49 results about "Crosstalk measurement" patented technology

Techniques are disclosed that efficiently obtain channel crosstalk estimates in DSL systems and other communication systems that may include unsynchronized channels. For example, a method includes obtaining a first set of estimated measures of crosstalk for a first portion of a plurality of communication channels over which data signals are to be transmitted from a transmitter to a plurality of receivers, and interpolating a second set of estimated measures of crosstalk for a second portion of the plurality of communication channels based on the first set of estimated measures of crosstalk. The first portion of the plurality of communication channels may be a subset of the plurality of communication channels and the second portion of the plurality of communication channels is a remainder of the plurality of communication channels. Each estimated measure of crosstalk may relate to at least one tone associated with at least one of the plurality of communication channels.

The invention provides a device and a method for improving polarization crosstalk measurement performance of an optical device. The device comprises a wide spectrum light source (301), a polarizer (311), a polarization device to be tested (632), an optical path correlator (640) and a polarization crosstalk detection and signal recording device (150), wherein the wide spectrum light source (301) is connected with the optical device to be tested (632) by the polarizer (311) and a first rotation connector (631) and then is connected with the optical path correlator (640) by a second rotation connector (633). By the device and the method, noise amplitude can be greatly suppressed, the sensitivity of polarization crosstalk measurement is improved, the dynamic range of polarization crosstalk measurement is expanded, and the device and the method are widely used for high-precision measurement and analysis on polarization performance of the optical device.

Techniques are disclosed for compensating for crosstalk using adaptation of data signals transmitted over respective channels of a communication system. For example, a method includes the following steps. A first set of estimated measures of crosstalk is obtained for at least a selected portion of a plurality of communication channels over which data signals are to be transmitted from a transmitter to at least a selected portion of a plurality of receivers. A first set of data signals based on the first set of estimated measures of crosstalk is adapted to generate a first set of adjusted data signals. The first set of adjusted data signals is transmitted to corresponding ones of the plurality of receivers. A second set of estimated measures of crosstalk is obtained for the selected portion of the plurality of communication channels. A second set of data signals for transmission based on the second set of estimated measures of crosstalk is adapted to generate a second set of adjusted data signals. Iteration of the obtaining, adjusting and transmitting steps is performed so as to reduce an error between subsequent estimated measures of crosstalk and actual measures of crosstalk for the plurality of communication channels.

A test system method for measurement of crosstalk in a multi-pair cable of the type used in local area networks. The system uses a far end signal generator at one end of the cable and a near end signal generator at the near end of the cable. For a far end crosstalk measurement, the far end test unit transmits a high frequency far end test signal and a lower frequency reference signal on one of the wire pairs of the cable. The near end test unit responds to the received reference signal to generate a near end test signal in phase coherency with the far end test signal. A far and crosstalk measurement analysis is then conducted using the received far end test signal, the near end test signal and a crosstalk signal induced by the far end test signal in one of the other wire pairs of the cable.

The present invention comprises a system and method for reduction of the influence of crosstalk, increase in and control over quality of service, increase in stability and reduction of power use in a system having multiple transmission lines. A novel crosstalk measurement method is introduced. Knowing the crosstalk, various algorithms may be employed, for example to reduce or eliminate its effects in order to guarantee a bit error rate equal to or less than the maximum allowed for each line. Similar methods are provided to minimize power consumption, or maximize related measures of line performance. Systems, devices, methods and techniques are provided that allow communication system to adapt transmission power margin, power spectral densities, and the like dynamically to changing subscriber's application needs in MIMO systems.

Techniques are disclosed for measuring crosstalk between at least two communication channels of a communication system. A receiver of the system receives a signal over a given one of the communication channels from a transmitter of the system. The receiver correlates the received signal with a sequence of time-domain signals associated with another of the communication channels, and generates a measure of crosstalk between the given communication channel and the other communication channel based on the correlation between the received signal and the sequence of time-domain signals. The sequence of time-domain signals may be selected from a designated set of M-sequences.

The invention belongs to the technical field of optical fiber measurement and relates to a high extinction ratio measurement method of an optical fiber polarizer. The high extinction ratio measurement method for an optical fiber polarizer comprises steps of respectively welding two segments of polarization maintaining optical fibers with various lengths on an input terminal and an output terminal of a Y waveguide (i.e. a high extinction ratio polarizing device to be detected) to construct a measurement assembly with a quantitative crosstalk mark; using a lumped extinction ratio tester to perform quantitative control on the extinction ratio of a welding point and recording the measurement value; setting the lengths of a polarizer pigtail, an analyzer pigtail, a high extinction ratio polarizer pigtail, and the welding polarization maintaining optical fiber; connecting the measurement assembly to the distributed optical fiber polarization crosstalk tester; and using a two-order crosstalk measurement value between the externally-connected optical fiber welding points to perform calibration and self-calibration on the extinction ratio of the polarizing device to be detected. During the measurement, the high extinction ratio measurement method of the invention can perform synchronous measurement on the crosstalk mark and the measurement peak, and avoids errors introduced by the change of the measurement environment and the member connection precision.

