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140 results about "Multi-frequency signaling" patented technology

In telephony, multi-frequency signaling (MF) is a signaling system that was introduced by the Bell System after World War II. It uses a combination of tones for address (phone number) and supervision signaling. The signaling is sent in-band over the same channel as the bearer channel used for voice traffic.

Method and system for reducing wireless multi-cell interferences through segregated channel assignments and segregated antenna beams

InactiveUS6907246B2Reducing multi-frequency signal interferenceHigh mutual interferenceNetwork traffic/resource managementRadio/inductive link selection arrangementsFrequency spectrumMulti-frequency signaling
A method and system is disclosed for reducing multi-frequency signal interference in a wireless communication network. An available frequency spectrum is divided into a plurality of channels, a first wireless communication coverage unit is then segregated into a first number of geographical segments. After the segregated channels are grouped into a second number of channel blocks, each channel block is assigned to at least one of the segregated geographical segments with predetermined priorities. All the above steps are repeated for each neighboring wireless communication coverage unit of the first wireless communication coverage unit, wherein the channels in different channel blocks exhibit no higher mutual interference than the channels in the same channel block, and wherein the channel block assigned for each segregated segment of the first wireless communication coverage unit is different from the channel block assigned for the segregated segment of a second wireless communication coverage unit that immediately borders with the segregated segment of the first wireless coverage unit even if the first and second wireless communication coverage units share the same frequency spectrum.
Owner:CISCO TECH INC

Miniature multi-frequency antenna

A miniature multi-frequency antenna, comprising at least one dielectric substrate, at least one signal electrode and at least one ground electrode. The signal electrode and the ground electrode are disposed on a substrate. The signal electrode contains at least two branches and at least one branch is partially overlapped with the ground electrode. Each interlayer region between the partially overlapped electrodes forms a specific capacitance. By utilizing this interlayer capacitive effect, the resonant frequency of lower frequency band is achieved while the size of the antenna is effectively reduced. For obtaining the resonant frequency of the high frequency bands, the design concept of PIFA is applied on other branches of the signal electrode. A miniature antenna thus obtained is capable of transmitting / receiving multi-frequency signals having the benefits of easily adjusting impedance and resonant frequency.
Owner:UNICTRON TECH CORP

Long-distance distributed type large-measuring-range rapid response optical fiber dynamic strain sensing device

ActiveCN103954226ARealize quantitative measurementExtended dynamic strain measurement rangeUsing optical meansContinuous lightElectrical impulse
The invention provides a long-distance distributed type large-measuring-range rapid response optical fiber dynamic strain sensing device. The device comprises a phase modulator, a multi-frequency signal generating module, an intensity modulator, a microwave switch, an electric pulse generating module, a microwave signal generating module and other components. The signal generating module comprising multi-frequency components is used for modulating the phase of detection continuous light, so that multi-light-frequency components are generated in the detection continuous light, and corresponding Brillouin gain spectrum amplitudes are adjusted through controlling the amplitudes of all the light-frequency components in the detection continuous light. A Brillouin gain spectrum of a needed spectrum width and a spectrum type is obtained through splicing, and the dynamic strain measuring range is greatly enlarged under the condition that the signal-to-noise ratio and the response speed of a system are not destroyed. The frequency difference between two light beams generating a Brillouin amplification effect is fixed in the middle of a beveled edge linear region of the spliced Brillouin gain spectrum, drifting of the spliced Brillouin gain spectrum is converted into power fluctuation of the detection light, and long-distance distributed type large-measuring-range high response speed quantitative measuring on optical fiber dynamic strain and optical fiber static strain is achieved.
Owner:SOUTH CHINA UNIV OF TECH

Method and system for reducing wireless multi-cell interferences through segregated channel assignments and segregated antenna beams

InactiveUS20050202784A1Reducing multi-frequency signal interferenceHigh mutual interferenceNetwork traffic/resource managementTransmission monitoringFrequency spectrumMulti-frequency signaling
A method and system is disclosed for reducing multi-frequency signal interference in a wireless communication network. An available frequency spectrum is divided into a plurality of channels, a first wireless communication coverage unit is then segregated into a first number of geographical segments. After the segregated channels are grouped into a second number of channel blocks, each channel block is assigned to at least one of the segregated geographical segments with predetermined priorities. All the above steps are repeated for each neighboring wireless communication coverage unit of the first wireless communication coverage unit, wherein the channels in different channel blocks exhibit no higher mutual interference than the channels in the same channel block, and wherein the channel block assigned for each segregated segment of the first wireless communication coverage unit is different from the channel block assigned for the segregated segment of a second wireless communication coverage unit that immediately borders with the segregated segment of the first wireless coverage unit even if the first and second wireless communication coverage units share the same frequency spectrum.
Owner:CISCO TECH INC

Apparatus and method for maintaining stability in a disc drive servo loop

An apparatus and method of maintaining stability in a servo loop of a disc drive is provided. A dither signal (a single frequency sine wave or a multi-frequency signal) is injected into the servo loop. A servo loop gain error signal is obtained in response to the injected dither signal. A gain of the servo loop is adjusted as a function of the servo loop gain error signal in real-time.
Owner:SEAGATE TECH LLC

Composite induced polarization instrument for advanced geological prediction of tunnel or gallery

