This paper describes a 0.8-µm CMOS LSI developed for a 156-Mb/s serial interface in ATM switching systems. Recently, there have been increasing problems of connector pin neck and higher power consumption when enhancing switching system capacity. To overcome these problems, we have developed an LSI with a high-speed interface by using CMOS technology to achieve low power consumption. A low-swing differential signal level is used to achieve 156-Mb/s data transmission. We named this new circuit technique ALTS (Advanced Low-level Transmission circuit System). Using the LSI, transmission can be achieved between boards or racks through a 10-meter twisted pair cable. The LSI has a 156-Mb/s transmitter-receiver, a serial-to-parallel converter and a parallel-to-serial converter. It performs 19.5-Mb/s parallel data/156-Mb/s serial data conversion and 156-Mb/s serial data transmission. In addition, it has a bit phase synchronizer and cell synchronizer, which enables it to transmit and synchronize serial data without a paralleled clock or a paralleled cell top signal, by distributing a common 156-MHz clock and a common cell top signal to the whole system. We evaluated the bit error rate and timing margin on data transmission under several conditions. The results show that we can apply this LSI to commercially available ATM switching systems. This paper also describes methods of expanding switch capacity and transmitting 624-Mb/s data using this LSI.

The approximation of the gain characteristics of linear phase FIR digital filters is reduced to the approximation by cosine polynomials. Therefore we can easily obtain an optimum solution under the LMS of Chebyshev error criterion. However the optimum solution does not always meet practical specifications, especially in the case where the gain is specified strictly at some angular frequencies. On the other hand in such a case, it is known that interpolation technique can be suitably applied for the approximation mentioned above. However, in this case, we encounter another difficulty in the approximation caused by interpolation. In order to overcome the above difficulty, this paper proposes a new method utilizing both of the interpolation and LMS techniques. Some parameters included in approximating functions are used to satisfy prescribed interpolating conditions and the other parameters are used to minimize the approximation error under the LMS criterion. In addition, interpolation technique is extended to include the case in which also higher derivatives are taken into interpolation conditions to make smooth interpolation. An example is shown to illustrate the effectiveness of the proposed method.

This paper presents newly developed very small MMIC bandpass filters along with novel positive and negative feedback techniques. In order to maintain the expected Q factor without unwanted oscillations in the positive feedback loop, the unity-coupler principle is proposed to stabilize the constituent amplifier. A prototype bandpass filter is monolithically integrated in a very small area of only 0.1 mm2 on a GaAs substrate. A sharp factor as high as 5.6/1-30 dB is achieved near the frequency range of 1 GHz. The other technique presented in this paper is to achieve the bandpass function without using any positive feedback. This is negative feedback consisting of feedback elements with the unique variable transfer function of b/(1as). A variable bandpass filter based on this design concept is also fabricated in a 1.21.3 mm2 area on a GaAs substrate. It has both a varactor and varistor integrated in the circuit, resulting in an independently controllable center frequency and Q factor. It is shown experimentally that the Q factor is controllable over a remarkable range of 20 to 400 and the center frequency is broader than 100 MHz at the 1 GHz band. By cascading two of the fabricated MMIC chips, a forth-order frequency response is successfully obtained along with a 35-40 dB forward gain and an in-band gain flatness of 0.35 dB.

A wideband high power amplifier design using a novel band-pass filter with FET's parasitic reactances has been developed. The feature of this design is in that it can provide wide bandwidth and high gain of high power amplifiers. Furthermore, the lower cutoff frequency and bandwidth can be varied independently. With the use of this design, a Ku-band two-stage high power amplifier having a bandwidth of 18% has achieved a linear gain of 9.751.75 dB, a saturated output power of greater than 37 dBm, and a power-added efficiency of greater than 10.4%.

Existing algorithmic debugging methods which can locate faults under the guidance of a system have a number of shortcomings. For example, some cannot be applied to imperative languages with side effects; some can locate a faulty function but cannot locate a faulty statement; and some cannot detect faults related to missing statements. This paper presents an algorithmic critical slice-based fault-locating method for imperative languages. Program faults are first classified into two categories: wrong-value faults and missing-assignment faults. The critical slice with respect to a variable-value error is a set of statements such that (1) a wrong-value fault contained in any instruction in the critical slice may have caused that variable-value error, and (2) a wrong-value fault contained in any instruction outside the critical slice could never have caused that variable-value error. The paper also classifies errors found during program testing into three categories: wrong-output errors, missing-output errors, and infinite-loop errors with no output. It finally shows that it is possible to algorithmically locate any fault, including missing statements, for each type of error.

