12 results about "Noise bandwidth" patented technology

This invention relates to the field of electronic measurement technology and discloses an online measurement method and system for the quality factor of resonant circuits. The method involves injecting a small-amplitude sinusoidal disturbance signal into the excitation end of the resonant circuit under test using weak electromagnetic coupling, extracting the amplitude and phase of the disturbance response using lock-in amplification technology, performing Lorentz fitting on the frequency response curve to calculate the negative 3 dB bandwidth, outputting the quality factor in real time from the ratio of the resonant frequency to the bandwidth, introducing cross-correlation narrowband filtering to compress the equivalent noise bandwidth to below 1 Hz, and having an automatic resonant frequency tracking function.

The invention discloses a noise frequency modulation signal generation device, which is realized based on a field programmable gate array (FPGA), and adopts the following method steps: S1, in the FPGA, constructing an arbitrarily distributed random number generator to obtain random numbers conforming to distribution; s2, linearly mapping the obtained random number into a frequency modulation noise bandwidth by using a linear mapping method to obtain a random frequency conforming to Gaussian distribution; and S3, converting the obtained random frequency into frequency modulation noise by using a direct digital frequency synthesis technology. Complex linear algebraic operation is simplified into integer addition, subtraction and shifting, FPGA parallelism and special hardware resources are fully utilized, high speed, low resources and high statistical quality are considered, and a reliable hardware noise source is provided for scenes such as communication simulation and radar interference.

The application relates to a thermoelectric array and a signal readout circuit thereof, the thermoelectric array comprising: a plurality of sensor pixel elements; and a readout circuit comprising a plurality of signal processing channels, each signal processing channel comprising: a preamplifier for amplifying a sensor signal, the preamplifier being a single-stage amplifier; and an analog-to-digital converter connected to an output of the preamplifier, the analog-to-digital converter being a delta-sigma analog-to-digital converter; wherein each signal processing channel is configured to process sensor signals output by i sensor pixel elements, i being a positive integer and not greater than the square root of the number of sensor pixel elements in the thermoelectric array divided by 4. The application effectively reduces the noise bandwidth of the signal channel, thereby effectively improving the signal-to-noise ratio of the signal processing channel, effectively improving the system performance, and significantly improving the thermal temperature resolution; at the same time, because the frequency is reduced, the area and power consumption of the preamplifier and the analog-to-digital converter can be significantly reduced.

This invention provides an adaptive cutoff frequency filtering method and apparatus for unsprung control, belonging to the field of automotive control technology. The method includes: determining a cutoff frequency based on the wheel's rotational fundamental frequency, the dominant frequency of vibration generated by road excitation, and the wheel's resonant frequency; establishing an initial upper cutoff frequency and a lower cutoff frequency; constructing a noise monitoring frequency band based on the cutoff frequency and preset pure noise setting frequency intervals and noise bandwidth; calculating the actual signal quality based on the theoretical target signal quality; determining the measurement deviation of the signal quality based on the cutoff frequency, the theoretical target signal quality, the total discretized signal power within the noise monitoring frequency band, the total discretized noise power within the noise monitoring frequency band, and the smoothing time constant; and determining the target upper cutoff frequency based on the measurement deviation, the theoretical target signal quality, and the actual signal quality, and performing cutoff frequency filtering based on the target upper and lower cutoff frequencies. This invention can solve the problem of poor consistency gains in unsprung control.

A device and method for improving the electronic polarization uniformity and stability of a SERF magnetic field measurement device are proposed. This method employs a laser with a spectral linewidth on the same order of magnitude as the gas cell pressure broadening as the pump light to polarize atoms. The spectral linewidth of the light source is broadened by applying voltage modulation to an electro-optic phase modulator, causing external phase modulation of the narrow-linewidth laser light passing through the modulator. Gaussian white noise is used as the modulation signal, and the output laser spectral linewidth is controlled by adjusting the noise bandwidth. Compared to SERF magnetic field measurement devices using a single broadband light source, using an electro-optic phase modulator to broaden the pump light linewidth not only possesses the ability of a wide-linewidth light source to improve the uniformity of electronic polarization in the gas cell, but also retains the advantages of a narrow-linewidth light source, such as center wavelength stability and relatively low intensity noise. This results in superior calibration coefficient stability and lower random noise in the SERF magnetic field measurement device, which is beneficial for improving the gradient differential sensitivity limit of the SERF magnetic field measurement device.

This invention relates to the field of electronic measurement technology and discloses an online measurement method and system for the quality factor of resonant circuits. The method involves injecting a small-amplitude sinusoidal disturbance signal into the excitation end of the resonant circuit under test using weak electromagnetic coupling, extracting the amplitude and phase of the disturbance response using lock-in amplification technology, performing Lorentz fitting on the frequency response curve to calculate the negative 3 dB bandwidth, outputting the quality factor in real time from the ratio of the resonant frequency to the bandwidth, introducing cross-correlation narrowband filtering to compress the equivalent noise bandwidth to below 1 Hz, and having an automatic resonant frequency tracking function.

