Showing papers on "Signal published in 1971"

Detection of signals in noise

Abstract: Probability. Random Processes. Narrowband Signals. Gaussian Derived Processes. Hypothesis Testing. Detection of Known Signals. Detection of Signals with Random Parameters. Multiple Pulse Detection of Signals. Detection of Signals in Colored Gaussian Noise. Estimation of Signal Parameters. Extensions. References. Bibliography. Index.

Stretch: A Time-Transformation Technique

Abstract: Stretch is a passive, linear, time-variant technique for performing temporal operations on many classes of signals. The technique employs three dispersive networks and a mixer. Signal slowdown, speedup, or time reversal can be attained by choice of network slopes. These temporal operations are performed within a signal "window," and the duration of the window is determined by the network time-bandwidth products. Both heuristic argumentation and rigorous analysis are presented, as are the results of a simple laboratory experiment.

Electronic system for the stimulation of biological systems

Abstract: A receiver totally implanted within a living body is inductively coupled by two associated receiving coils to a physically unattached external transmitter which transmits two signals of different frequencies to the receiver via two associated transmitting coils. One of the signals from the transmitter provides the implanted receiver with precise control or stimulating signals which are demodulated and processed in a signal processor network in the receiver and then used by the body for stimulation of a nerve, for example, while the other signal provides the receiver with a continuous wave power signal which is rectified in the receiver to provide a source of electrical operating power for the receiver circuitry without need for an implanted battery.

Apparatus for delivering electrical stimulation energy to body-implanted apparatus with signal-receiving means

Abstract: An apparatus for delivering electrical stimulation energy to body-implanted apparatus with signal-receiving means is described which is particularly useful in implanted devices, including nerve and muscle stimulators, artificial organs, and certain electro-mechanical devices such as implanted dispensers for the administration of fluids to the body system. The electrical portion of the system includes a transmitter and receiver, with the transmitter normally being disposed or worn externally of the body of the patient or user and being arranged to generate pulses of predetermined amplitude at radio frequencies. The receiver includes a pick-up, a receiver and an output electrode arrangement which is normally subcutaneously implanted within the body of the patient. Since variations in signal energy received by the receiver from its coupled transmitter may occur due to relative positioning of the transmitter-receiver pair, the receiver serves to regulate the amount of energy delivered to the output electrodes such that relatively uniform impulses are normally applied to the output electrodes. Thus, even though there may be variations in the energy coupled from the transmitter to the receiver, a uniform output occurs; the arrangement providing a means for coupling an electrical signal of variable magnitude to provide an output or stimulation signal of constant energy amplitude or magnitude to an implanted device.

Digital filter for pcm encoded signals

Abstract: A digital filter either of a recursive or transversal type responsive to successive digitally encoded analog signal samples of m bits each. The filter comprises an accumulator for multiplying and summing a weighted hybrid value obtained from a memory medium addressed by a selected one of the m bits of each of N digitally encoded signal samples. If the bits of the N samples used for addressing the memory are derived from successive input signals only, then the filter is of the transversal type. If V of the N signals whose bits are used for addressing are from the input samples and R of the N signals whose bits also are used for addressing are obtained from filter output signals, then the filter is recursive. By addressing the memory with the binary value of like bit positions of the signal samples, then a hybrid value may be stored, which hybrid value need only be multiplied and combined by the accumulator. This permits the use of a substantially smaller memory than that required if the digits of the signals looked up the completed weighted function.

Time-lapse interferometry and contouring using television systems.

Abstract: A novel approach to time-lapse interferometry and contouring is introduced that uses television rather than photographic techniques. A first interferogram is stored on a video storage device such as a magnetic disk. After a change in the stress of the object, a second interferogram is electronically compared to the stored pattern to form a signal representative of the fringe pattern caused by the deformation. This signal may be directly displayed on a cathode-ray tube or employed by some automatic inspection device.

