Showing papers on "Radio wave published in 1993"

Remote controlled spraying device

Abstract: A universal remote control mechanism for controlling a power spraying device comprises an electronic control contained within the nozzle housing of the sprayer. Membrane switches in the controller are actuated to cause radio wave signals to be generated and transmitted by an internal antenna. The radio signals are detected by a receiver which converts the radio signals into control signals for a main pumping unit. The radio waves may also control the introduction of various chemicals into the liquid solution by the main pumping unit. The nozzle also contains a deadman's switch for turning off the flow of liquid in case the unit is accidentally dropped. A delay feature lets the operator change hands without deactuating the system. The nozzle gun can be used for wired cable systems as well as for radio controlled systems.

Satellite radio wave capturing method for a global positioning system (GPS) receiver

Abstract: A satellite radio wave capturing method of a GPS receiver, in which an offset value of an oscillator of the GPS receiver is calculated by subtracting a Doppler frequency deviation of the first captured satellite radio wave from an actual received frequency of the first captured satellite radio wave, and with respect to the second and subsequent satellite radio waves to be captured, the search center frequencies are reset by using the calculated offset value, and an oscillating frequency of the oscillator is changed by using the set search center frequency as a reference, thereby capturing the radio wave of the target satellite. The elapsed time which is required from the power-OFF at the preceding position measurement by the GPS receiver to the power-ON at the present position measurement is measured. In accordance with the duration of the measured elapsed time, a determination is made to see whether or not the offset value of the oscillator which has been obtained at the preceding position measurement and stored in a memory in the GPS receiver is used as an offset value of the oscillator at the present position measurement. The mean value of a plurality of offset values obtained within a predetermined time just after the power-ON of the GPS receiver is calculated and stored. At the next power-ON of the receiver, the stored mean value of the offset values is used as an initial offset value at the start of the position measurement.

Radio communication system, radio equipment and switch

Abstract: PURPOSE:To attain efficient radio communication between a base station and a mobile station by selecting the direction of a communication beam in a direction in which a signal with a highest electric field strength is received at a point where a scanning means scanning surroundings intermittently is located. CONSTITUTION:A base station 101 executes scanning by a major beam in every direction in tow-dimension or stereoscopically by changing the directivity of an antenna mechanically or electrically intermittently, in response to the transmission rate concretely such as every 5msec in the case of 200kbps. A mobile station 107 receives the major beam and measures the electric field strength at a received point and informs the result of measurement to the base station 101, which fixes its direction of the major beam in a direction in which a signal with a highest electric field strength is received afterward. Thus, a new radio wave transmission channel Bb is found out corresponding to the reception environment of the mobile station 107 and the direction of the major beam is corrected. Furthermore, when the direction of the antenna is electrically changed, for example, a phased array antenna or the like is used.

Minimizing the effects of radio-frequency heating in multidimensional NMR experiments.

Abstract: Application of radio-frequency power in multidimensional NMR experiments can significantly increase the sample temperature compared to that of the surrounding gas flow. Radio-frequency heating effects become more severe at higher magnetic field strengths and ionic strengths. The effects are particularly noticeable for experiments that utilize 1H and/or 13C isotropic mixing and broadband decoupling. If radio-frequency power is applied during the systematically increasing evolution period t1, the sample temperature can change with t1 and thereby cause line-shape distortions. Such distortions are easily avoided by ensuring that the average radio-frequency power remains constant during the entire experiment.

Anomalous absorption during artificial modification at harmonics of the electron gyrofrequency

Abstract: Observations of the anomalous absorption of low-power HF probe waves caused by the action of a high-power HF ordinary mode radio wave are presented. At pump frequencies in the vicinity of harmonics of the electron gyrofrequency the anomalous absorption measured on the low-power probe waves exhibit local minima. Also at these frequencies, large-scale changes deduced from phase measurements of the low-power probe waves and heater self-absorption are reduced, whereas the growth time of the anomalous absorption is increased. The electron gyrofrequency estimated from the frequency of the absorption minimum compares favorably with that derived from the International Geomagnetic Reference Field (IGRF) magnetic field model.

On the generation of plasma waves in Saturn's inner magnetosphere

Abstract: Voyager 1 plasma wave measurements of Saturn's inner magnetosphere are reviewed with regard to interpretative aspects of the wave spectrum. A comparison of the wave emission profile with the electron plasma frequency obtained from in situ measurements of the thermal ion density shows good agreement with various features in the wave data identified as electrostatic modes and electromagnetic radio waves. Theoretical calculations of the critical flux of superthermal electrons able to generate whistler-mode waves and electrostatic electron cyclotron harmonic waves through a loss-cone instability are presented. The comparison of model results with electron measurements shows excellent agreement, thereby lending support to the conclusion that a moderate perpendicular anisotropy in the hot electron distribution is present in the equatorial region of L = 5-8.

