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133 results about "Measuring receiver" patented technology

In telecommunication, a measuring receiver or measurement receiver is a calibrated laboratory-grade radio receiver designed to measure the characteristics of radio signals. The parameters of such receivers (tuning frequency, receiving bandwidth, gain) can usually be adjusted over a much wider range of values than is the case with other radio receivers. Their circuitry is optimized for stability and to enable calibration and reproducible results. Some measurement receivers also have especially robust input circuits that can survive brief impulses of more than 1000 V, as they can occur during measurements of radio signals on power lines and other conductors.

Radio frequency control for communication systems

The present invention provides for a system and method for improvement of radio transmitter and receiver frequency accuracy for a local radio communication unit that communicates digital data with a remote communication unit. In the local unit the received radio signal is down-converted, and converted to complex baseband digital samples by an analog-to-digital converter. A downlink digital phase rotator applies a fine frequency shift to the samples in accordance with a receiver frequency offset command. The resultant baseband signal is used by the data demodulator and by a receiver frequency error estimator to obtain receiver frequency errors. A data modulator generates baseband complex samples which are shifted in carrier frequency by an integrated uplink digital phase rotator in accordance with a transmitter frequency offset command. The modulated samples are then converted by a digital-to-analog converter and upconverted in frequency for radio transmission to the remote unit. The local oscillator signals for both upconverter and downconverter are phase locked to a reference frequency generated by a VCXO. An automatic frequency control (AFC) function nulls the transmitter and receiver frequency error by the frequency adjustment commands to the uplink and downlink phase rotators or to the VCXO digital-to-analog converter (VCXO DAC) by feedback control principals based on measured receiver frequency error. During frequency track mode when communications between local and remote units are possible, the AFC only adjusts radio frequency via phase rotator commands and the VCXO command remains fixed, thereby avoiding communications performance degradation by VCXO frequency quantization error due to the VCXO DAC. The AFC adjusts VCXO frequency only during a preliminary acquisition mode prior to data communications, or to back out excessively large frequency offsets accumulated in the downlink and uplink phase rotators during track mode. When a VCXO adjustment is made in track mode, phase rotator adjustments are simultaneously applied to cancel the errors in transmitter and receiver radio frequencies caused by the step change due to VCXO frequency quantization thereby mitigating VCXO frequency quantization noise.
Owner:AVAGO TECH WIRELESS IP SINGAPORE PTE

Radio frequency control for communication systems

The present invention provides for a system and method for improvement of radio transmitter and receiver frequency accuracy for a local radio communication unit that communicates digital data with a remote communication unit. In the local unit the received radio signal is down-converted, and converted to complex baseband digital samples by an analog-to-digital converter. A downlink digital phase rotator applies a fine frequency shift to the samples in accordance with a receiver frequency offset command. The resultant baseband signal is used by the data demodulator and by a receiver frequency error estimator to obtain receiver frequency errors. A data modulator generates baseband complex samples which are shifted in carrier frequency by an integrated uplink digital phase rotator in accordance with a transmitter frequency offset command. The modulated samples are then converted by a digital-to-analog converter and upconverted in frequency for radio transmission to the remote unit. The local oscillator signals for both upconverter and downconverter are phase locked to a reference frequency generated by a VCXO. An automatic frequency control (AFC) function nulls the transmitter and receiver frequency error by the frequency adjustment commands to the uplink and downlink phase rotators or to the VCXO digital-to-analog converter (VCXO DAC) by feedback control principals based on measured receiver frequency error. During frequency track mode when communications between local and remote units are possible, the AFC only adjusts radio frequency via phase rotator commands and the VCXO command remains fixed, thereby avoiding communications performance degradation by VCXO frequency quantization error due to the VCXO DAC. The AFC adjusts VCXO frequency only during a preliminary acquisition mode prior to data communications, or to back out excessively large frequency offsets accumulated in the downlink and uplink phase rotators during track mode. When a VCXO adjustment is made in track mode, phase rotator adjustments are simultaneously applied to cancel the errors in transmitter and receiver radio frequencies caused by the step change due to VCXO frequency quantization thereby mitigating VCXO frequency quantization noise.
Owner:AVAGO TECH WIRELESS IP SINGAPORE PTE

