Showing papers on "Signal published in 1983"

A new approach to multipath correction of constant modulus signals

Abstract: An adaptive digital filtering algorithm that can compensate for both frequency-selective multipath and interference on constant envelope modulated signals is presented. The method exploits the fact that multipath reception and various interference sources generate incidental amplitude modulation on the received signal. A class of so-called constant modulus performance functions is developed which sense this AM term but are insensitive to the angle modulation. Simple adaptive algorithms for finite-impulse-response (FIR) digital filters are developed which employ a gradient search of the performance function. One of the resulting algorithms is simulated for the example of an FM signal degraded by specular multipath propagation. Substantial improvements in noise power ratio (NPR) are observed (e.g., 25 dB) with moderately rapid convergence time. These results are then extended to include tonal interference on a FM signal and intersymbol interference on a QPSK data signal.

Liquid jet recording apparatus

Abstract: PURPOSE:To enable the development of capacity having excellent faithfulness and certainly in the response to a recording signal and especially excellent in durability, by arranging a partition wall in the vicinity of a heat acting surface in such a shape that the flowline width of a liquid flowline is not made constant. CONSTITUTION:A heat acting surface 115 indicates a part where a heat generating part 116 is projected to an upward vertical direction with respect to the bottom surface of a liquid chamber while the vicinity of the heat acting surface 115 indicates a part where the distance from the end part of the heat acting surface 115 is in about 100mum and the indefiniteness in the flowline width W of a liquid flowline indicates both cases one of which is widen in the flowline width and the other of which has a part where the flowline width becomes narrow. When the flowline width is not constant in the vicinity of the heat acting surface, the resistance of a liquid stream during the replenishment of ink caused by the emission of the ink and the disappearance of bubbles becomes unbalanced in the vicinity of the heat acting surface and, therefore, the ink is re- replenished in the arrow direction. Bubbles B1 resulting in impact generated on the heat acting surface disappear as bubbles B2 at a position shifted from the heat acting surface and, therefore, the destruction of the heat acting surface, in its turn, an electricity- heat converting body can be avoided.

Signal Delay in RC Tree Networks

Abstract: In MOS integrated circuits, signals may propagate between stages with fanout. The exact calculation of signal delay through such networks is difficult. However, upper and lower bounds for delay that are computationally simple are presented in this paper. The results can be used 1) to bound the delay, given the signal threshold, or 2) to bound the signal voltage, given a delay time, or 3) certify that a circuit is "fast enough," given both the maximum delay and the voltage threshold.

Electrical control system

Abstract: The system of the present invention provides an electrical digital compass for use in a vehicle which includes a unique compensation and variation correction control which is readily set by the vehicle operator with the operation of push-button switches. The electrical display system and circuitry includes a microprocessor for comparing the information from a magnetic field sensor when the vehicle is aligned in a magnetically known direction and for providing a correction signal to assure the displayed output corresponds to the predetermined magnetic field alignment. In areas where magnetic variation is significant, the system generates, stores and processes a correction signal to assure the displayed output corresponds to the true heading of the vehicle. In one embodiment of the invention, a temperature sensor is provided to indicate the ambient temperature in which the vehicle is operating and which is digitally displayed to the operator.

Microwave signal generation with injection-locked laser diodes

Abstract: Heterodyne detection of the light from two slave lasers injection locked to FM sidebands of a modulated master laser is used to generate a narrowband microwave signal at 10.5 GHz.

Sampling Theory and Wave Propagation

Abstract: In the seismic reflection method, the seismic signal does vary in amplitude, shape, frequency and phase versus the propagation time

Current detector in combination with an electrical apparatus

Abstract: A device for incorporation into the power supply circuit of an electrical apparatus comprising (a) a switch which is movable from one condition to another on application of power to the switch and which is held in the moved condition, as long as power is applied to the switch; (b) a signal emitter adapted to emit a power signal of short duration and being connected to the switch so that on emission of the power signal the switch will be moved to the other condition for the duration of the power signal; and (c) a current detector capable of detecting when a current flows in a line and being connected to the switch to supply power thereto when current flows in the line. The current detector may be a light emitting diode (L.E.D.) and a light detector arranged to transmit current to a relay switch coil which is electrically connected to the line by a current transformer.