Radiant wave locating system

Abstract: A radiant wave electronic locating system for automatically locating a select group of persons or objects within a selected area of surveillance. Room sensors and a central console are linked together by radiant wave energy signals, which as light waves, acoustic waves, ultrasonic waves, microwaves, etc., which are coded and transmitted from the central console to track, locate or page a particular person. In one embodiment, signal transducers are common to a hallway and a room and transmit a coded signal present in the hallway into each adjoining room to page a personal pocket unit. In another embodiment, transceivers transmit a coded radiant wave signal in chain reaction from room to room by means of transceivers having a remote transducer, disposed through the wall of the room, to transmit the coded signal to the adjoining room. In a third embodiment of the invention, coded signals are transmitted throughout the rooms by carrier current at a selected frequency and one of three transducers present in the room units are activated to page the personal pocket unit of the person to be located. The pocket units receive the transmitted signal at the selected frequency, and transmit a return signal at another selected frequency to the room unit, where this signal is encoded to a third frequency, and transmitted in chain reaction from room to room back to a transducer on the central console. The returned signal is then decoded to determine the location of the person. A pocket unit in the shape of a writing pen for use with the locating system is also disclosed.

Convolution and time inversion using parametric interactions of acoustic surface waves

Abstract: We report on the observation of acoustic convolution, time inversion, and electronically variable delay in real time using 105‐ and 220‐MHz surface acoustic waves in YZ‐cut LiNbO3 delay rods. The time inversion is a special case of correlation, where a short ``pip'' pulse will create a reflection in time for the injected input signal pulse. The conversion losses in the processing were 64–74 dB.

Intermodulation rejection capabilities of field-effect transistor radio frequency amplifiers and mixers

Abstract: Mixers and amplifier circuits are disclosed which may include a plurality of identical FETs connected in parallel to form a composite FET. The decreased input impedance of the composite FET as compared to the input impedance of a single FET results in a decrease in intermodulation. The composite FET may also be a power or large signal FET. In either case, the pinch-off voltage of the composite FET can also be increased to provide a still further decrease in intermodulation.

Optical character recognition system

Abstract: As described herein, a program controlled image dissector tube scans the printed information recorded on a storage medium to provide analog information signals. The analog signals are converted into digital data signals representative of the segmental brightness of the scanned storage medium and thereafter accumulated in an image enhancement network. In the image enhancement network, selected arrays of the signals are scanned to develop directional and threshold digital data bits representative of the character information contained in each of the arrays. These digital data bits are, in turn, accumulated to provide arrays of the digital data bits representative of entire characters. The presence or absence of selected digital data bits in each of the arrays is then detected and the detected digital data bits combined to provide a character representative signal.

Fluid control system

Abstract: A battery operated fluid control system, which may be used in a sprinkler stem having a master valve unit with a battery operated electronic clock therein for periodically opening the valve for a preset duration in response to the clock turn-on pulse, and being operable with one or more slave valve units connected in series to sequentially open the slave valves for their corresponding preset time duration The clock is comprised of an oscillator having a plurality of countdown flip-flops, with the clock turn-on pulse being selectable from the outputs of a group of the lower flip-flops to give a selection of valve turn-on intervals A battery operated solenoid valve of the latching type and associated circuitry is located in the master valve unit and each of the slave valve units, with the circuitry being adapted to receive a pulse, either from the clock or from the turn-off signal of the previous valve unit, and to provide a turn-on pulse to the solenoid The circuitry is also comprised of an adjustable time delay circuit to measure the desired duration from the turn-on pulse and to provide a subsequent turn-off pulse to the solenoid One embodiment is adapted to replace the valve mechanism in a prior art anti-syphon valve assembly Another embodiment incorporates a unique anti-syphon valve which does not obstruct the primary flow path and further has a moisture collecting container on the side thereof, cooperatively disposed with the anti-syphon valve and having electrical probes therein connected to the circuitry When the valve turns on, the initial leakage of the anti-syphon valve fills the container, which will remain filled in rainy or very himid weather, thereby preventing subsequent opening of the valve until the moisture has evaporated The valve and time delay circuit is also adaptable for use in manually initiated systems, such as toilets and the like, and a unique toilet bowl and water valve component arrangement is disclosed to achieve the anti-syphon function