To reduce the phase noise of MMIC phase-locked oscillators (PLOs), we study the phase noise properties of PLOs given that the oscillator Q factor is relatively low in monolithic circuits. Such PLOs must have wide bandwidth in order to suppress monolithic oscillator noise. Therefore, to reduce MMIC PLO phase noise, the phase noise in the PLO passband has to be decreased. Noise generation by each component of the PLO, and its contribution to the output are discussed with emphasis on experimental estimation and rigorous analysis of the component phase- or baseband-noise. Based on these results, a new loop configuration is proposed for reducing phase noise in the PLO using a low Q-factor oscillator. It is demonstrated experimentally that PLOs based on the new loop exhibit 7 dB lower phase noise than conventional PLOs.

This paper discusses the development of a monolithic image-rejection mixer with very wide-band (about 60% of the center frequency) image rejection characteristics for 16-QAM digital microwave radio communication receivers. The mixer can be commonly used in 4-, 5-, and 6-GHz bands, which reduces the cost. The mixer consists of a wide-band 90splitter, in-phase divider and drain LO injection mixers. They are designed on a single 2.81.8 mm2 GaAs chip based on a uniplanar MMIC lumped-constant element technique. The mixer achieved an image rejection ratio of greater than 25 dB and a conversion loss of less than 2 dB at a wide LO frequency range from 3.5 to 6.5 GHz, without consuming any DC power.

We applied a filip-chip-bonding technique to GHz-band SAW filters. The SAW filters mounted by the stud-bump-bonding (SBB) technique which is a kind of flip-chip-bonding technique showed almost the same frequency characteristics as those mounted by the conventional wire-bonding technique at 1.5 GHz. The SAW filter configuration, fabrication process using the SBB, and its electrical characteristics are described and discussed. The SBB technique has a lot of potential to reduce the size and weight even above GHz frequencies.

This paper presents a simple numerical method for calculating the stationary transmission and reflection characteristics of a variety of nonlinear Fably-Perot resonators. In nonlinear media, Maxwell's equations are directly solved by using a numerical integration of complex variables. The input-output characteristics of the Kerr-like nonlinear film without reflection mirrors and with multilayer mirrors have been calculated to demonstrate the usefulness and versatility of the proposed method and to find out resonator configurations exhibiting optical bistability at low incident-power levels. The effects of saturation in the nonlinear permittivity on the input-output characteristics have also been investigated. It has been found that a single nonlinear film with oblique incidence exhibits optical bistability without using reflection mirrors even if the refractive index of the film is low. This offers a simple method for measuring third-order nonlinearities of optical materials.

AlGaAs/GaAs HBT ICs for high bit-rate optical transmission systems, such as preamplifier, D-F/F, differential amplifier, and laser driver, have been newly developed using the hetero guard-ring fully self-aligned HBT (HGFST) fabrication process. In this process, the emitter mesa is ECR-RIBE dry etched using a thick emitter-metal system of WSi and Ti-Pt-Au as etching mask, and a hetero guard-ring composed of a depleted AlGaAs layer is fabricated on p GaAs extrinsic base regions. This process results in highly uniform HBT characteristics. The preamplifier IC exhibits a DC to 18.5-GHz transimpedance bandwidth with a transimpedance gain of 49 dBΩ. The rise time and fall time for the D-F/F IC are 30 and 23 ps, respectively. The laser driver IC has a 40-mAp-p output current swing. The differential amplifier exhibits a DC to 12.1-GHz bandwidth with a 14.2-dB power gain.

We describe an approach for modelling a person's face for model-based coding. The goal is to estimate the 3D shape by combining the contour analysis and shading analysis of the human face image in order to increase the quality of the estimated 3D shape. The motivation for combining contour and shading cues comes from the observation that the shading cue leads to severe errors near the occluding boundary, while the occluding contour cue provides incomplete surface information in regions away from contours. Towards this, we use the deformable model as the common level of integration such that a higher-quality measurement will dominate the depth estimate. The feasibility of our approach is demonstrated using a real facial image.

In the field of computer vision the detection of edges in an image serves to simplify the date in the early stages, into a form which is more easily processed by the computer. But because of noise or due to the inherent weaknesses of the chosen edge detector, gaps or interruptions in the edges may be formed. In order for further processing to proceed with accuracy and confidence, these gaps must be filled or linked to form a more continuous edge. Proposed in this paper is a unique method of edge linking. This method consists of three steps, labelling, linking and merging. The procedure makes use of global information in the labelling process and local information with the use of templates in the linking and merging processes. As a result of the unique way in which the gaps between edge segments are filled, distortion of the edge image is kept minimal. One other advantage of the proposed edge linker is that it can be used in combination with different edge detection schemes. To show the effectiveness of the proposed method, comparisons are given. These include the linear feature extraction method of Zhou et.al., upon which the proposed method is based and also outputs from a method described by Nevatia.