Method and apparatus for evaluating rhythmic oscillations in aperiodic physiological response systems.

Abstract: A method and apparatus for detecting amplitude variations in the rhythmic oscillations of a physiological response pattern in a frequency range of interest. A sensor (1) is used to detect an occurrence of an event in the cycle of a physiological response and the interval between each reoccurring event is timed and placed in a buffer (9). The output from the buffer (9) is read out at predetermined time intervals and fed to a filter (90) which determines the aperiodic portion of the signal and substracts that aperiodic portion to output a residual data signal. The residual data signal is fed to a band pass filter (94) which filters in a region determined by the predetermined frequency range of interest and which outputs to a calculation and display device (96) wherein the variance of the rhythmic oscillation is calculated and displayed.

Pulse oximeter monitor

Abstract: A display monitor is disclosed for a pulse oximeter of the type wherein light of two different wavelengths is passed through body tissue, such as a finger, an ear or the scalp, so as to be modulated by the pulsatile component of arterial blood therein and thereby indicate oxygen saturation. A tonal signal is emitted having a pitch proportional to the ratio of oxygen saturation and a sequential repetition proportional to pulse. A visual cue consisting of an array of strobed light emitting diodes is flashed having a total light output proportional to the magnitude of the pulse and a sequential flashing rate proportional to pulse rate. A systematic rejection of extraneous or irregular detected data prevents undue sounding of alarms.

Apparatus and method for logging wells while drilling.

Abstract: An information while drilling apparatus and method for characterizing strata in the vicinity of a drill bit at the lower end of a drill string, including a down-hole module unit and surface receiving and control units. Excitation currents are caused to pass through the drill string, drill bit and surrounding strata and the current flowing through the drill bit is sensed by a first toroidal transformer that encircles the drill string immediately above the drill bit. The sensed current, which characterizes the strata adjacent to and below the drill bit, is detected to form logging signals. A second toroidal transformer couples the logging signals to the electrically conductive drill string for transmission to the surface receiving unit. The frequency of the excitation current is adjustable to permit characterization of the strata at various distances from the drill bit. The frequency of the transmitting signal is also adjustable to compensate for varying degrees of signal attenuation along the transmission path. Control of the excitation and transmission frequencies is effected by communications from the surface control unit in response to stored operating instructions or operator inputs.

An introduction to NMR imaging: From the Bloch equation to the imaging equation

Abstract: The emerging technology of NMR imaging is introduced here as a problem in system identification. We show how selected families of signals may be input into the system ("system," in this case, is almost synonymous with "patient") in order that the system's responses to these inputs may be directly interpreted in terms of the system parameters. Once identified, a raster display of the system parameters provides an internal image of the patient. Inputs to the system age four-component functions of time. One component describes the strength of an RF signal, and the other three components govern the strength of three spatially varying, independently controlled magnetic fields (the gradient fields) in which the patient is immersed. In response to these inputs some of the protons in the patient, acting in concordance with the Bloch equation, give rise to local fluctuations in the magnetization which are detected with a tuned antenna and a sensitive receiver. The relationship between this output signal and the system parameters is summarized in the imaging equation.

