35 results about "Immittance" patented technology

An apparatus and method manage impedance values in a radio in a wireless network. The apparatus includes a tunable matching network (TMN) positioned on a path between a transceiver and an antenna. The TMN includes a plurality of immittance elements. A voltage standing wave ratio (VSWR) detector is configured to detect a ratio of a signal passing the VSWR detector and a signal reflected from the TMN. A control circuit is configured to identify an operating setting for the radio, set a number of the immittance elements based on the operating setting, monitor the ratio detected by the VSWR detector, and modify a setting of at least one of the immittance elements based on the ratio detected.

The invention relates to sweat activity measurement, e.g. for determining a physiological state of a subject, embodied by a method as well as a kit with an immittance measuring circuit and electrodes with contact electrolyte. Sweat activity is considered a transport phenomenon and can be defined as a flux, e.g. gram water per skin area per second. Prior art methods determining water absorbed per gram dry stratum corneum measures skin moisture and do not truly reflect sweat activity. A periodic signal with frequency of 60 Hz or lower is applied to reduce contribution from complex admittance of the skin, and skin conductance is measured as a degree of sweat activity. The contact electrolyte allows filling of sweat ducts with sweat from sweat glands, this may be characterized in that it does not substantially fill the sweat ducts when being positioned on the skin and / or in that it has a re-absorption time constant from the sweat ducts into the Epidermis of less than 15 min.

The invention discloses a bidirectional direct current converter based on an immittance network, and a digital control system and a digital control method of the bidirectional direct current converter. The bidirectional direct current converter based on the immittance network comprises a storage battery, a low-voltage-side filter capacitor, a first active full-bridge circuit, the immittance network, a high-frequency transformer, a second active full-bridge circuit and a high-voltage-bus-side filter capacitor. The digital control system comprises a first voltage sensor, a second voltage sensor, a current sensor and a digital signal processing (DSP) digital controller, wherein the DSP digital controller comprises a BUCK controller, a BOOST controller, a signal conditioner, a first selective switch and a second selective switch. According to the basic characteristics of the immittance network, the two active full-bridge circuits in the bidirectional direct current converter can operate with high power factor, and the current stress of a switching tube can be greatly reduced. By the adoption of the system and the method, according to the characteristics of the immittance network, the zero-current turn on and zero-current turn off of all switching devices of a high-voltage-side active full-bridge circuit are realized, and the efficiency of the converter is improved.

Techniques are provided for detecting heart failure or other medical conditions within a patient using an implantable medical device, such as pacemaker or implantable cardioverter / defibrillator, or external system. In one example, physiological signals, such as immittance-based signals, are sensed within the patient along a plurality of different vectors, and the amount of independent informational content among the physiological signals of the different vectors is determined. Heart failure is then detected by the implantable device based on a significant increase in the amount of independent informational content among the physiological signals. In response, therapy may be controlled, diagnostic information stored, and / or warning signals generated. In other examples, at least some of these functions are performed by an external system.

The AC power generated by AC utility has been successfully transferred from AC-to-DC by means of an AC-to-DC converting circuit. This disclosure provides an AC-to-DC converting circuit applicable to a power-charging module, and the AC-to-DC converting circuit comprises two parts such as a first stage being a low-frequency AC to high-frequency AC converter comprising an input full-bridge rectifier, a full-bridge inverter and an immittance conversion circuit and a second stage being an AC-to-DC converter comprising a single-phase transformer and a full-bridge rectifier, where the inverter in the first stage is switched at high frequencies so as to reduce the size of the transformer in the second stage. Additionally, the immittance conversion circuit is further characterized in voltage to current conversion so as to simplify the control mechanism of the power-charging module, reduce the number of current measuring elements and the cost thereof.

