2201 results about "Spectrum analyzer" patented technology

An efficient method for compressing sampled analog signals in real time, without loss, or at a user-specified rate or distortion level, is described. The present invention is particularly effective for compressing and decompressing high-speed, bandlimited analog signals that are not appropriately or effectively compressed by prior art speech, audio, image, and video compression algorithms due to various limitations of such prior art compression solutions. The present invention's preprocessor apparatus measures one or more signal parameters and, under program control, appropriately modifies the preprocessor input signal to create one or more preprocessor output signals that are more effectively compressed by a follow-on compressor. In many instances, the follow-on compressor operates most effectively when its input signal is at baseband. The compressor creates a stream of compressed data tokens and compression control parameters that represent the original sampled input signal using fewer bits. The decompression subsystem uses a decompressor to decompress the stream of compressed data tokens and compression control parameters. After decompression, the decompressor output signal is processed by a post-processor, which reverses the operations of the preprocessor during compression, generating a postprocessed signal that exactly matches (during lossless compression) or approximates (during lossy compression) the original sampled input signal. Parallel processing implementations of both the compression and decompression subsystems are described that can operate at higher sampling rates when compared to the sampling rates of a single compression or decompression subsystem. In addition to providing the benefits of real-time compression and decompression to a new, general class of sampled data users who previously could not obtain benefits from compression, the present invention also enhances the performance of test and measurement equipment (oscilloscopes, signal generators, spectrum analyzers, logic analyzers, etc.), busses and networks carrying sampled data, and data converters (A/D and D/A converters).

A network profiling system is provided including providing a base station tester having both a spectrum analyzer and a vector network analyzer, inserting an optical time domain reflectometer system in the base station tester, and operating a touch screen display of the base station tester for testing a cellular base station having both a non-optical portion and a backhaul with an optical fiber. The operating of the touch screen display further includes testing the non-optical portion with the vector network analyzer, the spectrum analyzer, or a combination thereof. The operating of the touch screen display also includes testing the backhaul having the optical fiber with the optical time domain reflectometer system, and analyzing test data from the testing the non-optical portion with the backhaul.

Support vector machines are used to classify data contained within a structured dataset such as a plurality of signals generated by a spectral analyzer. The signals are preprocessed to ensure alignment of peaks across the spectra. Similarity measures are constructed to provide a basis for comparison of pairs of samples of the signal. A support vector machine is trained to discriminate between different classes of the samples. to identify the most predictive features within the spectra. In a preferred embodiment feature selection is performed to reduce the number of features that must be considered.

An apparatus includes a single or dual output port, dual-drive Mach-Zehnder Interferometer configured to generate a first optical signal in one path, and to generate a second optical signal in a different path. The apparatus also includes an optical spectrum analyzer configured to receive output from at least one port of the dual-drive Mach-Zehnder Interferometer. A method includes causing radio frequency signals from two different antennae to modulate an optical carrier at a corresponding drive of a dual-drive Mach-Zehnder Interferometer, and causing output from at least one port of the Mach-Zehnder Interferometer to be directed to an optical spectrum analyzer. The method further comprises determining arrival angle at each of a plurality of frequencies in the radio frequency signals based on output from the optical spectrum analyzer.

A spectrum analyzer is disclosed. The analyzer includes a detector, a trace memory, a controller, a trace math processor and a display. The controller generates a plurality of frequency selection signal values and records the measured amplitudes at each of the generated frequency selection values to form a measured trace that is stored in slots in the trace memory. The trace math processor performs trace mathematical operations on traces stored in the trace memory to generate a math trace that is stored in the trace memory. The controller stores a plurality of trace math programs, each program corresponding to one of the trace storage slots in the trace memory and specifies the trace mathematical operations that are to be performed to generate a new trace to be stored in that trace storage slot. The controller executes the stored trace math program for each trace slot in a predetermined order.

