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For the Tian-Guang HVDC Transmission Project, the fundamental frequency overvoltages which can occur as a result of partial or complete interruption to transmitted power play an important role in the design and operation of the converter at Tianshengqiao. The paper describes some of the operating conditions which may result in high values of overvoltages along with solutions and trade-offs which were adopted to limit the overvoltages to acceptable levels.

Passive measurements of a sample of an Erbium-doped silica fibre were performed following the standard methods. A Photon Kinetics equipment was used for spectral attenuation, mode field-diameter and cut-off wavelength measurements and for geometrical characterisation.

This paper has identified the key elements in designing a CDMA system in which two scenarios are considered: non-uniform capacity but uniform cell-size scenario; and nonuniform capacity and non-uniform cell-size scenario. Due to the many variables, the number of channels in each cell has to meet certain conditions from the reverse channel formula. Then the total transmitted power of all the forward-link channels at each different cell site can be determined based on the worst-case interference conditions.

During transcranial Doppler insonation of the basilar artery, 15 normal subjects heard high-frequency tones similar to tinnitus. The pitch of the tones equated with the PRF, and intensity equated with loudness. Alteration of pulse length did not change the tones heard, and the effect was highly dependent on probe position and direction. This is an example of ultrasonography acting as a sensory stimulus. The exact mechanism and implications of this effect will need to be clarified by further investigation. Although this phenomenon is not proved to be harmful, it would seem prudent to use the minimum transmitted power necessary to obtain a satisfactory signal from the basilar artery.

Plastic hollow fibers for the transmission of CO2 laser energy in curved paths were produced by plating the inner surface of plastic tubes with a metal film and dielectric film upon it. These fibers can transmit high power up to 40 W at the outlet, with high transmission yield even through several bendings. A three-dimensional simulator was built to simulate paths in the dog's body and the outlet power was measured. From the achieved data the expected transmitted power during real surgery was appreciated. The fibers were checked for their influence on live tissues of dogs. Incisions were made in the liver and ulcers in the dogs' stomachs were treated. The fibers were inserted into the stomach through the dogs' esophagus. Complete healing was observed after four weeks.

Telegraph and radiofrequency (longwave, medium wave, shortwave) broadcasting stations have been in operation for over half a century. Some of these facilities are assigned to transmit worldwide and must be operated with high transmitted power (field strenghts), sometimes exceeding 1 MW. As the field strenght may be very high in the immediate surroundings of radiofrequency broadcasting stations, limits for the allowable exposure to radiofrequency fields were established early. For example, allowable exposure limits in Germany are set forth in DIN/VDE 0848 by the national standard committee “Deutsches Institut fur Normung”, and in the United States in ANSI C95.1 provided by the American National Standards Institute. Concerning exposure limits, broadcasting companies must provide fences around transmitting facilities. Depending on power and frequency of transmission, fences may surround areas from 400 m2 to more than 100,000 m2.

An integral parameter is proposed for characterizing the long-term instability of multiprobe waveguide transducers of transmitted power. Experimental results are presented.

In this study we report a novel strained InGaAsP/InGaAsP/InAsP multiquantum well structure for electroabsorption modulators giving high power saturation together with polarization insensitivity. A careful design of the structure in terms of band‐gap engineering has been performed to fulfil both requirements. The polarization sensitivity is less than 0.5 dB for the on‐state and for a wide range of wavelengths. The carrier escape time, even at very low field, is estimated at lower than 20 ps. The transmitted power for different wavelengths is linear up to 16 dBm.

For multiple transmitters, with over-sampling and multiple antennas at the receiver, an algorithm is presented to achieve blind mitigation of both intersymbol interference (ISI) and multiple access interference (MAI) by selectively periodically varying the transmitted power of each user. In addition, the permutation ambiguity of many source separation algorithms is overcome.

An algorithm for allocating bits to several carriers of a discrete multitone (DMT) symbol is proposed. The target of the algorithm is to assign the required bits (supported service) among the carriers so that the transmitted power is kept to a minimum. Ultimately, this algorithm is a transmitted power back-off algorithm which enables the system to operate at the minimum required power, resulting in the minimisation of the crosstalk interference to other systems located in the same binder group. Even though this algorithm was originally designed according the very high speed digital subscriber line system specifications, it can equally be used in every DMT-based digital subscriber line system such as asymmetrical digital subscriber line systems.