An extreme scattering event in the direction of the millisecond pulsar 1937 + 21

Abstract: LARGE fluctuations in the radio emissions from the quasar 0954 + 658 (ref. 1) attest to the existence of large-scale inhomogeneities in the ionized interstellar medium. These fluctuations, termed extreme scattering events, are caused by the refractive focusing of the radio waves by discrete plasma structures. In principle, the radio emissions of pulsars should also be a sensitive probe of such phenomena2–5, which should be manifest as fluctuations in the flux density and increased delays in the timing measurements. Here we report the detection of an extreme scattering event, lasting about 15 days, in timing observations of the millisecond pulsar 1937 + 21. This event provides independent evidence for the existence of large-scale structure in the interstellar medium, and allows us to constrain the properties of the lensing structure (distance, velocity, linear dimension and electron density) more tightly than has been possible from detections of lensed extragalactic radio sources. Of more practical importance, such events could be the dominant source of timing noise in millisecond pulsars at ∼1 GHz, and will need to be considered when searching for the subtle signature of gravitational waves in pulsar timing measurements.

Polarization-rotation modulated, spread polarization-rotation, wide-bandwidth radio-wave communications system

Abstract: A wide bandwidth radio wave communication system having a dual feed pair of cross-polarized antennas having a common axis and being at orthogonal angles to each other. A source of RF signals is coupled to the antennas and a shifter device is between at least one of the pair of cross-polarized antennas and the source of RF signals for modulating the polarization of RF signals launched by the pair of cross-polarized antennas.

Building penetration characteristics of 880 MHz and 1922 MHz radio waves

Abstract: The data gathered revealed the effects of frequency, environment, and building height on the penetration loss, as well as information about building shadow loss at each frequency. Building penetration loss averages 19.2 dB for 880 MHz and 15.7 dB for 1922 MHz. The signal strength generally increases at higher floors within the building, but tends to level off at heights above the fifth floor. Exceptions to this are found in a high-rise office complex. Building shadowing effects are generally less at 1922 MHz.

Automatic control system for lighting projector

Abstract: A radio wave signal is transmitted from a radio wave transmitter according to a command from a central control unit, and a supersonic wave is transmitted from a supersonic wave transmitter held by a moving object according to this radio wave signal. A time counter in a supersonic wave detecting device determines the time required from the transmission of the radio wave signal to the detection of the supersonic wave. A coordinate position of the object is calculated on the basis of the thus-obtained time data from a plurality of the supersonic wave detecting devices and positional data of the supersonic wave detecting devices to control the lighting direction of a lighting projector according to a command signal from the central control unit referring to a positional data of the lighting projector. In the case of a plurality of moving objects, supersonic wave transmitters are separately held by the objects, and radio wave signals identified correspondingly to the supersonic wave transmitters are alternately transmitted from the radio wave transmitter. The supersonic wave transmitters detect the radio wave signals identified correspondingly thereto, thereby transmitting respective supersonic waves.

Site-Specific Propagation Prediction for PCS System Design

Abstract: Wireless communications has been plagued by our inability to fully understand how radio waves behave in complicated channels. In the past, anti-fading and anti-multipath techniques such as diversity and equalization have been used to combat the random small-scale fluctuations induced by radio channels, and propagation models were developed to help the communication engineer design radio links in a statistical sense, without much hope for complete understanding of the channel conditions at any particular time or location. Given the difficulty of predicting instantaneous channel conditions, a common thread in radio communication system design has historically been that first there must be good firstorder models to successfully deploy radio system links, and then some form of diversity or equalization must be used to ensure a particular outage criterion is met during rapid changes in the channel.

System for determining position from suppressed carrier radio waves

Abstract: The invention is a system for determining position by measuring phases of suppressed carrier-waves implicit in radio signals received from earth-orbiting satellites which include receiving the signals from a plurality of satellites simultaneously by means of an omnidirectional antenna, separating the received signals into first and second portions representing different radio-frequency bands and correlating the first portion with the second portion to obtain data representing the phases of the carrier-waves for a plurality of the satellites simultaneously.

Propagation measurements for satellite radio reception inside buildings

Abstract: Swept CW signals (from 700 to 1800 MHz) were received inside six buildings of brick, corrugated sheet-metal, wood-frame, mobile-home, and reinforced concrete-wall construction. A transmitter antenna was mounted outdoors on top of an 18 m tower to simulate a satellite, and a linearly scanned directional receiver antenna was used to probe the spatial, spectral, and temporal variability of the signal indoors. Levels were found to have much structure in the spatial and frequency domain, but were relatively stable in time. Typically, people moving nearby produced variations of less than 0.5 dB, whereas a person blocking the transmission path produced fades of 6 to 10 dB. Severe losses (17.5 dB) were observed in the concrete-wall building, which also exhibited the longest multipath delays (>100 ns). Losses inside a mobile home were even larger (>20 dB) and were independent of antenna orientation. The power-frequency distortion increased with the logarithm of the bandwidth, but could be reduced by moving to a position of higher power. Only the losses showed a clear frequency dependence, but they could be mitigated by moving the antenna. >

