Showing papers on "Signal published in 1972"

A primer of signal detection theory

Abstract: Contents: Foreword. Preface. What Are Statistical Decisions? Non-Parametric Measures of Sensitivity. Gaussian Distributions of Signal and Noise With Equal Variances. Gaussian Distributions of Signal and Noise With Unequal Variances. Conducting a Rating Scale Experiment. Choice Theory Approximations to Signal Detection Theory. Threshold Theory. The Laws of Categorical and Comparative Judgement. Appendices: Answers to Problems. Logarithms. Integration of the Expression for the Logistic Curve. Computer Programmes for Signal Detection Analysis. Tables.

Inductively coupled transmitter-responder arrangement

Abstract: An inductively coupled interrogator-responder arrangement having two dimensional and limited three dimensional capability. An interrogator means having AC power field generating capability and uniquely coded information field receiving capability may be positioned at a known location such as in a preselected position in a roadway. The interrogator generates an AC power field in regions adjacent thereto. A responder tag means may be positioned on, for example, vehicles. The responder tag may be completely passive, that is, receiving its power from the AC power field generated by the interrogator. As the vehicle approaches the interrogator unit power is received by the responder tag through inductive coupling and the responder tag generates an uniquely coded information field unique to the particular responder tag on the vehicle. The uniquely coded information field is inductively coupled into the uniquely coded information field receiving portion of the interrogator and an information signal is generated in the interrogator having an information content corresponding to the particular code in the uniquely coded information field. In embodiments where the responder tag is self-powered, the interrogator means does not generate an AC power field and the inductive coupling between the responder tag means and the interrogator means is limited to the inductive coupling of the uniquely coded information field generated in the responder tag and received by the interrogator means.

Direct phase detecting system.

Abstract: A system for extracting the phase components of an optical traveling wave field has been constructed. This system consists of the Mach-Zehnder interferometer to capture the wave field as the hologram, a photoelectronic scanning system, and an analog computing circuit. The detected phase signal is immediately displayed on a cathode ray tube as continuous-tone patterns. The method has been confirmed through the experimental results.

System for transmitting auxiliary information in low energy density portion of color tv spectrum

Abstract: DESCRIBED IS A SYSTEM FOR COMPATIBLY TRANSMITTING AND RECEIVING BOTH A COLOR TV SIGNAL AND AN ADD-ON SIGNAL WITHIN THE FREQUENCY BAND NORMALLY OCCUPIED BY THE TV SIGNAL ALONE. THIS SYSTEM UTILIZES A HIGH FREQUENCY-TIME PRODUCT SIGNAL CONTAINING ADD-ON INFORMATION AND HAVING FREQUENCY COMPONENTS WHICH ARE LOCATED IN A LOW ENERGY PORTION OF THE TV SIGNAL. INTERFERENCE BETWEEN THE ADD-ON AND TV SIGNALS IS MINIMIZED DUE TO THE NOISE-LIKE CHARACTERISTICS OF THE HIGH FREQUENCYTIME PRODUCT ADD-ON SIGNAL AND TO THE PARTICULAR LOCATION OF THE ADD-ON SIGNAL IN THE TV FREQUENCY BAND THUS ALLOWING ACCURATE AND RELIABLE TRANSMISSION OF BOTH THE ADD-ON AND TV SIGNALS.

Remote engine tachometer

Abstract: A tachometer which does not require connection with the engine. A probe placed near the engine picks up electromagnetic radiation produced by the distributor points and coil in bursts timed with engine speed. A bandpass filter suppresses all frequencies except a narrow band which is amplified in a circuit with automatic gain control using optic elements in the feedback loop. A reference voltage whose level is a constant fraction less than the signal maximum is produced and compared with the signal in a comparator, the output of which triggers a one shot pulse generator to produce a train of pulses of constant width and amplitude at a frequency proportional to engine speed.

Banding correction system for film recording apparatus

Abstract: The disclosure pertains to an apparatus for recording an image on a film in a scanned horizontal line pattern with a light beam, the scanned pattern being achieved by reflecting the light beam from a moving surface such as an optical spinner. There is disclosed a subsystem for improving the vertical registration of successive lines in the pattern. Means are provided for sensing the beam position at the beginning of a scanline and for developing a position-indicative signal which varies in accordance with the relative vertical position of the beam. The position-indicative signal is compared to a predetermined reference signal which is a function of the desired position of the beam and there is generated a correction signal which depends on the comparison. Further means are provided for vertically deflecting the beam in accordance with the correction signal.

