Showing papers in "IEICE Electronics Express in 2004"
TL;DR: An improved method for binarizing document images by adaptively exploiting the local image contrast is proposed, which aims to overcome the common problems encountered in low quality images, such as uneven illumination, low contrast, and random noise.
Abstract: We propose in this paper an improved method for binarizing document images by adaptively exploiting the local image contrast. The proposed method aims to overcome the common problems encountered in low quality images, such as uneven illumination, low contrast, and random noise. Experiments have been conducted and the results are presented to show the effectiveness of the proposed method.
88 citations
TL;DR: This paper can obtain optical frequency shift using the singnal-sideband modulator consisting of four optical phase modulators, where the frequency shift is precisely equal to that of an rf-signal fed to the modulator.
Abstract: This paper describes optical frequency comb generation using optical single-sideband modulation technique. We can obtain optical frequency shift using the singnal-sideband modulator consisting of four optical phase modulators, where the frequency shift is precisely equal to that of an rf-signal fed to the modulator. A series of optical spectral components can be generated by using an optical fiber loop having an optical single-sideband modulator.
79 citations
TL;DR: The demonstration of 11dB fiber-to-fiber optical gain in a silicon Raman amplifier is reported, employed to reduce the TPA induced free carrier losses resulting in net signal amplification.
Abstract: We report the demonstration of 11dB fiber-to-fiber optical gain in a silicon Raman amplifier. Pulsed pumping is employed to reduce the TPA induced free carrier losses resulting in net signal amplification. The influence of free carriers is elucidated by observing the dependence of gain on pulse energy.
75 citations
TL;DR: The extension of the Friis' transmission formula for the link budget estimation of UWB radio, considering the transmit signal waveform and the imperfect antennas gives the upper bound of the transmission gain, irrespective of the waveform distortion due to the frequency response of the antenna.
Abstract: The ultra wideband (UWB) radio has been a promising technology for the short range wireless systems. The frequency-dependent behavior of the antennas are not negligible in UWB systems, especially in the impulse radio (IR).This letter presents the extension of the Friis' transmission formula for the link budget estimation of UWB radio, considering the transmit signal waveform and the imperfect antennas. The results presented here give the upper bound of the transmission gain, irrespective of the waveform distortion due to the frequency response of the antenna.
48 citations
TL;DR: Experimental results of a test chip prototype in 0.5-µm CMOS technology are presented that verify the proposed technique and suggest simple schemes to generate the gate control voltages for the MOS transistors implementing large resistors so that they remain in high resistive state with large signal variations.
Abstract: The implementation of large-valued floating resistive elements using MOS transistors in subthreshold region is addressed. The application of these elements to bias wideband AC coupled amplifiers is discussed. Simple schemes to generate the gate control voltages for the MOS transistors implementing large resistors so that they remain in high resistive state with large signal variations are discussed. Experimental results of a test chip prototype in 0.5-µm CMOS technology are presented that verify the proposed technique.
47 citations
TL;DR: A novel electronically-controllable universal current-mode biquad realisable with only three multiple-output second generation Current-Controlled Conveyors (CCCII), two grounded capacitors and one grounded resistor is presented.
Abstract: A novel electronically-controllable universal current-mode biquad realisable with only three multiple-output second generation Current-Controlled Conveyors (CCCII), two grounded capacitors and one grounded resistor (which can also be implemented electronically) is presented which offers a number of advantageous features, not available simultaneously in any of the previously known electronically-controllable single-input-multiple-output type CM universal CCCII-based biquads. The proposed circuit is eminently suitable for implementation in both bipolar and CMOS/BiCMOS technologies. The workability of the new biquad configuration has been demonstrated by SPICE simulation results.
39 citations
TL;DR: The experimental results show that the device can operate at 450°C, which is impossible for conventional Si devices, but the current capability of the SiC JFET diminishes with rising temperatures, and the saturation current becomes 20% at450°C with respect to the value at the room temperature.
