Portable Telephones Research Articles

The significance of E. A. Martel for speleology in Slovenia

Three times Martel visited karst in Carniola: in 1879, 1893 and 1896. The importance of his visits and later publications lies in fact that he informed the francophone public about our karst and caves; his visit stimulated the introduction of new technical means into the then Austrian speleology (folding boat, portable telephone); in 1893 due to his researches Postojnska jama became the longest cave in Europe; public found out about existence of caving society Anthron, which was the first Slovene and Slav society of the kind; he set up the foundations of international speleological co-operation and included into it Austrian speleologists; he informed the public about Putick and his researches of karst underground; unknowingly he helped to introduce the term “karst” into francophone public.

Use of the method of moments for analysis of antennas composed of conducting wires and plates

When the characteristics of antennas with a junction of conducting wires and plates, such as antennas used for portable telephones, are analyzed by the method of moments, a special segment having a wire current and a radial surface current has been used. However, the radius of the radial current of this segment is required to be greater than about 0.2 wavelengths to obtain accurate numerical results. Therefore, this method cannot be applied to antennas having conducting plates whose dimension is less than 0.2 wavelengths. In this paper, another special segment, the “joint patch segment,” which connects the radial segment with the planar segment, is proposed to overcome the limitations of the radial segment. In order to demonstrate the accuracy and the advantages of the proposed method, the frequency characteristics of the input impedance of the planar inverted F antenna mounted on a conducting box are calculated and compared with experimental data. © 1997 Scripta Technica, Inc. Electron Comm Jpn Pt 1, 80(7): 61–69, 1997

携帯電話による医療機器への電磁干渉の確認

携帯電話による医療機器への電磁干渉が衆目を集めている。当院でも実際にどのような医療機器に,どういった干渉を起こすのか確認を行った。実験は,携帯電話3機種による医療機器への電磁干渉の確認を行い,医療機器21台中に12台に干渉を確認した。確認を行った医療機器は生命を維持するのに重要な機器であり,病院内での携帯電話の使用には適切な規制が必要と思われた

ディジタルスチルカメラと携帯電話を用いた視覚障害者支援システムの検討

ディジタルスチルカメラと携帯電話を用いた視覚障害者支援システムの検討

Improvement of soft magnetic properties of nanocrystalline FeMB (MZr and Nb) alloys and their applications

With the aim of developing good soft magnetic materials, we examined the magnetic properties of nanocrystalline FeMB alloys containing various additional elements. The nanoscale bcc FeZrNbBCu alloys exhibited excellent soft magnetic characteristics of 1.5 to 1.6 T for saturation magnetization (B s), 1 to 2 A/m for coercive force (H c), 10×10 4 to 12×10 4 for permeability (μ e) at 1 kHz and nearly zero saturated magnetostriction (λ s) which had not been achieved for soft magnetic materials reported up to date. The excellent soft magnetic characteristics have already enabled the practical use as pulse transformers for portable telephones which require high μ e above 10 5 at 1 kHz and high B s above 1.5 T. The application fields are hereafter expected to increase significantly because of the excellent soft magnetic properties which have been obtained only for the present materials.

Workhorses of the electronic era [microcontrollers

A closer look at the machines and appliances almost always reveals a microcontroller within. Controllers are embedded in cordless and portable telephones, point-of-sale retail electronic cash registers, scanners of all kinds, security systems, automobiles and gas pumps, automated tellers, computers, and compact disks and disk drives, not to mention phone-answering, fax, vending, and washing machines. Here, the author describes how today's microcontrollers are performing better than ever through their use of high-level languages and multitasking techniques.

An Exponential-Family Multidimensional Scaling Mixture Methodology

A multidimensional scaling methodology (STUNMIX) for the analysis of subjects' preference/choice of stimuli that sets out to integrate the previous work in this area into a single framework, as well as to provide a variety of new options and models, is presented. Locations of the stimuli and the ideal points of derived segments of subjects on latent dimensions are estimated simultaneously. The methodology is formulated in the framework of the exponential family of distributions, whereby a wide range of different data types can be analyzed. Possible reparameterizations of stimulus coordinates by stimulus characteristics, as well as of probabilities of segment membership by subject background variables, are permitted. The models are estimated in a maximum likelihood framework. The performance of the models is demonstrated on synthetic data, and robustness is investigated. An empirical application is provided, concerning intentions to buy portable telephones.

Thin Vibrator Alarm Using a Cantilever Piezoelectric Actuator

This paper deals with a cantilever piezoelectric vibrator alarm, which is aimed to be used in such telecommunication devices as pagers and portable telephones. A specific merit of this new alarm is that it is soundless and is available in a very thin form because of its simple construction. As results of experimental investigations, the tactile sense and the vibrational amplitude achieved by a pager equipped with the vibrator alarm were found to be similar to those of pagers currently on the market, in which a DC motor alarm was utilized.