Current controlled two-state modulation

Abstract: In a current controlled two-state modulation system having a power switch and a low pass filter, a current sensor provides a current feedback signal representative of the current delivered by the power switch to the low pass filter The low pass filter also provides a voltage feedback signal that is combined with a reference signal to provide a combined signal A limiting amplifier amplifies the combined signal for further combination with the current feedback signal to provide a switching signal that is delivered to a circuit characterized by hysteresis This circuit determines the instant when the power switch is switched so as to maintain the output voltage provided by the low pass filter substantially constant so long as the load current is less than a predetermined limiting value determined by the limiting amplifier and thereafter limits the output current to substantially the predetermined limiting value

Digitally compensated scanning system

Abstract: A self-scanned photodiode array operating in the recharge current mode generates a serial video information output signal as light from a light emitting diode illuminator is reflected from the scanned document and imaged onto the photodiode array. A photodiode sensitivity and illumination variance compensation signal is generated during a write mode as the photodiode array scans a white background. The serial compensation signal thus generated is converted into an N bit binary code for each photodiode in the array. The N bit binary code is stored. Thereafter, when scanning printed or written information on the document during an operational mode, the serial video information signal is digitized as in the write mode and forms an address together with the stored digitized compensation bits for addressing a stored table of normalized contrast ratios in the form of M data bits. These M data bits are passed to an output buffer and converted to an analog signal equal to 1 minus the contrast ratio to provide a corrected serial video information signal.

Difference threshold for intensity of tactile stimuli

Abstract: The difference threshold (DL) for brief tactile stimuli (taps) and vibrotactile stimuli was determined using a 2IFC procedure. The measurements were made at several intensities both in quiet and in the presence of a background vibration. The results show that in the absence of background vibration the DLs for higher intensity stimuli are similar for both taps and vibration, whereas at lower intensities the DL is larger for taps. In the presence of background vibration the DL for vibratory stimuli is elevated to a much greater extent than it is for tap stimuli. The DL is affected by both the intensity of the signal and the intensity of the background vibration.

Auditory Thresholds of a Killer Whale Orcinus orca Linnaeus

Abstract: Using standard operant conditioning techniques, a killer whale, Orcinus orca Linnaeus, was trained to respond to pure‐tone auditory signals by pushing a response manipulandum. An audiogram was obtained for frequencies between 500 Hz and 31 kHz. Greatest sensitivity to the signal was observed at 15 kHz at a level of −70±5 dB re 1 dyn/cm2. The observed upper limit of hearing was 32 kHz. At no time during training or testing did the animal respond to an undistorted signal above 32 kHz. Frequencies below 500 Hz were not tested, owing to high ambient tank noise levels.

Multi-purpose information gathering and distribution system

Abstract: A multi-purpose information gathering and distribution system in which a plurality of remote stations are controlled by and report to a central station. The central station includes an omni-directional antenna which radiates a modulated information signal to all of the remote stations. At predetermined intervals the information signal is interrupted and a query signal is transmitted to individual remote stations by means of a directional antenna directed to the particular remote station. Sensors located at the remote stations sense various conditions and upon receipt of a query signal transmit a signal to the central station which identifies the remote station and indicates the condition of the sensors at the remote station.

On the instantaneous measurement of bloodflow by ultrasonic means.

Abstract: Part of the problem of determining the flow through a blood vessel is the measurement of the instantaneous average blood velocity over a cross-section of the vessel. In this paper a new method is described to estimate that velocity from the received signal of a Doppler flowmeter using continuous ultrasound. The method is based on the determination of the frequency shift averaged over the power density spectrum of the received signal. Due to a new type of instrumentation this can be done without carrying through a complete frequency analysis of that signal. This provides a rather accurate determination of the instantaneous value of the blood velocity.

Infrared imaging system

Abstract: A pair of scanning mirror systems scans an object image in two dimensions over an infrared detector. The detector signal and signals proportional to the position of the mirror systems permit display of an image of the object on a video monitor. The video monitor display includes a portion thereof which is an image of the object and another portion thereof which is a temperature profile curve of the infrared intensity across one line of the image. A memory is optionally employed to store a frame of video information and to replay it at a much faster rate than it is scanned in order to form a persistent image on the video monitor. Automatic brightness control circuitry adjusts the displayed signal level according to the maximum temperature of the object being imaged.

Monitoring transmission link by comparing pseudorandom signals

Abstract: A monitoring remote location has alarm sensors and a data transmitter for transmitting alarm and pseudorandom number signals over a direct line to a data detector at the monitoring central location. The monitoring location has a pseudorandom number signal generator that generates at essentially the same time the same number signals generated at the monitored location. The portable pseudorandom number signal generator at the monitored location is first brought to the monitoring location. There both pseudorandom number signal generators receive the same initial number signal at the same time to simultaneously produce the same pseudorandom sequence of digital numbers. The portable pseudorandom number generated is then taken to the monitored location and coupled to the data transmitter which also receives alarm or other signals, if any. The data detector at the monitoring location then compares the sequence of number signals received over the direct line with those locally produced by its pseudorandom number signal generator to provide a line failure signal when the number signals thus compared are not the same for a predetermined time interval.

