Showing papers in "IEICE Electronics Express in 2005"
TL;DR: This letter introduces two new OTA-C universal Current mode biquads which offer almost all of the desirable features (expected from a good universal biquad) simultaneously, without any trade-offs.
Abstract: This letter introduces two new OTA-C universal Current mode biquads which offer almost all of the desirable features (expected from a good universal biquad) simultaneously, without any trade-offs. With first OTA removed and the input current source replaced by an input voltage source, both the new circuits can also realise trans-admittance-type universal biquad filters. The workability of the new circuits has been established by SPICE simulation results of their CMOS-implementable versions.
63 citations
TL;DR: An efficient short wavelength band erbium-doped fiber amplifier (S-band EDFA) is proposed and demonstrated using double-pass configuration and shows a gain enhancement of about 14dB for pump powers above 120mW.
Abstract: An efficient short wavelength band erbium-doped fiber amplifier (S-band EDFA) is proposed and demonstrated using double-pass configuration. This amplifier provides a gain as high as 30dB, but using only 15m depressed cladding erbium-doped fiber (EDF) and 130mW of 980nm pump power. Compared to the single-pass configuration, this amplifier shows a gain enhancement of about 14dB for pump powers above 120mW. However, noise figures penalties of about 0.5 ∼ 0.9dB are obtained for these pump powers. The proposed double-pass amplifier will play an important role in the development of a practical S-band EDFA from perspective of economical usage of EDF and pump power.
62 citations
TL;DR: This paper presents a novel biometric watermarking algorithm for improving the recognition accuracy and protecting the face and fingerprint images from tampering using Multi-resolution Discrete Wavelet Transform and an intelligent learning algorithm based on υ-Support Vector Machine.
Abstract: This paper presents a novel biometric watermarking algorithm for improving the recognition accuracy and protecting the face and fingerprint images from tampering. Multi-resolution Discrete Wavelet Transform is used for embedding the face image in a fingerprint image. An intelligent learning algorithm based on υ-Support Vector Machine (SVM) is introduced to enhance the quality of the extracted face image. The performance of the watermarking algorithm is experimentally validated using existing fingerprint and face recognition algorithms. The results show that the extracted fingerprint and face images are of high quality. The use of SVM enhances the performance of face recognition by at least 10% even when the watermarked image is subjected to certain geometric and frequency attacks such as scaling, cropping, compression and filtering.
58 citations
TL;DR: The effectiveness of CMSDA for reducing 1/f noise is analyzed and the analysis is in good agreement with time-domain simulations.
Abstract: Correlated multiple sampling differential averaging (CMSDA) is useful for realizing low-noise column readout circuits in CMOS image sensors. CMSDA involves sampling the signal and reset levels multiple times and differentiating the averages. In other words, this method is like averaging of correlated double sampling (CDS) for the multiple sampling of signal and reset levels. This paper analyzes the effectiveness of CMSDA for reducing 1/f noise and the analysis is in good agreement with time-domain simulations.
43 citations
TL;DR: A novel configuration has been presented, which realises all the five generic filter functions from the same circuit in all the four possible modes, employing only four-Current feedback operational amplifiers (CFOA) along with two grounded-capacitors as desirable for Integrated Circuit implementation.
Abstract: Although a variety of CFOA-based biquads have been known in the literature, any CFOA-based circuit capable of realising universal biquad filters in all the four possible modes i.e. voltage-mode, current-mode, trans-admittance-mode and trans-impedance-mode, has not been reported in the literature so far. In this paper, a novel configuration has been presented, which realises all the five generic filter functions (namely, low-pass, band-pass, high-pass, notch and all-pass) from the same circuit in all the four possible modes, employing only four-Current feedback operational amplifiers (CFOA) along with two grounded-capacitors as desirable for Integrated Circuit implementation. The workability of the circuit has been confirmed by hardware implementation based on AD844 type CFOAs.
39 citations
TL;DR: A system for the real-time image monitoring of electromagnetic near-field distributions over devices and circuits at a specific radio frequency (RF), which is the first to the best of the authors' knowledge, based on a 64-channel parallel electro-optic heterodyne detection scheme, in which arrays of photodiodes and mixers allow simultaneous acquisition of 8 × 8pixel data.
