We present a high-level synthesis scheme that considers weak testability of generated register-transfer level (RTL) data paths, as well as their area and performance. The weak testability, proposed in our previous work, is a testability measure of RTL data paths for non-scan design. In our scheme, we first extract a condition on resource sharing sufficient for weak testability from a data flow graph before synthesis, and treat the condition as design objectives in the following synthesis tasks. We propose heuristic synthesis algorithms which optimize area and the design objectives under the performance constraint.

In this study the spectral intensities of a breaking arc were measured near the cathode and the anode between separating Pd contacts in a DC 50 V/5 A circuit, and arc temperature and metal-vapor quantity and density were calculated. Results show the radial distribution of temperature in the cross section of an arc column was constant both near the cathode and the anode from the beginning to the extinction of the breaking arc. Near the cathode the arc temperature in the position of the peak value of spectral intensity rose to about 6000 K at the beginning and remained constant, but near the anode it rose to about 6000 K at the beginning and then decreased towards the extinction of the arc. Both near the cathode and the anode metal-vapor quantity and density rose suddenly at the beginning. Afterwards, they fell near the cathode until extinction. But they became constant approaching extinction near the anode. And the metal-vapor quantity was greater and the density higher near the cathode than near the anode.

For mobile telecommunication systems, it is important to accurately predict the propagation-path loss in terms of the estimation of the radiowave coverage area. The propagation-path loss has been estimated in a median obtained spatially from many received amplitudes (envelopes) within a region of several tens times as long as the wavelength, rather than in the envelopes themselves. Although ray tracing can obtain the envelopes and their median that reflect the site-dependent characteristics, the estimated median sometimes does not agree with the measured one. Therefore, the accuracy improvement has been expected. In this paper, an accuracy improvement is achieved by substituting a median with random phases for the median obtained spatially from many envelopes. The characteristic function method is used to obtain the cumulative distribution function and the median analytically where the phases are randomized. In a multipath environment, the phase-estimation error accompanying the location error of the ray tracing input influences the spatially obtained median. The phase-randomizing operation reduces the effects of the phase-estimation error on the median prediction. According to our estimation, improvements in accuracy of 4. 9 dB for the maximum prediction error and 2. 9 dB for the RMS prediction error were achieved. In addition, a probability-based cell-design method that takes the radiowave arrival probability and the interference probability into consideration is possible by using the percentiles obtained by the characteristic function method and the cell-design examples are shown in this paper.

Personal communication systems are increasingly required to accommodate not only voice traffic, but also various types of data traffic. Generally speaking, voice traffic is symmetric between uplink and downlink, while data traffic can be highly asymmetric. It is therefore inefficient to accommodate data in a conventional TDMA/TDD system with fixed TDD boundary. In this paper, focusing on the continuous data traffic which requires multi-slots in a circuit based TDMA/TDD system, an algorithm is proposed in which the TDD boundary are moved adaptively to accommodate data traffic efficiently. Comparing with the boundary-fixed conventional algorithm, computer simulations confirm that the proposed algorithm has superior performance in the excessive transmission delay of data while maintaining the performance of voice. The intercell interference between mobiles due to different TDD boundaries is also confirmed to be negligible. Moreover, almost the similar performance improvements of the proposed algorithm are confirmed for two different average message sizes of data calls.

We previously proposed a next generation cellular system for IMT-2000 based on the Wideband DS-CDMA with TDD scheme (W-CDMA/TDD) and have evaluated its performance by computer simulation, laboratory and field experiment. With the W-CDMA/TDD, because of its correlation between the downlink and the uplink, transmission and reception space diversity (SD) at a base station and open-loop transmit power control (TPC) can be simply realized. This paper reports performance of laboratory and field experiments using a developed testbed. The results shows it has been confirmed that transmission and reception SD and open-loop TPC have sufficient performance under a field environment as well as laboratory environment.

This paper presents a new algorithm that can solve the problem of selecting appropriate update step size in the LMS algorithm. The proposed algorithm, called a Complementary Pair LMS (CP-LMS) algorithm, consists of two adaptive filters with different update step sizes operating in parallel, one filter re-initializing the other with the better coefficient estimates whenever possible. This new algorithm provides the faster convergence speed and the smaller steady-state error than those of a single filter with a fixed or variable step size.

