A broadband RF front-end having a direct conversion architecture has been developed. The RF front-end consists of two broadband quadrature mixers, a multi-band local oscillator, and a broadband low-noise variable gain amplifier (LNVGA). The mixer achieves broadband characteristics through the incorporation of an in-phase power divider and a 45-degree power divider. The in-phase power divider achieves broadband characteristics through the addition of a compensation capacitor. The 45-degree power divider achieves broadband phase characteristics through the addition of a compensation capacitor and a compensation resistor. The local oscillator, which is composed of two VCOs, two frequency dividers, and four switches, can cover three systems including one FDD system. The LNVGA achieves its broadband characteristics without the use of reactance elements, such as inductors or capacitors. In a trial demonstration, when the RF frequency was between 900 MHz and 2.5 GHz, the mixer for a demodulator experimentally demonstrated an amplitude balance of less than 1.6 dB and a quadrature phase error of less than 3 degrees. When the RF frequency was between 900 MHz and 2.5 GHz, the mixer for a modulator demonstrated an image ratio of less than -30 dBc. The local oscillator demonstrated multi-band characteristics, which are able to cover the target frequencies for three systems (PDC, PHS, 2.4 GHz WLAN). From 900 MHz to 2.5 GHz, the amplifier shows a noise figure of less than 2.1 dB and a gain of 28 1.6 dB.

This paper proposes an operation-region model for analyzing and testing analog and mixed-signal circuits, which is based on observation of change in MOSFET operation regions. First, the relation between the change in MOSFET operation regions and the fault behavior of a mixed-signal circuit containing a bridging fault is investigated. Next, we propose an analysis procedure based on the operation-region model and apply it to generate the optimal input combination for testing the circuit. We also determine which transistors should be observed in order to estimate the circuit behavior. Since the operation-region model is a method for modeling circuit behavior abstractly, the proposed method will be useful for modeling circuit behavior and for analyzing and testing many kinds of analog and mixed-signal circuits.

Algorithms are presented for the four elementary arithmetic operations, to perform reliable floating-point arithmetic operations. These arithmetic operations can be achieved by applying residue techniques to the weighted number systems and performed with no accuracy lost in the process of the computing. The arithmetic operations presented can be used as elementary tools (on many existing architectures) to ensure the reliability of numerical computations. Simulation results especially for the solutions of ill-conditioned problems are given with emphasis on the practical usability of the tools.

Recently binary or real-valued sequences generated by Chebyshev maps are proposed as spreading sequences in DS/CDMA systems. In this article, we consider sequences of real-valued functions of bounded variation, which include binary functions, of iterates generated by Chebyshev maps, and evaluate explicitly the upper bound of mixing rate of such sequences by defining the modified Perron-Frobenius operator associated with the Chebyshev maps.

A novel common emitter common collector transistor pair (CECCTP) mixer is presented. A LO pumped CECCTP enables even harmonic mixing operation, and a balanced CECCTP mixer configuration enables the suppression of both 2fLO and fIM2 which are undesirable component for direct conversion mixer. A 2 GHz-band balanced CECCTP mixer is fabricated in SiGe HBT process, and the direct conversion characteristics are measured. It performs conversion gain of 8.8 dB, NF of 14.9 dB and IIP2 of 42.3 dBm when LO power is -6 dBm, supplied voltage is 3 V and current is 5 mA.

Wyner and Ziv considered the rate-distortion function for source coding with side information at the decoder (we call the Wyner-Ziv problem). In this paper we show an information-spectrum approach to the Wyner-Ziv problem for general class of nonstationary and/or nonergodic sources with side information at the decoder, where the distortion measure is arbitrary and may be nonadditive. We show that a general formula for the rate-distortion function of the Wyner-Ziv problem for general sources with the maximum distortion criterion under fixed-length coding by using the information spectrum approach.

In this paper, the forward link erlang capacity and outage probability for hierarchical cellular system based on 2 layer macrocell/microcell are derived analytically by considering the impact of imperfect power control and soft hand-off. The analysis on the outage probability is carried out using two methods: lognormal approximation and Chernoff upper bound. We assume that voice and multi-rate data service users are distributed uniformly in each cell and the same spectrum is applied in both layers. In addition, we take into account the base station transmission power ratio between tiers and the relative position of microcell having island distribution in macrocell. The forward link interference is evaluated by using Monte-Carlo simulation introduced in [2]. In this paper, we compare the forward link erlang capacity of 1x system to 3x system and show that 3x system can increase the user capacity by 3.4 times in case of macrocell and microcell, respectively, compared to 1x system.

The effectiveness and possible applications of all-optical wavelength conversion using optical fibers are described. Several types of ultra-broad and ultra-fast wavelength conversion using highly-nonlinear fiber are shown. Over 70 nm conversion band by four-wave mixing, 500-fs pulse trains conversion by cross-phase-modulation-based nonlinear optical loop mirror and time-based optical add-drop multiplexing for 160 Gbit/s signal using wavelength conversion by supercontinuum are successfully demonstrated.

