71 results about "THD analyzer" patented technology

A multi-channel analog-digital converter (ADC) subsystem for test device such as a spectrum analyzer may include multiple multi-channel ADCs to receive down-converted signals and convert the received signals to digital output signals, a field programmable gate array (FPGA) to select one or more ADCs based on a frequency, a bandwidth, and / or a signal type of each received signal and a characteristic of each ADC, and an ADC sample clock to provide a clock signal to the selected ADCs. Characteristics of the ADCs may include a resolution, a signal-to-noise-and-distortion ratio (SINAD), an effective number of bits (ENOB), a signal-to-noise ratio (SNR), a total harmonic distortion (THD), a total harmonic distortion plus noise (THD+N), and / or a spurious free dynamic range (SFDR).

The invention relates to the technical field of audio equipment testing, and discloses a frequency response testing method, in the method, an upper computer can compare a frequency response curve, generated by an audio analyzer, of audio equipment with a standard frequency response curve, and whether the waveform of the frequency response curve is consistent with the waveform of the standard frequency response curve or not can be judged through comparison. If the frequency response curve is inconsistent with the standard frequency response curve, the sound effect of the audio equipment is not good, the PEQ parameter of the audio equipment needs to be further adjusted according to the comparison result of the frequency response curve and the standard frequency response curve, and the audio equipment can continue to carry out the frequency response test based on the adjusted audio parameter. Therefore, in the frequency response test process of the audio equipment, the upper computer can automatically adjust the PEQ parameter of the audio equipment, a tester does not need to manually adjust the PEQ parameter, and the time consumption of the frequency response test of the audio equipment is shortened. Therefore, the frequency response test efficiency can be improved. The technical effect of the method is explained. The invention also discloses a frequency response test device and equipment, and a storage medium.

This invention proposes a rapid and non-destructive method for identifying the resonant frequency of heavy-duty mechanisms. The load-end speed curves and motor-end speed curves under closed-loop and open-loop conditions at the motor end are obtained using the speed step response method and the current step response method, respectively. By performing an FFT transform on the two speed curves, the resonance peak is obtained, allowing for rapid measurement of the structural resonant frequency and the combined resonant frequency. This method eliminates the need to purchase an additional resonance analyzer, reducing measurement costs, and avoids the damage to large, heavy-duty servo mechanisms caused by sinusoidal frequency sweep measurements. It can not only be used for rapid identification of structural resonant frequencies but also to guide the design of servo controllers.

The invention provides a noise acquisition device and a noise measurement device of an operational amplifier. The noise acquisition device comprises a preset resistor matched with a target operational amplifier, a total noise acquisition circuit and a resistance noise acquisition circuit, the total noise acquisition circuit acquires the total noise of the current working environment and amplifies the total noise so as to output the amplified total noise to external preset measurement equipment; the resistance noise acquisition circuit acquires and amplifies first noise correspondingly generated by the preset resistor in the current working environment and carries out amplification processing so as to output the amplified first noise to preset measurement equipment. The total noise and the first noise are collected, the first noise is used for compensating the total noise to obtain the noise of the target operational amplifier, and the defects that measurement cannot be conducted due to the fact that the bottom noise of the spectrum analyzer is too large and the measurement accuracy is reduced due to the first noise are overcome; low-ripple positive and negative direct-current power supply voltage is provided, and the size is small; the spatial noise coupling interference is reduced, and the accuracy is improved.

The invention provides a sine small distortion degree signal measuring method, a measuring device comprises a distortion degree measuring instrument and a spectrum analyzer, and the method comprises the following steps: S1, deducing a total distortion formula D of a sine small distortion signal; s2, calibrating the distortion degree measuring instrument, and determining the fundamental wave suppression amount C of the distortion degree measuring instrument; s3, determining a harmonic residual distortion degree Dns; an output signal of the fundamental wave suppressor comprises a residual fundamental wave and each harmonic signal, the signal is monitored by the distortion degree measuring instrument and output to the spectrum analyzer, and the spectrum analyzer visually displays the power intensity of the residual fundamental wave and each harmonic signal; and S4, calculating the distortion degree D of the measured small sine signal. According to the method, the advantages of the fundamental wave suppression method and the spectrum analyzer method are combined, the fundamental wave suppression quantity of the fundamental wave suppression network and the harmonic levels measured by the spectrum analyzer are integrated, the lower limit of sinusoidal signal distortion degree measurement can be reduced to-130 dB, and therefore the problem that small sinusoidal distortion signals cannot be accurately measured is solved.

