Showing papers on "Signal published in 1974"

Linear Amplification with Nonlinear Components

Abstract: A technique for producing bandpass linear amplification with nonlinear components (LINC) is described. The bandpass signal first is separated into two constant envelope component signals. All of the amplitude and phase information of the original bandpass signal is contained in phase modulation on the component signals. These constant envelope signals can be amplified or translated in frequency by amplifiers or mixers which have nonlinear input-output amplitude transfer characteristics. Passive linear combining of the amplified and/or translated component signals produces an amplified and/or translated replica of the original signal.

Broadcast signal identification system

Abstract: A process for automatic electronic recognition and identification of programs and commercial advertisements broadcast on television and radio wherein a digitally sampled reference signal segment derived from either the audio or video portion of the original program content to be identified is compared with successive digitally sampled segments of the corresonding audio or video portion of a broadcast signal in a correlation process to produce a correlation function signal. The sampling rates and the time duration of the reference signal segment and the broadcast signal segments are the same. When the signal segments which are compared are the same, the correlation function signal is relatively large and a recognition thereof is achieved when such correlation function signal exceeds a selected threshold level. The compared signal segments may also be obtained as low frequency signals derived from the original reference and broadcast signals by non-linear and envelope formation processing techniques.

Signal propagation during aggregation in the slime mould Dictyostelium discoideum.

Abstract: Summary: We have analysed the pattern of concentric waves visible at the onset of aggregation of amoebae of Dictyostelium discoideum and have shown that each wave consists of a light band of elongated, moving cells, and a darker interband zone of rounded cells. Our analysis supports earlier suggestions that aggregation occurs in response to chemotactic signals emanating from a centre and which are propagated outwards through the field by a relay mechanism. The width of each band of moving cells corresponds to the distance the signal is propagated during the time that the cells remain elongated after stimulation, and does not vary with signal frequency. The width of the interbands of non-moving cells depends upon the distance the signal is propagated between signalling events, and varies with the signal frequency which increases during aggregation. The velocity of signal propagation decreases slightly with increase in the density of the monolayer of aggregating cells. We have shown by time-lapse films taken at high magnification that the signal is relayed radially outwards in steps of approximately 57 μm (relay zones) and that the response of each successive zone occurs approximately 12 s after the previous one (relay time). We have attempted to demonstrate the existence of a refractory period for chemotactic responsiveness. Our results indicate that such a refractory period, if it exists, cannot be more than 12 s.

Signal, Noise and Resolution in Position-Sensitive Detectors

Abstract: An analysis is presented of signal, noise and position resolution relations for some of the most interesting position-sensing methods. "Electronic cooling" of delay line terminations is introduced in order to reduce noise in the position-sensing with delay lines. A new method for terminating transmission lines and for "noiseless" damping which employs a capacitance in feedback is presented. It is shown that the position resolution for the charge division method with resistive electrodes is determined only by the electrode capacitance and not by the electrode resistance, if optimum filtering is used.

Video system for conveying digital and analog information

Abstract: A video system having a transmitter in which a composite signal is formed by combining digital information with scanlines of an analog video signal generated by a line scanning device, and a receiver in which the digital information is recovered. The digital information is combined with the analog video signal at predetermined locations along scanlines of the video signal, and these predetermined locations are varied in order to prevent visible deterioration of the video image. In the video receiver, the digital information is recovered by examining the composite signal at the predetermined locations to extract the digital information. Each bit of digital information to be conveyed is represented by a first pseudo-random digital pulse sequence (or its complement, depending on whether the data bit is 1 or 0) which is superimposed on a selected scanline of the analog video signal to form the composite signal. The digital information is recovered at the receiver by generating a second pseudo-random digital pulse sequence in synchronism with the first sequence, and by examining the composite signal at locations determined by the second digital pulse sequence to extract the digital information contained in the composite signal.

Signal repeater for power line access data system

Abstract: A signal repeater is described for relaying information in a two-way communication system superimposed on a power distribution network. The repeater senses signals passing in either direction in the system, translates the received signal to a different band or group frequencies, and transmits the frequency translated information. Provision is made for address-coding the repeaters so that, when connected in several levels, a particular path can be selected through the various levels. Provision is also made for a signal having priority in a system of such repeaters.

Induction charging system

Abstract: A normal 117-volt, 60 cycle source is converted into a high frequency signal resulting in radiation of a substantial portion of the energy in the signal. A receiving coil is inductively coupled to the radiation over a given distance substantially less than a wave length of the high frequency signal to provide a received signal without the necessity of any electrical wires. The received signal in turn is converted into a D.C. signal and passed to a rechargeable battery for charging. The inductive coupling can be utilized for recharging portable electrical instruments having rechargeable batteries or for charging larger rechargeable batteries such as used in electrically driven vehicles.