Electronic security system

Abstract: An electronic security system especially adapted for use in retail stores and employing a multi-frequency resonant tag circuit having distinct frequencies for detection and deactivation. A transmitting system provides an electromagnetic field within a controlled area at a frequency which is swept through a range including the detection frequency of the resonant circuit. In the presence of a tag circuit within the controlled area and operative at the detection frequency, pulses are detected by a receiver which includes noise rejection circuitry for discriminating true signals from noise. The receipt of a predetermined number of signal pulses within a prescribed interval of time causes an alarm actuation. The resonant circuit is formed by printed circuit techniques as a relatively small tag which can be affixed to an article of merchandise. The tag includes a fusible link integrally formed as part of the circuit and which can be fused upon application of an electromagnetic field of predetermined magnitude at the deactivation frequency of the resonant circuit. Deactivation of the tag destroys the resonant properties of the tag at the detection frequency such that a deactivated tag produces no alarm when passing through a controlled area.

Vehicle guidance system

Abstract: A vehicle guidance system includes first and second current-carrying conductors defining a portion of the vehicle guide path and in which current flows. The current in one conductor is equal in magnitude to 90 DEG and out of phase with the current in the other conductor. The conductors, when located in a parallel substantially overlapping relationship, establish a magnetic field having an effective phase different from the phase of the current in either conductor. The conductors are separated at at least one point of divergence to define separate vehicle guidepaths. A sensor unit on the vehicle sense the magnetic field of the conductors and controls the steering of the vehicle. The circuit which responds to the sensing unit is selectively controlled so that an output signal from only one or the other of the conductors controls the vehicle steering. In addition, the sensor unit which is on the vehicle senses data located along the guidepath in the form of lobes or nodes defined by the conductors. Furthermore, the sensor functions to sense phase modulation in the guidepath conductors as controlled from a central processor, and additional circuit means senses a change in phase modulation in the current flowing through the conductors and provides an output in response thereto so that data can be transmitted to the vehicle by phase modulation of the current transmitted through the guidepath conductors.

Multiple axis control system for vibration test apparatus

Abstract: Four vertically disposed hydraulic actuators act at spaced drive points on the underside of a rigid structure so as to impart vibratory motion thereto. The system herein disclosed takes signals representing displacement and load, and provides individual control signals for each actuator so that the actuators all work together to produce the desired motion called for by a program or command signal. In addition to correcting for vertical motion errors, the system also specifically corrects for roll errors. Correction for errors in the horizontal direction and also errors with respect to pitch are also contemplated.

Self-latching solenoid actuator

Abstract: A self-latching solenoid actuator having a low power consumption and an internal switching arrangement whereby latching and unlatching may be accomplished by such means as a simple singlepole, double-throw remote switch. The solenoid has a permanent magnet in the magnetic circuit thereof so that an actuating current in a first direction will actuate the solenoid and charge the permanent magnet, and a smaller current in the opposite direction will de-magnetize the permanent magnet and allow a return spring to force the plunger to the fully extended position. A single-pole, double-throw switch electrically coupled to the solenoid coil is disposed adjacent the magnetic circuit and mechanically coupled to the solenoid plunger. The switch is coupled in the circuit so as to be operative to turn off the actuating current and the unlatching current as the plunger approaches the latched and unlatched positions respectively, and to re-connect the solenoid coil in preparation for the next operating signal.