A proposed neural network for the integrator of the oculomotor system

Abstract: Single-unit recordings, stimulation studies, and eye movement measurements all indicate that the firing patterns of many oculomotor neurons in the brain stem encode eye-velocity commands in premotor circuits while the firing patterns of extraocular motoneurons contain both eye-velocity and eye-position components. It is necessary to propose that the eye-position component is generated from the eye-velocity signal by a leaky hold element or temporal integrator. Prior models of this integrator suffer from two important problems. Since cells appear to have a steady, background signal when eye position and velocity are zero, how does the integrator avoid integrating this background rate? Most models employ some form of lumped, oositive feedback the gain of which must be kept within totally unreasonable limits for proper operation. We propose a lateral inhibitory network of homogeneous neurons as a model for the neural integrator that solves both problems. Parameter sensitivity studies and lesion simulations are presented to demonstrate robustness of the model with respect to both the choice of parameter values and the consequences of pathological changes in a portion of the neural integrator pool.

Recorded program communication system.

Abstract: A two-way telephone network (16) between a subscription television broadcast location and a plurality of subscriber stations (12) having standard broadcast signal receivers provides dialed telephone links through which subscribers select recorded programs in a library at the broadcast location for reception on the standard signal receivers, the broadcast signals being transmitted along one-way signal paths (18) from the broadcast transmitter to the subscriber stations Signal processing at the broadcast location and special signal detection and traffic control at the subscriber stations prevents unauthorized reception

Device for determining the speed, distance traversed, elapsed time and calories expended by a person while running

Abstract: A device for measuring the speed of a person while running along a surface is disclosed. A pressure switch or transducer located in a shoe senses when a foot of the runner is in contact with the surface and produces a foot contact signal having a duration proportional to the time the foot is in contact with the surface. A radio frequency transmitter is coupled to the pressure switch or transducer and transmits the foot contact signal. A radio frequency transmitter receives the foot contact signal transmitted by the frequency transmitter and a microprocessor coupled to the radio frequency receiver calculates, solely from the foot contact signal, an output speed signal representing the speed of the runner. A liquid crystal display coupled to the output of the microprocessor displays the speed of the runner in accordance with the output speed signal.

Regenerator for an intrabundle power-line communication system

Abstract: A regenerator (10) for providing detection, remodulation, and retransmission of a digital data signal (20) propagated in the differential mode over a pair of bundle conductors (12,16) of a power line. The electric power signal, propagated in the common mode over the same bundle conductors, is conducted through the regenerator and provides a power supply voltage (V.) for the regenerator electronics. A series of electrical traps (38, 40, 42, 44) prevent the electric power signal from being conducted into that portion of the regenerator utilized for processing of the data signal. The regenerator also includes bypass switches for bypassing the regenerator electronics when a power supply voltage sufficient to operate the electronics is unavailable.

Frequency-hopped single sideband mobile radio system

Abstract: The present invention relates to a frequency-hopped single sideband (SSB) mobile radio system implemented by hopping the carrier frequency of an input signal (s(t)) every τ seconds. The hopping is controlled by a carrier-frequency-hopped sequence (f i (t)) generated by a carrier-frequency-hopping generator (16,24). When employed in a frequency-hopped SSB transmitter (10), the carrier sequence functions to modulate the input signal, "hopping" it to a different carrier frequency every τ seconds. The carrier-frequency-hopped SSB receiver (20) employs the identical carrier sequence as used by the transmitter to demodulate the transmitted carrier-frequency-hopped SSB signal, thereby recovering the original single sideband signal (s(t)). By frequency hopping the carrier signal of an SSB signal, the present invention mitigates the effects of co-channel interference and frequency selective fading inherent in prior art SSB cellular mobile radio systems.

Doppler radar velocity measurement horn

Abstract: Doppler radar apparatus for use in a velocity measuring system for farm tractors and the like. The apparatus includes a dual mode conical horn having a flare angle substantially in excess of 12.5°, and a dielectric lens formed of a glass filled polymer. The doppler output signal provided by the RF transceiver associated with the dual mode horn is high pass filtered to remove low frequency signals therefrom. The horn is mounted in such a way that it is isolated from mechanical vibrations which would induce doppler signal frequencies in excess of the cutoff frequency of the high pass filter. Moreover, the horn assembly (which is aluminum) and a steel housing assembly are coupled together in such a way that thermal expansion and contraction will not loosen the friction fit between the two assemblies. The two assemblies are held together by a single, large diameter annular locking ring.