The cutoff wavelength of a fibre is very quickly and accurately determined by a new method based on the analysis of transmitted power variations at the output. When excited by alternate even/odd field patterns. The results are in very good agreement with those obtained by the ITU-T recommended technique.

Acoustic radar records are reproduced to show the effects which may result from varying system parameters such as transmitted power, pulse length, pulse repetition frequency and recording techniques. Improved results can often be achieved by such variation but examples of records which are open to misinterpretation are also given.

We solve the problem of determining the average dielectric constant and thickness of the layers that constitute a stratified dielectric medium from measurements of transmitted power at a single frequency. Each sample of the medium that is available for measurement is modeled as a stack of ’’n’’ layers of dielectrics of thicknesses li and dielectric constants Ki (see Fig. 1). We assume that n, li, Ki, i=1,2,..., are all independent random variables and their values, of course, depend on the particular sample and the layer indexed by ’’i’’. Furthermore, it is assumed that the li are identically distributed with some exponential distribution and that the Ki are identically distributed. There are no other constraints or assumptions about these distributions except the following which are made more precise in the text: (1) The various averages of interest are finite. (2) Distributions which precipitate certain singular conditions (which is not a problem in ’’almost all cases’’) are excluded. Then the method de...

The authors have already proposed small-sized waveguides with periodically loaded posts along a single line placed inside the cut-off rectangular waveguides. This paper proposes small-sized waveguides with periodically loaded double posts which have two lines of posts inside the waveguides aiming at an increase of the transmitted power there. The phase constants, the field distribution and other characteristics were obtained theoretically. They were evaluated numerically and these numerical results were confirmed by experimental measurements. This paper considers the transmitted power. Using the same size of the waveguide with a single line of posts, the maximum transmitted power increased by a factor of 1.7 and the transmission losses were reduced by about 6.38 percent by using double posts for the same numerical results of the waveguide with a single line of posts. As in the case of the waveguide with a single line of posts, either slow waves or fast waves can be transmitted. The transmission characteristics can be controlled easier by the values of the reactive loads by the double post structure.

A system is described and analysed which applies random signal correlation techniques to ultrasonic flaw detection. The use of correlation and time integration techniques gives it a signal-to-noise ratio correlation gain of the order of 10 4 , and the use of a random transmitted signal whose range resolution is independent of its duration permits a peak-to-average transmitted power ratio of the order of unity. It is shown that random signal correlation systems should therefore be capable of much greater range and/or resolution than is possible with current pulse-echo systems.

A high-precision microwave system has been built to measure the complex permittivity of small needle-shaped specimens continuously with temperature. The system is based, in part, on the standard cavity perturbation technique, and works at constant input power and frequency to minimise errors due to standing waves. The loss produced by the specimen in the cavity is determined, with the use of a single calibration, by measuring the on-resonance transmitted power of a two-port cavity of novel design. For highly conducting specimens this is sufficient to give relative values of their conductivity with a precision of about 1%. In addition, by measuring the shift in resonance frequency produced by the specimen, an estimate can be made of the absolute value of the conductivity and, when the specimen is not too highly conducting, of the dielectric constant also.

We present quantitative results for the effect of cladding absorption on the transmitted power and impulse response of a typical multimode, graded-index fibre that is excited by a Lambertian source. Power attenuation is due to the absorbing cladding material and the radiation loss of the tunnelling rays. Graded-index fibres are shown to be far less susceptible to the effect of cladding absorption than step-index fibres.

Transmission holograms in dichromated gelatin are studied under conditions when a number of spurious gratings (both transmission and reflection types) are also present due to boundary reflections at recording. It is shown that the experimental results, in the form of transmitted power against incident angle measured on the developed hologram, agree well with the predictions of a simple, linear theoretical model based on coupled wave theory.

In previous papers, we have studied the variations of radiofrequency susceptibility of a junction versus dc polarization. Here, we study the effect of variations of the refraction index on a microwave. An increase of the carrier concentration produces a diminution of the index, a decrease of reflected power, and an increase of transmitted power. This is in agreement with the theory, which takes into account the local microwave field.