Coherent optical processing

Abstract: The principles of communication theory were applied in the 1950's to optical imaging systems and to the analysis of images. Optical systems were analyzed in much the same way as linear systems (modulation transfer functions and channel capacities) and images were characterized in ways analogous to time signals (space-bandwidth products, spatial frequency content, etc.). Both coherently and incoherently illuminated optical systems can be treated using these concepts. Coherently illuminated systems are most useful for performing operation such as convolution, cross correlation, and spectral analysis because the Fourier transform of an optical signal physically exists and can, therefore, be measured or modified. The basic Fourier transform relationship for coherently illuminated systems is developed in this paper. It can be detected directly and used to estimate the distribution of spatial frequencies contained in the signal. Methods for constructing complex-valued spatial filters are described; these filters can be used to realize such operations as convolution or cross correlation, addition or subtraction, and differentiation or integration. Experimental results are given to illustrate the concepts and to susgest potential applications. To extend the range of applications, interface devices are needed to allow optical processing of two-dimensional raster-scanned time signals, wide bandwidth electrical signals, and incoherent optical signals. Interface devices are often needed to convert the output optical signal to an electrical signal for post-processing by a digital computer. For some applications, interface devices are needed to construct spatial filters in real time, so different operations can be performed on a given signal. The desired characteristics of these three interface devices and the current state of their development are briefly reviewed.

Uncomplicated load-adapting electrosurgical cutting generator

Abstract: A high frequency signal for cutting human tissue is generated by common-emitter configured oscillator circuit that is adapted to maintain the cutting signal relatively constant in spite of impedance variations in the load caused by variations in the conduction of the tissue being cut.

Data record tracking using track identifying information in the gaps between recorded data groups

Abstract: A technique for tracking lines of recorded analog or digital data and records which can be played back using such tracking, are described in which tracking information is recorded in the gaps between groups of data on such records at positions spaced along the entire length of each track line to enable the track lines to be scanned one line at a time during readout. The tracking information includes recorded track identifying information which is distinguishable from the recorded data and which identifies a given track line from the two adjacent lines on opposite sides thereof. A time related sampling type of tracking method is described by which a light beam or other sensing means is scanned along the track lines, one line at a time, to produce an electrical readout signal corresponding to the digital data and tracking information being scanned. First and second sample signals are stored and compared to produce a correction signal corresponding to the difference between sample signals, and the correction signal is applied to a tracking means for moving the sensing means toward the center of the line being scanned by an amount proportional to the correction signal.

Timing technique for NRZ data signals

Abstract: Circuit for modifying a transmitted Non-Return-to-Zero signal to insert a frequency component at the bit rate to permit linear processing at the receiver to extract timing signals.

Removal of dark current spikes from image sensor output signals

Abstract: There is produced for each location of an image sensor, such as an X, Y addressed photodiode array or a self-scanned charge transfer array, a signal indicative of the dark current amplitude at that location. During operation of the sensor, when a location producing excessive dark current is read out, rather than using the signal stored at that location, there is instead substituted a signal level which is the average of that stored in adjacent locations of the sensor.

Electronic license plate for motor vehicles

Abstract: An electronic license tag or plate formed into a unitary structure and including a single antenna system cooperating in a system comprising a harmonic radiator which transmits a pulse coded identification signal in response to an interrogation signal, and in a signal communication path for detecting and decoding code modulations in the interrogation signal and deriving therefrom an information signal which is communicated to the operator of a vehicle to which the tag or plate is affixed.

Method and apparatus for ultrasonic detection of inclusions in a flowing fluid

Abstract: Inclusions in a flowing fluid, such as bubbles in a flow of blood, are detected by transmitting a continuous ultrasonic signal normally across the flow and detecting changes in the amplitude of the received ultrasonic signal, these changes being caused by changes in the acoustic impedance of the fluid due to inclusions.

Emergency radio frequency warning device

Abstract: An electronic whistle in the form of broad band radio frequency interference generator. A broad band generator generates a coherent or random noise signal which is modulated by an audio signal which corresponds to an audible warning signal such as a whistle or a siren. The modulated signal is then utilized to modulate a carrier signal and amplified and transmitted so that the radios in vehicles in the immediate area will receive an audible interference signal regardless of the particular channel to which the radio is tuned. The audible interference signal may be an intelligible reproduction of the input audio signal so that the driver of the vehicle can determine whether the warning signal is generated by a train whistle, a siren or a human voice.