A system for monitoring reverse paths of a bi-directional cable communication network such as a CATV network, to detect and analyze ingress signals entering a reverse path and ending at a network sub-headend or headend through a corresponding one of communication lines, comprises a plurality of radio frequency signal detectors connected thereto. The radio frequency signal detectors are provided with bandpass filter for receiving a radio frequency signal within the frequency band used, to generate corresponding output signals indicative of the strength of the received radio frequency signal. The output signal generated by the frequency signal detector which is coupled to the communication line corresponding to the ingress signal carrying path is indicative of the strength of the received ingress signal with received reverse signals. The system further comprises a signal processor for analyzing the detector output signals through comparison with one or more predetermined ingress thresholds to generate an alarm signal whenever the ingress signal is detected. The system further comprises a control computer receiving the alarm signal to generate monitoring sequence control data indicative of the communication line corresponding to the ingress signal carrying path to be monitored. The system also comprises a selector switch having a plurality of inputs being connected to the communication lines and being responsive to the monitoring sequence control data to select the input connected to the communication line to be monitored, and signal monitoring instrumentation such as a spectrum analyzer and a broadband analyzer coupled to an output of the switching device and being responsive to the monitoring sequence control data for analyzing the ingress signal and generating alarm message data accordingly. The control computer receives the alarm message data to further generate diagnostic sequence control data for the monitoring instrumentation also used to determine source characteristics of the ingress signal.

The invention discloses a COTDR (coherent detection based optical time-domain reflectometry) fused long-distance coherent detection brilouin optical time-domain analyzer which comprises a narrow-linewidth laser, two couplings, a microwave signal source, an electro-optic modulator, an isolator, a long-distance sensing optical fiber, an optical circulator, a 3 db coupling, a pulse modulator, an Er-doped fiber amplifier, a scrambler, a pulse signal generator, a balancing photoelectric detector, an electrical frequency spectrum analyzer, a data processing module and an acousto-optic modulator. According to the invention, the signal-to-noise ratio of BOTDA (brilouin optical time domain analysis) is improved by using a coherent detection method, a non-local effect of a BOTDA system is reduced in a double-sideband detection mode, and the sensing distance is more than 70 km under the condition of no light amplification such as raman; and according to the invention, the COTDR is fused to a coherent detection based BOTDA system, and the system can run in a breakpoint testing mode, so that the defect that the traditional BOTDA can not run when a sensing fiber has breakpoints and can not carry out positioning on breakpoints is effectively overcome, thereby enhancing the adaptability and practicability of the sensing system.

Thickness measurement apparatus for measuring layer thicknesses on patterned areas of a semiconductor wafer, comprises: a spectrum analyzer for obtaining reflection data taken from a patterned area and obtaining therefrom a frequency spectrum, a peak detector for searching the spectrum to find peak frequencies within said spectrum, the search being restricted to regions corresponding to peak frequencies found in an earlier learning stage, a frequency filter, associated with the peak detector, for filtering the spectrum about said peak frequencies, and a maximum likelihood fitter for using parameters obtained in the learning stage to carry out maximum likelihood fitting of said filtered spectrum to obtain the desired layer thicknesses. By carrying out maximum likelihood fitting using parameters obtained beforehand in a high resolution non-real time learning stage, it is possible to provide high resolution results in real time.

The invention provides a laser spectrum analyzer combining a confocal micro-Raman spectrometer with a laser-induced breakdown spectrometer (LIBS). The analyzer comprises a micro-Raman system, a micro LIBS system, a high resolution micro-imaging system, a confocal micro-light path, and a spectrum receiving system with a time resolution function, and automatically switches into a white light micro-imaging observation mode, an automatic focusing mode, a LIBS spectrum working mode, and a Raman spectrum working mode. The significant characteristics of the invention are that compact combination of Raman with LIBS is realized by a micro confocal system; qualitative and quantitative analysis of substance elements at the same minimal position and molecular structure is realized; with the high-resolution imaging function, element spatial discrimination and substance structure chemical analysis can be carried out in micrometers so as to obtain complete information of spatial distribution images of chemical elements, substance structure and physical conditions of a sample.