Telemetering system for oil wells

Abstract: An acoustic communication method and system for transmitting information through a well bore drill string or other pipe by establishing in the pipe modulated torsional acoustic waves, preferably of zero order, which contain the information to be transmitted and travel from a signal transmitting station to a signal receiving station spaced along the pipe, and for demodulating the modulated waves arriving at the receiving station to recover the transmitted information. The modulated waves may be established in the pipe either by driving the pipe in torsional oscillation and modulating the resulting torsional waves in the pipe at the transmitting station or by launching modulated torsional waves through the pipe at the transmitting station. In its principal application, the invention is utilized to monitor selected well drilling parameters, such as temperature, formation pressure, formation porosity, drill string orientation, and/or to operate devices within the well bore. Primary advantages of the invention are reduced acoustic transmission losses from acoustic coupling to the drilling fluid and well bore wall and the ability to transmit information while drilling is in progress. According to the preferred practice of the invention, when monitoring drilling parameters, the torsional acoustic waves are launched downwardly through the drill string from the surface by exciting the upper end of the string in a zero order torsional acoustic oscillation at frequencies within the base band of the drill string acoustic transmission characteristics so as to minimize attenuation of the acoustic waves by the couplings between the drill string pipe sections. These torsional acoustic waves are modulated at a subsurface signal-transmitting station along the drill string and returned back through the string to a surface signal-receiving station where the modulated waves are demodulated to recover the transmitted information.

Muscle stimulation and/or contraction detection device

Abstract: The apparatus detects contraction of muscles of living animals, the contraction causing an elastomer body whose impedance changes when flexed, positioned adjacent muscle to flex when the contraction occurs. When a bias voltage is applied to the elastomer body, any change in impedance is readily detectable. The change in impedance may produce a rhythmically repeated elecrical signal, as, for example, when the elastomer body is used to monitor heart activity. This electrical signal can be used for triggering or controlling purposes. For example, this signal can be used to control a pulse generator so that a cardioverting or pacing pulse is generated only after a specified period of time has elapsed since the latest heart activity was sensed by the elastomer body.

Physiological pressure sensing and telemetry means employing a diode connected transistor transducer

Abstract: Pressure measurement apparatus and method, the apparatus having a pressure sensitive element, an audio oscillator, a transmitter, a receiver, a frequency-to-voltage converter and a read-out device The pressure sensor is connected to and capable of varying the frequency of the audio oscillator as a function of the pressure applied to the sensor The audio oscillator is connected to and capable of modulating the signal of the transmitter The pressure sensor, audio oscillator and transmitter are implanted internal to the scalp of a living test subject, the pressure sensor being placed between the skull and the dura mater Additionally, a remote receiver is connected to a frequency-to-voltage converter and is capable of receiving the radio frequency signal transmitter by the transmitter and supplying the detected audio oscillation of the radio frequency signal to the frequency-to-voltage converter The frequency-to-voltage converter is capable of supplying a variable voltage to the read-out device, depending upon the frequency of the input signal delivered by the receiver The read-out device is capable of optically displaying and/or recording the amount of signal voltage being fed to it by the frequency-to-voltage converter

Sigset: a computer program for calculating traffic signal settings

Abstract: SIGSET IS A FORTRAN PROGRAM WHICH CALCULATES TRAFFIC SIGNAL SETTINGS AT SINGLE ROAD JUNCTIONS. THE GREEN TIMES AND, IF REQUIRED, THE CYCLE TIME ARE CALCULATED SO AS TO MINIMIZE, SUBJECT TO SPECIFIED CONSTRAINTS, THE ESTIMATED DELAY PER UNIT TIME TO ALL TRAFFIC PASSING THROUGH THE JUNCTION WHEN THE SIGNALS ARE WORKING FIXED-TIME. IN THE CASE OF VEHICLE-ACTUATED SIGNALS, THIS OCCURS WHEN THE GREEN TIME RUNS TO MAXIMUM FOR EACH PART OF THE SIGNAL CYCLE. THE PROGRAM IMPROVES ON EARLIER METHODS BY TAKING ALL TRAFFIC STREAMS INTO ACCOUNT, INSTEAD OF ONLY SELECTED ONES; BY MINIMIZING THE ESTIMATED DELAY EXACTLY, INSTEAD OF ONLY APPROXIMATELY; AND BY BEING ABLE TO DEAL EQUALLY WELL WITH BOTH SIMPLE AND COMPLICATED JUNCTION LAYOUTS AND SIGNAL CYCLES. AS A RESULT, THE ESTIMATED DELAY CORRESPONDING TO SETTINGS PRODUCED BY SIGSET IS QUITE OFTEN APPRECIABLY LESS THAN THAT CORRESPONDING TO SETTINGS GIVEN BY EARLIER METHODS, ESPECIALLY IN COMPLICATED CASES. EVEN WHEN THERE IS LITTLE IMPROVEMENT IN ESTIMATED DELAY, SIGSET OFTEN INDICATES A SHORTER CYCLE TIME. /RRL/