Spurious signal removal in optical processor fingerprint identification apparatus

Abstract: An improved incoherent optical processor fingerprint identification apparatus employs a rotatable grating for inspecting the ridge orientations in a plurality of preselected finite sample areas of a fingerprint. A detector array including a plurality of detectors each related to a discrete sampled area is disposed to receive an image of the fingerprint filtered by the rotating grating. An incoherent light source and a lens and retroreflective prism assembly function in cooperation with the grating to produce an image thereof superposed on the grating itself such that minimum light is propagated to the detector array in the absence of an input fingerprint pattern whereas, in the presence of a fingerprint pattern, light is diffracted thereby to be filtered by the grating for supply to the detectors. Maximum light may occur at each detector under a condition of spatial alignment of the grating lines with the ridge lines of the related sampled area whereby the time interval between a reference orientation of the grating and the instant of maximum light at each detector may be converted to equivalent electrical signals uniquely representative of a particular fingerprint pattern. The signal to noise factor of the optical system is significantly improved by the use of a novel grating element having plural reflecting and transmitting stripes, with optically absorbing stripes interposed between them.

Pulse control circuit for electrosurgical units

Abstract: A control circuit for electrosurgical units establishes a particular output signal to patient electrodes in response to condition of the patient electrodes. The duty cycle of the output signal is reduced when the patient electrodes are not in contact with the patient so as to prevent unwanted cutting and the duty cycle is increased when both patient electrodes are in contact with the patient so as to maximize the coagulation effect.

Two-input automatic source selector for stereo entertainment center

Abstract: An automatic electronic control system for a home entertainment center, the system utilizing audio signal sensors for the preferential selection of a record player or tape deck as a signal source but with provision for returning to a tuner upon the cessation of the signal from either of the preferred sources.

Data processing system

Abstract: A data processing system comprising an assembly of buses for interconnecting a plurality of units, the units including data processing units, a memory unit and peripheral data processing units, the data processing units being connected in series with each other via a signal line and being further connected to said bus assembly in parallel relationship with each other. A bus control unit is provided for delivering a "who" signal (which is used for detecting a requesting unit) to the first one of said serially connected data processing units when said unit requests the use of said bus assembly. Further provided is an interface circuit unit which receives the "who" signal from the signal line and which, when any of the units does not make its own request for the use of the bus assembly upon receipt of the "who" signal, transmits said "who" signal to the immediately following unit and, when the first mentioned unit requests the use of the bus assembly for itself, prevents said "who" signal from being further transmitted, and selects another unit associated with the address signal delivered from said bus requesting unit and interconnects both units through said bus assembly.

Adaptive feed forward system

Abstract: A feed forward system for reducing the distortion products from a device such as an amplifier, wherein a sample of the device input signal is subtractively combined with a sample of the device output signal to produce a sample of the distortion products. The distortion sample is adjusted in phase and amplitude and subtractively combined with the device output to produce a distortion-reduced system output. First and second pilot signals, applied to the device input and output respectively, are detected in the sample of the distortion products and in the system output to produce control signals which adjust the phase and amplitude of the input signal sample and the distortion sample to provide an adaptive system which automatically compensates for uncontrolled variations in the system components. A portion of the distortion sample produced by the feed forward process is fed back to the device input by way of a negative feedback circuit to reduce the signal handling capacity required of components such as an auxiliary amplifier used in processing the distortion sample.

Hydrostatic transmission control

Abstract: An electronic control for a hydrostatic or hydromechanical transmission governs the transmission ratio as a primary function of a manual ratio request and as a secondary function of throttle setting, engine speed, pressure in the hydrostatic transmission and manual range selection. A ratio control signal is developed by comparing ratio request with the existing ratio control signal and integrating the difference to provide a smoothly changing ratio, and the rate of change is limited to a maximum value. Ratio change of the hydrostatic unit is carried out by varying the displacements of the hydrostatic pump and motor. The displacements are changed by servo motors electrically controlled by the electrical ratio signal. Synchronous range shifting in a gear set is accomplished by applying one torque transmitting device (e.g. brake or clutch) and releasing another torque transmitting device, each of which is fluid pressure operated. Pressure switches associated with each device determine whether it is applied or released. During range shifting, the hydrostatic unit is prevented from changing ratio until the shift is effected as indicated by the condition of the pressure switches. Engine speed is maintained within programmed limits by varying the ratio to prevent overspeed or underspeed. Shift logic and inhibit circuits responsive to manual range selection, transmission output speed, and the ratio control signal initiate range shifting only under desirable conditions.

Linear amplification using quantized envelope components to phase reverse modulate quadrature reference signals

Abstract: Available devices including quadrature detectors, delta coders and nonlinear amplifying devices are used to produce linear amplification of a bandpass analog input signal having amplitude variations. This linear amplification technique is primarily useful at high frequencies. The analog input signal is resolved into two variable amplitude quadrature components, the envelopes of which together contain the total information content of the input. The envelopes are applied to separate delta coders which each produce a delta bitstream whose weighted time average approximates the respective envelope. The constant amplitude delta bitstreams phase reverse (phase shift key) modulate two quadrature reference signals. In one embodiment, nonlinear high level phase reverse modulators are used to produce two high level output signals, which are then summed and bandpass filtered to produce a linearly amplified replica of the original analog input signal. In another embodiment, two output signals from low level phase reverse modulators are each amplified by separate nonlinear amplifiers. The amplified resultants are then summed and bandpass filtered to produce a linearly amplified replica of the original analog input signal. In all embodiments, a decoder feedback loop is required. This loop may be either internal to the delta coder or external and coupled to the linearly amplified replica.