Recent technologies of organic film devices are reviewed. New technologies of fabrication and characterization of organic thin films, electro-mechanical conversion materials, and applications for electrical and optical devices are discussed. In this review paper, especially organic light emitting diodes, tunneling junctions using polyimide Langmuir-Blodgett films, tunneling spectroscopy and high-density recording, plastic actuators using conducting polymers, molecular self-assembly process for fabricating organic thin film devices are reviewed.

A new radar system is presented, which consists of one main radar and cooperative plural transponders. The transponders are integrated in the respective retrodirective antennas which are arranged beyond the horizon in such a manner as they surround the main radar. An algorithm for determining the three-dimensional target position is given. Computer simulations have been made for different target positions by assuming measurement errors. A target whose monostatic radar cross section is small or has been specially reduced by absorbing materials could be detected by this system if it is properly constructed.

Radio transmission technologies for IMT-2000 are being studied and standardized all over the world. Several national/regional standardization bodies are developing proposals on radio transmission technologies to meet the cut off date of June 30, 1998 set by ITU. This paper shows necessity to develop and standardize IMT-2000 in Japan, principle attitude on IMT-2000 standardization, selection process of W-CDMA, and the current situation of study on IMT-2000 in ARIB (Association of Radio Industries and Businesses).

A photorefractive ring resonator with self-pumped four-wave mixing (PRRR-SPFWM) in which the Cat mirror region and the four-wave mixing region are formed in a single photorefractive crystal is proposed, and the steady-state analysis of this unknown device is first performed. Since the backward pump beam is generated as a phase conjugate of the forward pump beam in the Cat mirror region, counterpropagation of both pump beams is spontaneously obtained. We analyze its oscillation intensities in steady state, and show that the threshold coupling strength of oscillation depends on the cavity mirror reflectivity and the reflectivity of the Cat mirror region. We also show interesting property of PRRR-SPFWM, the possibility to switch over between unidirectional and bidirectional oscillation by controlling the amplitude of coupling strength.

Testing for delay faults is very important in the verification of the timing behavior of digital circuits. When a circuit which is unable to operate at the desired clock speed is identified, it is necessary to locate the delay fault(s) affecting the circuit in order to remedy the situation. In this paper, we present a path-tracing method of multiple gate delay fault diagnosis in combinational circuits. We first present the basic rules for deducing suspected faults based on the multiple gate delay fault assumption. Next, in order to improve diagnostic resolution, we introduce rules for deducing non-existent faults based on the fault-free responses at the primary outputs. Using these rules, we present the detailed method for diagnosing multiple delay faults based on paths sensitized by test-pairs generated for marginal delays and gate delay faults [7]. Finally, we present results obtained from experiments on the ISCAS '85 benchmark circuits. The experimental results show the effectiveness of our method.

In this paper, we briefly describe the proposed radio access scheme based on CDMA/FDD for next-generation mobile radio systems, and evaluate its performance through laboratory and field experiments on transmission power control (TPC) and diversity, which are the key technologies to achieve efficient CDMA systems. The design of the practical TPC method is discussed, and a robust method is presented for operation in low signal to interference power ratio (SIR). Laboratory experiments demonstrate that space and path diversity effectively improve the TPC performance in the Doppler frequency range of 40 to 80 Hz, and reduces the required Eb/N0 to achieve the BER of 10-3. The necessary diversity order for multipath fading mitigation in all the Doppler frequency range is also investigated. Through the field experiments in urban area of Tokyo using a developed system at 0. 96 Mcps, a low required Eb/N0 of 2. 8 dB can be obtained because of the effectiveness of the diversity.

From an information geometric viewpoint, we investigate a characteristic of the submanifold of a mixture or exponential family in the manifold of finite discrete distributions. Using the characteristic, we derive a direct calculation method for an em-geodesic in the submanifold. In this method, the value of the primal parameter on the geodesic can be obtained without iterations for a gradient system which represents the geodesic. We also derive the similar algorithms for both problems of parameter estimation and functional extension of the submanifold for a data in the ambient manifold. These theoretical approaches from geometric analysis will contribute to the development of an efficient algorithm in computational complexity.

This paper newly proposes the CMT/IM/DD system for universal radio access networks where radio base stations (RBSs) and an optic backbone network are universally available among different radio services and providers. In the proposed system, the Chirp Fourier transformer at an RBS, converts the received FDM multiple radio service signals into optical TDM format signals, then transfers them over the optic fiber-link. This paper is focused on the discussion about the performance on the up-link of the CMT/IM/DD system. A new type of the configuration of CMT and the direct demodulation for the CMT signal are also proposed, and the SNR considering inter-symbol and inter-channel interferences caused by the CMT is theoretically analyzed. Analysis results show that the overall SNR performance of the CMT system is superior to the conventional SCM system when the number of radio channels is more than 26.