Breath testing system

Abstract: A breath testing system for under-supervised or unsupervised alcohol intoxication breath testing. The system includes a breath input unit, a controller which delivers a sample of deep lung breath to an evaluator including an alcohol detector and an output apparatus. The controller includes a breath flow sensing means, e.g., a pressure sensitive switch and timer, to require a predetermined and essentially continuous and uninterrupted breath flow prior to testing to thereby insure that alung breath sample is tested. Means for signaling failing or passing of the test are provided. A passing signal cannot be obtained unless the predetermined continuous nnd uninterrupted flow has occurred and the resulting sample tests below a predetermined alcohol concentration. The system is disclosed in one environment of use: in a motor vehicle, wherein failure to take or pass the test modifies the operation of the vehicle (e.g., prevents it from being driven or governs its maximum speed).

Optical card reader drive

Abstract: A card reader for optically scanning a field of machine-sensible numeric information imprinted on an identifying tag or card attached to an article of merchandise and generating therefrom electronic signals representative of the information. The card is translucent and the imprinting material is opaque with respect to illumination directed against the surface of the card from a light source on one side thereof. Photodetecting means are positioned in light receiving alignment with the light source on the opposite side of the card to record the presence of light passing through the blank areas of the card and the absence of light blocked by the imprinted areas. The photodetector output is connected to a suitable electronic signal generating circuit. Means are provided to move the aligned light source and photodetector unit along the card to scan across the machine readable data field and to return them to their initial position with respect to the card after the scan is completed.

Positioning system including servo track configuration and associated demodulator

Abstract: The invention relates to a positioning system which provides a series of adjacent servo tracks, the boundary between adjacent servo tracks defining a path for the servo system to follow. The servo track configuration generating an output signal in a transducer which has positive pulses for synchronization and negative pulses for positioning information and gain control information. A demodulator is used for separating the synchronization signal from the position and gain control signals. The synchronization signal is used to separate portions of the positioning and gain control signal so as to generate a positioning signal that is indicative of the position of the transducer with respect to the servo tracks and for generating an automatic gain control signal for the demodulator itself.

Signal cancellation system

Abstract: An unwanted r-f signal produced on a receiver line by a nearby transmitter is reduced by adding to it a sample of the transmitted signal, automatically adjusted in phase and amplitude to cancel the unwanted signal.

Recording device with automatic gain range changer and d.c. correction means

Abstract: An automatic recording device incorporating a range changer and an asymmetrical DC level correcting means. The range changer automatically selects a gain capable of supplying the recorder, for example, with an electrocardiograph signal of suitable amplitude regardless of the amplitude of the detected electrocardiograph signal. The asymmetrical DC level correcting means corrects the DC level of the recorder so as to center the electrocardiogram on the recording chart.