The invention relates to an optic fiber gyroscope testing method and device, a storage medium and computer equipment. The method includes acquiring corresponding parameters of a light source in a light path of an optic fiber gyroscope, optical fiber butt fusion points, a polarization maintaining optical fibre segment and a polarizer; acquiring a polarization crosstalk measurement result of a polarization maintaining optical fibre loop in the optic fiber gyroscope; and according to the corresponding parameters of the light source in the light path, the optical fiber butt fusion points, the polarization maintaining optical fibre segment and the polarizer, and according to the polarization crosstalk measurement result of the polarization maintaining optical fibre loop, operating an optical path transmission physical model set in advance to acquire quality parameters of the optic fiber gyroscope. Through the method, quality of the optic fiber gyroscope can be evaluated before the optic fiber gyroscope is subjected to a high- and low-temperature actual measurement, and the gyroscope quality before actual measurement is assessed in advance and can be adopted as a reference for actual measurement to prevent a phenomenon that a large error in an actual measurement process is unaware, thus increasing testing precision and ensuring accuracy of a testing result.

The present invention relates to the technical field of optical fiber measurement and specifically relates to a noise suppression device and a noise suppression method for the distributed polarization crosstalk measurement of an optical polarizer. The noise suppression device for the distributed polarization crosstalk measurement of the optical polarizer comprises a broadband optical source, a polarizer, a first fiber-optic rotary connector, a second fiber-optic rotary connector, a to-be-detected optical fiber device, an optical path correlator, and a polarization crosstalk detecting and signal recording device. According to the technical scheme of the invention, the transmission light and the coupled light are thoroughly separated by means of a polarization beam splitter, so that the noise influence on the interference beat length can be avoided. On the basis of the thermal noise of a control circuit, the transmission light is attenuated by an attenuator, and the coupled light is enabled to be main detecting light. In this way, the shot noise becomes the main noise for limiting the signal noise ratio of the system. Based on the above method, the parameters of the device are adjusted to be appropriate. In this way, on the premise that the dynamic range of the system is kept unchanged, the signal noise ratio of the system is improved by 20 to 40 dB. Therefore, the measurement sensitivity is effectively increased.

The invention relates to a four-port apparatus for measuring microstrip transmission line network crosstalk, which is characterized in that including a vector network analyzer, which includes a data terminal and two signal terminals, wherein the two signal terminals are connected to a coaxial cable separately; a plurality of coaxial standards, which cooperate with the signal terminals of the vector network analyzer for splicing and measuring circuit; a digital signal processor, which is connected to the data terminal of the vector network analyzer through a data line, and receives the measured data of the vector network analyzer to calculate.

An alien cross-talking testing system employs a plurality of alien cross-talk test signal units, an alien cross-talk measurement unit and an interconnection base unit. Each alien cross-talk test signal unit is in electrical communication with a different disturber cable to participate in a transmission of a RF test signal thereon. The alien cross-talk measurement unit is in electrical communication with a victim cable to measure an alien cross-talk signal generated on the victim cable in response to any alien cross-talk coupling between the victim cable and one or more of the disturber cables. The interconnection base unit is in electrical communication with the alien cross-talk measurement unit and the plurality of alien cross-talk test signals units to control non-simultaneous transmissions by the plurality of alien cross-talk test signal units of the RF test signals at a same frequency on the disturber cables as commanded by the alien cross-talk measurement unit.

An operating method adapted in an ultra-sound sensor is provided. The method includes the steps of emitting an ultra-sound wave, receiving a crosstalk signal within a crosstalk measuring window, determining whether the crosstalk signal is larger than a crosstalk threshold and triggering a crosstalk application if the crosstalk signal is smaller than the crosstalk threshold.