Low-profile, miniaturized and highly efficient power inverters are required to light up backlights, which include cold cathode fluorescent lamps (CCFLs), in color liquid crystal displays (LCDs), replacing conventional power inverters with electromagnetic transformers. The object of this study is to actualize a power inverter to which a novel multilayered piezoelectric ceramic transformer operating in the third order longitudinal mode is applied. The piezoelectric transformer has a symmetrical structure in the lengthwise direction and its generating part operates in a piezoelectric stiffened mode in order to increase both energy conversion efficiency and power density. This transformer has great advantages. Namely, all the electronic terminals in this transformer can be connected at the vibration nodes of the transformer, which contributes to the guarantee of stable transformer performances at high power operation, and this transformer is superior in impedance matching against the backlight load at steady state, because the output impedance of this transformer is much lower than that of conventional Rosen type transformers. Then a power inverter with the transformer was fabricated. In this power inverter, a separately excited oscillation circuit was adopted to drive the transformer with high efficiency, and the transformer drive frequency was controlled by detecting the backlight current in order to adjust the backlight luminance properly. As a result, the fabricated power inverter exhibited more than 90% overall efficiency and 4. 5-W output power, which is enough power to light up a 9. 4 inch color LCD, including the stray capacitance loss resulting from CCFL mounting. The luminance value on a light transmission plate of the backlight was more than 2000 cd/m2.

Non-uniform traffic can affect communications quality in microcell systems, and this disparity in communications quality between base stations (BSs) lowers the system efficiency in CDMA systems. If traffic distribution and propagation conditions are already known during the introduction of a CDMA system, it is desirable to design cell areas according to the non-uniformity of traffic distribution and BS locations. Cell area is determined by the transmission power of the pilot-signal from the BS and it is necessary to control the transmission power of mobile stations in the uplink, which is determined by the desired power level at the BS, according to the cell area. The disparity in communications quality can be rectified by optimally designing the two parameters of the pilot-signal power and desired power level. This paper describes an algorithm for setting both the pilot-signal power and the desired power level during the cell design stage in CDMA systems. The proposed algorithm operates that the communications qualities of all BSs in the system converge to average quality by adjusting the two parameters. The parameters of all BSs in the whole system can be determined through computer calculation. Through performance evaluations, we confirmed that the average SIRs of all BSs attained almost the same value and the variance between the BSs was less than half by adopting the cell design algorithm when there was dispersion in BS placement. This algorithm is also effective using the actual measured SIR after a system has been established.

This paper proposes a scheme for synchronization of stored video and audio streams in PHS. A video stream of H. 263 is transmitted over a PHS channel with ARQ control, while an audio stream of 32 kbit/s ADPCM is sent on another channel without any control. In order to preserve the temporal constraints within the video stream as well as the relationship between the video and audio streams, we adopt a new control scheme which modifies the target output time according to the amount of video data in the receive-buffer. Through simulation we assess the characteristics of this scheme in both random and burst error environments and confirm the effectiveness of the scheme.

With the advance of computer technologies, mobile computers can hold many local resources in themselves. In many cases it is impossible to announce local resources on them because almost information announcement systems are not designed for them. In this paper, an information announcement system for mobile computers based on WWW is proposed. The system efficiently announces resources on mobile computers independently of whether they are connected to a network or not, and wherever they are connected. The system can also select suitable announcement methods according to the type of resources. We implement a prototype of proposed system and evaluate it. The result of evaluation confirms effectiveness of the proposed system.

We have developed a new type of phase interpolation DDS with a digitally controlled delay generator. The new DDS is similar to a sine output DDS in that it produces low spurious signals, but it does not require a sine look-up table. Periodic jitter in the MSB of the DDS accumulator is reduced with the digitally controlled delay generator. Experimental results confirm successful frequency synthesizer operation in which the spurious signal level is successfully reduced to less than that the MSB of the accumulator.

This letter proposes a method to transform normalized ARMA lattice filters, which are originally realized for signal analysis, into signal synthesis lattice filters. Although the transformation method has been proposed for normalized ARMA lattice filters with the MA order which is greater than or equal to the AR order, it has not been done when the AR order is greater than the MA order. With the proposed method, once an ARMA lattice filter with the AR order greater than the MA order is realized, then it can be transformed to the signal synthesis filter.