Virote Pirajnanchai

Modification of data transmission filter with Generalized Bessel transformation

This paper present modification of data transmission filter by the application of Generalized Bessel transformations with rational filter. The technique gives the denominator of filter transfer function in analytic closed form, while its numerator is determined by solving a set of transmission zeros and even polynomial of order. The results to filter is straightforward and will be given in a later more detailed contribution together with comparison with the other existing design methods, such a comparison reveals the superiority of the present technique.

Continuous-time low-pass filter using an active distributed mosfet transistor

This paper describes continuous-time low-pass filter using an enhancement MOSFET transistor as a double uniformly distributed RC line (DUE). The proposed circuit configuration consists of a new low-pass active distributed MOSFET filter and one pole gain amplifier. For continuous-time low-pass filter using proposed frequency adjustable type circuit, the experimental result of the frequency characteristics give us a good agreement with theoretical values. The proposed circuit can all used in modem electronic communication systems and most measuring equipments.

An IIR digital video equalizer design with the Bernstein Polynomial and generalized bilinear transformation for gain chrominance distortion

Video equalizer design for compensated the distortion of the chrominance amplitude in color television transmission system is presented. The approximation is based on the Bernstein polynomials and generalized bilinear transformation to obtain the transfer function. This approach has several parameters can be varied satisfying stability conditions. And the advantages of the Bernstein polynomials when compared to the Butterworth, Chebyshev and Thomson polynomials are three parameters available control the amount of phase and magnitude, linear phase, and flexible for variable of phase. Among all referred advantages so that these methodologies were applied in this paper. In addition, the pulse and bar test signal which has been used to measure linear waveform distortion in TV system is special the modulated 20T sine squared pulse with color sub-carrier 4.43 MHz for PAL system. As a result, the proposed digital video equalizer can be enhance and compress the gain chrominance distortion without degraded it phase characteristic.

Wideband CPW-Fed aperture antenna by using a semicircle ring tuning stub

This research paper presents a wideband CPW-Fed aperture antenna. The CPW-Fed is applied on planar semicircular ring tuning stub. The aperture antenna is printed on the same side of a FR4 dielectric substrate. The simulation is performed by using the IE3D program. The simulation results can be proved that bandwidth is within a range of 2.98 – 9.748 GHz. The measured impedance bandwidth is between 3.068 – 10.838 GHz which covers WLAN and WiMAX band. The measured results of resonant frequencies are coincident well with the simulated results. The proposed antenna performs small size, light weight and simple structure. The antenna is applied in wireless communication systems.

Active notch uniformly distributed RC circuit and their application

Many application of the RC parallel-T network, only two performance characteristics are considered important the frequency and depth of the attenuation notch. In this paper the design presented, active notch distributed RC network (URmacrCmacr) circuit from design values. The proposed circuit configuration consists of URmacrCmacr, one external resistor (Rn) or capacitor (Cn) and single gain amplifier. The parameters of the proposed circuit can be adjusted to improve the magnitude response with notch tunable frequency. This structure reduces an amount of circuit complexity and is simple to use for application. The experiments and computer simulation showed good agreement with theoretical values. The active notch URmacrCmacr can application to experiments high frequency active band-pass filter, sinusoidal wave oscillator and frequency discriminator.

Frequency Discriminator Using Double Capacitive Layer Distributed RC Network

The paper describes a frequency discriminator using double capacitive layers uniformly distributed RC network (DURC). The configuration of the circuit consisted of two active DURC notch networks. Herein, the capacitive ratio of the DURC network are used to adjust it steepness of the magnitude slope of a frequency discriminator. It is shown that the output voltage of the circuit has more steepness of slope than does a simple capacitive layer URC. Simulated results of the proposed circuit is investigated.

Bernstein polynomial and rational Bézier curve for blood pressure simulation

This paper presents blood pressure waveform simulation using the Bernstein polynomial model, Bézier-Bernstein model, and Rational Bézier-Bernstein model. All mathematical models can generate the blood pressure waveform which is similar to the normal blood pressure waveform. Moreover, all mathematical models can simulate a normal blood pressure waveform as well. As the results, the Rational Bezier-Bernstein model is a simple form, low order, easy to implement in the microcontroller.

Design and improve the performance of OTA low pass filter with Fractional-order step

This article presents a circuit design to improve the performance of analog filter at high frequency fp = 1 MHz by used the Fractional-order (n + α) step, where n is an original of integer-order in circuit and α is an approximation order step 0 <; α <; 1, The approximation order is designed from the Fractance circuit.This article also presents the approximation function of the Fractional-order Laplacian sα which is designed on the OTA low pass filter circuit. This circuit used single active component. OTA and CFA components are in monolithic chip (IC LT1228). The CFA is designed to work with the Fractional-order elements to feedback control the OTA for relative stability gain of amplifier. The results shown that the improvement by Fractional-order step provides the sustainability of flat passband, reduced the peaking at the cut-off frequency, improved slope of magnitude response of filter and result comparable with high-order filters.

Printed circuit antenna for UWB systems

A printed-circuit antenna for UWB systems is presented. The antenna consists of a rectangular slot etched out from the ground plane of a RT/Duroid 5880 (dielectric constant = 2.2) and a CPW-fed bowtie stub for excitation. The antenna is successfully designed, implemented and measured. A compact antenna area of 31.8 times 34.2 mm2 is obtained. The proposed antenna in this study is capable of measured a very wide operating bandwidth approximately 2.93-11.97 GHz.

Equalization of the Distorted Chrominance Signal using IIR Digital Filter with the Bernstein Filter

In this paper, we present the use of the Bernstein polynomials to obtain an IIR digital filter transfer function, which can be applied to video equalizer for compensating the amplitude of chrominance signal in color television. In addition, experimental results are carried out by using the modulated 20T sine squared signal on the color sub carrier 4.43 MHz. It is shown here that the proposed equalizer can either enhance or compress the chrominance signal in color television transmission.