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Class 324/667 - By frequency signal response, change or processing circuit


Subclass of Class 324 - Electricity: measuring and testing
Definition: Subject matter including circuit means to measure using
No. of patents: 86
Last issue date: 01/03/2012


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NumberTitleIssue Date
8089287Soil humidity evaluation with contact free coupling
Systems and methods that evaluate moisture content of the soil through change of capacitance and alternative current. A contact free inductive coupling can be provided between a sensor arrangement associated with the soil, and a reader arrangement (e.g., combination...
01/03/2012
7719290Circuit configuration and method for measuring humidity
A circuit configuration for measuring air humidity includes a measuring system which includes an oscillator unit and a signal-processing unit, as well as a frequency-determining impedance, which is determined largely by a parallel connection of a capacitive humidity...
05/18/2010
7432725Electrical field sensors for detecting fluid presence or level
The present disclosure provides several systems. In general, it provides E-field sensor systems that utilize at least one electrode 100 adapted for creating an E-field in an area 210 within a detection volume where fluid presence 400 or presence...
10/07/2008
7375633Methods and systems for in-line RFID transponder testing
Methods and apparatus for testing the health of each of a plurality of RFID transponders is provided. The apparatus includes an antenna support assembly including an antenna support body and an antenna coupled to a surface of the antenna support body, the antenna in...
05/20/2008
7301458Method and apparatus for testing RFID devices
A method and apparatus for testing RFID straps. Arrays of RFID straps in a roll-to-roll process are coupled to an array of test elements. RF programming and interrogation signals are frequency and time multiplexed to the RFID array. Return signals are detected to de...
11/27/2007
7282927Use of a configurable electronic controller for capacitance measurements and cable break detection
A method and apparatus for measurement of capacitance by use of an adaptive input-cell circuitry, part of a configurable electronic controller, or generally by a computer controlled adaptive input-cell. The input-cell comprises a comparator, two transistor switches ...
10/16/2007
7259575Method for on-line fuel-dilution monitoring of engine lubricant
A method for determining a fuel-dilution condition of a lubricant used in transportation and industrial equipment. The method uses apparatus that applies a high frequency and optionally a low frequency oscillating signal to electrodes immersed in the fluid and quant...
08/21/2007
7250775Microfluidic devices and methods based on measurements of electrical admittance
Microfluidic devices and methods that use electrical admittance as the basis for measuring flow rate of fluids and/or for distinguishing (e.g., characterizing, sorting, separation, etc.) different particles, chemical compositions or biospecies (e.g., different cells...
07/31/2007
7205780Multi-frequency capacitive measurement device and a method of operating the same
A method and a system is provided that includes a multifrequency generator supplying signals of at least three different frequencies to an electrode assembly, the capacitance of which is detected for a plurality of different frequency points. In this way, the capaci...
04/17/2007
7180305Sensor systems and methods of operation
A technique for operating a sensor system is provided. The method includes exciting a first sensor with a first excitation signal at a first frequency and exciting a second sensor with a second excitation signal at a second frequency. The technique also includes com...
02/20/2007
7173438Measuring capacitance
A method for determining capacitance includes alternately charging a capacitor to a first voltage and discharging the capacitor to a second voltage, generating an output signal having a frequency that is a function of a time period, and determining the capacitance b...
02/06/2007
7148701Apparatus for measuring electrical impedance
The present invention provides an apparatus for measuring electrical impedance comprising: two input electrodes contacted to a subject for measuring impedance; a difference amplifier to which two signals inputted to the two input electrodes are inputted; a device fo...
12/12/2006
7149633Displacement method of knot sizing
A method of estimating the displaced size of a knot in a lumber piece includes the steps of: translating the lumber piece downstream along a flow path between a radiation source and sensor while simultaneously irradiating the lumber piece with radiation from the fir...
12/12/2006
7126352Method and device for determining the moisture content and conductivity in the ground and in bulk materials
In a method and device for determining the moisture content and conductivity in the ground and in bulk materials, a capacitive sensor is disposed in the ground or the bulk material, the sensor is charged from a constant external voltage supply with a given initial c...
10/24/2006
7102517Test fixture for evaluating RF identification system and related methods
A test fixture for evaluating an RF identification system and related methods for evaluating an RF tag and/or an RF antenna, are disclosed. The test fixture provides predefined RF tag positions that can be used to test: read position, distance and antenna capability...
09/05/2006
7088112Sensor capacity sensing apparatus and sensor capacity sensing method
A capacitor C and an impedance converter Hiz are included in a feedback circuit of the first operational amplifier OP1 in series; an electrode P1 of a capacitive sensor is connected to a connection point of the said capacitor and the converter ...
08/08/2006
7034551Electrostatic capacitance detection circuit and microphone device
An electrostatic capacitance detection circuit 10 comprises an AC voltage generator 11, a first operational amplifier 14 of which non-inverting input terminal is connected to specific potential (a ground in this example), a second operational am...
04/25/2006
7023223Impedance measuring circuit and capacitance measuring circuit
An electrostatic capacitance detection circuit 10 comprises an AC voltage generator 11, an operational amplifier 14 of which non-inverting input terminal is connected to specific potential (a ground in this example), an impedance converter 16...
04/04/2006
7023221Structure of object proximity and position detector
The present invention offers an object proximity detector and an object position detector. The variation of frequency of an oscillator is used to detect the proximity of an object to the sensor plates. The dependence of frequency on process parameter is minimized by...