This paper describes design optimization and performances of hybrid optical transmission lines consisting of effective-area-enlarged pure silica core fiber and dispersion compensating fiber. As a result of the design optimization, considering low nonlinearity and good bending characteristic, the developed fibers exhibit a span average loss of 0.208 dB/km, a span average dispersion slope of 0.02 ps/nm2/km and low nonlinearity with an equivalent effective area of 60 µm2. Further optimization of the relationship among the nonlinearity, the dispersion slope and the bending characteristic enables perfectly dispersion-flattened hybrid optical transmission lines exhibiting a low transmission loss of 0.211 dB/km, low nonlinearity with an equivalent effective area of 60 µm2 and small dispersion deviation of 0.03 ps/nm/km in a wavelength band wider than 40 nm.

785 nm (AlGaAs) laser diode (LD) with a window-mirror structure is demonstrated to be a potential candidate as a highly reliable light source of CD-R. The intermixing of a multi-quantum well structure by silicon implantation is used to form the window-mirror structure. Carbon is adopted as an acceptor because of its low thermal diffusion constant in crystals. As a result, the window-mirror-structure 785 nm AlGaAs LDs with ordinary far field patterns suitable for the actual CD-R drives have shown stable single lateral mode operation up to 250 mW. A mirror degradation level is significantly increased by the window-mirror structure. The pulsed operation current at 160 mW, 70 of the carbon doped LD is reduced by about 15% from that of zinc doped one. Highly reliable 160 mW pulsed operation is also realized at 70. This LD believed to be suited for the next generation high-speed (16-24x) CD-R drives necessitating 160 mW class LD.

An efficient construction of a permutation network has been proposed by Waksman. However, his construction is only for permutation networks with 2k inputs. This paper provides a construction of permutation networks with arbitrary number of inputs that is an extension of Waksman's construction. By applying our construction to Abe's Mix-net, we can improve the efficiency of the Mix-net.

Fourier synthesis of ultrafast optical-pulse trains was demonstrated using a simplified experimental configuration consisting of three independent continuous-wave lasers and a semiconductor optical amplifier (SOA) used as a four-wave mixer. When the three lasers were phase-locked, ultrafast optical-pulse trains were successfully generated at repetition frequencies ranging from 504 GHz to 1.8 THz with high waveform stability.

In this paper, we describe a method for estimating external camera parameters in real time. We investigated the effectiveness of this method for annotating real scenes with 3-D virtual objects on a wearable computer. The proposed method enables determining known natural feature points of objects through multiplied color histogram matching and template matching. This external-camera-parameter calculation method consists of three algorithms for PnP problems, and it uses each algorithm selectively. We implemented an experimental system based on our method on a wearable vision system. This experimental system can annotate real objects with 3D virtual objects by using the proposed method. The system was implemented in order to enable effective annotation in a mixed-reality environment on a wearable computing system. The system consists of an ultra small CCD camera set at the user's eye, an ultra small display, and a computer. This computer uses the proposed method to determine the camera parameters. It then renders virtual objects based on the camera parameters and synthesizes images on a display. The system works at 10 frames per second.

This paper presents a novel approach to water pollution detection from remotely sensed low-platform mounted visible band camera images. We examine the feasibility of unsupervised segmentation for slick (oily spills on the water surface) region labelling. Adaptive and non adaptive filtering is combined with density modeling of the obtained textural features. A particular effort is concentrated on the textural feature extraction from raw intensity images using filter banks and adaptive feature extraction from the obtained output coefficients. Segmentation in the extracted feature space is achieved using Gaussian mixture models (GMM).

In this paper, a novel three-port antenna structure, named 180 antenna hybrid, is proposed and demonstrated. This structure is composed of a Wilkinson power divider with the isolation resistor replaced by an aperture-coupled patch antenna. The equivalent series impedance of the antenna can be adjusted to the required one by properly choosing the dimensions of the patch and the coupling aperture. When a signal is fed to the balanced port of this antenna hybrid, the power is equally split, with equal phases, to the two unbalanced ports. No power is radiated out from the antenna. In the other hand, a signal received from the antenna will be split with equal power but 180 phase difference to the two unbalanced ports. The balanced port is an isolation port. The measurement results showed good agreement with the characteristics to be designed. Three applications of this 180 antenna hybrid are introduced, that is, a balanced mixer, an active transmitting antenna, and a dual-radiation-mode antenna array. The balanced mixer was constructed with diodes directly mounted on the two unbalanced ports of the antenna hybrid. The LO signal is fed from the balanced port and RF signal is received from the antenna. The active transmitting antenna was implemented with feedback configuration. The route from one of the unbalanced port to the balanced port of the antenna hybrid was used as the feedback path. A locking signal may be injected from the other unbalanced port. Finally, through a three-quarter-wavelength microstrip line, the balanced port of the antenna hybrid was connected to another aperture-coupled patch antenna to form a dual-radiation-mode antenna array. The in-phase and out-of-phase radiation patterns of this two-element array can be obtained from two unbalanced ports of the antenna hybrid, respectively.