The present invention provides an apparatus for measurement of Raman scattered radiation comprising. The apparatus comprises at least one source of electromagnetic radiation for producing an electromagnetic radiation beam characterized by a narrow spectral width, an integrating cavity having an interior and an exterior, wherein a sample is placed in said interior. The integrating cavity further having at least one port for insertion of the sample in the interior and for transmission of the electromagnetic radiation into and out from the interior, the at least one port extending from the exterior to said interior of said integrating cavity. The integrating cavity also comprises a first optical element for transmitting the electromagnetic radiation into the interior of the integrating cavity through the at least one port, and a second optical element for collecting Raman scattered electromagnetic radiation from the sample through the at least one port. The apparatus also comprises a spectrum analyzer for determining spectral composition of the Raman scattered electromagnetic radiation, a detector for measuring the Raman scattered electromagnetic radiation; and a system for determining concentration of at least one chemical compound from the measured Raman scattered electromagnetic radiation. The apparatus may also comprise a radiation expanding element. A method for measuring the concentration of one or more chemical compounds in a sample using Raman scattering is also provided.

A multi-wireless access technology based over-the-air test system, used for evaluating over-the-air index of a wireless terminal device, has the principle of putting a device to be tested in a three-dimensional space, and establishing a communication link with a base station simulator (namely wireless communications test set); controlling Phi, Theta axles (two axles perpendicular to each other) to rotate according to set step, performing measurement on various angle positions; measuring spherical effective Total Radiated Power of a moving station in the three-dimensional space and Total Isotropic Sensitivity of a receiver. The system mainly comprises a darkroom, a high-accuracy positioning system and its controller(including a rotating axle controller and a polarization controller), a radio frequency test instrument and a main control terminal computer with automatic test program, wherein the radio frequency instruments comprises a wireless communications test set, a spectrum analyzer, a network analyzer and a radio frequency unit.

The invention relates to a sensing method with an optical-fiber Bragg grating laser device. An optical-fiber Bragg grating is used as a reflector of the resonant cavity, an active optical fiber capable of generating sufficient gains is added, and a double wavelength/multiple wavelength optical-fiber Bragg grating laser device is formed under the action of a pump light source and used as a sensor. When the outside strain, temperature and other physical quantities act on the sensing system, the beat signal frequency among the double wavelength or multiple wavelength laser can shift, and counter stress, temperature and other physical parameters can be measured precisely by detecting the beat signal frequency information. The invention has the advantages of simple manufacture, stable and reliable operation, stable measurement result and high precision, and is free from the interference of light intensity, polarization and other optical information quantities. The multipoint distribution sensing measurement can be realized in a frequency-division multiplexing mode. An electrooptical modulator is added before the spectrum analyzer starts detection so as to randomly adjust the beat signal frequency, thereby greatly reducing the spectral range of the spectrum analyzer and reducing the detection cost.

The invention provides a method for measuring the baseband remote radio frequency subsystem RRU of WCDMA and TD-SCDMA in 3G technology, a measuring system and an analog BBU device for measuring the baseband remote radio frequency subsystem RRU; the invention is characterized in that: an analog BBU is arranged as an unvarnished transmission channel and connected with the RRU to be tested; the control signaling and IQ data are transferred to RRU after coding by the control platform; the radio frequency output of RRU is connected with a spectrum analyzer to detect the output signals, and connected with an input signal of a signal generator; the digital signals transferred by BBU are transferred to the spectrum analyzer by RRU after DAC converting to detect, and the starting, resetting, module detecting of RRU and measurement of the whole machine in the receiving and sending performances are finished. The invention has the advantages that the problems that the current non-mainstream equipment manufacturers need to have the baseband resource pool BBU to finish testing the downlink uplink IQ data of the RRU and the optical fiber link are solved, the testing cost is greatly reduced, and the testing efficiency is improved.

