceiver. The analog array is designed using the transconductor-capacitor (Gm-C) technique and may implement a wide variety of analog filters of programmable order and transfer function. The filtering stage implemented by the analog array is envisioned as part of a combined low-IF/zero-IF receiver architecture for an SDR transceiver. A modular method of synthesizing various order state-variable filters is used as tool for demonstrating the capabilities of the analog array. Different filters have been modeled, in both the complex and real domains, to demonstrate the capability of the analog array.

An evolutionary approach to design and calibration of reconfigurable OTA-C filters

Latest trends in communication and consumer electronics target the development of fully adaptive systems on mixed signal systems-on-chip. This paper proposes an evolutionary approach to adaptive filter design. The hardware support of the evolutionary design algorithm is a field programmable analog array (FPAA). The FPAA has been implemented with OTA-C techniques. The synthesis algorithm has been developed considering the particularities of the proposed FPAA and of the supported filter structures. Topological reconfiguration is performed with a lookup table, parametric design is performed with evolutionary computation methods and wide-band self-calibration is achieved by means of a phase locked loop. The filter sizing algorithm is suitable for both intrinsic or extrinsic evolution and has the potential to be hard-wired in dedicated digital circuitry. Extensive transistor level simulations performed on the evolved adaptive filters prove the functionality of the proposed software and the underlying circuitry.

Machine Vision Application to the Detection of Micro-organism in Drinking Water

The work presented in this paper uses a novel Machine Vision application to detect and identify micro-organism oocysts on drinking water. This new concept of water borne micro-organism detection uses image processing to allow detailed inspection of parasite morphology to nanometre dimensions. The detection results are more reliable than existing manual methods. Combining Normarski Differential Interface Contrast (DIC) and fluorescence microscopy using Fluorescein Isothiocyanate (FITC) and UV filters, the system provides a reliable detection of micro-organisms with a considerable reduction in time, cost and subjectivity over the current labour intensive time consuming manual method.

Improving the beam quality in LMA fibers

The paper presents the results concerning with beam quality improvement by concurrently modifying the index and the doping profile in LMA fibers. Further, the mode effective area is maximized by providing a passive ring in the cladding. The influence of the index profile over the distribution of the optical power among various modes is presented. The aim is to favor the fundamental mode by concurrently rejecting the higher modes, i.e. generating a quality beam. Simulation results and manufacturers tests led to a novel design which consists in providing a passive ring in the cladding. That was of great help in rejecting the higher-order modes, and it can be applied to a large range of LMA fibers. The cladding ring procedure is of interest for Liekki, and it is very likely that it would be put into production.

Machine vision application to the detection of water-borne micro-organisms

The work presented in this paper uses a novel Machine Vision application to detect and identify micro-organism oocysts on drinking water. This new concept of water borne micro-organism detection uses image processing to allow detailed inspection of parasite morphology to nanometre dimensions. The detection results are more reliable than existing manual methods. The machine vision proposed provides a 100% detection of cryptosporidium micro-organism as test case. Combining Normarski Differential Interface Contrast (DIC) and fluorescence microscopy using Fluorescein Isothiocyanate (FITC) and UV filters, the system provides a reliable detection of micro-organisms with a considerable reduction in time, cost and subjectivity over the current labour intensive time consuming manual method.

A variable topology analog filter suitable for multi-mode wireless applications

A reconfigurable channel or band-select filter is one of the key elements of multi-mode analog front ends. This paper presents the system level aspects of a fully reconfigurable analog filter. The proposed circuit is based on analog array-like architecture that enables the mapping of low pass and polyphase band pass filters on a regular structure of reconfigurable unit elements. The current conveyor based topology represents a compromise between the generality of traditional field programmable analog arrays and the highly specialized requirements imposed by multi-mode wireless receiver architectures.

Digitally controlled current-mode quadrature oscillator

A digitally controlled current-mode quadrature oscillator (DCC-MQO) is proposed. The circuit consist of four cascaded log-domain first order low-pass filter and a digitally programmable current division network. The lossy log-domain integrator gain and time constant can be adjusted using the bias currents of the logarithmic and exponential building blocks. The programmable current division network provides the bias currents for the log-domain cells which can be adjusted using a digital control word. The building blocks were implemented in a generic 180nm BiCMOS process and Spice simulation were performed to demonstrate de viability of the design.

Machine vision applied to highly variable objects

The work presented in this paper addresses Machine Vision (MV) applications to objects of ill defined shape, size, colour or texture. Development of Machine Vision through the years from its origin in the 1950s to date is analysed and their progress and trends are discussed. The paper concentrate in the small number of MV applications to object of high variability, it discusses and present solutions to main problems associated with the MV application to this type of objects. The problem of autofocus and problems associated with changes in illumination are discussed in details and solutions presented. The paper present and discuss general software architecture for MV applications. Two examples of this type of applications are presented: detection of microorganism in water and detection of suspicious activity in humans.