Electronic ignition spark advance system

Abstract: An electronic ignition spark advance system for use with internal combustion engine transistor ignition systems having an ignition coil primary winding switching transistor. A reference pulse, produced a selected number of degrees before the top dead center position of each engine piston, enables an ignition spark advance gate to gate a series of crankshaft position pulses, each indicating one degree of crankshaft rotation, to a counter circuit. When the counter circuit has counted the number of crankshaft position pulses equal to the number of selected degrees before top dead center the reference pulses are produced, an ignition signal is produced which extinguishes the ignition coil primary winding switching transistor and operates circuitry which produces a signal which may disenable the ignition spark advance gate. To provide speed ignition spark advance, however, delay circuitry responsive to each ignition signal provides two consecutive delay periods during which the disenabling of the ignition spark advance gate is delayed. Consequently, the counter circuit continues to count crankshaft position pulses during the delay periods, thereby providing a speed ignition spark advance in degrees equal to the number of crankshaft position pulses counted during the delay periods at any engine speed. To provide two speed ignition spark advance limits, the first delay period is terminated with a first selected crankshaft position pulse count if it occurs before the end thereof and the second delay period is terminated with a second greater selected crankshaft position pulse count if it occurs before the end thereof. To provide vacuum ignition spark advance, a vacuum spark advance signal is provided at the conclusion of the delay periods for the number of crankshaft position pulses equal to the degrees of vacuum ignition spark advance required which enables the ignition spark advance gate to gate the crankshaft position pulses to the counter circuit after the delay periods.

Method and apparatus for controlling an animal

Abstract: Method and apparatus for controlling a domestic animal to prevent it from moving into or out of a predetermined area wherein a signal emitting wire is placed to surround the area, and a low-powered, high voltage receiver circuit is mounted to the animal such as through a collar for receiving the signal from the wire and producing a physical effect on the animal as it approaches the wire.

Infrared intrusion detector system

Abstract: Infrared intrusion detector system utilizing a single sensing element and optical means for focusing radiation from one or more discrete fields of view onto the sensing element. An amplifier tuned to have a frequency response corresponding to the walking speed of an intruder amplifies the signal from the sensing element and provides means for discriminating between changes in infrared radiation due to the presence of an intruder and gradual temperature changes such as room or ambient changes.

Postal tracking system

Abstract: A system for tracking mail bags, letters, and parcels through a post office to determine mail processing times accurately as well as processing delays is disclosed. An unobtrusive transponder in the form of a card is located in letters or mail bags to be tracked. A number of stations are located along the route of the mail bags and irradiate these bags. Each station includes an array of three antennas disposed in mutually orthogonal relationship so as to irradiate the transponder notwithstanding its position. When irradiated by ultra high frequency (UHF) energy, the transponder is activated and transmits a VHF signal. The transponder includes a transmitting circuit which may be selectively set to transmit a signal having a frequency uniquely identifying the transponder. The system includes a receiver for tracking a plurality of transponders and providing an output as to when and if the transponder is tracked as it passes through each station along the mail route.

Interpretation of a hot wire signal using a universal calibration law

Abstract: This paper describes the interpretation of the hot wire signal from a single hot wire in terms of a universal function. The calibration curves for probes with nominally the same geometry have been studied for deviations in the shape of calibration curves, yaw dependence and the effect of angle of incidence. From these results the basic equations for the interpretation of the signal from normal and yawed hot wires have been derived.

Method and apparatus for thermal viscosity modulating a fluid stream

Abstract: A method and apparatus for thermal viscosity modulating a fluid stream by time varying the temperature of the stream in response to an intelligence signal. The method and apparatus are useful for ''''printing'''' or forming an ink image of an original in black and white or color. In the preferred embodiment, a plurality of fluid printing ink streams are thermal viscosity modulated in response to an electrical signal which represents a scanned original. Each fluid ink stream corresponds to a resolution element across the serially or parallel scanned original. The image of the original is formed or ''''printed'''' on a suitable fluid receptor, such as paper, by depositing the fluid streams in varying amounts on the receptor according to the viscosity of each of the streams. The thermal viscosity modulation of the fluid stream is accomplished in a preferred embodiment by passing the fluid streams under pressure through capillaries each having a thin film electrical resistor formed on the inner wall thereof. The scanned original electrical signal is impressed across the capillary electrical resistor to heat the fluid ink stream in accordance with the signal. By varying the amount of heat, the viscosity of each stream is modulated as a function of the value of the corresponding resolution element of the original.