Abstract: This paper reports on the measured dc characteristics of a SiC JFET device from room temperature up to 450°C in order to evaluate the device's capability for high-temperature operation. The authors packaged SiC JFET bare die into a dedicated high-temperature package to be able to perform experiments under extremely high ambient temperatures. The experimental results show that the device can operate at 450°C, which is impossible for conventional Si devices, but the current capability of the SiC JFET diminishes with rising temperatures. For example, the saturation current becomes 20% at 450°C with respect to the value at the room temperature.
27 citations
TL;DR: The paper demonstrates how to three-dimensionally synthesize such a scene as an array of computer-generated characters moving around a standing person in real time.
Abstract: We have developed a system of compositing three-dimensional (3D) video images based on the depth information of the objects. The system consists of the Axi-Vision Camera that can measure object distance in real time and an arithmetic image processor that can synthesize video images according to the depth information. The paper demonstrates how to three-dimensionally synthesize such a scene as an array of computer-generated characters moving around a standing person in real time. The feasibility of using such a signal processor to create realistic TV programs in a broadcasting station has been studied.
24 citations
TL;DR: Two novel configurations of second-order sinusoidal oscillators have been presented which employ only unity-gain voltage followers and current followers as active elements.
Abstract: Two novel configurations of second-order sinusoidal oscillators have been presented which employ only unity-gain voltage followers and current followers as active elements. The workability of the new circuits has been demonstrated by the SPICE simulations of their CMOS-implementable versions.
21 citations
TL;DR: A novel family of SRCOs has been presented which employ a reduced number of (only two) unity-gain cells as active elements, confirmed by the SPICE simulations of their CMOS-implementable versions.
Abstract: Recently, the authors introduced two new second-order single-resistance-controlled oscillators (SRCO) employing four/three unity-gain cells (unity-gain voltage followers and unity-gain current followers). In this communication, a novel family of SRCOs has been presented which employ a reduced number of (only two) unity-gain cells as active elements. The workability of the new circuits has been confirmed by the SPICE simulations of their CMOS-implementable versions.
20 citations
TL;DR: A new approach of reference point localization is based on so-called identification masks which have been composed on the basis of analysis of biometric characteristic of human finger, which shows that it locates a unique reference point with high accuracy for all types of fingerprints.
Abstract: Fingerprint matching is one of the most important problems in Fingerprint Identification System (AFIS). In this paper a new method of the reference point alignment has been presented. A new approach of reference point localization is based on so-called identification masks which have been composed on the basis of analysis of biometric characteristic of human finger. Construction of such masks has been presented.Experiments show that our approach locates a unique reference point with high accuracy for all types of fingerprints. Generally, fingerprint matching consists with three steps: core (reference) point detection, filter the image using a bank Gabor filters, and comparison with imprint pattern. It seems, that today, the Gabor filtering gives the best results in fingerprint recognition. The proposed method was evaluated and tested on various fingerprint images, included in the FVC2000 fingerprint database. Performed results with representative investigations have been compared.
TL;DR: The purpose of this paper is to propose a new dividing method which consists of a reciprocal and the best multiplication and the performances of the new method and the conventional method are compared.
Abstract: Affine arithmetic (AA) is a variant of interval arithmetic. In AA, it is difficult to realize the efficient nonlinear binomial operations. The purpose of this paper is to propose a new dividing method which consists of a reciprocal and the best multiplication. And the performances of the new method and the conventional method are compared through some numerical examples.
TL;DR: It is predicted that a 3 dB-modulation bandwidth can be increased by 50% with optimizing an external cavity length, and better eye opening can be expected in 40Gbps direct modulation.
Abstract: We propose a monolithic external-cavity vertical-cavity surface emitting laser (VCSEL) for achieving ultra-high speed direct modulation beyond the limit of a relaxation oscillation frequency. We present the modeling of small-signal and large signal modulation characteristics of VCSELs with optical feedback. It is predicted that a 3 dB-modulation bandwidth can be increased by 50% with optimizing an external cavity length. Also, better eye opening can be expected in 40Gbps direct modulation.