Abstract: Described in this paper is a system for the real-time image monitoring of electromagnetic near-field distributions over devices and circuits at a specific radio frequency (RF), which is the first to the best of our knowledge. It is based on a 64-channel parallel electro-optic heterodyne detection scheme, in which arrays of photodiodes and mixers allow simultaneous acquisition of 8 × 8pixel data. Its highest frame rate of 10Hz enables even a motion picture display of RF near-field images. It has been applied to a patch antenna and a moving RF emitter for performance demonstration.
33 citations
TL;DR: The optical scanner integrated with SAVC has shown good electrostatic scanning performance and the initial angular offset of the movable combs is prepared by using the process stiction which occurs during drying process after sacrificial release.
Abstract: We report a very simple and reliable method for making Self-Assembled Vertical Comb (SAVC) drive actuators by using the standard SOI bulk micro-machining processes. The initial angular offset of the movable combs is prepared by using the process stiction which occurs during drying process after sacrificial release. The optical scanner integrated with SAVC has shown good electrostatic scanning performance of over 1.0-degree static-rotation angle with a typical drive voltage of 20V without any in-use electromechanical failure.
30 citations
TL;DR: A newly developed micro electromechanical XY-scanner for micro-optical spatial light modulation using the silicon micromachining technology and can be used to construct a free-space optical crossconnect of 9-input by 9-output port counts.
Abstract: We report the design, fabrication and electromechanical performance of a newly developed micro electromechanical XY-scanner for micro-optical spatial light modulation using the silicon micromachining technology. A two-dimensional stage is integrated with a silicon micro lens to scan a transmitting infrared light of 1.55-micron-wavelength by the mechanism of the ƒ-θ lens scanner. Mechanical displacement of up to ± 10 microns (optical angle of ± 0.57 degrees) was obtained with a drive voltage of 30V; optical simulation has suggested that the scanner can be used to construct a free-space optical crossconnect of 9-input by 9-output port counts.
26 citations
TL;DR: The authors packaged SiC JFET and Schottky diodes in thermally stable packages and built a high-temperature inductor to demonstrate the suitability of the SiC devices for high-Temperature power converter applications.
Abstract: This paper reports on SiC devices operating in a dc-dc buck converter under extremely high ambient temperatures. To this end, the authors packaged SiC JFET and Schottky diodes in thermally stable packages and built a high-temperature inductor. The converter was tested at ambient temperatures up to 400°C. Although the conduction loss of the SiC JFET increases slightly with increasing temperatures, the SiC JFET and Schottky diode continue normal operation because their switching characteristics show minimal change with temperature. This work further demonstrates the suitability of the SiC devices for high-temperature power converter applications.
25 citations
TL;DR: A technique to efficiently partition a vector into two dynamic subvectors according to the patterns inside the block (or vector) and then further improve the computational load is introduced.
Abstract: The encoding of vector quantization (VQ) needs expensive computation for searching the closet codeword to the input vectors. In order to reduce computational burden, many researchers have developed some efficient full-search-equivalent algorithm by using the characteristics of the means and variances of a vector. However, some computational redundancies still exist in them. In this paper, we introduce a technique to efficiently partition a vector into two dynamic subvectors according to the patterns inside the block (or vector) and then further improve the computational load. Experimental results show that the proposed method provides a higher codeword searching efficiency than other existing algorithms.
24 citations
TL;DR: This letter describes two sinusoidal oscillator circuits and demonstrates their practicability through experimental results based upon AD844 type IC CFOAs.
Abstract: Although a number of sinusoidal oscillators have been described in earlier literature which employ only a single current feedback op-amp (CFOA) to generate voltage-mode sinusoidal oscillations, any sinusoidal oscillator circuit, which can provide a current-mode output signal explicitly (i.e. from a high output impedance node) while using only a single CFOA, has not been reported till date. This letter describes two such circuits and demonstrates their practicability through experimental results based upon AD844 type IC CFOAs.
TL;DR: A novel electronically tunable single-input three-output (SITO) universal filter employing three current controlled conveyors and two grounded capacitors ideal for integration is presented.