Optimal reception for binary partial response channels

Abstract: This paper describes an exceptionally simple scheme for binary partial response signal formats of the form a k ± a k-1 (for l ≧ 1, and a k = ±1). The receiver implements the maximum likelihood detector of the sequence a k assuming additive white Gaussian noise as the channel impairment. It is simpler and more efficient than the scheme recently described by G. D. Forney.1 It is, however, not generalizable to multilevel signaling while still retaining its simplicity.

Laser imaging device

Abstract: This invention relates to the imaging device in which a spatial picture corresponding to an original picture is reproduced from a time-sequence video-signal corresponding to said original picture. Said device comprises means with which an acoustic wave propagated through an acousto-optic medium such as the transparent saphire crystal is modulated by said time-sequence video-signal, thereby to convert a time-sequence distribution of said signal into a spatial distribution of an optical property of said medium, and means which irradiates pulse laser light beam and which emits said light beam in a manner to be synchronized in time with said video-signals. If the laser light beams of different colors is used in this device, the multi-color imaging device is obtained.

Electronic combination lock including sequential signal generator and signal display

Abstract: A manually-actuated electronic combination lock is provided in which the combination code consists of certain preselected digital signals out of a field of many such signals. Circuit means provide for generating a sequence of digital signals constituting the field in response to sustained manual engagement with a push-button switch and a solid state alpha-numeric indicator is connected to display by symbolic representation each of the signals as generated. Selection of the proper combination of signals is provided by manually releasing the switch as each of the proper signals is displayed, whereupon each such selected signal is f ed to a decoding circuit. The signals selected in this manner are collected in the decoding circuit, which upon completion of the proper code operates an electromagnetic lock or the like. In one embodiment of the invention, the solid state indicator is mounted together with the push-button switch on a portable key member adapted for a detachable connection at a security station, such as a door equipped with an electricallyoperated lock. Other disclosed embodiments include, mounting of the solid state indicator and manual push-button within a door handle disposed adjacent to and for operation of an electromechanical door lock; and an arrangement of the solid state indicator and push-button in the driver''s compartment of a vehicle, preferably and as disclosed with the indicator disposed in a window panel overlying the steering column, for controlled operation of the vehicle ignition and hood locks.

Simultaneous transmission of a video and an audio signal through an ordinary telephone transmission line

Abstract: A communication system for simultaneously transmitting a video and audio signal through the same transmission line. The transmission line can be a standard telephone line, and the video signal can be transmitted by FM slow scan TV techniques, while the audio signal can be transmitted by AM single sideband techniques. Simultaneous transmission of video and voice is accomplished over the same transmission line by separating the AM signal and FM signal into separate channels, and since AM reception is relatively insensitive to FM, and FM reception is relatively insensitive to AM, the signals do not interfere with one another.

A Simple Approach to Digital Signal Processing

Abstract: From the Publisher: Digital signal processing (DSP) has been a very active area of research and application for over thirty years Applications range from audio and video electronics to sensors, image processing and medical applications Provides a basic introduction and simple overview of DSP

Linear amplification with nonlinear devices

Abstract: Available nonlinear amplifying devices are used to produce bandpass linear amplification of a signal having amplitude variations. The input signal is transformed into two constant amplitude phase modulated components which together contain in their phase fluctuations the total information content of the input. The components are amplified separately by devices which preserve phase, and the recombination of the amplified components reproduces a linearly amplified replica of the original input. The technique is primarily useful at high frequencies and can be modified to provide frequency translation.

Geophysical surveying system employing electromagnetic impulses

Abstract: A geophysical survey system is disclosed for determining the character of the subterrain by analysis of reflections from electromagnetic pulses radiated into the ground. The system repetitively radiates into the ground a short duration electromagnetic pulse having a rise time in the order of 1 nanosecond. The antenna which radiates the pulse into the ground is employed to receive the reflections of the pulse. The received signals are coupled through a transmit-receive network to a receiver which permits the input signal waveform to be reconstructed from a sequence of samples taken by the receiver. The system is capable of generating a profile chart indicating the magnitudes of the reflected signals and the depths at which the reflections occurred.

Clocked bootstrap inverter circuit

Abstract: A clocked bootstrap inverter circuit including an inverting amplifier, an active load for the inverting amplifier including a capacitive bootstrapping circuit, a biasing circuit responsive to a first clocking signal and a second clocking signal 180* out of phase with the first clocking signal, and an amplifier disabling device responsive to a third clocking signal which is more than 180* out of phase with the first clocking signal. The biasing circuit alternately activates and inactivates the active load while the disabling device alternately disables the amplifier and provides a small time delay for allowing the bootstrapping circuit to be precharged.

