Břetislav Ševčík

An Example of Easy Synthesis of Active Filter and Oscillator using Signal Flowgraph Modification and Controllable Current Conveyors

An Example of Easy Synthesis of Active Filter and Oscillator using Signal Flowgraph Modification and Controllable Current Conveyors The paper deals with synthesis of active frequency filters and oscillators for applications in the video band. The synthesis is based on the modified signal flow graph design approach in the current mode. The commercially available high frequency current conveyors and second order structures are used. Basic structure is employing loss-less and lossy current mode integrators in two distributed feedback loops. Some of the used active elements allow to control current gain which is very useful in applications. High frequency multi-functional filter and electronically adjustable quadrature oscillator configurations are discussed. Most of the used passive elements (mainly capacitors) are grounded which is suitable for IC implementation. Simulation and experimental results demonstrate function and features very well.

High-speed serial differential signaling links with commercial equalizer

This paper describes an analysis of signal integrity problems in High-Speed serial links that achieves Gbps data rate and has the advantage of low cost. In this paper is implement the high-speed data serial link transceiver with pre-emphasis and commercial equalizer 6.25 Gbps into one complete model that demonstrate impact of pre-emphasis and differential equalization on the quality of received data.

Adaptive time-domain pre-emphasis techniques for high-speed VLSI systems

This paper presents a different approach to the implementation of a transmitter pre-emphasis. The digital transmitter pre-emphasis techniques are commonly based on conventional FIR (Finite Impulse Response) filtering methods which can be insufficient for future sub-micron CMOS design, where the voltage headroom will become lower, and the noise margin will become limiting factor. A very effective time-domain method based on pulse-width modulation is proposed to improve data signal quality of recent high-speed VLSI systems.

Application of pulse-width modulated pre-emphasis in closely-spaced transmission lines with additional discontinuities

Transmitter pre-emphasis techniques to overcome high-slope losses of printed circuit board (PCB) with closely-spaced copper interconnect are presented. The pre-emphasis technique based on pulse-width modulation (PWM) using a timing resolution instead of an amplitude resolution to adjust the filter transfer function is presented. In addition only one coefficient can be used to set the equalizer transfer function depending on channel properties. The standard approaches to transmitter pre-emphasis, receiver equalization and PWM pre-emphasis are compared in advanced PCB backplane models.

Simulation of MTLs via Wendroff method combined with modified nodal analysis

The paper deals with a time-domain simulation of multiconductor transmission lines (MTLs) based on the connection of the implicit Wendroff method and modified nodal analysis (MNA). The work improves the Wendroff-based techniques, with MTLs boundary conditions treated via generalized Thévenin equivalents, and thus enabling to consider simple terminating circuits only. The utilization of the MNA approach ensures a high universality and covers arbitrarily complex systems on principle. The solution of resultant MNA differential algebraic equations (DAEs) is based on the backward Euler technique. All the computer experiments have been performed in the Matlab language environment.

Time-domain pre-emphasis technique based on pulse-width modulation scheme

In this paper, sophisticated pre-distortion techniques based on time-domain resolution are analyzed. In modern CMOS circuits where the maximum voltage swings are pushed below IV it can be an alternative to FIR pre-emphasis which is conventionally used. However additional jitter which is a typical for pre-emphasized data pattern can be a problem. The possible solution is based on using adaptive time-domain pre-emphasis technique where the data-dependent jitter can be eliminated. Describe and implementation of this technique into the accurate model are realized in MathCAD environment and Agilent ADS development studio.