TL;DR: A special CMOS circuit for reaction-diffusion computers that accepts optical inputs in parallel and generates excitable spatial waves on a chip surface is designed and demonstrated by fabricated LSIs.
Abstract: We designed a special CMOS circuit for reaction-diffusion computers that accepts optical inputs in parallel and generates excitable spatial waves on a chip surface. We demonstrated the spatiotemporal properties of the proposed circuits by fabricated LSIs.
TL;DR: This work proposes and demonstrates the Coherent Optical Multiple-Input Multiple-Output (COMIMO) communication technique, which exploits the modal diversity, inherent in a multi-mode fiber, to transmit independent data channels through a single fiber without the need for wavelength division multiplexing.
Abstract: We propose and demonstrate the Coherent Optical Multiple-Input Multiple-Output (COMIMO) communication technique. In analogy to the spatial diversity in wireless communication, the concept exploits the modal diversity, inherent in a multi-mode fiber (MMF), to transmit independent data channels through a single fiber without the need for wavelength division multiplexing. Central to the MIMO concept is the requirement for sufficient modal diversity in the fiber. The coherent-optics implementation is the key as it ensures that the diversity requirement is met for practically any fiber length and at any data rate. A 2x2 proof-of-concept COMIMO system is experimentally demonstrated.
TL;DR: An alternative formulation for a frequency dependent (FD) ADI-FDTD method is proposed, based on an electric flux field D tridiagonal matrix rather than an electric field matrix, which shows that the accuracy of the method is unaffected by the inclusion of frequency dependency in the model.
Abstract: An alternative formulation for a frequency dependent (FD) ADI-FDTD method is proposed, based on an electric flux field D tridiagonal matrix rather than an electric field matrix. The procedure for D source excitation is explained. Results show that the accuracy of the method is unaffected by the inclusion of frequency dependency in the model, compared with FD-FDTD.
TL;DR: SIASCA includes schematic capture of a more general class of analog circuits, namely: operational transconductance amplifiers and current conveyors, which demonstrates the suitability and usefulness of SIASCA to be used within ADA environments.
Abstract: To improve analog design automation (ADA) of electronic circuits, an interactive system for symbolic analysis called SIASCA is introduced. SIASCA includes schematic capture of a more general class of analog circuits, namely: operational transconductance amplifiers and current conveyors. The options of analysis are focused on calculating simplified symbolic expressions (SEs), representing the dominant behavior of a circuit, for AC and noise analysis. To minimize complexity in manipulating SEs, all active devices are modeled at different levels of abstraction by using nullors. Several examples demonstrate the suitability and usefulness of SIASCA to be used within ADA environments.
TL;DR: A new double Hadamard coding scheme is demonstrated to enable both chip-level timing coordination and full interference suppression without the need for synchronous detection.
Abstract: We demonstrate a multi-user, 10Gb/s spectrally phase coded O-CDMA system with hybrid chip and slot-level timing coordination utilizing low power nonlinear processing. A new double Hadamard coding scheme is demonstrated to enable both chip-level timing coordination and full interference suppression without the need for synchronous detection.
TL;DR: A silicon Raman laser is demonstrated and observation of simultaneous lasing at 1675nm and parametric Raman emission at 1540nm is reported, with a threshold at 9W peak pulse power.
Abstract: We demonstrate a silicon Raman laser and report observation of simultaneous lasing at 1675nm and parametric Raman emission at 1540nm. The laser is pumped with 1540nm pulses and has a threshold at 9W peak pulse power.
TL;DR: In this study, pseudo Zernike moments are selected as feature extractors due to its enhanced feature representation capability and implementation of moments on wavelet subband affords advantages of performing local-to-global analysis and decomposing image into lower resolution.
Abstract: Moments are widely-used feature extractors due to their superior discriminatory power and geometrical invariance. Unfortunately, moments suffer heavy computational load and result long time spending. In viewing of the problem, we proposed a new technique in using moments- apply moments on wavelet subband. In this study, pseudo Zernike moments are selected as feature extractors due to its enhanced feature representation capability. Implementation of moments on wavelet subband affords advantages of performing local-to-global analysis and decomposing image into lower resolution. Experimental results show that this hybrid achieves computational time reduction of 36.23% with enhanced authentication performance.
