The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
This paper proposes a novel structure of wavelength selective optical switches based on MMI assisted microring resonators. The analysis and design are based on the scattering matrix theory. The device has been designed on Silicon on Insulator technology. The device parameters are then considered and optimized to obtain the best performance with a high FSR and a low switching power.
This paper proposes a novel structure of wavelength selective optical switches based on MMI assisted microring resonators. The analysis and design are based on the scattering matrix theory. The device has been designed on Silicon on Insulator technology. The device parameters are then considered and optimized to obtain the best performance with a high FSR and a low switching power.
This paper presents the dual frequency for broad- beam microstrip reflectarray which is duplicated the same radiating aperture as parabolic backscatter. A reflectarray with two stacked arrays of variable element sizes has been designed at 5.8 and 10 GHz. The proposed antenna has good gain and its HPBW can meet the target area to be covered (plusmn65deg).
This paper presented the effects of attenuation from rain rate together with rain drop size distribution analysis on the model of transmitter broadband satellite in Ka-band frequency. We illustrated a new model by simulating transmission broadband signal and studied the rain attenuation which has effects to high frequency. The results of the model were represented by the relation between error probability...
In this paper, the regression models of ultra wideband (UWB) ground reflection path loss are proposed. The UWB ground reflection path loss is defined as the ratio between the maximum amplitude of the transmitted and received signal waveforms. The polarizations of transmitted signal and ground characteristics are considered. The double and triple linear regression models are derived from the closed...
An ultra wideband impulse radio (UWB-IR) is applied for short-range system such as wireless personal area network (WPAN) in office and home network. The characteristics of transmission signal are very complicated and difficult to predict. Therefore, the performances of transmission gain should be considered. In this paper, an experimental study of transmission loss for UWB-IR is presented. We discuss...
Dog breed classification or identification is important for dog training, and curing. The conventional identification method is based on experts which is hard to find. This paper proposes a method to classify dog breed based on the dog face images. The proposed method is based on the coarse to fine concept, where the template matching technique is applied for coarsely classifying the images into 5...
This paper presents the Thai syllable segmentation of human speech algorithm using the 1-D stationary wavelet transform (SWT). The detail coefficient component of SWT, which represents the high frequency part of input signal, is used to analyze the boundaries of syllables. Our proposed approach, the input signals are separated into two parts. First part, the data of signal is used to find the boundaries...
This paper proposes a fingerprint features extraction method using curve-scanned DCT coefficients. Generally, the fingerprint features contained in a fingerprint image, such as ridge line patterns and minutiae point, can be extracted from the DCT domain, and used for fingerprint matching. By considering the oscillate pattern contained in the top-left corner of DCT coefficients, we can divide those...
Based on the medical image detection after segmentation, the features from each domain such as spatial, texture, spectral domain have been extracted for detection. With no regard to other unknown features, these features are sometime redundant. This paper proposes a factor analysis for a reduction features procedure and constructs ways to fulfill good detection by using an optimal features set.
There has been several research on car license plate recognition (LPR). However, the number of research on Thai LPR is limited, besides, most of which are published in Thai. The existing work on Thai LPR have faced problems caused by low- quality license plates and a great number of similar characters that exist in Thai alphabets. Generally, car license plates in Thailand come in different conditions,...
An implementation of a Chua's chaotic oscillator is proposed based on a coarsely cubic-like CMOS resistor. A simple current mirror and a single-ended differential pair form a grounded nonlinear CMOS resistor. Such nonlinearity resembles a coarse version of cubic-like voltage-current characteristics. Simulated trajectories of the single-scroll and the double-scroll chaotic attractors are demonstrated.
A 10.7-MHz fully balanced, high-Q, wide-dynamic-range current-tunable bandpass filter is presented. The technique is relatively simple based on three fully balanced components, i.e. an adder, a low-Q-based bandpass filter and a differential amplifier. The high-Q factor is possible through a tunable bias current. As a simple example at 10.7 MHz, the paper demonstrates the high-Q factor of 267, the...
A gigahertz wideband analog multiplier is proposed. The multiplier based on the MOS cascade operation circuit. The inputs are in voltage mode and become in current mode after multiplication. The result shows that the multiplier can be applied for UWB communications. The circuit is based on 0.18 mum CMOS technology simulated using HSPICE with level 49.
Single-stage operational transconductance amplifier is proposed for OTA-RC filter design. The concept is developed from a resistive source-degeneration long-tail pair where large transconductance is obtained by utilising negative resistance as a degeneration resistor. Such single-stage structure poses obvious advantage in consuming small current consumption compared to conventional two-stage OTA....
In this paper, a design of pass-pipelined architecture for context modeling implemented on FPGA is proposed. The architecture is separated into 4 pipelined stages. As a result, the processing time and the critical path delay can be reduced while the multiple symbol context pairs are allowed to be generated simultaneously. Moreover, dual memories and data multiplexer are employed in order to accelerate...
This paper investigates IQ cross-talk estimation and correction in a direct-conversion receiver for terrestrial digital video broadcasting (DVB-T). The cross-talk introduced by gain and phase imbalances are estimated using pilot signals. A way of correcting the IQ cross-talk in the presence of residual frequency offset is presented. It is shown that the bit error rate requirements for a DVB-T receiver...
Viterbi algorithm is the basic technique for space- time trellis codes (STTC) decoding. The received information affected by the channel impairments can be corrected by the path record determined by accumulating the branch metrics in the state transitions. However, the computation complexity of the branch metric accumulation in STTC Viterbi decoding is extremely high in spite of the well error-correction...
The commercial application of the wireless metropolitan area networks(WMANs) is getting popular worldwide such as the launch of WiBRO and WiMax systems. Quality service in wireless, high-speed data, and multimedia communication for such wider range transmissions has also received much attention. In this paper, we demonstrate how the binary Gray codes can be rearranged to match with the QAM schemes...
An algorithm of interference suppression for the Very High Frequency (VHF) air-ground communication in civil aviation is presented in this paper. Based on the analysis of the civil aviation VHF air-ground communication characteristics, the blind signal extraction (BSE) model for the civil aviation VHF air-ground communication is established, and the interference suppression scheme is proposed. The...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.