The utility model discloses a shield tunnel segment wall back grouting real-time detection device which is arranged at the shield tail of a shield tunneling machine, two construction platforms are symmetrically arranged in the shield tunneling machine, and the shield tunnel segment wall back grouting real-time detection device comprises an annular track which is movably installed between the two construction platforms in the tunneling direction of the shield tunneling machine. The circular track has an arc consistent with the radian of the outer wall of the duct piece; the sound wave detector is arranged on the outer side of the annular track in a reciprocating motion mode along the annular track, and the height of the sound wave detector can be adjusted in the radial direction of the duct piece; according to the grouting plumpness detection device, the grouting plumpness on a propagation path is reflected by utilizing the propagation speed of the sound waves in different media and the frequency change of the waves, the grouting plumpness can be detected in real time along with tunneling of a shield, and the grouting plumpness can be accurately detected. And a certain popularization value is achieved.

A kind of transmission equipment intelligent monitoring system and method based on noise feature analysis, through the method, expert can input the sound evaluation information heard from console, the sound evaluation value of expert corresponds to the state of specific reduction mechanism, the loudness and frequency characteristic of noise signal output by spectrum analyzer as input layer, the sound evaluation value of expert as output layer, mapping relationship between the two is established through data accumulation and neural network algorithm. Through the database of abnormal noise experts as a reference, warning is found by comparing similar abnormal noise data, ensure that noise meets the standard, through the noise evaluation of experts and neural network algorithm, the timbre can be evaluated, and then the specific type of fault can be judged. Moreover, the influence of on-site noise on sound signal collection is excluded, and the accuracy of machine detection is further improved.

The application discloses a kind of mill sound analyzers, receiver, for receiving the audio signal frequency band in the process of ball mill equipment operation;Filter module, amplification module, intelligent analysis module, output module;The processing analysis module includes: energy spectrum calculation module, carries out spectrum analysis to audio signal frequency band, extracts the energy of each frequency band as feature, and constructs feature vector in combination with historical state;Model inference module, using the constructed feature vector is handled to predict the current ball mill capacity.The application receives the audio signal of ball mill equipment in real time, and carries out processing and analysis to it, quickly responds the change of ball mill equipment operating state, realizes accurate prediction to ball mill capacity, optimizes the operating parameter of ball mill equipment by accurately predicting ball mill capacity, improves production efficiency and product quality, the application of intelligent analysis module and model inference module makes the management of ball mill equipment more intelligent and automated, reduces the complexity and cost of manual intervention.

The utility model relates to an abnormal sound detection device, which is arranged in a test box and comprises a tool clamp, a detection device and a control device, the tool clamp is installed on the bottom wall of the test box and used for clamping a to-be-tested product. An internal fixture; the internal fixing piece is mounted on the top wall of the test box and is arranged above the tool clamp; a pressing device; the pressing device is arranged on the internal fixing piece and is used for pressing a key of the product to be tested and enabling the product to be tested to generate air medium noise; the microphone is arranged on the internal fixing piece and is used for collecting audio data of the air medium noise and sending the audio data to an acoustic analyzer; the acoustic analyzer is electrically connected with the microphone; and the acoustic analyzer detects whether the to-be-detected product generates abnormal sound or not according to the audio data. According to the invention, manual detection is replaced by a mechanical device, the sound is accurately analyzed, and the efficiency and accuracy of abnormal sound detection are improved.

The objective of the present invention is to provide a Brillouin gain analysis device and a Brillouin gain analysis method with which it is possible for high-speed strain changes in an optical fiber to be measured distributionally.　A Brillouin gain analysis device 301 according to the present invention comprises: a laser 11 for outputting continuous light having a single frequency; a pulse generator 12 for pulsing the continuous light from the laser and inputting the same into one end of an optical fiber 50 being measured; an ASE light source 13 for generating continuous light having frequency components over a wider band than the frequency of the continuous light output by the laser 11, and inputting the same into the other end of the optical fiber 50; a modulator 14 for generating local light obtained by shifting the frequency of the continuous light from the laser 11 by an arbitrarily defined frequency; and a wave detector 15 for performing heterodyne detection between Brillouin scattered light generated by the optical fiber and the local light.