04/04/2006
7019540Electrostatic capacitance detection circuit and microphone device
An electrostatic capacitance detection circuit 10 comprises an AC voltage generator 11, an operational amplifier 14 of which non-inverting input terminal is connected to specific potential (a ground in this example), an impedance converter 16...
03/28/2006
7010394Intelligent environmental sensor for irrigation systems
The invention provides a regulator system for regulating the operation of an irrigation system which is responsive to user programmed information. It has a control element for issuing watering control signals to an irrigation system, having at least one of (i) a dur...
03/07/2006
7005865Circuit and method for impedance detection
An electrostatic capacitance detection circuit 10 comprises a DC voltage generator 11, an operational amplifier 14 of which non-inverting input terminal is connected to specific potential, an impedance converter 16, a resistance (R1
02/28/2006
6989755Signal transmission device and method
A signal transmitting apparatus which makes exchanging information when pouring a liquid possible. A container body 201 of a transmitter side container 20 holds an electrically conductive liquid 402. A display 306 for confirming data rece...
01/24/2006
6962526Combine tailings sensor system
A system for sensing the presence of tailings in a combine includes a tailings sensor configured to generate a signal indicative of a flow rate of tailings and a first microcontroller module coupled to the tailings sensor and configured to receive the signal and fil...
11/08/2005
6933733Method and apparatus for measuring the concentration of hydrogen peroxide in a fluid
A method and apparatus for measuring the concentration of hydrogen peroxide in a liquid or gaseous fluid. A capacitor is exposed to the fluid, wherein the fluid acts as the dielectric between the conductors of the capacitor. The permittivity and dielectric constant ...
08/23/2005
6917206Multiple frequency grain moisture sensor for combines
A grain moisture sensor having a sensor cell that includes a driven plate, a sense plate proximate to and substantially parallel with the driven plate for capacitive measurement across a spacing between the driven plate and the sense plate, and a fill plate adjacent...
07/12/2005
6904789Moisture detection apparatus and method
A sensor to detect the presence of water or moisture in bulk materials includes a standard circuit board and a three element transmission line. The sensor electronics include an oscillator responsive to a direct current voltage supply which provides a square wave vo...
06/14/2005
6872298Determination of sample volume adequacy in biosensor devices
Systems and methods are provided for determining whether a volume of biological sample is adequate to produce an accurate analyte concentration measurement. Certain such systems and methods provide the additional function of compensating for a sample volume determin...
03/29/2005
6674294Drive feedthrough nulling system
The present invention relates to a system for nulling drive feedthrough error in a sensor having first and second drive electrodes which impart vibratory motion to first and second proof masses in response to first and second opposite phase drive signals,...
01/06/2004
6586950Volume charge density measuring system
A capacitive sensor is shielded against external electric fields to maximize measurement accuracy. The sensor may include two coaxial, tubular conductors with a chamber between them into which a material sample to be measured is introduced. A measurement ...
07/01/2003
6583631Precise dielectric constant sensor
An assembly for sensing the dielectric constant of liquids, and for detecting contamination, includes a central ceramic chip with a sensing capacitor formed on one end thereof and a signal processing circuit on the other end thereof. The capacitor is form...
06/24/2003
6498501Measuring circuit
A measuring circuit includes a symmetric transmission line connecting a transducer to a measurement amplifier and to a fault indicating signal amplifier, the transducer delivering symmetric input signals to amplifiers, the first amplifier delivering a mea...
12/24/2002
6496020Method and apparatus for capacitance measurement of a dielectric medium utilizing the ratio of capacitance measurement made at different frequencies
A method for analyzing a dielectric medium comprises the step of measuring, at one or more frequencies, the capacitance between a pair of electrodes immersed in the dielectric medium. The proportion of the or each capacitance measurement due to electrode ...
12/17/2002
6496013Device for testing circuit boards
An instrument to test electronic components, the instrument including a drive unit electrically connecting the component and electrically driving the component to generate a field in the nearby space. The instrument also includes a test device electricall...
12/17/2002
6489785Comparative contactless conductivity detector
A comparative conductivity detection system includes a sample channel assembly and a reference channel assembly. The sample channel assembly includes a sample-fluid channel, a drive electrode, and a detection electrode. The reference channel assembly incl...
12/03/2002
6489784Method and apparatus for measuring parameters of material
A method and apparatus for measuring at least one parameter of material are disclosed herein. The method includes generating multiple frequency signals having frequencies selectable by control signals, combining the multiple frequency signals into a combi...
12/03/2002
6469525Method for sensing humidity in a tape library
An electrical system for measuring humidity which is capable of measurements accurate to +/-6 percent from board to board. The accuracy provided by this electrical system makes it possible to correlate errors in data on backup magnetic tapes to variations...
10/22/2002
6420882Apparatus for capacitive electrical detection
Apparatus for capacitive electrical detection or measurement relating to a medium, comprising at least one electrode having a given surface extension and an oscillator circuit the output frequency of which is a function of the capacitance being associated...
07/16/2002
6388453Swept-frequency dielectric moisture and density sensor
A swept-frequency shunt-mode dielectric sensor system is used to measure complex impedance parameters such as capacitance and/or dielectric loss of an object or substance being sensed. A precision, digitally synthesized sinusoidal voltage waveform is appl...
05/14/2002
6373264Impedance detection apparatus and method of physical variable
An apparatus for detecting an impedance variable in response to a sensed physical amount of a sensor is provided which comprises an impedance-frequency conversion unit and a counter. The impedance-frequency conversion unit converts the sensor impedance to...
04/16/2002
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