Abstract: A novel electronically tunable single-input three-output (SITO) universal filter employing three current controlled conveyors and two grounded capacitors is presented. The proposed filter offers the following advantageous features: low input impedance and high output impedance- a desirable property of current mode filters, realization of low pass, band pass, high pass, notch and all pass signals from the same configuration, no matching constraint, low sensitivity performance and use of grounded capacitors ideal for integration. The validity of the proposed filter is verified through PSPICE simulations.
NEC1
TL;DR: Although there is no single-mode waveguide region inside the cavity, the novel active MMI-LDs emitted in stable single-transverse-mode output up to maximum output power.
Abstract: Here we propose novel active multi-mode-interferometer (MMI) laser diodes (LDs) for 14XXnm fiber amplifier pump applications. The waveguide of the LDs is consisted from 1x1-MMI couplers integrated with 1st order-mode permitted waveguides to enhance the total active area. Although there is no single-mode waveguide region inside the cavity, the novel active MMI-LDs emitted in stable single-transverse-mode output up to maximum output power. Moreover, they achieved high output power of 1.46W, and low driving voltage of only 1.75V at 1W output power.
TL;DR: Experimental results show that the proposed method outperforms the sole PZM and the integrated FLD with PzM methods, achieving recognition rate of 98.11% and 93.03% in the face databases with facial expression variations and illumination variations, respectively.
Abstract: This paper presents an approach to boost the performance of pseudo Zernike moments in face recognition. This approach is a hybrid of a kernel trick, discriminant function and pseudo Zernike moments (PZM), namely as Kernel-based Fisher Pseudo Zernike Moments (KFPZM). KFPZM maps the moment-based features into a high dimensional feature space via kernel function for disclosing the underlying variables which carry significant information about the image. Then, it performs discriminant analysis onto the mapped features to enhance the discrimination power via Fisher's Linear Discriminant (FLD). Experimental results show that the proposed method outperforms the sole PZM and the integrated FLD with PZM methods, achieving recognition rate of 98.11% and 93.03% in the face databases with facial expression variations and illumination variations, respectively.
TL;DR: It is shown by experimental investigations that a 3-element modulated scattering array antenna composed of one λ/4 monopole and two κ/4 modulated scatter monopoles with λ-4 array spacing can provide diversity gain up to 8dB diversity gain at 0.1% of the cumulative distribution function in Rayleigh fading environment.
Abstract: A concept of modulated scattering array antenna is proposed based on the modulated scattering technique. The array antenna consists of one antenna element and several modulated scattering elements (MSE). The configuration of the array antenna is very simple because only one branch of the front-end circuit is required. It is shown by experimental investigations that a 3-element modulated scattering array antenna composed of one λ/4 monopole and two λ/4 modulated scattering monopoles with λ/4 array spacing can provide diversity gain up to 8dB diversity gain at 0.1% of the cumulative distribution function in Rayleigh fading environment. The array antenna is suitable to the mobile handset applications where the space and the cost are strictly limited because of its simple configuration.
TL;DR: A semiconductor multi-mode interference photonic switch with partial index-modulation regions (MIPS-P) was fabricated and high-speed switching operation was demonstrated, for the first time, at a repetition rate of 10 MHz.
Abstract: Advanced photonic networks require high-speed switching in nano-second order switching time, low power consumption and low crosstalk, etc. For these purposes we proposed a semiconductor multi-mode interference photonic switch with partial index-modulation regions (MIPS-P) which can operate by current injection for refractive index change and is expected as a high-speed optical switch. In this letter we have experimentally confirmed small-current and low-crosstalk operation by using InAlGaAs/InAlAs, which is effective for injected carrier confinement. And also high-speed switching operation in a switching time of about 1.5ns has been demonstrated, for the first time, at a repetition rate of 10MHz.
TL;DR: Experimental results demonstrate that the incorporation of an active single-quantum well in the tuning layer of a DBR laser achieves stable single-mode operation during wavelength tuning while maintaining the efficiency of tuning.
Abstract: The incorporation of an active single-quantum well in the tuning layer of a DBR laser is proposed as a way of compensating for optical loss and achieving stable single-mode operation during wavelength tuning. Experimental results demonstrate that the structure achieves these goals while maintaining the efficiency of tuning. In application to a short-cavity DBR laser with a gain region 35-µm long, continuous wavelength gtuning over a broad 4.8nm is achieved with stable lasing properties (more than 40dB of side-mode suppression). Fast wavelength switching less than 10ns to cross a wavelength spacing of 2nm is also confirmed.