The invention relates to a crosstalk measurement analysis method for a high-speed ADC circuit board based on frequency-domain characteristics. The crosstalk measurement analysis method includes the following steps that S1, an ADC circuit board is powered on and runs, and then a noise waveform of an ADC-chip analog input pin is extracted; S2, data of the noise waveform is subjected to fourier transformation, the frequency-domain characteristics of noise are extracted, frequency points which are large in frequency-domain value and capable of stably appearing are screen out, and are matched withmain frequencies and harmonic frequency doubling frequencies of potential interference sources, and if matching is coincident, the matched potential interference sources are corresponding interferencesources; S3, intensities of noise frequency points are detected along an analog receiving circuit, and a position with a maximal interference intensity is recorded; S4, according to the position withthe highest interference on the analog receiving circuit and the position of an interference source circuit, it exists that wirings of two adjacent positions are potential interference coupling pathssimultaneously. By means of the crosstalk measurement analysis method for the high-speed ADC circuit board based on the frequency-domain characteristics, interference sources and potential interference coupling paths can be obtained by extracting the frequency-domain characteristics, and an important measured-data support can be provided for crosstalk trouble removing and designing and simulationanalyzing.

A device (10) for limiting crosstalk between vectoring modems connected to a group of communication lines (18, 20, 22, 24, 26, 28, 30, 32) comprises a subgroup determining element (60) that obtains information of the division into subgroups, each subgroup being made up of lines experiencing cross-talk from each other, and assigns operational pilot sequences to the group according to the division, an operational sequence transmission control element (58) that transmits the operational sequences on the lines to the modems, which sequences are mutually orthogonal to each other and each communication line receives a corresponding sequence, and a corrective action determining element (62) that obtains cross-talk measurements related to the transmitted operational pilot sequences and determines, for each subgroup, cross-talk and corrective action based on measurements made for a number of sequence symbols, which number corresponds to the minimum number required for obtaining mutually orthogonal pilot sequences within the subgroup.

The invention belongs to the technical field of optical fiber measurement, and particularly relates to an optical fiber distributed polarization crosstalk rapid measurement device based on optical frequency domain interference, which comprises a tunable laser source module (1), a to-be-measured device module (2), an auxiliary interferometer module (3) and a signal acquisition and analysis module (4). The device is characterized in that a high-coherence tunable laser is used for carrying out rapid wavelength scanning on an optical signal, linear frequency modulation continuous light (501) is output, the linear frequency modulation continuous light (501) sequentially passes through a polarizer (202), a to-be-measured device (206) and a polarization analyzer (210), a beat frequency signal generated by interference of coupling light (704) and transmission light (701) is obtained on an optical frequency domain, then an optical path difference and a normalized interference signal amplitude are obtained through calculation, and polarization crosstalk position and intensity are respectively determined. The tunable laser is combined to get rid of dependence on an optical path scanning delayer in polarization crosstalk measurement, the speed and the dynamic range of polarization crosstalk measurement are greatly improved, and the device is compact in structure, stable, reliable and easy to implement.

The invention provides a hydraulic optical fiber sensing system and a manufacturing method of the inner sensing baseband of the hydraulic optical fiber sensing system. The hydraulic optical fiber sensing system includes a distributed polarization crosstalk measurement system, a sensing baseband, and an input and output polarization-maintaining optical fiber patch cable; the sensing baseband includes a supporting baseband, a sensing polarization-maintaining optical fiber and pressure applying units; the pressure applying units are used for applying pressure to the sensing polarization-maintaining optical fiber in liquid and are also used for fixing the sensing polarization-maintaining optical fiber onto the supporting baseband; and the pressure applying units as well as the sensing polarization-maintaining optical fiber and the supporting baseband form a sensing unit. According to the hydraulic optical fiber sensing system of the invention, a relationship between polarization crosstalkintensity and the pressure or depth of the liquid can be established, and the pressure intensity, depth, and stratification position of the liquid can be measured. With the hydraulic optical fiber sensing system of the invention adopted, high-spatial resolution and wide-depth range quasi-distribution type measurement can be realized. The hydraulic optical fiber sensing system and the manufacturingmethod of the invention have a potential application value in large-scale liquid storage facility monitoring, water level monitoring, liquid depth or liquid detection and other engineering fields.

The invention discloses a design method and system for improving crosstalk measurement between signal lines on a PCB. The method comprises the steps that firstly, the effective coupling crosstalk length between the two signal lines on the PCB is determined; The effective coupling crosstalk length is determined; The signal transmission delay time between the two signal lines is greater than or equal to 1ns by prolonging the wiring length of the terminal which is not terminated in the two signal lines, so that the influence of signal reflection at each signal wiring terminal of the PCB on the crosstalk waveform can be effectively avoided, and the accuracy and the measurement precision of the crosstalk waveform test are further improved. The system comprises a four-port VNA device and a PCB connected with the four-port VNA device. Through the system, the crosstalk waveform test accuracy and measurement precision can be improved, the test difficulty is reduced, the test efficiency is improved, and the space of the PCB can be saved, so that the space utilization rate of the PCB is improved.