Techniques are provided for estimating electrical conduction delays with the heart of a patient based on measured immittance values. In one example, impedance or admittance values are measured within the heart of a patient by a pacemaker or other implantable medical device, then used by the device to estimate cardiac electrical conduction delays. A first set of predetermined conversion factors may be used to convert the measured immittance values into conduction delay values. In some examples, the device then uses the estimated conduction delay values to estimate LAP or other cardiac pressure values. A second set of predetermined conversion factors may be used to convert the estimated conduction delays into pressure values. Techniques are also described for adaptively adjusting pacing parameters based on estimated LAP.

This invention relates to a high efficiency single-phase and the three-phase incorporation generating system. This incorporation generating system is composed by the high frequency inverter, immittance convertor, high-frequency transformer, high frequency rectifier, power frequency inverter, lowpass filter, voltage zero crossing detector, high frequency drive circuit and power frequency drive circuit. This system counter turn the direct voltage which are gained by light battery array, fuel cell, windpower generation and other methods to high-frequency voltage and input immittance convertor. The high-frequency current output by immittance convertor is merged into single-phase or three-phase electric network olationand by the high-frequency transformer, ranking transformed by electric current, commutated by the high frequency rectifier, counter turned by the power frequency inverter and filtered by lowpass filter. By improving the system topology, reducing the power transistor number, this invention not only reduces the cost, realize installment miniaturization, but also reduces the power loss in the energy transfer process.

An apparatus and method amplify a signal for use in a wireless network. The apparatus includes a power amplifier, an envelope modulator, a tunable matching network (TMN), and a controller. The power amplifier outputs the signal at an output power. The envelope modulator controls a bias setting for the power amplifier. The TMN includes a plurality of immittance elements. The controller is operably connected the envelope modulator and the TMN. The controller identifies a desired value for the output power of the power amplifier, controls the output power of the power amplifier by modifying the bias setting of the power amplifier, and sets a number of the plurality of immittance elements based on the bias setting of the power amplifier.

A differential circuit topology that produces a tunable floating negative inductance, negative capacitance, negative resistance / conductance, or a combination of the three. These circuits are commonly referred to as “non-Foster circuits.” The disclosed embodiments of the circuits comprises two differential pairs of transistors that are cross-coupled, a load immittance, multiple current sources, two Common-Mode FeedBack (CMFB) networks, at least one tunable (variable) resistance, and two terminals across which the desired immittance is present. The disclosed embodiments of the circuits may be configured as either a Negative Impedance Inverter (NII) or a Negative Impedance Converter (NIC) and as either Open-Circuit-Stable (OCS) and Short-Circuit-Stable (SCS).

A testing device detects and quantifies cell deterioration of an electrochemical cell or battery. The device contains measuring circuitry adapted to apply time-varying electrical excitation to said cell or battery, to sense time-varying electrical response to said excitation, and to utilize said excitation and response to determine components of complex immittance (i.e., either impedance or admittance) at n+m discrete frequencies, where n is an integer equal to or greater than two and m is an integer equal to or greater than one. Computation circuitry utilizes measured complex immittance components at the n discrete frequencies to evaluate the elements of a 2n-element equivalent circuit model. It then calculates the complex immittance of this model at the m discrete frequencies and mathematically compares components of the calculated immittances with components of the measured immittances at the m discrete frequencies. The results of this comparison are related to the degree of cell deterioration. A pass / fail determination can thus be made based solely upon cell deterioration—without even knowing the battery's manufacturer, group size, or its electrical ratings.

This invention relates to a sensor assembly and a method for measuring characteristics of a surface, preferably skin, comprising a first pair of current supply electrodes coupled to a current source, providing an electrical current to the skin, at least one pickup electrodes at chosen positions relative to the current supply electrodes, at least a first of said pickup electrodes being coupled to an instrument for measuring the voltage between said first pickup electrode and at least one of the pickup or current supply electrodes.