Phase control for a drop generating and charging system

Abstract: There is disclosed a phase control system for a jet drop generator wherein the phase of drop generation is adjusted by adjusting the amplitude of a stimulating disturbance applied to the jet. A time varying electrical signal, preferably a binary or ON/OFF signal, is applied to a charging electrode located near the point of drop formation, so that newly forming drops are charged or uncharged in correspondence to the signal. During normal operation as a recording device, the charged drops pass through an electrical deflection field for deflection into an appropriately placed catcher. Drops which are uncharged pass undeflected through the deflection field and deposit on a recording sheet. During non recording or dead times a calibrating signal is applied to the charging electrode and the charge carried away by the drops formed during that period is measured by an electrometer connected to the catcher. This measurement provides an indication of the phase of drop generation relative to the phase of the calibrating signal. Deviations of this relative phase from a desired relative phase are corrected by adjusting the amplitude of the drop stimulating disturbance.

Broad-band thin-film signal sampler

Abstract: Previous developments in high frequency signal sampling have been extended by applying thin-film and solid state techniques to the sampler design. The basic elements of a sampler are a signal-carrying transmission line, a sampling gate, a drive line for the gate pulse, and a video output. In the design reported here, a thin quartz substrate supports the circuits. To reduce signal-line reflections the gate is made the center element of a low-pass signal-line filter. The gate pulse is developed across a length of slot transmission line in the signal ground plane parallel to and beneath the signal transmission line. A beam-lead Schottky diode pair is mounted across the slot with its center node connected to the signal transmission line through the substrate.

Method and system for the infrared analysis of gases

Abstract: A dual path analyzer and a single path analyzer are disclosed, each for determining the concentration of one or more gaseous components in a mixture of gases. The preferred analyzer is a single path instrument which includes a source of infrared energy, a detector for the energy, a sample cell for the gas mixture positioned between the source and detector, and a filter wheel having a plurality of filters and a source blocking device positioned between the sample cell and detector for sequentially interposing the filters and the source blocking device between the source and the detector. Means are provided for amplifying the output signal of the detector and for processing the signal to provide a direct readout display which indicates the concentration of the gaseous components being analyzed. The processing electronics preferably include provision for calibrating the analyzer with clean ambient air, for compensating for background levels of radiation, and for correcting the displayed output signal for the effects of absorption band interferences between two or more gases in the gas mixture. The structure of the dual path analyzer includes a source of infrared energy, a detector for the energy, a sample cell for the gas mixture, a cell for a reference gas, and optical path means between the source and detector for sequentially directing the source energy through the sample cell, the reference cell, and through neither cell. Processing electronics similar to the single path instrument can be incorporated to compensate for background radiation and absorption band interferences.

Contacting integrated circuit chip terminal through the wafer kerf

Abstract: A test system for selectively accessing mechanically difficult to access terminals in an integrated circuit chip by the combination of an externally accessible circuit terminal formed in the wafer kerf, a conductive bus bar formed in the kerf connected to the terminal, connecting means for connecting each of a plurality of chip terminals to the conductive bus bar, means for connecting the kerf terminal to a tester, and means for selectively activating a connecting means between the chip terminal and bus bar to provide conductive signal paths from selected chip terminals to the kerf terminal.

Method and apparatus to reduce noxious components in the exhaust emissions of internal combustion engines

Abstract: The composition of exhaust gases from internal combustion engine is sensed, particularly the oxygen component thereof, and a sensed signal is derived, which is applied to a threshold detector, which triggers whenever the sensed signal passes a certain threshold value. The trigger signal controls and integrating controller to commence integrating, the integrating controller providing an output signal which is applied to set the air-fuel ratio such that the air number lambda is constantly controlled to be about 1. If integration by the integrating controller persists for a period of time in excess of a predetermined lapsed time, as determined by a pulse source controlled by speed of the engine, the integrating rate of the integrating controller is changed to provide for more rapid response when large changes have to be compensated.

Optical measuring apparatus

Abstract: A narrow laser beam is directed towards a mirror which is rotated to effect rotary planar scanning or sweeping of a lens constructed to convert the rotary scanning beam into a parallel scanning beam. An article to be measured is positioned in the path of the parallel scanning beam at generally the focal point of the lens, and the interruptions of the parallel scanning beam, as produced by the article, are sensed by a photodetector. The photodetector transmits corresponding pulses or signals through an amplifier to an edge decoder which receives a reset signal with each pass of the scanning beam. The edge decoder may provide for selecting different combinations of signals received from the amplifier to control the counting of constant pulses received by a counter from a high frequency generator or clock so that the counted pulses correspond to the dimension of the article at the plane of the parallel scanning beam. Preferably, the motor which rotates the scanning mirror is supplied with electrical energy from the clock through a frequency divider, and the amplified signals from the photodetector are compared with a reference level to provide an automatic gain control for the amplifier.