TL;DR: RK has no benefit for the ignition of NAB, and other kinds of ignition aid should be found, according to results of a micro-thruster tested in vacuum.
Abstract: A φ0.8mm micro-solid propellant rocket array thruster for simple attitude control of a 10kg class micro-spacecraft was tested in vacuum. The micro-thruster uses boron/potassium nitrate propellant (NAB), because NAB has ignition temperature as low as 500°C, and easily start to burn in vacuum. For a half of the rockets, an ignition aid (RK) was also loaded. Ignition was succeeded in vacuum with NAB + RK and NAB. The maximum impulse thrust of 4.6 × 10-4 Ns, which is approximately a half of our requirement, was obtained with NAB. Compared to NAB, NAB + RK generated lower impulse thrust. The success rate of ignition was as low as 30%, although RK was used. These results suggest that RK has no benefit for the ignition of NAB, and other kinds of ignition aid should be found.
TL;DR: The high-sensitive PFM photosensor is proposed and demonstrated, whose output frequency is proportionate to the incident light intensity, that utilizes MOS interface-trap charge pumping (ITCP) as a frequency-controlled ultra-low current.
Abstract: A high-sensitive CMOS photosensor based on a pulse frequency modulation (PFM) scheme is presented. We propose and demonstrate the high-sensitive PFM photosensor, whose output frequency is proportionate to the incident light intensity, that utilizes MOS interface-trap charge pumping (ITCP) as a frequency-controlled ultra-low current. The proposed pixel sensor consists of only 4 transistors: a transistor as an ultra-low current source; a sense amplifier transistor; a selection transistor; and, a reset transistor. The prototype device is fabricated using 0.6-µm standard CMOS technology. High sensitivity 4.0 × 105Hz/(W·m-2), which is larger than two orders of magnitude compared to previous works, was obtained.
TL;DR: In this paper, a two-stage asymmetric parallel-coupled coplanar waveguide (CPW) bandpass filter was designed at 5.0 GHz and achieved broad rejection band, ranging from 5.8GHz to 18.0GHz.
Abstract: Asymmetric parallel-coupled coplanar waveguide (CPW) is originally characterized here as an equivalent unified K-inverter network. On a basis of our developed self-calibrated method of moments (MoM), the relevant network parameters are extracted to explicitly demonstrate the frequency-dependent coupling behavior with the 1st zero coupling at the λ/2 length of overlapped section. By differentiating the coupled spaces and overlapped lengths, the two CPW coupling structures are dissimilarly constructed and utilized as the input/output excitation of a λ/4 CPW bandpass filter. Through allocating the two unequal zeros towards the spurious harmonic around 3λ/4, an improved two-stage λ/4 CPW filter is designed at 5.0GHz. Optimized results achieve broad rejection band, ranging from 5.8GHz beyond 18.0GHz, as verified by the ADS simulation.
TL;DR: A highly efficient and low noise gain-clamped long-wavelength-band erbium-doped fiber amplifier (L-band EDFA) is demonstrated using a ring laser in double-pass system.
Abstract: A highly efficient and low noise gain-clamped long-wavelength-band erbium-doped fiber amplifier (L-band EDFA) is demonstrated using a ring laser in double-pass system. The broadband fiber Bragg grating (FBG) operating at L-band region is used to retro-pass the test signal into the system for enhanced gain. A length of forward pumped EDF is incorporated in front of the double-pass amplifier to achieve a low noise figure. The gain clamping is achieved by routing the backward ASE into the feedback loop to create ring laser. The gain is clamped at 18.6dB from -40 to -8dBm with gain variation of less than ±0.1dB and a noise figure of less than 6dB.
TL;DR: The experimental results for the transform are compared with the well known ternary Reed-Muller transform and it was found that the helix transform is quite efficient in terms of non-zero spectral coefficients and corresponding memory storage.