A high quality speech synthesis technique based on the wavelet subband analysis of speech signals was newly devised for enhancing the naturalness of synthesized voiced consonant speech. The technique reproduces a speech characteristic of voiced consonant speech that shows unvoiced feature remarkably in the high frequency subbands. For mixing appropriately the unvoiced feature into voiced speech, a noise inclusion procedure that employed the discrete wavelet transform was proposed. This paper also describes a developed speech synthesizer that employs several random fractal techniques. These techniques were employed for enhancing especially the naturalness of synthesized purely voiced speech. Three types of fluctuations, (1) pitch period fluctuation, (2) amplitude fluctuation, and (3) waveform fluctuation were treated in the speech synthesizer. In addition, instead of a normal impulse train, a triangular pulse was used as a simple model for the glottal excitation pulse. For the compensation for the degraded frequency characteristic of the triangular pulse that overdecreases than the spectral -6 dB/oct characteristic required for the glottal excitation pulse, the random fractal interpolation technique was applied. In order to evaluate the developed speech synthesis system, psychoacoustic experiments were carried out. The experiments especially focused on how the mixed excitation scheme effectively contributed to enhancing the naturalness of voiced consonant speech. In spite that the proposed techniques were just a little modification for enhancing the conventional LPC (linear predictive coding) speech synthesizer, the subjective evaluation suggested that the system could effectively gain the naturalness of the synthesized speech that tended to degrade in the conventional LPC speech synthesis scheme.

In this paper, a CMOS down-conversion double-balanced mixer is presented with the modified low voltage design technique. The frequencies of the radio frequency (RF) signal, local oscillator (LO) and intermediate frequency (IF) are 2.4 GHz, 2.3 GHz and 100 MHz, respectively. Measurement results of the proposed mixer exhibit 6.7 dB of conversion gain, -18 dBm of input 1 dB compression point (P-1 dB), -8 dBm of input-referred third-order intercept point (IIP3), and 14.7 dB single-side band (SSB) noise figure (NF) while applying -8 dBm LO power and consumes 3.3 mA from 1.8 V supply voltage. It can provide 0.7 dB conversion gain when the supply voltage reduces to 1.3 V. This mixer was fabricated in a 0.35 µm 1P4M standard digital CMOS process and the die size is 1.5 1.1 mm2.

This paper presents a new approach to modeling speech spectra and pitch for text-independent speaker identification using Gaussian mixture models based on multi-space probability distribution (MSD-GMM). MSD-GMM allows us to model continuous pitch values of voiced frames and discrete symbols for unvoiced frames in a unified framework. Spectral and pitch features are jointly modeled by a two-stream MSD-GMM. We derive maximum likelihood (ML) estimation formulae and minimum classification error (MCE) training procedure for MSD-GMM parameters. The MSD-GMM speaker models are evaluated for text-independent speaker identification tasks. The experimental results show that the MSD-GMM can efficiently model spectral and pitch features of each speaker and outperforms conventional speaker models. The results also demonstrate the utility of the MCE training of the MSD-GMM parameters and the robustness for the inter-session variability.

A robust moving object velocity estimation method in the mixed domain (MixeD) is proposed. By obtaining phase, that is, normalizing the 1-D complex sinusoid signals with their magnitudes, the velocity estimations of moving objects with conditions such as object rotation, shape and graylevel variation have been accomplished. Based on the appropriate spatial frequency selection, which choose the points where the signals are less influenced by the background and noise, the spectra of these 1-D temporal complex signals in selected points are estimated by FFT. The simulation results show that velocity vectors have been correctly estimated.

This paper concerns resource planning in a VLSI assembly facility. The facility can process more than 100 sorts of WIPs (Works-In-Process) simultaneously. Specifically it performs product-mix production. An old resource estimation system, which gave a good estimation for a memory VLSI production facility, went wrong for an assembly facility. To adjust the estimation of required machinery resources of the assembly facility, a new parameter--the tuning value for the service time--is introduced. The tuning value expresses the reduction in machine utilization in the processing steps due to the product-mix. The value is empirically determined and the machinery resources can be estimated in good accuracy. Also the waiting time for processing in the incoming buffer is successfully considered in the estimation of turnaround time. However the tuning value is not enough in estimating human resources. A novel algorithm to estimate the resources for machine adjustments is proposed. The algorithm is based on a periodic assignment of multiple sorts of WIPs in a single machine, where the adjustments of machines for the product-mix are considered. The adjustments are additional operator's jobs in the product-mix. It estimates the operator request rate and machine utilization rate when multiple sorts of WIPs with different arrival rates are processed in a single machine. Finally, this resource estimation system considers the operator allocated not only to the preprocessing and postprocessing but also to the adjustments of machines for the product-mix. The estimated machinery, human resources, and turnaround time were evaluated in a real facility, and the proposed method is confirmed to be applicable in the weekly or monthly resource planning for the facility.