A 170-mW class GaAs Power MESFET and a 10-mW class MMIC pre-amplifier operating at very low drain bias have been developed for use in personal handy phones (PHP). The MESFET provided P0(1dB)22.5 dBm, ηadd38.8% at VDS3 V with IDS0.14 A (0.4 IDSS) at 1.9 GHz, and also provided P0(1dB)22.4 dBm, ηadd32.6% at VDS2 V with IDS0.24 A (0.6 IDSS). The MMIC using the same MESFET structure had a linear power gain of 13 dB, a linear output power of more than 10 dBm, and P0(1dB)13.7 dBm, ηadd24.3% at VDD3 V with ID30 mA at 1.9 GHz. The MESFET had a buried p-layer and our improved LDD n self-aligned structure both of which were optimized so as to satisfy a high V(BR)GDO of more than 10 V, a minimized bias dependence of S-parameters and low VK of less than 0.5 V.

A dielectric rod waveguide applicator for microwave heating such as microwave hyperthermia is described. The applicator consists of the acrylic cylinder filled with deionized water. By circulating the deionized water, the dielectric rod waveguide applicator acts as a surface cooling device, so that it doesn't need any bolus. This surface cooling device enables the dielectric rod waveguide applicator to control the site of effective heating region along the depth axis. Useful pattern of the circular or spheroidal shape and axially symmetric effective heating region were obtained. Furthermore metal strips provided on the aperture of applicator control the shape of the heating pattern.

This paper briefly considers future broadcasting technologies, including digital television as a system for the near future and three-dimensional television as a part of a system to be developed rather later. However, due to limitations of space, this paper discusses only video technologies in detail. First, the status of bit reduction technologies for digital television is described and then satellite digital broadcasting and terrestrial digital broadcasting are also discussed. The authors stress the necessity of the further development of digital video compression technologies. Later, we discuss three-dimensional television, we describe requirements for the service and the present status of the technologies. And last, the paper considers the future prospects for a three-dimensional television service.

The transient spectral spread of directly modulated DFB LD's, which appears in the time-resolved chirping measurement, is studied experimentally and numerically. Such a phenomenon has been already reported as a side mode oscillation called "subpeak", but there has been little argument as to the physical origin. We make it clear that the subpeak is a spurious mode due to the influence of the photodetector bandwidth. The minimum photodetector bandwidth which is necessary in the time-resolved chirping measurement is examined. Furthermore the distortion of the long-distance transmitted waveform is also explained by one mode oscillation.

This paper describes bandpass filters using linear tapered transmission line resonators (LTLR's). Bandpass filters are designed on the basis of the approximate description of LTLR's with cascaded multi-sections of uniform transmission lines whose widths are slightly different. By this design method, the fundamental characteristics of LTLR's and filter design parameters can be easily obtained using a general-purpose microwave circuit simulator. Trial LTLR bandpass filters showed excellent performance such as low insertion losses and the ability to control spurious responses, then their measured responses indicated close correspondence with the design results.

It has been reported that generalization performance of multilayer feedformard networks strongly depends on the attainment of saturated hidden outputs in response to the training set. Usually standard Backpropagation (BP) network mostly uses intermediate values of hidden units as the internal representation of the training patterns. In this letter, we propose construction of a 3-layer cascaded network in which two 2-layer networks are first trained independently by delta rule and then cascaded. After cascading, the intermediate layer can be viewed as hidden layer which is trained to attain preassigned saturated outputs in response to the training set. This network is particularly easier to construct for linearly separable training set, and can also be constructed for nonlinearly separable tasks by using higher order inputs at the input layer or by assigning proper codes at the intermediate layer which can be obtained from a trained Fahlman and Lebiere's network. Simulation results show that, at least, when the training set is linearly separable, use of the proposed cascaded network significantly enhances the generalization performance compared to BP network, and also maintains high generalization ability for nonlinearly separable training set. Performance of cascaded network depending on the preassigned codes at the intermediate layer is discussed and a suggestion about the preassigned coding is presented.

This paper presents a new Hypermedia communication platform supported by the new digital image medium of super high definition (SHD) images. This new image communication platform will encourage the integration of all existing media to realize rich and realistic visual communication over B-ISDN. SHD images have a resolution of more than 20482048 pixels and the frame rate is more than 60 frames/sec. To achieve an real-time compression of SHD moving images, parallel signal processing systems with peak performance of 0.5 Tera Flops will be necessary. The specification requirements, signal processing and communication technologies needed to achieve SHD image communication are discussed. The relationship of hypermedia to SHD images is also examined.