90 results about "Nonlinear noise" patented technology

A perforated plate flow conditioner includes a central hole; and at least one outer array of alternating large outer holes and small outer holes, wherein the difference between the diameters of the holes in the array is between 0.25% and 25% of the large hole diameter. In an alternate embodiment, the conditioner further includes an inner array of alternating large inner holes and small inner holes, and wherein no two adjacent holes have the same diameter. In another alternate embodiment, the conditioner has no central hole, and has an array of alternatingly-sized holes.

The invention relates to the field of manufacturing of semiconductor integrated circuits, in particular to a method for establishing a nonlinear noise model of a GaN HEMT (high electron mobility transistor). The method is characterized by comprising the following steps: S1, establishing a nonlinear equivalent circuit model of the GaN HEMT; S2, introducing noise sources into an intrinsic area in the nonlinear equivalent circuit model of the GaN HEMT to obtain expression formulae of three noise sources; S3, under different drain-source current bias conditions, acquiring a change relationship of a channel noise coefficient in the nonlinear equivalent circuit model of the GaN HEMT along with drain-source current; S4, according to the change relationship of the channel noise coefficient along with the drain-source current, acquiring an intact expression formula of a drain noise current source along with the drain-source current, and according to the three noise sources introduced into the nonlinear equivalent circuit model of the GaN HEMT, establishing the nonlinear noise model of the GaN HEMT. The nonlinear noise model of the GaN HEMT can simulate noise characteristics of a GaN HEMT device in a nonlinear state, namely, change of noise parameters of the device along with input power, and can be used for designing a GaN HEMT low-noise power amplifier.

An optical transport system configured to transmit a set of two or more optical variants per bit-word, with the optical variants in the set being different from one another in one or more of the time of transmission, spatial localization, polarization of light, carrier wavelength, and subcarrier frequency. Differences between the optical variants may also be due to different respective constellation mapping. The optical variants of each set are detected and processed at the receiver in a manner that enables coherent summation of the corresponding electrical signals prior to constellation de-mapping. The coherent summation tends to average out the deleterious effects of linear and nonlinear noise / distortions imparted on the individual optical variants in the optical transport link because said noise / distortions are incoherent in nature. A BER reduction enabled by the use of optical variants may be implemented in addition to or instead of that provided by FEC coding.

The invention provides a system and a method for reducing environmental noise as well as a device applying the system, and is particularly applied to a stereo radio module with at least two input terminals. The method comprises the following steps: respectively receiving audio frequency including a main audio frequency part and most part of the environmental noise; executing signal calibration in the system so as to reduce the difference between the input terminals; respectively obtaining an environmental noise part with less main audio frequency and a main audio frequency part with less environmental noise by virtue of adaptive beam forming and speech extraction technologies; after frequency domain transformation, estimating the environmental noise received by the system by virtue of a nonlinear noise suppression technology; obtaining a gain; denoising by means of the gain; and finally generating the continuously output audio frequency through carrying out domain transformation again. The system and the method as well as the device applying the same have the beneficial effects of effectively suppressing the environmental noise during call, improving the intelligibility and comfortability during the audio or speech communication process, preventing the call from being affected by too much noise, ensuring instant signal calibration, and maximally reducing the noise included in the audio frequency.

The invention provides an OFDM channel estimation method based on a depth feature fusion network, which comprises the following steps: S1, inserting a pilot into an original transmission signal; S2, the serial data stream of the transmission signal obtained in the step S1 is changed into a parallel data stream, and the transmission signal is OFDM modulated by the IDFT; 3, chan a transmission signal from a parallel data stream to a serial data stream; Transmitting to a receiving end via an OFDM channel; 4, aft receiving that transmission signal, the receive end changes the transmission signal from the serial data stream to the parallel data stream, and then demodulates the transmission signal by using the DFT; 5, chan a transmission signal from a parallel data stream to a serial data stream, inputting that transmission signal into a channel estimation model of a depth characteristic fusion network, and output the transmission signal fused by the channel estimation model; The invention can effectively recover the transmission signal in the OFDM channel under the condition of limited pilot frequency, CP removal and non-linear noise while ensuring the performance of channel estimation,thereby reducing the influence of data distortion and channel noise.

An optical transport system configured to transmit a set of two or more optical variants per bit-word, with the optical variants in the set being different from one another in one or more of the time of transmission, spatial localization, polarization of light, carrier wavelength, and subcarrier frequency. Differences between the optical variants may also be due to different respective constellation mapping. The optical variants of each set are detected and processed at the receiver in a manner that enables coherent summation of the corresponding electrical signals prior to constellation de-mapping. The coherent summation tends to average out the deleterious effects of linear and nonlinear noise / distortions imparted on the individual optical variants in the optical transport link because said noise / distortions are incoherent in nature. A BER reduction enabled by the use of optical variants may be implemented in addition to or instead of that provided by FEC coding.

An example system comprises a first antenna and a modem. The first antenna is configured to receive a signal from a transmitting radio frequency unit. The signal includes data and a known sequence. The modem is configured to retrieve the known sequence from the signal, transform the known sequence and the data into a frequency domain, calculate averages of groups of neighboring frequency points in the frequency domain to reduce the effect of nonlinear noise in the signal, the neighboring frequency points corresponding to the preamble in the frequency domain, compare the calculated averages to an expected frequency response in the frequency domain, determine a correction filter to apply to the data based on the comparison, apply the correction filter on the data in the frequency domain to create corrected data, transform the corrected data from the frequency domain to the time domain, and provide the data.

The embodiment of the invention provides a light signal to noise ratio monitoring device, a signaling device and a receiver; according to noise power and pilot signal power of a received signal on different polarization states, the white noise power of the received signal can be calculated, thus removing non-linear noise influences, and accurately estimating the light signal to noise ratio; the calculation process is simple and the application scope is wide.

The present invention provides systems and methods for highly efficient bit error rate (BER) modeling in quasi-linear communication networks. In the present invention, nonlinear noise is treated within a linearization approach along with the amplified spontaneous emission (ASE) noise, and the nonlinear noise is considered as another source of noise in addition to the ASE noise. This enables a quasi-analytical approach to the BER calculation. First, a covariance matrix is analytically computed. An equation is derived for a noise component of a signal and an implicit analytical solution is found depending on the signal and system parameters. Second, probability distribution functions (pdfs) are computed for the signal. An analytical calculation is performed of the characteristic function for the noise statistics. Next, a numerical computation of the Fourier transform of the characteristic function is performed to yield the pdf, and numerical integration is performed on the pdfs to yield the BER.

The invention discloses a voice control intelligent fan which comprises a motor driving the fan to rotate, a first microphone, a second microphone, a noise eliminating module, a voice storage module, a voice recognition module and a processor. By means of the voice control intelligent fan, the first microphone is used for obtaining a noise signal sent by the intelligent fan, and a voice instruction signal sent by a user is obtained through the second microphone; then a noise signal needing to be filtered out is simulated according to a nonlinear noise eliminating algorithm prestored in the noise eliminating module and the noise signal obtained by the first microphone, and the voice instruction signal obtained by the second microphone is filtered; and finally, the voice instruction signal obtained after the noise signal is filtered out is recognized through the voice recognition module, corresponding voice instruction information is obtained, voice instructions are executed by using the processor for controlling the intelligent fan, and therefore the intelligent fan can be controlled to work through voice, the intelligent fan can be used simply and conveniently, and the user experience is good.