Impulse responses are calculated for parallel-beam injection into fibres havingα-type profiles with a varying from 1 to 8. The responses obtained exhibit characteristic features which can guide the interpretation of experimental investigations of such fibres. The ray model is used and leaky-mode attenuation is taken into account. Finally, the dependence of the transmitted power on the injection angle is investigated, suggesting a possible functional relation to the index profile.

Low-loss joints between single-mode optical fibers have been made without microscopic alignment, without fusing the tips, and without monitoring the transmitted power while the joints are assembled. The fibers are tightly held in an embossed groove; an index-matching liquid is added. Average power coupling efficiencies close to 90 percent in the red and to 85 percent in the infrared have been obtained. Mediocre end faces are acceptable. Realistic discrepancies between the fiber cladding diameters (slightly in excess of twice the core diameter) do not deteriorate the results.

The reflection of VHF radio waves from the sun has been observed regularly over the period April 19 to July 7, 1961, in a series of radar experiments conducted by the M.I.T. Lincoln Laboratory, Lexington, Massachusetts. The VHF radar system, designed for radio studies of the solar corona and other associated propagation research, is located near El Campo, Texas, at 29.00° north latitude and 96.25° west longitude. The radar was operated at a frequency of 38.25 Mc/s with a transmitted power of 500 kw, CW.

Laboratory abrasion data were obtained on various tread vulcanizates over a large range of severities, including the region equivalent to the low severity encountered on straight, smooth California highways. The constant transmitted power principle was used as a severity criterion for comparison of abrasion of different tread vulcanizates. Load, wheel angular velocity, and ambient temperature were held about equal to those prevalent during road tests. These data were compared with road tests on the same vulcanizates, conducted on tires tested on courses varying from low to high severity. The laboratory data and the California low severity test data show a high degree of correlation for BR vs SBR (50 HAF) over the entire range of severities tested. The loss rate-severity plots for BR and SBR show a crossover point, with the BR showing the higher abrasion resistance at the higher severities. The BR shows a substantially higher abrasion resistance than the SBR on the Texas straight highway course. This is in opposition to the California data, which shows a substantially lower abrasion resistance of the BR compared to SBR on the straight highway course. The abrasion rates for BR and SBR in Texas, California, and laboratory tests are consistent if the severity of the Texas course is assumed to be equivalent to a linear combination of at least two California or laboratory severities. A plausible cause of the difference between California and Texas results is the difference in pavement surface texture. This viewpoint is shown to be consistent with abrasion patterns observed on tires in the California and Texas straight highway tests. The laboratory data and California test data on NR relative to SBR are consistent at the high severities, and for laboratory data extrapolated into the low severities from the high severity data. However, the actual laboratory data taken at low severities are more erratic and show consistently higher loss rates than those observed in the California freeway test. It is postulated that this may be the result of increased susceptibility to thermal oxidative degradation of the NR surface, caused by relatively longer exposure in the laboratory than on the road at a given severity. The investigation described in this paper lends a great deal of encouragement to the usefulness of laboratory abrasion testing for the screening of treadstock vulcanizates. The ability to obtain abrasion results under carefully controlled conditions of transmitted power, temperature, load and wheel angular velocity allows results to be investigated confidently as a function of conditions in the instrument, or of the polymeric properties. These investiagtions can be quite fruitful in eventual understanding of the polymer behavior or of the mechanism of abrasion. An important observation has also been the large variations in tire test results on different courses of assumed equal severities. Thus, the laboratory abrasion test can also assume the position of a guide to more effective road tests.

The mechanism of a group of multiple-stage, variable-speed transmission is examined. These transmissions allow a change of speed stage to occur without a drop in transmitted power and without a change in setting of the variable-ratio unit. The kinematic restrictions imposed on the mechanism by synchronous coupling of the speed stages are outlined for all possible sequences of speed stages.

A device is described whereby millimeter or submillimeter wave images obtained from reflecting targets can be converted to visible displays providing a cathode ray tube presentation. The principle of the technique is based on the fact that transmitted power at these wavelengths can be modulated by a semiconductor panel in which the bulk conductivity is changed by electronic means. Experimental data is reported.

The admittance of a gas discharge may be obtained from measuring the ratio of the transmitted power through a microwave cavity to the incident power as a function of signal frequency near the cavity resonance. The method involves balancing the transmitted and incident signals to zero at the cavity resonance after they have passed through two separate receiving systems. When the signal frequency is changed, an attenuator is used to rebalance the two signals. The change in frequency from resonance and the corresponding change in attenuation gives the necessary data which will plot as a straight line whose slope yields the desired information.