Abstract: In this article, the new multi-polarity helix transform for ternary logic functions has been introduced. In addition, an extended dual polarity property that had been used to optimize Kronecker and quaternary Fixed-Polarity Reed-Muller (FPRM) expressions has been applied to generate efficiently the multi-polarity helix transform over GF(3). The experimental results for the transform are compared with the well known ternary Reed-Muller transform and it was found that the helix transform is quite efficient in terms of non-zero spectral coefficients and corresponding memory storage.
TL;DR: The circularly polarized post-wall waveguide array is designed and fabricated for the first time and the peak gain of 29.3dBi with 39.7% efficiency is realized at 77GHz band for the antenna with about 5cm square aperture.
Abstract: The circularly polarized post-wall waveguide array is designed and fabricated for the first time. The aperture illumination and the characteristics of the antenna are investigated by using analysis/design method developed for oversized rectangular waveguide slot arrays. The uniformity as well as the polarization is perturbed along the periphery of the aperture; the narrow walls are identified to be the dominant factors for degrading the amplitude uniformity and the polarization purity in the aperture illumination. The peak gain of 29.3dBi with 39.7% efficiency is realized at 77GHz band for the antenna with about 5cm square aperture.
TL;DR: The present results show the possibility of the practical use of pseudomorphic HEMTs with a scaled-down structure for various applications, such as ultra-high-speed digital circuits and millimeter-wave communications/observations.
Abstract: Pseudomorphic In0.25Al0.75P/In0.75Ga0.25As high electron mobility transistors (HEMTs) were fabricated to investigate the short-channel effect in the sub-0.1-µm gate-length region. Employing a thin Schottky barrier and a thin channel layer structure enabled us to suppress the short-channel effect in short-gate HEMTs, and a high-performance 47-nm-gate HEMT with a 423-GHz current gain cutoff frequency was achieved. The present results show the possibility of the practical use of pseudomorphic HEMTs with a scaled-down structure for various applications, such as ultra-high-speed digital circuits and millimeter-wave communications/observations.
TL;DR: An image contrast enhancement algorithms for BDCT (Block Discrete Cosine Transform) based compressed images is presented and the performance is compared with other methods and better visual quality is obtained.
Abstract: An image contrast enhancement algorithms for BDCT (Block Discrete Cosine Transform) based compressed images is presented. Contrast enhancement is achieved by modifying the quantized DCT coefficients based on a contrast measure defined within the DCT domain. The performance is compared with other methods and better visual quality is obtained.
TL;DR: Simulation results show that the proposed algorithm can produce a completely identical fractal code to that of the exhaustive search in reduced time.
Abstract: The major drawback of the fractal image compression is the high encoding complexity to find the best match between a range block and a large pool of domain blocks. This paper presents a fast fractal-encoding algorithm based on the law of cosines. The number of domain blocks searched to find the best match for each range block is safely reduced by eliminating the ineligible domain blocks using the law of cosines. Simulation results show that the proposed algorithm can produce a completely identical fractal code to that of the exhaustive search in reduced time.
TL;DR: I fabricated an inverted-mesa quartz resonator having a 2.2-µm-thick vibrating area by wet etching that excited a 622-MHz-fundamental thickness vibration and exhibited a cubic curve over a range of temperature from -40°C to +85°C.
Abstract: I fabricated an inverted-mesa quartz resonator having a 2.2-µm-thick vibrating area by wet etching. The resonator excited a 622-MHz-fundamental thickness vibration. By selecting a 30-nm-thick gold electrode, the temperature-frequency characteristics exhibited a cubic curve with a frequency deviation of 26ppm over a range of temperature from -40°C to +85°C. Furthermore, the resonator was miniaturized to reduce loss caused by the film resistance, and to decrease the parallel capacitance. The series resistance at the noninductive resonance frequency was 33ohm and the parallel capacitance was 0.96pF. Therefore, the fundamental thickness vibration had a wide inductive region.