Agricultural machinery automatic driving control system based on Beidou navigation and method thereof

The invention provides an agricultural machinery automatic driving control system based on Beidou navigation and a method thereof, and belongs to the technical field of agricultural machinery control. The agricultural machinery automatic driving control system comprises a differential reference station, an automatic driving instrument and a visual sensor. The differential reference station comprises a first measurement antenna which is connected with a first measurement receiver. A transmitting radio is connected on the first measurement receiver. The automatic driving instrument comprises a vehicle-mounted navigator, a vehicle-mounted display controller, an electric steering wheel controller and a guide wheel angle sensor. The vehicle-mounted navigator is connected with the vehicle-mounted display controller. The output ports of the electric steering wheel controller and the guide wheel angle sensor are connected with the vehicle-mounted display controller. The vehicle-mounted display controller comprises a graphic processing module. The visual sensor is connected with the graphic processing module. Obstacle avoidance of the agricultural machinery can be guaranteed through control of the guide wheel angle and omitted cultivation of the agricultural machinery can be reduced so that cultivation quality of the agricultural machinery can be enhanced, and the agricultural machinery automatic driving control system can be used for control work of agricultural machinery automatic driving cultivation.
Owner:YANGZHOU UNIV

Multilayered medium material multi-parameter measurement method and system

The invention provides a method for simultaneously obtaining the multiple electromagnetic parameters of a multilayer material by measuring for one time; by the experiment measurement of an electromagnetic reflecting angular spectrum of one time, accurate determination simultaneously to the thickness and the refractive index of each layer of a multilayer dielectric material is realized by optimal calculation according to an angle when the reflecting angular spectrum is at minimum reflection (or maximal reflection). In the invention, electromagnetic wave energy entering a certain working frequency of a multilayer material system is transmitted and reflected on each material interface, the reflecting electromagnetic wave energy of an incident surface is received by a measuring receiver. The angle of incident wave and the angle of the receiver are adjusted continuously so as to lead the reflecting energy to reach an extremum. The incident angle is supposed to be a given value, optimal search is carried out to the parameters of multilayer material by utilizing the simulated annealing algorithm, and the result is the result of the detected multiple parameters. The method can be applied in the fields of remote sensing parameter inversion and the measurement of plasma on a laser surface, etc., and also can be popularized to the field of the multiple parameter measurement of acoustical multilayer material, and is characterized by high efficiency and accuracy.
Owner:BEIHANG UNIV

Sense finding device for solid base line broad band microwave radiation source and sense finding method thereof

The invention provides a stereo baseline wide-band direction-finding device and method for microwave radiation source comprising 6 antenna array elements, a hi-frequency assembly, an instantaneous frequency-measuring receiver, a frequency mixer, a mid-frequency amplifier, a local oscillation source, a digital receiver and a signal processor. The info on phase of the microwave radiation source got through the antenna array elements is used to calculate the phase difference between antenna array elements; the position angle and pitch angle of the microwave radiation source are calculated based on the relationship between the phase difference of the microwave radiation source and the position angle/pitch angle of the microwave radiation source; the 2D direction-finding fuzzy is worked out by using the results of the antenna array elements. In this way, the concurrent no-fuzzy hi-accuracy direction finding of the position angle and pitch angle of the microwave radiation source are realized in a wideband range; and the flexible arrangement form of the antenna array elements allows reasonable arrangement of the location of the antenna array elements so as to meet the requirement for application in cases with limited volume of antenna tray or with limited position for the antenna array elements.
Owner:HARBIN ENG UNIV