The invention discloses a laser self-mixing multi-physical parameter measurement method and a laser self-mixing multi-physical parameter measurement device for an atmospheric particulate. The laser self-mixing multi-physical parameter measurement device comprises a microchip laser, a collimating lens, a beam splitter, converging lenses, a photodetector, an amplifier, a data acquisition card and a spectrum analyzer. Laser emitted by the microchip laser is focused onto the atmospheric particulate to be measured through the collimating lens and the converging lens, and part of generated backwards-scattered light is fed back to the laser due to the reversibility principle of an optical path, so that parameters such as power and wavelength of the laser are changed, namely a laser self-mixing effect is achieved. In addition, the beam splitter is additionally arranged in the optical path to split a small part of laser beam for the photodetector to receive, and a laser self-mixing signal is acquired and analyzed by the amplifier, the data acquisition card and the spectrum analyzer. The laser self-mixing multi-physical parameter measurement device has a simple structure, and is easy to regulate; and the detection accuracy of an atmospheric particulate detection device is effectively improved.

The invention relates to a mobile terminal parallel radio frequency testing device, which comprises a CDMA signal resource, a frequency spectrum analyzer and a switch matrix connected to the CDMA signal resource and the frequency spectrum analyzer; a testing control unit via the GPIB connecting the CDMA signal resource, the frequency spectrum analyzer, and the switch matrix; and a communication direct current power resource connected to the CDMA signal resource, the frequency spectrum analyzer and the tested mobile terminal to supply power for them. The invention uses the dynamic power testing technique based on the single point trigger and the mobile terminal sender, to realize the parallel correction test. The invention can correct and test the radio frequency property of the sender and the receiver of CDMA mobile terminal to improve the testing speed and improve the utilization of device.

A communications system is provided that includes a detector that has I/Q mismatch, a calibration circuit that estimating a phase and/or an amplitude mismatch of the detector, and a compensation circuit that uses the estimated phase and/or amplitude mismatch to mitigate the effects of the amplitude and/or phase mismatch. An IQ-modulated signal produced by the I/Q-modulator can be communicated over a loop back connection to the detector of the communication system. The calibration circuit can estimate the I/Q mismatch for the IQ-modulator and can provide the estimated values to a pre-compensation circuit. In one aspect, I/Q mismatch in the IQ-modulator of a communication system can be determined using a spectrum analyzer. Power measurements can be used to compute the amplitude mismatch and the phase mismatch of an IQ-modulator.

A time domain measurement instrument and method are provided. The instrument comprises an acquisition circuit for acquiring a signal in a time domain and a processor for performing a Fast Fourier Transform (FFT) processing on the acquired signal to generate an FFT of the acquired signal. A frequency domain analysis tool is also provided for analyzing and manipulating the FFT, wherein the frequency domain analysis tool instructs the processor to automatically determine the frequency of a peak amplitude of the FFT, and to determine the amplitude at the determined peak frequency.

A BOTDA system based on pulse coding and coherent detection comprises a narrow linewidth laser device (10), a first polarization-maintaining coupler (11), a second polarization-maintaining coupler (12), a microwave signal source (17), testing optical fibers (18), an optical circulator (19), a 3dB coupler (20), a balance photoelectric detector (21), a scrambler (16), a spectrum analyzer (22) and a digital signal processing unit (23), wherein continuous light emitted by the arrow linewidth laser device (10) is divided into two channels of continuous light, namely, a first channel of the continuous light and a second channel of the continuous light, through the first polarization-maintaining coupler (11); and the system further comprises a frequency shifter (9), a first electrooptical modulator (13), a pulse signal source (14) and a second electrooptical modulator (15). The system adopts a pulse coding technology and a coherent detection method, so that the signal to noise ratio of the BOTDA and the measurement accuracy can be improved, the sensing distance is increased, and the system has the function of breakpoint detection.

The invention discloses a device of measuring the line-width of a laser with narrow line-width and a method of measuring the line-width based on a optical fiber delay self-heterodyne method; in the hardware device, an optical fiber delay line is connected between a first and a second couplers; an acousto-optic modulator is connected between the first and the second couplers; the measured laser is connected to the input of the first coupler, and a photoelectric detector is connected to the output of the second coupler; the photoelectric detector is connected with a spectrum analyzer. In the line-width measurement, simulation models of the line-width triangle v of the laser and the spectrum-width triangle f of the photoelectric current heterodyne signal are built in the frequency shift delay self-heterodyne methodology, and the function relation between the line-width triangle v of the laser and the spectrum-width triangle f of the photoelectric current heterodyne signal is obtained fitting of the three-level proportion function model. The invention presents that with the short optical fiber delay self-heterodyne method, the device can eliminate the deficiency of greatly reduced measuring precision because of not enough delayed time in the delay self-heterodyne method when the length of the delay optical fiber is less than 6 times coherence length of the laser, so as to provide an effective method of precisely measuring the line-width of the laser with narrow line-width in projects.