Vibratory signal sweep seismic prospecting method and apparatus

Abstract: Disclosed are a method and apparatus for vibratory seismic prospecting in which a vibratory signal sweep is produced by a vibrating apparatus in accordance with a power spectrum function S(f), which is proportional to a noise component function n(f) and a subsurface signal amplitude attenuation function B(f) for an area to be surveyed, to thereby produce reflection signals having an improved signal-to-noise ratio.

Method and apparatus for displaying at a selected station special service information during a silent interval between ringing

Abstract: Method and apparatus for displaying special service information at a selected station during a silent interval between ringing. The apparatus, a data receiver (100), is connected to the tip and ring leads of any well-known station set and comprises a line interface unit (101), a converter (102), a control circuit (103), and a display unit (126). A frequency shift keyed (FSK) signal which represents the special service information is filtered from the ringing signals by the line interface unit. The converter detects the FSK signal and demodulates the special service information from the FSK signal. Upon detection of the FSK signal, the control circuit receives and stores the special service information. The stored special service information is then periodically sent to the display unit to begin exhibiting the information during the silent interval before the next ringing signal.

Interframe coding apparatus

Abstract: An interframe coding apparatus performs motion detection and vector quantization on the basis of a block of interframe differential signals and includes a vector quantizer. The data of the interframe differential signal or the block scanning predictive error signal is compressed using a vector quantizer. The vector quantizer receives a plurality of suppressed predictive error signals (624) as input signals in block form and operates to form input vectors. The data is analysed by a motion detector (652) and where motion is detected, the relevant block is coded as a significant block. A coder (638-642) operates to determine an output vector having the least distortion with respect to an input vector by various techniques. A coded output or output vector codetable address (625) is output from the coder of the device for receipt by a decoder (639,642,654,655) which constructs a proper output vector signal.

Noninvasive device for photoelectrically measuring the property of arterial blood

Abstract: A noninvasive device for photoelectrically measuring a property of arterial blood is provided. Light that contacts living tissue with arterial blood is converted into a pair of electrical signals. The electrical signals are processed to provide information of the amplitude of the measured signals and are further processed to produce a final output signal that is substantially a square function of a ratio between the electrical signals representative of the amplitudes.

Analysis of pressure-wave methods for the nondestructive determination of spatial charge or field distributions in dielectrics

Abstract: A pressure wave propagating through a charged dielectric produces an electric signal at the sample electrodes. This signal reveals information on the spatial charge or field distribution in the sample. In the present study, the mathematical relations between the signal response and the desired distribution are derived from first principles. For the derivation, the pressure dependence of the relative permittivity must be known; therefore this dependence was calculated for nonpolar as well as for polar dielectrics with the use of the Clausius-Mossotti equation. The resulting response equations are applicable to pressure-pulse, pressure-step, and arbitrary pressure-profile experiments on one- and two-sided metallized samples in open-circuit and in short-circuit configuration. The common features and the differences between the present analysis and existing theoretical descriptions are discussed in detail.

Distributed variable bandwidth switch for voice, data, and image communications

Abstract: A variable bandwidth branch exchange system is disclosed for interfacing a network ring to a plurality of peripheral loops, each of the peripheral loops being connected to one or more local stations and to a node on the network ring. Time bit slots on the network ring signal stream are assigned, on a dynamic basis, for communication between local stations. The network ring signal stream is diverted to the peripheral loop by the node when the bit slots assigned to the local station connected to that loop become accessible at the node, thereby placing the peripheral loop in the network ring signal stream. Bit slot bandwidth is variable in accordance with the requirements of a particular local station. Voice, data, and image communications are supported. The modular nature of the system permits the implementation of multiple rings for wide area networking.