Holographic grating exposed interference fringe phase shifting and locking device

The invention discloses a holographic grating exposed interference fringe phase shifting and locking device and belongs to a device related in the technical field of spectrums. A technical scheme is that the holographic grating exposed interference fringe phase shifting and locking device comprises a light source laser device, a plane mirror, a beam-splitting plate, an acousto-optic frequency shifter, a fixed-frequency acousto-optic modulator, an optical grating substrate, phase measuring receivers and a controller. After light source laser is split, two light beams are subjected to frequency shifting by the fixed-frequency acousto-optic modulator and the acousto-optic frequency shifter, so that part of emergent light is subjected to interference to form exposed interference fringes, and the other part of the emergent light respectively enters the two phase measuring receivers to obtain the phase difference of coherent light beams by adopting a heterodyne method; the controller controls the drive frequency of the acousto-optic frequency shifter to keep the phase difference constant. The device disclosed by the invention can accurately carry out effective movement control and phase locking on phases of the holographic-grating exposed interference fringes, and has significance in improving a holographic grating manufacturing technology and the process level.
Owner:CHANGCHUN INST OF OPTICS FINE MECHANICS & PHYSICS CHINESE ACAD OF SCI

Electromagnetic radiation emission real-time measurement system for high-speed train

ActiveCN102818954ARealize electromagnetic radiation experimentAchieving electromagnetic radiation experimental limitsElectrical testingWireless transmissionElectromagnetic interference
The invention provides an electromagnetic radiation emission real-time measurement system for a high-speed train and relates to the technical field of the wireless electric signal and electromagnetic radiation emission measurement and the interference source positioning. The system comprises a vehicle-mounted measurement subsystem, a ground measurement subsystem, a vehicle-mounted vehicle positioning subsystem and a vehicle ground wireless transmission subsystem, wherein the vehicle-mounted measurement subsystem is used for carrying out real-time statistical parameter measurement on the electromagnetic interference inside a high-speed train vehicle by a multi-channel measurement receiver, extracting and classifying the electromagnetic interference with different characteristics and positioning source equipment emitting the electromagnetic interference inside the vehicle by the mode identification; the ground measurement subsystem is used for measuring real-time electromagnetic radiation emission signals by the multi-channel measurement receiver and filtering interference signals in the real-time electromagnetic radiation emission signals, which are from the outside of the high-speed train by utilizing blind signals; the vehicle-mounted vehicle positioning subsystem is used for acquiring real-time position and speed information of the high-speed train vehicle by utilizing a GPS (Global Positioning System) cooperative positioning technology; and the vehicle ground wireless transmission subsystem is used for implementing the time and space synchronization between the vehicle-mounted measurement subsystem and the ground measurement subsystem.
Owner:CHINA RAILWAYS CORPORATION +1

Pipeline locator receiver coil structure, signal processing method, pipeline locator receiver

The invention belongs to the technical field of power cables, and discloses a pipeline locator receiver coil structure, a signal processing method, and a pipeline locator receiver. The pipeline locator receiver is characterized in that the pipeline locator receiver acquires magnetic field signals of buried cables through a coil and can calculate the location information of the cables by combiningwith methods of analog signal conditioning and digital signal processing; a first horizontal coil detects the magnetic field signals of the buried cables in the horizontal direction, and is combined with a second horizontal coil to measure the buried depth of the buried cables and the magnitude of the current of the buried cables; a vertical coil detects the magnetic field signals of the buried cables in the vertical direction, and is combined with the first horizontal coil to detect the left and right locations of the buried cables; and a third horizontal coil is combined with the second horizontal coil to measure the included angle between the receiver and the buried cables to realize the compass function. The pipeline locator receiver has the advantages of high reliability, compact andreasonable coil structure, complete detection functions, low cost, high anti-interference capability, relatively higher detection accuracy and relatively higher sensitivity.
Owner:XIDIAN UNIV
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