Overall Mortality of Cellular Telephone Customers

Unlike mobile cellular telephones, in which the antenna is not part of the handset, a portable cellular telephone exposes the user's head to radio frequency energy transmitted from the antenna. This exposure has prompted concerns about potential biological effects, including brain cancer. As a first step in a record-based mortality surveillance of cellular telephone customers, we report on overall mortality of a cohort of more than 250,000 portable and mobile telephone customers during 1994. We found age-specific rates to be similar for users of the two types of telephones. For customers with accounts at least 3 years old, the ratio of mortality rates in 1994 for portable telephone users, compared with mobile telephone users, was 0.86 (90% confidence interval = 0.47-1.53).

A Low-Profile Ladder Filter for Portable Telephones Employing Length Expander Mode

A low-profile piezoelectric ceramic ladder filter was developed. It is less than 2 mm high. Therefore it is suitable for super compact portable telephones. New rectangular bar resonators using the length expander mode were presented and a ladder filter was constructed using these new resonators. The optimization of capacitance ratio and resonator support structure in resonator design and a new piezoelectric ceramic material were discussed. In particular, the heat resistant properties of the material and the vibration transmission to the support structure were considered. These properties were improved by using the new ceramic material and a new support structure. Finally an experimental filter was constructed. It exhibited excellent characteristics which satisfied the specifications for the second IF filter of a digital cellular telephone.

Dual-band antenna for hand held portable telephones

A novel planar dual-band inverted F-antenna for hand held portable telephones has been realised to operate at 0.9 and 1.8 GHz bands. The dual-band antenna is almost the same size as a conventional inverted F-antenna operating at 0.9 GHz, and has an isolation between bands of better than 17 dB.

A 0.2-mW CMOS ΣΔ modulator for speech coding with 80 dB dynamic range

A CMOS /spl Sigma//spl Delta/ modulator for speech coding with continuous-time loopfilter is presented. Compared to switched-capacitor implementations, the relaxed bandwidth requirements of the active elements of the loopfilter reduce the power consumption. Furthermore, the need for an antialiasing filter at the modulator input is eliminated. A fourth-order, 64/spl times/ oversampling /spl Sigma//spl Delta/ modulator for application in portable telephones was designed and shows 80 dB dynamic range over the 300-3400 Hz voice bandwidth. Its input is directly connected to the microphone (maximum 40 mV/sub RMS/). Total harmonic distortion (THD) is below -70 dB at 95 /spl mu/A current consumption from a 2.2 V supply voltage. The active die area of the modulator is 0.5 mm/sup 2/ in a standard 0.5-/spl mu/m CMOS process.

A finite element analysis of the impact-contact problem of a portable telephone using I-DEAS and ADINA

A finite element analysis has been carried out to simulate the phenomenon of a portable telephone that falls and collides with a rigid surface. The new I-DEAS Master Series has been used to create the complicated geometry and finite element mesh for the portable telephone model. The finite element data obtained in I-DEAS is converted to input data for the ADINA system by TRANSOR, an interface program between I-DEAS and ADINA. The large scale finite element model has been solved by the iterative solver on a SUN 4 10 engineering workstation. Interesting results at various stages are: free-fall, impact-contact and, rebound. The possibility of partial breaking of the portable telephone undergoing the impact-contact condition is also discussed.

Improved Power Durability of Surface Acoustic Wave Filters for an Antenna Duplexers

For portable telephone applications, we improved the power durability of ladder-type filters composed of one-port surface acoustic wave (SAW) resonators. In these ladder-type filters, the chip temperature was raised and power durability was weak around both cut-off frequencies in transmission characteristics. Power durability tests of a duplexer composed of ladder-type filters showed that the receiver filter (Rx) in which the power was leaked from the transmitter one (Tx) was weaker than the Tx. We therefore studied Rx in this work. In filter design, reducing the resonator resistance to suppress the rise in chip temperature improved power durability. The lifetime of electrode material was improved to up to 10,000 times longer than that of an Al-Cu single-layer film by use of a 3-layered film of Al-Cu/Cu/Al-Cu.

Cordless loud speaking telephone

A cordless loud-speaking telephone of the present invention is shaped to be placed on a table or desk or to be suspended from a ceiling. Unlike cordless portable telephones of the handy transceiver type, it enables hands-free talking or communication through a receiving speaker and a transmitting microphone located outside a casing. An antenna conductor and counterpoises are projected from the casing, and a microphone is attached to the counterpoises or the antenna conductor such that the microphone is separated as remotely as possible from the speaker in the casing. As a result, howling and echo which disturb talking or communication via the telephone can be suppressed. Further, plural microphones are attached to plural antenna conductors or counterpoises to cancel the sound of the receiving speaker to prevent the voice from again entering the microphones, or the microphones are attached to the counterpoises or the antenna conductors in such a manner that they effectively receive the voice from the mouth of a talking person from a certain direction. This enables hands-free talking or communication to be more effectively and reliably achieved.