Small signal analysis of resonant converters

Abstract: It is known that the dc-to-dc conversion ratio of resonant converters can be controlled by changing the ratio of switching frequency to resonant frequency. In this work the small signal response of resonant converters to small signal perturbations in the switching frequency and input voltage is determined.

Vibration monitoring device

Abstract: A portable vibration monitoring device (10) for use in connection with a base computer (11) which stores data regarding the nature and parameters of vibration measurements to be made on preselected machines for predictive maintenance purposes. The device includes a power module (36) which energizes the various components. A vibration sensor (14) produces an analog signal which is representative of selected vibration parameters. The signal generated by the vibration monitor is conditioned by a signal conditioning module (16) which includes anti-aliasing filters which enhance the accuracy of the data collected. A multiple function module (18) includes various selectively energized modules which enhance the speed and reliability of the data collected. This data is analyzed by a microprocessor and displayed as desired.

Measurement of electrical signals with picosecond resolution

Abstract: Electrical signals are measured (analyzed and displayed) with subpicosecond resolution by electro-optic sampling of the signal in an electro-optic crystal, the index of which changes in response to the electric field produced by the signal, in accordance with the Pockels effect. The crystal is disposed adjacent to a transmission line along which the signals propagate the line may be a coplanar wave guide having a plurality of parallel strips of conductive material on the surface of the crystal. The crystal may be disposed adjacent to and in the fringe field of a line on a substrate, which may be part of an integrated circuit, for measuring signals propagating along the line during the operation of the circuit. A beam of short optical (laser) sampling pulses in the picosecond range is focused so that the region where the beam is confocal is disposed where the field is parallel in the crystal. The confocal region (where the optical wavefront is planar is preferrably close to the surface of the crystal and perpendicular to the optical axis of the crystal. The optical pulses transmitted through the crystal are processed to provide a display affording a measurement of the electrical signal.

Multiple frequency message system

Abstract: In the preferred embodiment the multiple frequency receiver comprises a decoder responsive to a transmitted coded message signal having a special code for designating that the message is being sent on the local frequency and which is also responsive to the absence of the special code which indicates that the signals are being transmitted on a designated nationwide frequency. The decoder includes a microprocessor which generates an output to turn on the local frequency channel element so that the pager may receive the local frequency when the special code is detected and generates a second output to turn-on a nationwide frequency channel element so that the receiver can receive a nationwide frequency when the special code is absent. This enables the pager user to transfer from his local city to another city without having to manually adjust the pager.

Magnetic recording medium

Abstract: PURPOSE:To use various types of magnetic recording media with high interchangeability for various types of recording devices, by recording previously magnetic characteristic information at a part of a magnetic recording medium. CONSTITUTION:A format contains a magnetic tape 1 itself, a part 2 where the bias current and the equalizer time are recorded as the magnetic characteristic information, and an unrecorded part 3 which can be used by a user. It is ideal to record the magnetic characteristic information by converting the bias current into a coefficient since the absolute current value of the bias current differs by magnetic heads. For a magnetic disk 4, the optimum recording current coefficient is recorded as the magnetic characteristic information at a part of the most outer circumference of an encoder and on the basis of the format. A magnetic head 7 functions as a magnetic sensor which reads the magnetic characteristic information of the disk 4 and also serves as a reading/writing head which can function as a writing head to record the data on a magnetic disk 5. An amplifier 8 converts the signal which read the magnetic characteristic information through a magnetic head 7 into the pulse signal.

Multiple-measurement noise-reducing system

Abstract: In a multiple-measurement system, a weighted sum of the measurements is used to provide a selective image. An additional weighted sum is used to provide an increased signal-to-noise ratio of some desired parameter of the image. The high frequency components of the increased signal-to-noise ratio image are combined with the low frequency components of the selective image to provide a selective image with improved signal-to-noise ratio. The combining operation can utilize the ratios of the derivatives in each signal to provide the correct amount of high frequency signal at each transition.