A comparison of two radio propagation channel impulse response determination techniques

Abstract: A comparison of two radio propagation channel impulse response determination techniques is described. Presented are typical impulse response and transfer functions obtained from each measurement system. Also included for comparison are average impulse response envelopes and cumulative probability distributions for the RMS delay spread of static indoor radio channels calculated from 120 measurements using each system. The comparisons show good agreement between results. >

The bandwidth of millisecond radio spikes in solar flares

Abstract: The bandwidth of 196 individual millisecond spikes has been measured and analyzed. The spikes occurred in the impulsive phase of eight solar flares in different active regions. The measurements have been made at various frequency resolutions and spectral windows in the range from 0.1 to 8.5 GHz. The major results are (i) that the individual bandwidths show a scatter of a factor 2-3 or more within an event, (ii) that the mean bandwidth differs significantly from event to event at the same center frequency, (iii) that the mean bandwidth increases only slightly with the center frequency and (iv) that there is no qualitative difference between spikes in decimeter waves and spikes in microwaves

ULF waves in the Io torus: Ulysses observations

Abstract: Throughout the Io torus, Ulysses has observed intense ultralow frequency (ULF) wave activity in both electric and magnetic components Such ULF waves have been previously suggested as the source of ion precipitation leading to Jovian aurorae The peaks of the wave spectra are closely related to the ion cyclotron frequencies, which is evidence of the waves being ion cyclotron waves (ICWs) Analysis of the dispersion relation using a multicomponent density model shows that at high latitudes (approximately 30 deg), peak frequencies of the waves fall into L mode branches of guided or unguided ICWs Near the equator, in addition to the ICWs below f(sub cO(2+)), there are strong signals at approximately 10 Hz which require an unexpectedly large energetic ion temperature anistropy to be explained by the excitation of either convective or nonconvective ion cyclotron instabilities Their generation mechanism remains open for the future study Evaluation of the Poynting vector and the dispersion relation analysis suggest that the waves near the equator had a small wave angle relative to the magnetic field, while those observed at high latitudes were more oblique The polarization of the waves below f(sub cH(+)) is more random than that of the whistler mode waves, but left-hand-polarized components of the waves can still be seen The intensity of the ICWs both near the equator and at high latitudes are strong enough to meet the requirement for producing strong pitch angle scattering of energetic ions

Mobile communications in the 21st century

Abstract: If a scientist in 1892 had been sufficiently foolish to predict the development of communications in the 20th century, we can be certain that his prophesies would have been substantially incorrect. He perhaps would have forecasted correctly that the telephone would be nearly ubiquitous, but it is doubtful that he would have concluded that digital communications, with its roots in telegraphy, would be used to convey the human voice. Marconi had not conducted his famous radio communication experiments, but Hertz had demonstrated radio waves. It was therefore predictable, given some unforeseen and clever means of production and detection of radio waves, that these waves could be transmitted around the world. Satellite communications would have seemed unthinkable in an age before the South Pole was discovered, the first car appeared, or the first flight was made.

On the applicability of the critical state model to the description of electromagnetic properties of high-Tc superconductors

Abstract: The frequency dependence of the surface impedance of superconductors have been studied experimentally and theoretically in the radio frequency range. Its essential deviation was found from the linear law predicted by the usual critical state model. The character of this deviation depends qualitatively on the amplitude of the radio wave. We have established the frequency limits of applicability of the traditional critical state model. Results obtained print out an explanation in the frame of the modified model where we take into account the contribution of a dissipative term to the screening current. The value of this is connected with the V-I plot of the superconductor, so it is possible to obtain information about the V-I characteristics by the contactless method.

Digital measurements of LF radio wave absorption in the lower ionosphere and inferred gravity wave activity

Abstract: Low frequency (LF) radio wave absorption in the lower ionosphere has been measured at Průhonice (∼ 50°N) since 1957. A new digital computer-controlled measuring-recording-processing system was introduced in 1988. The A3 method or radio wave absorption measurement, the measuring equipment used for the digital measurements at 270 kHz, is briefly described. The digital nighttime LF A3 measurements allow the use of absorption data for studying and monitoring the gravity wave activity in the upper middle atmosphere in the period range 10 min-3 (2) hours. The resulting gravity wave spectra are as expected even though their shapes vary. Individual period bands sometimes exhibit a similar general pattern of variability in gravity wave activity (winter 1990), while in other intervals we observe a shift of gravity wave energy from one period band to another (winter 1991). No strong, pronounced and consistent response to strong geomagnetic storms and midwinter stratospheric warming is found. An apparent seasonal variation with winter minima observed in shorter-period gravity wave activity is an artefact of the changing length of the night. There is no significant seasonal variation of gravity wave activity in the analysed data. The method is very cheap - the results are a by-product of measurements made for ionospheric purposes