In order to improve the detection sensitivity of flow rate measurements in a low-pressure, low flow rate cleaning system of an automatic analysis device, the present disclosure proposes a control method for an automatic analysis device comprising a liquid delivery pump that delivers a cleaning liquid to a cleaning mechanism of a dispensing nozzle through a flow channel, and a control unit that controls operation of the liquid delivery pump. The control method comprises: operating the liquid delivery pump through the control unit to deliver the cleaning liquid to a low-pressure flow channel that constitutes at least a portion of the flow channel and is of a low pressure and a low flow rate; and operating, through the control unit, a flow rate estimating mechanism arranged in the low-pressure flow channel to determine a value of an estimated flow rate in the low-pressure flow channel (see fig. 2).

The invention discloses a TDLAS (Tunable Diode Laser Absorption Spectroscopy) analyzer for H2O2 gas, and belongs to the technical field of gas concentration detection. In the H2O2 gas TDLAS analyzer, the inner surface of the gas path system in contact with H2O2 gas is subjected to inert treatment to form a chemical inert layer, so that the gas adsorption loss can be effectively inhibited; the optical path system is arranged in the heat preservation case, a stable physical environment is provided for TDLAS measurement, an instrument is almost not interfered by the field environment, and the long-term drift is extremely small; the laser driving module adopts a composite current source architecture and comprises an operational amplifier serving as an error amplification stage and a push-pull circuit serving as an output stage, so that the stability problem under high-current and high-frequency modulation is fundamentally solved, nearly ideal light source modulation signals are provided for TDLAS detection, and a basis is provided for high-precision harmonic detection. According to the invention, high-performance driving, enhanced protection and precise environment control are deeply coupled, and the precision, stability and reliability of H2O2 gas detection are effectively improved.

The present invention belongs to the technical field of power supply and power detection, and specifically relates to a detection circuit and an evaluation method for the output voltage quality of a variable-frequency power supply for high-voltage tests. The technical solution adopted is as follows: After adjusting the output frequency of the variable-frequency power supply to be tested to a maximum of 300 Hz, adjust the output voltage to reach a maximum of 350 V in steps of 5 V. Adjust the internal impedance of the variable load device to make the output of the variable-frequency power supply reach a maximum current of 1142 A, and calculate the total harmonic distortion THD of the output voltage waveform of the variable-frequency power supply to be tested by a waveform analyzer. While maintaining the maximum output voltage and maximum output current of the variable-frequency power supply to be tested, adjust the power interference generator to make the input voltage of the variable-frequency power supply fluctuate within ±5%, and calculate the output voltage instability ΔU% of the variable-frequency power supply at this time by a waveform analyzer. After the entire test is completed, reduce the output voltage through the variable-frequency power supply control box and disconnect the input of the variable-frequency power supply. The method of the present invention is simple, practical and efficient, and the results are reliable.

1. Name of the product in this design: Multifunctional Signal Analyzer. 2. Application of this design: This design is intended for use in information science electronic measuring instruments. 3. The key design feature of this product is its shape. 4. The image or photograph that best illustrates the design's key points: a 3D model.

The application relates to a plate material dielectric stability test method and a test system, and relates to the technical field of electromagnetic measurement.The plate material dielectric stability test method comprises the following steps: step 1: a planar capacitive resonance module is attached to the upper surface of a material to be measured, the planar capacitive resonance module comprises a resonance coil and two capacitive plates arranged on the same plane, and the two terminals of the resonance coil are connected to the two capacitive plates in a one-to-one correspondence; step 2: a frequency analyzer reads resonance frequency information through a coupler matched with the planar capacitive resonance module; step 3: the temperature of the material to be measured is measured, the temperature and the characteristic points of the resonance frequency information are compared with a pre-stored parameter comparison table, and the corresponding dielectric constant is obtained as a measured dielectric constant, the parameter comparison table records the corresponding relationship among the temperature, the characteristic points of the resonance frequency information and the dielectric constant; and step 4: the measured dielectric constant is compared with a theoretical dielectric constant.The application can realize nondestructive testing.