TL;DR: Results show that the XPM induced dispersion in an SCM-WDM system is directly proportional to the transmission distance and frequency and inversely proportional toThe channel spacing.
Abstract: The crosstalk effects in a subcarrier multiplexed-wavelength division multiplexed (SCM-WDM) system due to cross phase modulation (XPM) have been investigated. The variation of XPM induced distortion is investigated for parameters such as transmission distance, frequency and channel spacing. Results show that the XPM induced dispersion in an SCM-WDM system is directly proportional to the transmission distance and frequency and inversely proportional to the channel spacing.
TL;DR: The ultimately pure red OLED using new electrophosphorescent compound, bis(2,3-diphenylquinoxaline)iridium(acetylace-tonate) [(QH)2 Ir(acac]], which is the closest to the ultimate limit of pure red among reported OLEDs, was attained and maintained even in luminance brighter than 600cd/m2.
Abstract: The ultimately pure red OLED using new electrophosphorescent compound, bis(2,3-diphenylquinoxaline)iridium(acetylace-tonate) [(QH)2 Ir(acac)] is described. Electrophosphorescence peak wavelength and bandwidth were advanced for the purest red color stimulus to 680nm with full width at half maximum of 89nm by doping (QH)2 Ir(acac) into a light emitting electron transport layer composed of 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole. The most vivid red electrophosphorescence with CIE chromaticity coordinates better than x=0.70 and y=0.28, which are the closest to the ultimate limit of pure red among reported OLEDs, was attained and maintained even in luminance brighter than 600cd/m2. A very high maximum external electrophosphorescent quantum efficiency of 10.2% was also realized.
TL;DR: A rectangular-waveguide output UTC-PD module integrating a HEMT power amplifier has been developed for operation in the 125-GHz band and exhibits maximum output power of more than 14 dBm with nearly flat frequency dependence.
Abstract: A rectangular-waveguide output UTC-PD module integrating a HEMT power amplifier has been developed for operation in the 125-GHz band. The fabricated module exhibits maximum output power of more than 14 dBm with nearly flat frequency dependence in the 115-135GHz range. A 10-Gbit/s error-free wireless transmission at 125GHz with a minimum sensitivity of −34 dBm for a bit-error-rate of 10−12 is also demonstrated using the fabricated module.
TL;DR: A four-Current feedback operational amplifier (CFOA)-based state variable biquad is described which permits the accommodation of or compensation for the z-pin parasitic impedances of the CFOAs and offers a number of advantages over previously known CFOA-based biquAD configurations.
Abstract: A four-Current feedback operational amplifier (CFOA)-based state variable biquad is described which permits the accommodation of or compensation for the z-pin parasitic impedances of the CFOAsand offers a number of advantages over previously known CFOA-based biquad configurations. The workability of the circuit has been confirmed by SPICE simulation results based on commercially available AD844 type CFOAs.
TL;DR: It is found that the device characteristics are almost the same as those of devices fabricated on as-grown GaN layers, although the surface morphology ofGaN layers is degraded due to the ICP etching.
Abstract: We evaluated the possibility of monolithic integration of electron devices and surface acoustic wave (SAW) devices on GaN. We removed top n+ GaN layers of n+ GaN/unintentionally-doped GaN structures by inductively coupled plasma (ICP) etching and fabricated SAW filters on the exposed unintentionally doped GaN layers. We found that the device characteristics are almost the same as those of devices fabricated on as-grown GaN layers, although the surface morphology of GaN layers is degraded due to the ICP etching. The results indicate that SAW devices and electron devices can be monolithically integrated on GaN-based semiconductor structures.
TL;DR: It is shown that a step waveform is spontaneously generated after many charge-recycle processes and an adiabatic stepwise charging SRAM is proposed, suitable for nanoscale circuits.
Abstract: The stability of adiabatic stepwise charging reversible logic is discussed. In the case of adiabatic logic with asymmetric tank capacitors, we derive a matrix which connects the initial state and the final state after the charge-recycle process. From the analytical discussion, it is proved that the absolute value of the eigen value of the matrix is less than 1. Therefore, it is shown that a step waveform is spontaneously generated after many charge-recycle processes. Next, an adiabatic stepwise charging SRAM is proposed. The SRAM is immune to hot-carrier effects and electromigration even in the less-than-45-nm process, while it maintains an operating voltage of 1V or more. The SRAM is suitable for nanoscale circuits.