Programmable keyboard arrangements

Abstract: A programmable keyboard of the kind in which a member presents a plurality of discrete areas to a co-operating probe, each of which areas produces a unique signal when addressed by the probe, is provided with a liquid crystal display to identify the current function of a particular area. Separate additional addressable areas are provided by means of which one of a number of alternative display functions can be selected as desired.

Signal compressors and expanders

Abstract: The invention concerns a dynamic range compressor type encoder or expander type decoder, in which a main signal component in a main path is boosted or bucked by a further signal component derived from a point in the main path by a further path having the characteristics of so restricting the further signal component that the boosting or bucking action is only appreciable below a low level threshold. In the present invention the further signal component is a difference signal formed between a direct signal derived from a point in the main path and a delayed version of either the same signal or of another signal derived from another point in the main path. At the frequency equal to the reciprocal of the delay, and at harmonics of this frequency, the direct and delayed signals cancel. The compressor or expander action, and hence noise reduction action, takes place only at intervening frequencies. The invention enables carrier components or other repetitive components of signals to be excluded from the compressor or expander action (which they would otherwise choke).

System for processing data signals for insertion in television signals

Abstract: In any television transmission system there are periods during which the wide-band picture signals are absent. The invention provides a signal generator system for the transmission of digital information representing a series of pages of alphanumeric or graphical symbols piecewise during these periods. At least one peripheral generating device is provided for supplying digitized data to a main storage device (conveniently of the magnetic disc type) and transfer means is operable to read out portions of the data from the main storage device and store them temporarily in a second storage device. Discharge means is operable to discharge portions of the data from the second storage device at intervals to provide output signals for insertion in a television signal during periods as aforesaid.

Design and operation of a floating gate amplifier

Abstract: A unique amplifier configuration is examined that fully exploits the intrinsically high signal-to-noise performance of charge-coupled devices (CCD's). In this amplifier, the signal charge is detected with a conducting `floating gate' embedded in the oxide between a bias electrode and the silicon substrate. The change of voltage on the floating gate produced by the signal charge in the CCD channel is then used to modulate the current flow in a metal-oxide-semiconductor (MOS) transistor. The signal charge remains isolated and can be moved downstream in the CCD channel; thus, it can be detected again by other similar structures. Computer analysis, test structure design, and experimental results of a floating gate amplifier (FGA) are presented.

Seizure suppression device

Abstract: A method and apparatus for suppressing epileptic seizures whereby an EEG electrical signal from an epileptic is amplified, filtered to remove components above roughly 8 Hz and below 2 Hz, and applied to a level detector which produces a trigger signal when the EEG amplitude exceeds a predetermined, variable level. The gated signal operates an oscillator to produce a signal which is in turn applied to a speaker, such as a set of earphones, to produce an audio signal which is maintained for as long as the seizure lasts, and then for an additional 4 seconds.

Adaptive digital servo system

Abstract: The invention relates to an adaptive digital servo system which comprises a track position profile sequencer for generating a sequence of binary position signals, a track correction profile sequencer for generating a sequence of binary correction signals, where there exists a correction signal in the track correction profile sequencer for each position signal in the track position profile sequencer, a present position decoder for generating a binary signal indicative of the actual position of the member being moved and controlled by the servo system, an error generator for comparing the commanded position signal from the track position profile sequencer and the actual position signal to generate a binary error signal, a combination means for combining the generated error signal with the correction signal associated with the position signal used to generate the error signal to form a controlled signal for controlling the actuator of the servo system, a track correction profile generator for extracting the repeatable error component from the error signals being generated by the error generator, and updating means for modifying the correction signals associated with the position signals presently controlling the servo system by a correction signal generated from the repeatable error component extracted from the error signals by the track corrector profile generator.

Portable miniature type information treating device

Abstract: An electronic timepiece, used as a pager watch, has a speaker for emitting an alarm sound at a preset time and also for reproducing an external call signal intercepted by a receiver for incoming electromagnetic waves. The receiver may be maintained normally inactive, being periodically activated for short time intervals under the control of a frequency divider in the output of a crystal oscillator serving to drive an electro-optical display. Sensors responsive to abnormal ambient conditions, e.g. temperature or blood pressure of the wearer, may also operate the speaker.