The invention discloses a method for measuring insertion loss of a harmonic filter. Measurement is carried out under the condition of rated voltage and rated current of a 50Hz / 400Hz power grid actually used by the harmonic filter, the method is simple, operation is convenient, and data are real and visual. Meanwhile, high-end equipment such as a network analyzer and a measurement receiver is not needed, and the measurement system is low in cost and reliable in operation. According to the method disclosed by the invention, the acquired analog data is transmitted after A / D conversion, so that the measured data is real and reliable and is prevented from being interfered by an electromagnetic environment. Finally, data processing is completed by means of existing mature software, a measured result is displayed in a frequency spectrum graph, the system is stable, new software does not need to be developed, time and money are saved, and efficiency is high.

The utility model provides a phase noise analyzer spread spectrum device and a phase noise analysis system. The phase noise analyzer spread spectrum device comprises a to-be-detected source signal processing assembly, a first reference signal generating assembly, a second reference signal generating assembly, a first frequency conversion assembly and a second frequency conversion assembly. The to-be-tested source signal processing assembly is electrically connected with the first frequency conversion assembly and the second frequency conversion assembly. The first reference signal generation component is electrically connected with the first frequency conversion component; the first reference signal generation assembly is used for generating two paths of first reference signals, one path is input into the first frequency conversion assembly, and the other path is connected to the phase noise baseband analyzer; the second reference signal generation component is electrically connected with the second frequency conversion component; and the second reference signal generation assembly is used for generating two paths of second reference signals, one path is input into the second frequency conversion assembly, and the other path is connected to the phase noise baseband analyzer. According to the invention, the reference source and the local oscillator are combined into one, so that the cost of the device is reduced, and the accuracy of phase noise measurement is improved.

The embodiment of the application discloses a thromboelastography generation method based on a magnetic bead method, and the method is characterized in that the method comprises the following steps: acquiring magnetic bead oscillation waveform data detected based on the magnetic bead method; and performing conversion calculation based on the magnetic bead oscillation waveform data to obtain the thromboelastography. The thromboelastography generation method greatly reduces the cost, and greatly improves the timeliness due to the simple detection method. In addition, a thromboelastography generation device based on the magnetic bead method, a sample analyzer and a storage medium are also provided.

The application relates to the field of nonlinear measurement, in particular to a nonlinear characteristic measurement system based on a vector analyzer. The application is provided with a signal transmitting module used for controlling a transmitting end to transmit a plurality of transmission signals; a transmission collecting module used for collecting transmission data of the transmission signals and extracting transmission characteristics of the transmission signals corresponding to single transmission; a cumulative analysis module used for determining transmission cumulative characteristic values of the transmission signals according to the transmission characteristics and the number of transmission signals received by a target body, so as to mark the single transmission; a stability evaluation module used for analyzing and processing the transmission signals of the single transmission based on the marking result of the cumulative analysis module; and a feedback warning module used for issuing a warning prompt information in response to the evaluation result of the stability evaluation module. The application can more comprehensively and accurately dynamically evaluate the nonlinear distortion degree of the target body.

The invention discloses a test field design method based on target scattering characteristics, and relates to the technical field of target scattering measurement, and the method comprises the steps: determining the dominant scattering type of a measured target according to the appearance structure of the measured target, and the dominant scattering type comprises simple mirror surface scattering, coupling scattering with multiple reflections as the main part or antenna / load scattering; system parameters are optimized based on scattering types, and for a coupling scattering or antenna / load scattering target, according to a plane where an equivalent large aperture is located, a receiving and transmitting antenna vertical layout of a feed source system is set by combining a single-station and double-station RCS equivalent theorem; the sweep frequency interval and pulse parameters of the vector network analyzer are configured according to the position of the scattering source, so that the vector network analyzer has enough distance measurement capability; background, calibration and target measurement are carried out, and a high-precision single-station RCS result is obtained. According to the method, the accuracy and applicability of RCS measurement of the complex target are remarkably improved.