A differential circuit topology that produces a tunable floating negative inductance, negative capacitance, negative resistance / conductance, or a combination of the three. These circuits are commonly referred to as “non-Foster circuits.” The disclosed embodiments of the circuits comprises two differential pairs of transistors that are cross-coupled, a load immittance, multiple current sources, two Common-Mode FeedBack (CMFB) networks, at least one tunable (variable) resistance, and two terminals across which the desired immittance is present. The disclosed embodiments of the circuits may be configured as either a Negative Impedance Inverter (NII) or a Negative Impedance Converter (NIC) and as either Open-Circuit-Stable (OCS) and Short-Circuit-Stable (SCS).

Described herein are devices, systems, and methods for determining the composition of liquids, including the identity of one or more drugs in the liquid, the concentration of the drug, and the type of diluent using immittance spectroscopy. These devices, systems and methods are particularly useful for describing the identity and, in some variations, concentration of one or more components of a medical liquid such as intravenous fluid. In particular, described herein are devices, systems and methods that may operate in low ionic strength diluents. Also described are methods of recognizing complex immittance spectrograph patterns to determine the composition of a liquid by pattern recognition.

The invention discloses a vector quantization method of an immittance spectrum frequency (ISF) parameter and a vector quantization device of the ISF. The invention also closes a vector quantization coding end method of the ISF parameter, a vector quantization decoding end method of the ISF parameter, a vector quantization device of the ISF parameter, a vector quantization coding end device of the ISF parameter and a vector quantization decoding end device of the ISF parameter. The methods or devices utilize prediction coefficients of unequal coefficient interframe predictor in each dimension to compute the prediction vector of the ISF parameter. Applying the invention can equalize the quantization performances when losing the frame or not in the process of bandwidth voice coding and decoding, improving the quality of voice synthesis.

The invention provides a digital automatic acoustic-control otoacoustic immittance detection system and a digital signal compensation method thereof. The system sequentially comprises a probe tone D / A (digital to analog) conversion circuit, a drive circuit, a speaker, a human ear, a pick-up and an A / D (analog to digital) conversion circuit which are connected in series, wherein the input end of the probe tone D / A conversion circuit and the output end of the A / D conversion circuit are connected with an FPGA (field programmable gate array) chip correspondingly and respectively; the output end of the FPGA chip is connected with the probe tone D / A conversion circuit through an acoustic-control D / A conversion circuit; and the FPGA chip is also connected with a CPU (central processing unit) which is connected with a display / peripheral interface unit. The method comprises the following steps of: calculating an echo signal difference deltaV= Vi-Vref between a test ear and a standard ear, wherein Vi is a test ear echo signal, and Vref is standard ear reference voltage; and calculating a volume control voltage value delta= KdeltaV+ Vref according to the echo signal difference between the test ear and the standard ear, wherein K is between 0 and 1. According to the system and the method, digital real-time otoacoustic immittance measurement and a constant-voltage acoustic control functioncan be realized, and acoustic measurement strength in a detection and measurement process is maintained to be constant.

An apparatus and method for encoding / decoding a speech signal which determines a variable bit rate based on reserved bits obtained from a target bit rate, is provided. The variable bit rate is determined based on a source feature of the speech signal and the reserved bits is obtained based on the target bit rate. The apparatus for encoding the speech signal may include a linear predictive (LP) analysis unit / quantization unit to determine an immittance spectral frequencies (ISF) index, a closed loop pitch search unit, a fixed codebook search unit, a gain vector quantization (VQ) unit to determine a gain vector quantization (VQ) index, and a bit rate control unit to control at least two indexes of the ISF index, the pitch index, the code index, and the gain VQ index to be encoded to be variable bit rates based on a source feature of a speech signal and the reserved bits.

A hemolysis detection method and system includes measuring a conductance of a blood sample in a sample test module at a plurality of multiple-frequency AC inputs provided by a sine-wave generator module, calculating an immittance value for each of the plurality of multiple-frequency AC inputs received from a multichannel A / D converter module using a computer processing module, and subjecting each immittance value calculated to a function that maps immittance values to either lysed blood levels or hematocrit levels residing in the processing module and applying further processing residing in a memory module to produce respective percent-lysed value or hematocrit value of the blood sample.