The invention provides an energy method-based high-temperature radiation rate measuring device of a semi-transparent material and a revising method for deducting background radiation, relating to a high-temperature normal spectral radiation rate revising and testing method of the semi-transparent material and belonging to the technical field of high-temperature material physical property measurement. The energy method-based high-temperature radiation rate measuring device of the semi-transparent material and the revising method for deducting the background radiation solve the problems of high construction cost, low temperature heating upper limit and lower testing precision of the traditional test system. The high-temperature radiation rate measuring device comprises a Fourier infrared spectrum analyzer, a reference blackbody furnace, a rotatable reflection mirror, a heating furnace, a heater, a temperature collecting device, a temperature routing inspection operation instrument, an incidence light source, a data processing system, a diaphragm and a semi-transparent test piece; the heating furnace is internally provided with a light-transmitting opening, a fixing device of the semi-transparent test piece, and the temperature collecting device; the central axis of a light-emitting opening of the incidence light source, the central axis of the light-transmitting opening of the heating furnace, the mirror surface of the rotatable reflection mirror and the central axis of the light outlet opening of the reference blackbody furnace are collinear with a horizontal axis. The energy method-based high-temperature radiation rate measuring device of the semi-transparent material and the revising method for deducting the background radiation, disclosed by the invention, are used for measuring the high-temperature spectral normal radiation rate of the surface of the semi-transparent material.

In a frequency analysis system, such as a signal detection system or a spectrum analyzer, the frequency domain resolution is enhanced by compression and decompression of the signal samples. The limited capacity of the data storage and/or data transfer resources limit the number of samples that can be stored or transferred. A compressor forms a compressed signal prior to data transfer or storage. A decompressor decompresses the compressed signal prior to transformation to the frequency domain, by a fast Fourier transform or other frequency domain transform. The frequency domain resolution is enhanced because more decompressed samples are available for the frequency domain transform. The compressor and decompressor apply computationally efficient algorithms that can be implemented to operate in real time.

The invention relates to a mobile communication terminal radio frequency testing system, which belongs to the field of mobile communication terminal radio frequency test. The system comprises a comprehensive tester, a frequency spectrum analyzer, a vector signal source, a wideband signal source, a power meter, a direct current source, a temperature control box, a switch control unit and a controller thereof , and a system control platform, wherein the system control platform is connected with the controller of the switch control unit, the temperature control box, the comprehensive tester, the frequency spectrum analyzer, the vector signal source, the wideband signal source, the power meter and the direct current source respectively; and the comprehensive tester, the frequency spectrum analyzer, the vector signal source and the wideband signal source are connected with the switch control unit and a terminal to be tested respectively. The system has the advantages of simple operating flow, clear testing process, quick testing, serious processing on testing result, and good reliability and stability; in addition, the system can quickly and accurately develop a test case meeting self requirement, realize diverse and standard test, also can flexibly extend to the control on other instruments and meters, and realize flexible configuration of the system.

Channel and test plans are implemented in connection with a plurality of nodes that communicate signals. The channel plan enables a monitoring system to, among other things, conduct automatic periodic test plans, comprising tests, on the nodes, based upon the predefined data specified in the channel plan. The monitoring system includes a controller controlling a spectrum analyzer and a node interface switch. Notably, the controller also enables user friendly plan set-up and warning interface logic implementation. The warning interface logic generates a channel percent advisory indicator on the display device within a channel level interface component upon an occurrence of an advisory event in a channel associated therewith and generates a channel critical alarm indicator on the display device within a channel level interface component upon an occurrence of a critical event in a channel associated therewith.