The signal synchronization method, device and spectrum analyzer based on phase shift keying provided by this application relate to the technical field of signal synchronization. In this application, first, a first frequency offset estimation can be performed on the signal to be synchronized to obtain the first frequency offset corresponding to the signal to be synchronized, and frequency offset compensation can be performed on the signal to be synchronized based on the first frequency offset to obtain the first frequency offset compensation signal corresponding to the signal to be synchronized; secondly, a second frequency offset estimation can be performed on the first frequency offset compensation signal to obtain the second frequency offset corresponding to the signal to be synchronized, and frequency offset compensation can be performed on the signal to be synchronized based on the second frequency offset to obtain the second frequency offset compensation signal corresponding to the signal to be synchronized; then, the output of the synchronization signal can be performed based on the second frequency offset compensation signal to obtain the target synchronization signal corresponding to the signal to be synchronized. Based on the above content, the problem of poor signal synchronization effect existing in the prior art can be improved.

A first detector that receives and detects 3-tone signals of three patterns of a first 3-tone signal obtained by combining three waves of angular frequencies ω1, ω2, and ω3 (here, ω2−ω1=ω3−ω2=Δω is established), a second 3-tone signal in which each tone has a phase offset, and a third 3-tone signal having a phase offset different from the phase offset of the second 3-tone signal, a BPF that allows only a beat component of an angular frequency difference Δω between adjacent waves of the 3-tone signals among signals output from the first detector to pass, a second detector that detects power of the beat component that has passed through the BPF, a voltmeter that measures a voltage of a signal output from the second detector, and a phase calculator that calculates a phase based on the measured voltage values of the three patterns.

The present invention discloses a method for measuring the non-linear distortion components of a dual-frequency excitation of an amplifier, which includes a dual-frequency excitation signal source, an amplifier, and a spectrum analyzer. The dual-frequency excitation signal source is a dual-channel dual-frequency excitation signal source. The output end of the first channel of the dual-frequency excitation signal source is connected to the input end of the amplifier, and the output end of the amplifier is connected in series with the output end of the second channel of the dual-frequency excitation signal source and then connected to the measurement end of the spectrum analyzer. The present invention uses a dual-channel series cancellation method to enable the spectrum analyzer to measure the residual non-linear distortion components at the output end of the amplifier without dual-frequency excitation. Moreover, the cancellation method effectively reduces the signal amplitude entering the spectrum analyzer, so that the non-linear distortion generated by the spectrum analyzer can be ignored.

The present application relates to the technical field of acoustic metrology, and more particularly to a standard phase generation and calibration device based on a pressure field coupling cavity. The present application comprises two end surfaces of an equal-phase plane wave coupling cavity, which are respectively sealed and connected with a receiving microphone and a transmitting microphone. In the equal-phase plane wave coupling cavity, the phase of the sound pressure signal is equal everywhere. A reciprocity phase calibrator is connected with the receiving microphone and the transmitting microphone, and collects voltage, current and phase information of the equal-phase plane wave coupling cavity. A multi-channel sound analyzer is connected with the reciprocity phase calibrator, and is used to measure the phase difference between the transmitting channel and the receiving channel. An output end of a signal source is connected with an input end of the reciprocity phase calibrator. Measuring and control software is connected with the reciprocity phase calibrator and the multi-channel sound analyzer, respectively. The present application proposes a reciprocity method for calibrating the sensitivity and absolute phase, so as to realize the standard phase generation and calibration based on the pressure field coupling cavity.