The invention discloses a photo-thermal spectrum device and method based on orthogonal pseudo-random code modulation, and the device comprises a control and signal processing unit, a pseudo-random code generator, a laser driver, a tunable laser, a collimator, an air chamber, a focusing lens, a quartz tuning fork, a pre-amplifier, a data collector, and a related demodulator. A pseudo-random code sequence with good self-correlation and cross-correlation characteristics is used for carrying out binary orthogonal modulation on laser intensity, and weak photo-thermal signals are extracted from strong noise through a correlation demodulation technology. The method has the advantages that the method is insensitive to narrow-band noise due to the broadband modulation characteristic, any noise irrelevant to pseudo-random codes can be effectively suppressed by relevant calculation, and the method has extremely high anti-interference capability; related processing is equivalent to long-time energy accumulation, and the noise bandwidth can be compressed; the broadband characteristic of the pseudo-random code enables the pseudo-random code to cover the drift range of the resonant frequency of the quartz tuning fork, and the system is higher in adaptability to environmental changes and higher in stability.

Disclosed are a power-efficient continuous-discrete time hybrid delta-sigma capacitance-to-digital converter for capacitance measurement and an operation method thereof. The power-efficient continuous-discrete time hybrid delta-sigma capacitance-to-digital converter for capacitance measurement proposed in the present invention comprises: a continuous-time capacitance-to-voltage converter which reduces a total noise bandwidth by using anti-aliasing characteristics, and converts an input capacitor value into a voltage; a discrete-time switched-capacitor integrator which receives the voltage, increases power efficiency by using a floating inverter amplifier (FIA), and performs an integration operation; a second-order noise-shaping SAR ADC which quantizes an output of the discrete-time switched-capacitor integrator; and a DSM C-DAC which provides third-order noise-shaping characteristics, increases resolution, and constitutes a DSM loop.

This application discloses a method, apparatus, device, and storage medium for generating order spectra, belonging to the field of fault diagnosis for rotating machinery. Under variable speed conditions, this application can generate high-quality order spectra. Specifically, this application converts the time-domain signal into an angular-domain signal through angular-domain resampling, and then performs time-frequency analysis on the angular-domain signal. This processing eliminates the influence of speed variations on order analysis. After time-frequency analysis of the angular-domain signal, a high-quality order spectra can be generated without energy smearing, facilitating fault diagnosis of rotating machinery by engineers. Furthermore, this application no longer relies on experience to select the window length, but determines the window length based on the equivalent noise bandwidth of the window function and the target order resolution. Because the method of determining the window length is more reasonable, the generated order spectra have higher quality stability.

The invention relates to a device for reducing tinnitus. According to the invention, the characteristics of the tinnitus—frequency, noise bandwidth before and after the frequency, slope before and after the frequency, and masking level—are transmitted to a programmable signal processing component (2). This component transforms the frequency envelope of a sound source by adding a gain corresponding to the frequency envelope of the tinnitus and then transmits the signal to the person's ear. An application allows the tinnitus characteristics to be modified. In one particular configuration, if the person with tinnitus has associated hearing loss, the programmable signal processing component takes the hearing loss data into account to compensate for it. In another particular configuration, the device does not use an external sound source and can also create soothing sounds that perfectly match the tinnitus noise.A smartphone app allows you to adjust the noise. Figure to be published with the abbreviation: figure 1.

The embodiment of the invention provides a signal processing method and device, and the method comprises the steps: obtaining a first radio frequency signal, and carrying out the down-conversion processing of the first radio frequency signal, and obtaining a baseband signal corresponding to the first radio frequency signal; converting the baseband signal into a frequency spectrum value in a frequency domain corresponding to the baseband signal by adopting a preset frequency domain conversion algorithm; determining a noise threshold value according to the frequency spectrum value in the frequency domain; comparing the noise threshold value with the frequency spectrum value in the frequency domain, and determining a noise bandwidth area and a target signal bandwidth area; according to the method, noise signals in a noise bandwidth area are filtered, target signals in a frequency domain corresponding to a target signal bandwidth area are obtained, the target signals in the frequency domain are converted into baseband signals in a time domain, final required target signals are obtained, the boundary of the signals and noise can be accurately identified through frequency domain analysis, and the accuracy of the target signals is improved. More accurate filtering is realized, and the filtering accuracy is improved.

This application provides a method for dynamically adjusting the output gain of a sound card, relating to the field of audio signal processing technology. The method includes: separating the components of the sound card's output signal through harmonic extraction and noise analysis; calculating the harmonic-to-noise ratio and comparing it with a preset threshold to identify the air-sound mode; dynamically evaluating the proportion of harmonics and noise in the total signal energy; adjusting the energy classification criteria based on the noise bandwidth, tilting towards harmonic energy; and calculating and applying the target gain of the harmonic components, replacing the uniform boosting method based on total energy. The beneficial effects of this application are: by identifying the harmonic-to-noise ratio and adaptively classifying the bandwidth, it accurately boosts the harmonic level in the air-sound mode, avoiding the contradiction of simultaneous amplification of harmonics and broadband airflow noise in the traditional uniform gain mode, achieving a dynamic balance between improving vocal clarity and suppressing noise, and significantly optimizing the intelligibility and quality of the sound card's output signal in the air-sound mode.