TL;DR: The noise characterization of a capacitive servo-accelerometer using a linear model is presented, suggesting that the model can be effectively used for noise evaluation of accelerometers fabricated in a similar fashion.
Abstract: The noise characterization of a capacitive servo-accelerometer using a linear model is presented in this paper. The input reference noise of electronic circuit is expressed as a capacitive variation and it is introduced to a linear model for frequency response, separately with the thermal mechanical noise. The simulated noise was generally found to conform to the measured noise in the experiment, suggesting that the model can be effectively used for noise evaluation of accelerometers fabricated in a similar fashion.
TL;DR: An ultrafast imaging system to record and observe the femtosecond phenomena in air and an optical medium as a form of a temporally continuous motion picture and achieves a temporal microscope with more than 1011 magnification is developed.
Abstract: We have developed an ultrafast imaging system to record and observe the femtosecond phenomena in air and an optical medium as a form of a temporally continuous motion picture. To obtain the motion picture, the light-in-flight recording by holography using a femtosecond pulsed laser is applied. We demonstrate the recording and observation of femtosecond laser pulse propagating in air and a dispersion prism. The time and spatial behavior of such femtoseconed light pulse in the prism and at the boundary between the prism and air is clearly observed. This technology achieves a temporal microscope with more than 1011 magnification.
TL;DR: This paper presents a fully distributed software solution to the arbitration problem in multiport memory systems that is simple, efficient, and assures LRU fairness.
Abstract: Multiport memories are increasingly used in smart-phones, multimode handsets, multiprocessor systems, network processors, graphics chips, and other high performance electronic devices [1,2,4,8]. This paper presents a fully distributed software solution to the arbitration problem in multiport memory systems. Our solution is simple, efficient, and assures LRU fairness.
TL;DR: A low-threshold-current distributed reflector laser consisting of phase-shifted distributed feedback (DFB) grating and quantum-wire distributed Bragg reflector (DBR) sections was realized.
Abstract: A low-threshold-current distributed reflector laser consisting of phase-shifted distributed feedback (DFB) grating and quantum-wire distributed Bragg reflector (DBR) sections was realized. The device with a DFB length of 150µm, a DBR length of 240µm and a stripe width of 1.5µm achieved a threshold current as low as 1.2mA and a differential quantum efficiency of 13% from the front facet under RT-CW conditions. A good single-mode operation was also realized at a mode determined by the phase-shifted grating.
TL;DR: Performance analysis is carried out to evaluate Frequency-Hopping Optical Code Division Multiple Access in the presence of group velocity dispersion (GVD) and self-phase modulation (SPM), it is found that the system suffers higher power penalty as the dispersion increases.
Abstract: Performance analysis is carried out to evaluate Frequency-Hopping Optical Code Division Multiple Access (FH-OCDMA) in the presence of group velocity dispersion (GVD) and self-phase modulation (SPM). It is found that the system suffers higher power penalty as the dispersion increases. At a distance of 200-km the power penalty is reduced to 1 dB for DSF and to approximately 7 dB for SMF when SPM is included. The SMF without SPM suffers the highest power penalty of 6.7 dB at 100-km and 9.5 dB at 200-km.
TL;DR: This poster presents a probabilistic procedure to constrain the number of particles in the response of the immune system to infectious disease.
Abstract: Reference LSM-ARTICLE-2005-003View record in Web of Science Record created on 2005-11-21, modified on 2017-05-10
TL;DR: If the waveguide lengths and pump powers are optimized, the net continuous-wave Raman gain and thus lasing activities in such waveguides without any additional free carrier extraction schemes is possible.
Abstract: Stimulated Raman scattering in silicon waveguides are attractive for optical amplification/lasing due to high Raman coefficient and high optical pump intensity in the small waveguide core. In this paper, we investigate the effect of two-photon absorption and freecarrier absorption for continuous-wave light propagation in submicron size silicon wire waveguides. We also show that if the waveguide lengths and pump powers are optimized, the net continuous-wave Raman gain and thus lasing activities in such waveguides without any additional free carrier extraction schemes is possible.