A study on the scattering of radio waves from buried spherical targets using the step frequency radar

Abstract: The step frequency radar has been implemented and scattering experiments conducted on buried spherical targets to gather insight on the radar's limitations and target classification. Theoretical results are obtained using a combination of ray optics and a full wave solution for target scattering. These theoretical results are compared with experimental results to show the effect of target size on the received signal. >

Position confirmation system of mobile body using radio wave

Abstract: PURPOSE: To detect a position of an object or a person in which a portable radio equipment is installed by utilizing a conventional pocket pager by constituting the system so that a position of the portable radio equipment, map information in the periphery, and a transmitting mode are outputted by a computer, based on azimuth information of the portable radio equipment. CONSTITUTION: The system is provided with a portable radio equipment 60, a pocket pager 61 installed in the portable radio equipment 60, three or more fixed stations 62-65 for receiving a radio wave of the portable radio equipment 60, a central station 66 connected to the fixed stations 62-65 through a wire circuit, and a search automobile 67. In such a state, when the pocket pager 61 is operated, the portable radio equipment 60 detects a call means operated by light of the pocket pager 61, and transmits a prescribed radio wave. The radio wave transmitted from this portable radio equipment 60 is received by the fixed stations 62-65 having a radio wave azimuth detecting means 85, an azimuth of the portable radio equipment 60 is detected, its azimuth information is informed to a computer of the central station 66, and from the azimuth information and positions of the fixed stations 62-65, a position and a transmitting state of the portable radio equipment 60 are retrieved. COPYRIGHT: (C)1994,JPO&Japio

Car-mount adapter with sound signal transfer function

Abstract: PURPOSE: To connect the voice output of an already existing acoustic device to an audio reproducing player provided in a car room through wireless by using radio waves of such a radio broadcasting band as the FM band, etc., instead of a cable. CONSTITUTION: A CD player 2 is fixed to an adapter body 11 and, at the same time, aural signals outputted from the CD player 2 are transferred to a radio 3 equipped with an FM receiver by converting the aural signals into FM-band radio waves by means of an FM transmitter 7 installed to the adapter body 11. When the radio 3 is tuned, the voices from the player 2 can be outputted from the acoustic system in a car room. COPYRIGHT: (C)1994,JPO

HF antenna for a helicopter

Abstract: Disclosed is a combined antenna and helicopter rotor blade. The antenna has one or more electrically non-conductive rotor blades, each having an electrical conductor positioned parallel to the major axis of a respective rotor blade. An electrical connection is provided to connect the antenna to a radio for the reception or transmission of radio waves. Also disclosed is a communications system including apparatus for the transmission or reception of radio waves. Two of the electrical conductors, having angular positions nearer to a predetermined angular position are connected via the electrical connector to the radio. The remaining conductors may either be connected to the body of the helicopter or supplied with a signal out of phase compared to that supplied to the two electrical conductors.

Wideband propagation measurements of short range millimetric radio channels

Abstract: There is an increasing emphasis to extend the services available on fixed telecommunication networks to the mobile user. One area of the RACE 1043 project examined the possibility of universal mobile services within future integrated broadband communications networks. Essential to the feasibility of such a scheme is an understanding of the wideband characteristics of the radio channel. The article describes the results of a wideband channel sounding programme conducted at 39 and 60 GHz, together with a channel-modelling exercise based on these measurements, aimed at producing a statistical model of the wide band millimetric channel.

Adjusting receiving time of radio clock with time output unit and receiver unit - receiving radio wave contg. time information using detector unit for determining time at which radio wave can be most effectively received by the receiver unit

Abstract: The method involves using a time correction unit (7) for the correction of the time given on the basis of the time information, contained in the radio wave, which is received at the time, determined by the detector unit (9). The method for adjusting the receiving time of a radio clock involves activation of a receiver unit (2) for receiving a radio wave contg. an item of time information, at each desired time cycle, or at a desired time. The reception conditions at the time point are established, at which the receiving unit is activated, and the time, at which the radio wave can be received most effectively within an entire day, is determined for the receiving time. ADVANTAGE - Automatically selects time point at which radio wave can be most effectively received. Receiving operation can be selected at this time. Receiving time can be adjusted and time output corrected.

Radio Wave Tomography: Imaging Ore Bodies Using Radio Waves

Abstract: Radio tomography (RT) extrapolates geological information between boreholes, by producing attenuation images of the intervening rockmass. In this paper the underlying principles of this novel geophysical technique are described, and case studies from a variety of geological and rnining environments are presented.