Questions of Identity in Contemporary Hong Kong Theater

In July 1997, Hong Kong will be handed over to the control of the People's Republic of China (or as is the customary phrase) after more than a century of British rule. The Cantonese, who populate Hong Kong and a good deal of southern China, have tolerated the foreign presence fairly amicably and have benefited from the territory's low taxation and trade freedoms. Today, Hong Kong is one of the world's most dynamic financial centers. In most banks there are video monitors displaying the latest share prices on the Hang Seng Index; at underground stations large screens trail live foreign currency exchange rates. Pocket pagers bringing instant financial news are commonplace; portable telephones are ubiquitous. By and large, Hong Kong is a vibrant, financially-oriented, sophisticated, and informed society. Cantonese movies with English subtitles offer one of the many benefits of living in Hong Kong. They are an immensely popular formula-oriented art form. One story runs something along these lines: a mainland Chinese policeman arrives in Hong Kong to investigate a crime. He is gauche and unsophisticated - a sort of Chinese Inspector Clouseau. Someone's mobile phone rings next to him on a bus and he jumps with fright. He tells jokes that no one finds funny; he orders a beer and then swaps it for a glass of tap water because he considers the price extortionate; he is baffled by dishwashers, compact disk players, kettles that turn themselves off, urinals that flush automatically. Predictably he solves the crime; predictably, the smart, sophisticated Hong Kong heroine, who has spent so much of the film in scornful mood, falls in love with him. The intentions of Cantonese films are usually comic, and perhaps we should not take them too seriously as comments on the

Electromagnetic energy exposure of simulated users of portable cellular telephones

Describes a method to quantify the RF exposure of the users of portable cellular phones in terms of specific absorption rate (SAR). The method involves a robotic system to accurately position an isotropic E-field probe within equivalent biological tissue. The user of cellular phones is simulated by a simple human model (a phantom) consisting of a thin shell of fibreglass filled with a liquid having the complex dielectric constant of human brain tissue. The authors present the results of the dosimetric assays conducted using current and previous models of cellular telephones. The peak SAR values detected using the measurement method described are below the limits recommended by the National Council for Radiation Protection and Measurements (NCRP) Report 86 for the protection of humans exposed to RF electromagnetic energy.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

特集 薄形・多層配線板による最小・最薄・最軽量機器実装技術の動向 携帯電話

特集 薄形・多層配線板による最小・最薄・最軽量機器実装技術の動向 携帯電話

Consideration of effects of handover during data communications and error reduction

AbstractEfficient handover during both mobile telephone and portable telephone communication is a technology essential in implementing ideal mobile communications. However, there exists the possibility of a transmission data slip during the process of circuit switching, which has become a problem in communication using terminal machines such as data modems and FAX machines connected to mobile telephones and portable telephones.In this paper, a transmission data slip accompanying route changes inside digital exchanges in a handover during telephone communications is assumed; it is shown on the basis of this assumption that a lag in synchronism occurs in the receiver terminal equipment.Then a sync lag of the receiver terminal modem during handover has been confirmed by tests using actual analog cellular phones and a transmission data slip has been shown on the basis of the results of the tests. In this paper, a synchronism control method minimising the sync lag has been studied. The efficacy of this method has been confirmed as a result of applying the method to a mobile telephone FAX modem.

Design of a low‐phas noise VCO for an analog cellular portable radio application

AbstractA voltage‐controlled oscillator (VCO) with a small power consumption and an excellent signal‐to‐noise (C/N) ratio was developed for a portable telephone. In the domestic analog portable cellular portable telephone, C/N is reguired to be more than 107 dBc/Hz at an offcarrier frequency of 12.5 kHz. to realize this value, the noise behavior was studied for a 900‐MHz oscillator using a small‐signal, high‐frequency silicon transistor.First, the relationship between the transistor noise and the C/N, the operating voltage and current dependence of the C/N and the relationship between the collector breakdown voltage and the oscillator output were studied experimentally. A transistor was selected which is most suitable for a low‐noise VCO at a low operating current of 3 to 7 mA.Next, by using this transistor, the relationship between the unloaded Q of the resonant circuit and the C/N was studied. It was found that Q of 60 is needed to obtain a C/N with a 3‐dB margin. On the other hand, with a view to miniaturizing the resonator, a dielectric coaxial resonator with a material having a relative permittivity of 90 was studied experimentally. A Q of 200 was realized with a resonator having a cross‐sectional size of 1.8 × 1.8 mm2. By combining it with a varactor diode, a Q of more than 60 was attained. Based on these results, a low‐noise VCO was realized which has dimensions of 10 × 10 × 3 mm and is operated with a power supply voltage of 3 V and a current consumption of 10 mA.