To provide a phase characteristics measuring instrument and the like that uses a voltmeter and a wave detector not requiring a high-speed trigger operation to avoid increase in the scale of an apparatus used for phase measurement, and thereby can achieve phase measurement at a relatively low price.SOLUTION: A phase characteristics measuring instrument comprises: a first wave detector 11 that receives and detects two patterns of three-tone signals, a first three-tone signal obtained by combining the three waves of angular frequencies ω1,ω2,ω3 (wherein ω2-ω1=ω3-ω2=Δω) and a second three-tone signal obtained by changing the phase of one tone of the first three-tone signal; a BPF 12 that allows only a beat component of an angular frequency difference Δω of adjacent waves of the three-tone signal from the signal output from the first wave detector to pass therethrough; a second wave detector 13 that detects power of the beat component that has passed through the BPF 12; a voltmeter 14 that measures the voltage of the signal output from the second wave detector; and a phase calculator 15 that calculates the phase on the basis of the measured voltage value.SELECTED DRAWING: Figure 2

The utility model provides an audio analyzer assembly structure, and relates to the technical field of audio analyzer assembly, the audio analyzer assembly structure comprises a main housing, the top ends of the two sides of the main housing are provided with pad grooves, and the pad grooves are fixedly provided with curved edge plates. Although a part of weight can be shared, the equipment is still inevitable to shake in the carrying process due to the fact that the walking speed, the force exerting direction and the like are difficult to be completely synchronized, the risk of equipment damage is greatly increased due to the unstable state, and especially for the design of the handle, if stress is uneven or accidental collision occurs in the carrying process, the equipment cannot be damaged. At present, the connection part of the handle and the equipment main body is easily broken, or more seriously, the deformation of the metal box body is directly caused, and once the situation occurs, the appearance integrity of the equipment is influenced, and more importantly, the precision structure in the equipment is damaged, and the test performance and accuracy of the equipment are influenced.

The utility model discloses an electric energy quality analyzer, which comprises a main sampling module, a standby sampling module and a high-frequency interference suppression module. And the main sampling module and the standby sampling module both adopt standardized slot design, so that quick plugging can be realized, and the flexibility and maintainability of the equipment are improved. The analyzer is compact in structure, integrates a high-precision sampling circuit and an embedded processing unit, and is used for collecting and processing signals. The high-frequency interference suppression module is located in a signal link, high-frequency noise is effectively filtered, and the signal quality is ensured. The beneficial effects are that high precision and strong anti-interference capability of signal acquisition are ensured. The equipment can visually display a harmonic histogram, a total harmonic distortion rate, a peak factor and inter-harmonic distribution through real-time analysis of electric energy quality parameters. The structural design is convenient to operate and maintain, is suitable for electric energy quality monitoring of a complex electric power system, and has remarkable technical advantages and market application potential.

The invention belongs to the technical field of wireless communication, and particularly discloses a phase compensation method and system for restraining intermodulation and harmonic waves of a short wave transmitter and application, and the system comprises a phase compensation module, a digital pre-distortion model training and pre-distortion signal generation module, a digital up-conversion module and the like which are connected through a feedback loop. After time delay and amplitude alignment are carried out on feedback signals through the data preprocessing module, fundamental wave and harmonic wave phase deviation caused by factors such as radio frequency time delay and down-conversion is accurately estimated and compensated through the phase compensation module, and a group time delay compensation coefficient measured through the vector network analyzer is introduced to carry out further compensation on harmonic waves. According to the method, the digital pre-distortion model can more accurately represent the nonlinear characteristic of the power amplifier, so that an effective pre-distortion signal is generated, intermodulation distortion and multiple harmonic distortion output by the power amplifier are remarkably suppressed, the linearity and communication quality of a short wave transmitter are improved, and meanwhile, equipment miniaturization is facilitated.

The invention relates to a high-specific-surface-area titanium sol porous ceramic air purification filter element and a manufacturing method thereof, and belongs to the technical field of material science and engineering.The manufacturing method comprises the steps that S1, a heat treatment cavity body, a sensing and control unit and a suspension type weighing structure are arranged, the sensing and control unit comprises a high-precision pressure sensor, an atmosphere analyzer, an acoustic analysis part, a sample thermocouple and a reference thermocouple, and the suspended weighing structure comprises a ceramic suspender and a ceramic hanger. The upper end of the ceramic hanging rod is connected with the high-precision pressure sensor, a sound wave exciter of the acoustic analysis part and a sound wave receiver, and the lower end of the ceramic hanging rod is connected with the ceramic hanging tool. The problem of mechanical interference in traditional high-temperature weighing and acoustic measurement is successfully solved, and fingerprints of four key processes in the heat treatment process are acquired in real time.