The first paper in this series described the results of laboratory measurements and road evaluation tests on a series of tread stocks over a wide range of severities, and indicated the various advantages and limitations involved in the laboratory and road measurements. It is the purpose of the present paper to describe in greater detail the abrasion instrument used in these studies. The laboratory measurement of abrasion resistance was reviewed by Buist in 1950. The paper describes 21 laboratory abraders. Developments in abrasion instruments and methods which have since appeared in the literature have been primarily concerned with modifications and refinements on these basic types. A novel type of instrument described by Newton, Grinter and Sears, uses stationary knife blades to scrape a rotating rubber disc. The research group at the Emeryville Shell Development laboratories investigating characterization of elastomeric properties some years ago decided that its requirements in laboratory abrasion testing could best be satisfied by an abrader of the Dunlop-Lambourn type because of its versatility in providing control of angular velocity, load, slip, energy transfer, and temperature. Also, in the Lambourn abrader, the motor-driven vulcanizate wheel driving a braked abrasive wheel resembles the action of a driven tire rolling on a pavement. A given section of the tire tread surface is subjected to stressing and abrasion only during the portion of the cycle when in direct contact with the abrading surface. Cooling and relaxation occur during the portion of the cycle when the section is not in contact with the surface. Viscoelastic and abrasion mechanisms can operate in the laboratory at frequency levels approximating those encountered in road tests.

The testing of the above ponderomotive wattmeter leads to the conclusion that it is advisable to use such instruments in UHF measurements. The fact that these instruments measure transmitted power, and that they can be calibrated by an absolute method and are relatively accurate makes them particularly suitable for use as reference instruments for calibrating power meters of other systems.

A previous paper showed that constraining the total energy transmitted on all pairs in a cable during any time interval of a specified duration limits the maximum instantaneous near-end crosstalk voltage on any pair. This paper determines a constraint on the energy that is the same for each pair and that guarantees the same limit on near-end crosstalk. While the new constraint permits less variation of transmitted power among the pairs, it permits greater average power per pair. Thus, the constraint developed herein would be particularly useful when a cable is used principally for one type of capability, e.g., ISDN basic access.

Calculations which include the effects of lattice heating on recent transient nanosecond experiments done near the band gap of cadmium sulfide at low temperatures are presented. For a detuning of 5.7 meV below the A free‐exciton resonance and for input intensities of about 1×107 W/cm2 large optical hysteresis in the transmitted power is predicted. Good agreement between our theoretical predictions based on lattice heating and the experimental results of Bohnert, Kalt, and Klingshirn [Appl. Phys. Lett. 43, 1088 (1983)] is obtained.

Around 1890, the mining industry of Telluride, Colorado, was going broke because of the high cost of fuel for steam power, and alternative sources of power had to be found. The author describes the transition that was made to AC power. A 133 Hz, 3000 V generator was installed with a 6 foot Pelton water wheel at Ames, Colorado, that transmitted power for a distance of 2.65 miles. This was followed by a number of additional installations, and by 1896, the original system of 133 Hz was replaced by the Tesla system that used 60 Hz. >

Thresholds and propagation constants for longitudinal modes in distributed feedback lasers with external reflectors are computed. The general case in which the reflectors are located asymmetrically with respect to the grating is treated, and it is shown that depending on reflector spacing and position, modes may have lower thresholds than conventional lasers with identical reflectors. Also computed is the ratio of transmitted power through the right−hand reflector to that transmitted through the left−hand reflector. In general, since the device is asymmetric that ratio differs from unity.

The performance and measurement of the single-mode optical fiber (SMF) systems can be affected by the presence of reflections and their interference effects that may occur at fiber joints such as connectors and splices.1,2 To reduce these effects, fiber joints are designed to have physical contact,1 are index matched, or have tilted endfaces. In fiber joints designed for endface contact, an air gap between fiber endfaces may still exist due to either the nonperpendicularity of endfaces or the presence of contaminants or design tolerances. Also, in convex-polished connectors, physical contact may occur away from the core region due to off-axis polishing.

