Authentix, Inc.

Rochester Sensors, LLC

Other

University of Texas System

Chester Wildey

Paul John Cronin

Alan Hunt

Gagik Farmanyan

Duncan Leo MacFarlane

Georgios Alexandrakis

Amber Ansari

Bilal Khan

Jeremy Horvath

Jim Rittenburg

Patrick Kindell

In a Time Domain Reflectometry (TDR) measurement system including a measurement probe and an electronics assembly, a method for generating a time delay between transmit and receive pulses for capturing measurements in a given measurement cycle, comprising initiating first relatively slow and second relatively fast time-dependent non-linear ramped waveform functions associated with transmit and receive signals, respectively; and initiated at a time prior to initiation of the first time-dependent non-linear ramped waveform at a second time t; comparing outputs of the first and second time dependent non-linear ramped waveform functions and activating a receive signal to measure a data point along the waveguide at a third time twhen the outputs of the first and second time-dependent non-linear functions are equal; wherein the first and second time-dependent non-linear ramped functions are configured such that their waveform characteristics produces a time delay between time tand time tthat is a linear function of time.

Method for generating a time delay

A method of calibrating a TDR measurement comprising determining an echo profile of a calibration trace, and comparing a determined length of an actual physical length taking into account dimensional variables due to temperature fluctuations, then deriving and storing a calibration factor, and using that calibration factor to determine a system clock distance calibration, with the calibration factor being a ratio of the clock cycles to ensure that the determined electronic length is equal to the actual physical length. Once the system clock has been calibrated, measurement of the distance along the probe to the liquid height, plunger height, and so on, can then be determined with very high accuracy, using very low-cost electronic components.

Calibration method for a TDR measurement

A Time Domain Return measurement system for measuring liquid level, linear movement or other measurements which includes a first and second electrode, the second electrode spaced from the first electrode to define a gap, and an electronics assembly connected to the first and second electrodes equipped with a generator for transmitting an electromagnetic signal for propagation along the electrodes. The signal generator has a first analog timing circuit for actuating a slow-rising function of voltage versus time, a second analog timing circuit associated with the first analog timing circuit for actuating a fast-rising function of voltage versus time, and a receive circuit electrically connected to the electrodes, the receive circuit being activated for receiving return echo data associated with the electromagnetic signal transmitted when the fast-rising function is equal or greater than the slow-rising function to determine the position of the second medium with respect to the electrodes.

Calibration method for first time use of equipment

A time domain reflectometer (TDR) transducer () for determining a level () of liquid () in a container () includes a first electrode () and a second electrode portion () with a measuring volume () therebetween for receiving material () to be measured. The second electrode portion () has a shielded electrode section (A) isolated from the first electrode () and an unshielded electrode section (B), such that an energy pulse propagates along the shielded electrode section (A) without signal loss, and boomerangs along a second opposite direction across the first conductive electrode portion (), the measuring volume () and the unshielded electrode section (B) where partial reflection of the pulse occurs at least at the interface () of the material () to create a return echo that travels in reverse direction, boomeranging back through the shielded electrode section (A) for analysis by an electronic assembly ().

TDR transducer with boomerang waveguide

Low-cost measurement system using time domain reflectometry

Disclosed is a functional NIRS imaging system including an elastomeric cap, a set of transmit optical fibers and a set of receive optical fibers terminating on the inside surface of the elastomeric cap. A pair of light sources combines to produce a collimated light beam at two wavelengths. An optical modulation system, converts the light beam into a plurality of probe light beams, modulates the plurality of probe light beams and directs each probe light beam into a transmit fiber. An optical detection system accepts scattered photons from subcutaneous tissue underneath the elastomeric cap as a plurality of collected light beams and converts them into a time series of electronic images, stores the electronic images into the memory and processes the electronic images using. The system displays the resulting image on a display as a hemoglobin oxygen saturation map.

Functional near infrared spectroscopy imaging system and method

A device detects multi-spectral imaging by using scan elements. The device may include an illumination module and a detection module to detect light scattered from an object illuminated by the illumination module. The device may also include an array of light sources to produce light at a plurality of different wavelengths, and create a line of illumination with each of the different wavelengths. The light detection may be applied to authenticate and validate documents, such as banknotes moving along a document conveyer.

Object authentication

This invention teaches a way to multiplex and de-multiplex unipolar signals using spread spectrum methods. While bipolar spread spectrum signal multiplexing may be used in may applications, for example for systems using radio signals, when using unipolar signals there is a loss of orthogonally which makes the standard algorithms unworkable. This invention teaches a method to recover orthogonally and make spread spectrum multiplexing useful for unipolar signals. One example is in the measurement of optical absorbance along multiple paths simultaneously using light signals, as for functional near infrared spectroscopy (fNIRS).

Unipolar spread spectrum modulation for low computation and power cost signal multiplexing with application to fNIRS measurments

A device detects multi-spectral imaging by using line scan elements. The device may include an illumination module and a detection module to detect light scattered from an object illuminated by the illumination module. The device may also include an array of light sources to produce light at a plurality of different wavelengths, and create a uniform line of illumination with each of the different wavelengths. The light detection may be applied to authenticate and validate documents, such as bank notes moving along a document conveyer.

Document sensor

A method and apparatus for spread spectrum distance and for spread spectrum velocity profile measurement is provided where the short pulse of traditional ultrasonic and radar level gauges is replaced by low peak power direct sequence spread spectrum (DSSS) modulated energy. An echo sequence subtraction process is provided that increases the signal to noise ratio of each echo sequence thus increasing the dynamic range of the system. In addition to providing a higher signal to noise ratio (SNR), better precision and accuracy in ranging Doppler applications and the ability to use lower peak power transmissions, the system is more immune to interference from the environment and allows for less expensive and less bulky ultrasonic transducers.

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Euless, TX, United States of America

Chester Wildey