The invention relates to a composite induced polarization instrument for the advanced geological prediction of a tunnel or gallery. The composite induced polarization instrument structurally comprises a transmitter and a receiver. The transmitter comprises a transmission singlechip system, a double-exciting current module, a multi-frequency signal waveform synthesis module, a power drive module, a double-frequency bridge inverter, a constant current inversion oscillator, an overvoltage overcurrent protection module and the like. The receiver comprises a receiving singlechip system, an input protection module, a ground compensation module, a power frequency signal suppression and noise processing module, a differential input amplification module, an industrial personal computer and the like, wherein the industrial personal computer finishes operating a hardware circuit and processing time-domain and frequency-domain signals. The composite induced polarization instrument can finish measuring parameters such as apparent resistivity, ground resistance, apparent polarizability, half-life, excitation ratio, apparent frequency dispersibility and the like, realizes multifunction saves instrument cost, effectively weakens field working strength, and can realize rock integrity detection and particularly solve the problems of three-dimensional water body positioning and water volume prediction.
Owner:SHANDONG UNIV

Wearable electrical impedance tomography gastric motility information extracting device and method

The invention discloses a wearable electrical impedance tomography gastric motility information extracting device. The wearable electrical impedance tomography gastric motility information extracting device comprises an electrode array belt, a switch array, an impedance signal measurement module, a DSP and a wireless data transmission module. The electrode array belt is composed of a pasting strip and electrode buckles distributed on the belt at equal intervals and is connected with the switch array through a wire. The switch array is composed of an excitation gating switch and a measurement gating switch. An excitation current source is composed of a DDS multi-frequency signal generation unit and a voltage and current conversion module, and excitation current is injected in a corresponding electrode pair of the electrode array belt through the excitation gating switch. The impedance signal measurement module is composed of an instrumentation amplifier, a programmable amplifier, a demodulator and an AD conversion module. The measurement gating switch picks up impedance signals of the corresponding electrode pair on the electrode array belt and converts the impedance signals into digital information, and the DSP uploads the generated digital information to a portable intelligent device through the wireless data transmission module for processing.
Owner:INST OF BIOMEDICAL ENG CHINESE ACAD OF MEDICAL SCI

Method for nondestructive examination of oxide thickness distribution in stainless steel tubes

The invention discloses a method for nondestructive examination of oxide thickness distribution in stainless steel tubes, vortex flow transducer is sticked on external wall of bend section in stainless steel tubes, motivated by a multi-frequency signal, vortex flow sensing signal is obtained by the vortex flow transducer, the signal is processed by a computer processing system into data in correspondence position corresponding to oxide thickness of bend section in stainless steel tubes after signal amplification, phase sensitive detection and frequency mixing of interference signals, whole perisporium of the stainless tube is detected by surrounding, a plurality of data in a plurality of positions correspondinig to oxide thickness of bend section in stainless steel tube to be tested is obtained, the computer processing system proceeds imaging treatment according to data of oxide thickness corresponding to stainless steel tubes, images corresponding to stainless steel tubes for mapping oxide vortex flow sensing signals are obtained; and then a pseudo-three-dimensional image corresponding to shape of stainless steel tube is obtained, and oxide distribution conditioin inside the stainless steel is displayed.
Owner:林俊明

Magnetic tracker system and method for use for surgical navigation

A method and system for magnetically tracking a device of interest generating a plurality of pre-determined multi-frequency signals. The method and system transmits a plurality of magnetic fields from a transmitter circuit based on the corresponding pre-determined multi-frequency signals. The magnetic fields propagating through an area of examination encompassing the device of interest and a magnetic sensor coupled to the device of interest. The method and system generate a sensor signal at the magnetic sensor indicative of field strength of the magnetic fields transmitted by the transmitter circuit. Further, the method and system determine a position of the magnetic sensor relative to the transmitter circuit based on the multi-frequency signals and the sensor signal.
Owner:GENERAL ELECTRIC CO

Audio test apparatus and test method thereof

An audio test apparatus, and an exemplary audio test method that includes: processing an audio file through two independent channels; outputting no signals from a left channel and from a right channel in a first time period; receiving noise signals from the left and right channels; outputting single-frequency signals from the left channel only in a second time period; receiving the single-frequency signals from the left channel and crosstalk signals from the right channel; outputting multi-frequency signals from the left and right channels in a third time period; receiving the multi-frequency signals from the left and right channels; outputting single-frequency signals from the right channel only in a fourth time period; receiving the crosstalk signals from the left channel and the single-frequency signals from the right channel; and testing parameters according to the signals received during the four time periods.
Owner:HONG FU JIN PRECISION IND (SHENZHEN) CO LTD +1

Photoelectric oscillator on basis of stimulated Brillouin scattering amplification effects and method for regulating photoelectric oscillator

PendingCN106785812AChange frequency distributionEasy accessSolid masersLaser lightBrillouin scattering
The invention provides a photoelectric oscillator on the basis of stimulated Brillouin scattering amplification effects and a method for regulating the photoelectric oscillator, and relates to the field of photoelectric technologies. The photoelectric oscillator comprises a first laser device, a circulator, an optical fiber unit, a second laser device, a phase modulator, a tunable attenuator, a photoelectric detector unit, a tunable filter, a coupler and a power amplifier. Multi-frequency signals can be generated by laser light outputted by the second laser device via the phase modulator, back Brillouin scattering signals are generated by laser signals outputted by the first laser device in the optical fiber unit, the multi-frequency signals and the back Brillouin scattering signals are subjected to stimulated Brillouin scattering amplification, amplified multi-frequency signals are subjected to attenuation, photoelectric conversion and filtering and then are divided into two channels of signals by the coupler, one channel of signals is used as feedback signals to be inputted into the phase modulator, and the other channel of signals is used as microwave signals to be outputted. The photoelectric oscillator and the method have the advantages that output wavelengths of the first laser device can be changed, accordingly, frequencies of the feedback signals can be changed, the required multi-frequency signals can be obtained, and the tunable microwave signals can be ultimately outputted.
Owner:YANCHENG INST OF TECH
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