The information produced by most sources of information is not in a suitable form for transmission via a channel, so that some type of coding procedure is necessary. The channel may be analogue or digital, and will have various characteristics such as bandwidth, transmitted power, error rate etc. Two important requirements of the system may be firstly that the information be transmitted as rapidly as possible and secondly that it be transmitted with as few errors as possible. These two requirements cannot easily be attained together; in order to increase the speed the redundancy of the code used has to be low, whereas to reduce the error rate the redundancy has to be high. However, we will see in chapter 5 that Information Theory offers a surprising compromise, whereby under certain conditions both can be achieved together.

In the letter we show a new structure, the untapered multifibre union, with similar oscillation behaviour to that of tapered single-mode fibres. As a consequence conical regions are not relevant to the final results. This oscillatory behaviour opens the way to low-cost all-fibre devices such as optical filters.

This paper presents an analytical framework to discriminate the impact that the neighbouring cells have over a reference cell in a multicellular W-CDMA scenario, based on establishing the mutual relationships between cells in terms of uplink cell load factor and downlink transmitted power. The derivatives of these two parameters, with respect to the neighbouring cells, are taken as a measurement of the interactions between cells. Based on this analytical framework, a multicell load control algorithm is proposed and compared with two other algorithms by means of simulations.

Cell sectorization is commonly used to increase system capacity in cellular systems and is easily implemented. We propose a technique to improve system capacity based on adaptive sectorization. Sectors are rotated and/or resized adaptively in order to equalize the uplink C/I or the total downlink transmitted power in each sector The performance of the proposed procedure is analyzed for both uplink and downlink transmissions. Noticeable performance improvements are obtained when traffic is not uniformly distributed both spatially and in terms of data rate.

The transmission of vibrational power between two thin plates in an L‐shape configuration is investigated using an SEA model. Only bending waves are considered in the model. Expressions are developed for both the ratio of energy levels in the two plates and the ratio of the transmitted power to the input power. It is found that these ratios are only dependent upon three parameters: frequency, dampings of the plates, and coupling loss factors between the two plates. Therefore, a way to decrease both the transmitted power and the energy level in the receiving plate over a wide range of frequencies is to increase the damping of the source plate. The coupling loss factor is influenced by the physical characteristics of the plates, such as area, thickness, and material. The effect of these parameters on the coupling loss factor and on the power and the energy ratios is found to be small. Thus the most efficient way to control the transmission of power and the energy levels is to increase the damping of the pla...

This paper describes a lightweight high‐power TE01 mode duplexer in which weight reduction is achieved by using hexagonal ferrites. This duplexer operated at 35 GHz and has been tested at 150 KW peak power. Transmitted power loss is typically less than 0.5 dB. This device is basically a ``zero dB'' coupler using circular waveguide for the primary line and ferrite loaded rectangular waveguide for the secondary line. Hexagonal ferrites in the secondary waveguide produce the desired nonreciprocal phase shift. The ferrite is a (NiCo)2W compound with Hanis=6500 Oe. The method of selecting material and configuration is discussed, along with the effects of ferrite properties, configuration and location on performance and magnetic‐field requirements.

The equivalent step index (ESI) parameters associated with single-mode fibres can be evaluated by observing the changes in transmitted power on the far field when a Ronchi ruling is inserted between the end face of the fibre and a detector collecting the output intensity. Measurements as a function of wavelength allow one to determine the cutoff wavelength, ESI parameters for short lengths of fibre and effective cutoff wavelength for long lengths.

Stimulated Brillouin scattering (SBS) in low-loss single-mode silica fibre is observed at 1.32 μm using a continuous-wave single-frequency Nd:YAG laser. The threshold for SBS is 5 mW and the transmitted power reaches a saturated maximum for launch powers exceeding about 10 mW. A conversion efficiency of 65% is observed. The Stokes frequency shift is 12.7±0.2 GHz.

For many years now single-sideband (SSB) modulation has been used for almost all speech communication channels in the short-wave (2?30 MHz) bands. This is because SSB is the most spectrally efficient mode and does not waste transmitted power in redundant carrier components. Why has it not yet been adopted for use in the VHF and UHF land-mobile-radio bands?

The variation of transmitted power through tapered coaxial couplers is presented as a function of the surrounding refractive index. This response allows us to select suitable cladding materials for the tapers that would desensitize their performance to environmental changes. Further, the use of tapers as refractive-index sensors is outlined.