An electromagnetic field intensity calculation apparatus calculates a virtual current vector from a voltage vector and a mutual immittance matrix of an object including a wave source where a wave source power is applied. The voltage vector and the mutual immittance use a wave voltage of the wave source as a unit voltage. The apparatus also calculates an input impedance of the wave source based on a virtual wave source current of the virtual current vector and a unit voltage of the wave source, and calculates the wave source voltage based on the input impedance and the wave source power. The apparatus further calculates a current vector based on the wave source voltage calculated and the virtual current vector, and calculates an electromagnetic field intensity around the wave source which is determined based on the current vector.

An immittance conversion circuit includes a first terminal and a second terminal, and includes: a conversion target circuit configured to amplify or attenuate a signal with desired frequency and gain characteristics, and output the resultant signal; a difference signal detection circuit configured to supply the input terminal of the conversion target circuit with a signal of a difference between signals generated at the first and second terminals; an immittance conversion drive circuit configured to perform differential output processing to generate a voltage of a difference between a correction voltage and the signal outputted from the conversion target circuit, and output feedback signals to an immittance conversion generation circuit; and the immittance conversion generation circuit having an immittance conversion generation action to generate, at each of the first and second terminals, a signal of currents or voltages of the corresponding inputted feedback signal and the signal inputted to the first or second terminal. A signal of a difference between the signals generated at the first and second terminals is inputted to the immittance conversion drive circuit as the correction voltage.

Electrochemical detection method and related aspects Herein is disclosed an electrochemical test method comprising (i) comparing how a plurality of immittance functions and / or components thereof vary with a change in a parameter of interest for a first system, and then selecting an immittance function or component thereof for use in an electrochemical test; (ii) carryingout an electrochemical test step for a second system to determine at least one value for the immittance function or component thereof selected in step (i), and then, by using a quantitative relationship between the selected immittance function and the parameter of interest, determining a value in the parameter of interest. A computer program and apparatus are also disclosed herein.

An immittance conversion circuit includes a first terminal and a second terminal, and includes: a conversion target circuit configured to amplify or attenuate a signal with desired frequency and gain characteristics, and output the resultant signal; a difference signal detection circuit configured to supply the input terminal of the conversion target circuit with a signal of a difference between signals generated at the first and second terminals; an immittance conversion drive circuit configured to perform differential output processing to generate a voltage of a difference between a correction voltage and the signal outputted from the conversion target circuit, and output feedback signals to an immittance conversion generation circuit; and the immittance conversion generation circuit having an immittance conversion generation action to generate, at each of the first and second terminals, a signal of currents or voltages of the corresponding inputted feedback signal and the signal inputted to the first or second terminal. A signal of a difference between the signals generated at the first and second terminals is inputted to the immittance conversion drive circuit as the correction voltage.

The invention discloses a method for analyzing the acoustic conductance of the middle ear by using input electrical impedance parameters. The method calculates the acoustic conductance of the middle ear by measuring the electrical impedance of a receiver. The method includes: within a predetermined ear canal pressure range , put pressure on the subject's ear canal; send a sound pressure signal with a certain frequency range and amplitude to the subject's ear canal through the receiver; measure the input electrical impedance of the receiver based on the pre-built receiver detection circuit; according to the input electrical impedance of the receiver , based on the pre-established acoustic immittance calculation model, obtain the middle ear acoustic impedance under the pressure value; traverse the ear canal pressure range, repeat the above steps, and output the set of pressure values ​​applied to the subject's ear canal and the corresponding middle ear Otoacoustic Immittance collection. The invention uses the electrical impedance parameters of the receiver to calculate and measure the middle ear acoustic conductance, so that the middle ear acoustic conductance measurement and analysis device no longer depends on the built-in microphone in the ear canal, and is more convenient.