116 results about "Nonlinear gain" patented technology

An on frequency repeater for wireless networks with feedback oscillation detection is disclosed. The on frequency repeater includes an automatic gain control loop which samples amplified signal envelope. The automatic gain control loop is monitored and a characteristic saw tooth pattern in the gain control loop indicating feedback oscillation is detected. A nonlinear gain expander circuit may be periodically activated to allow feedback oscillation detection in repeater applications employing linearized amplifiers.

A predistorter is disclosed that predistorts an input signal based on one or more static coefficients that are representative of a non-linear distortion characteristic of an amplifier. The input signal is also processed based on a non-linear gain parameter that reduces an error metric between the input signal and a feedback signal. The nonlinear gain parameter adapts an amount of nonlinearity introduced by the predistorter. The non-linear gain adaptation is performed, for example, when the input voltage is above a threshold input voltage. The input signal can be processed by multiplying the input signal by the non-linear gain parameter followed by table-coefficient processing, or by both multiplying the input by the non-linear gain parameter followed by dividing the table-coefficient processed output signal by the same non-linear gain parameter. The input signal can also be processed based on a feedback gain parameter that compensates for a small-signal gain of the feedback loop. The feedback gain parameter attempts to maintain a small-signal gain of approximately unity.

A predistorter is disclosed that predistorts an input signal based on one or more static coefficients that are representative of a non-linear distortion characteristic of an amplifier. The input signal is also processed based on a non-linear gain parameter that reduces an error metric between the input signal and a feedback signal. The nonlinear gain parameter adapts an amount of nonlinearity introduced by the predistorter. The non-linear gain adaptation is performed, for example, when the input voltage is above a threshold input voltage. The input signal can be processed by multiplying the input signal by the non-linear gain parameter followed by table-coefficient processing, or by both multiplying the input by the non-linear gain parameter followed by dividing the table-coefficient processed output signal by the same non-linear gain parameter. The input signal can also be processed based on a feedback gain parameter that compensates for a small-signal gain of the feedback loop. The feedback gain parameter attempts to maintain a small-signal gain of approximately unity.

The invention requests to protect a neural network nonuniformity correction method based on scene statistics, belonging to the infrared focal plane detection field. The invention provides the method aiming at the shortcoming that the traditional neural network correction method is difficult to eliminate low-frequency spatial noises. The method comprises the following steps: initializing image related matrices and parameters; detecting and compensating blind pixels according to the image pixel gray value; carrying out nonuniformity correction on image offset by a scene statistics method; judging the regional attributes of the pixels by a neural network correction method according to the standard deviation thresholds of correction errors, and carrying out nonlinear gain correction on the images which are corrected based on scene statistics and contain no low-frequency spatial noises. By the method, the correction effects of the desired image signals are good, target fade-out and ghostingare inhibited, and the changes of the background images hardly affect the correction effects. The method can be widely applied to image detection and processing.

The invention relates to the field of voice technologies, in particular to a self-adaptive denoising method based on sub-band noise analysis. The method includes the steps that firstly, framing and short time frequency domain transformation are conducted on input time domain audio signals with noise, and then frequency domain audio signals with noise are generated; secondly, a noise energy spectrum of the frequency domain audio signals with noise is estimated through a minimum value tracking method; thirdly, the posterior signal to noise ratio and the prior signal to noise ratio of the noise energy spectrum are calculated; fourthly, through a nonlinear gain extension method, denoising gains of all time frequency units are calculated through the posterior signal to noise ratio and the prior signal to noise ratio; fifthly, smoothing filtering is conducted on the denoising gains of all the time frequency units to reduce tone quality distortion; sixthly, the denoising gains act on all the time frequency units of the audio signals with noise in the first step, and then denoised frequency domain audio signals are acquired; seventhly, short time frequency domain inverse transformation is conducted, and then the final denoised time frequency audio signals are acquired and output. According to the method and system, stable noise in target signals can be greatly lowered.

An apparatus for controlling a volume of an audio signal and method thereof are disclosed, by which a volume of an input signal can be controlled by using a non-linear gain curve and a target volume of the input signal. The present invention includes storing a non-linear gain curve indicating relations between volumes of an input signal and an output signal; receiving an input signal and target volume information; determining a first gain by using the volume of the input signal and the target volume information; determining a second gain from one of a) the volume of the input signal and the target volume information or b) the first gain, by using the non-linear gain curve; and adjusting the volume of the input signal by applying the second gain to the input signal, wherein the non-linear gain curve is generated by using non-linearity information. A volume of an input signal of this invention is controlled using a non-linear gain curve indicating a relation between a volume of an input signal and a volume of an output signal. Therefore, the present invention is able to reduce or expand a dynamic range of an output volume.

The invention relates to a CDMA receiver power calibration and real-time correction device and the realization method thereof, and the method can be used for the power calibration and the real-time correction of terminal equipment such as the CDMA system, the base station facilities, and the road measurement meter. The method adopts a segment look-up table approach, and not only uses the fastness and simplicity of the look-up table approach but also combines segment treatment, thereby reducing the consumption of the storage room as much as possible. For linear gain section of a receiving link, i.e. the so-called big signal calibration, the look-up table approach is used directly; for non-linear gain section, i.e. small signal calibration, a noise compensation calibration method is adopted. The invention is used especially for the power calibration and the real-time correction of the massive equipment, and the power calibration method can meet the demand of automation and have the advantages of low cost, fast speed and high calibration precision.

An apparatus and method for processing an image by a wide dynamic range (WDR) process, and for obtaining an image having a wide dynamic area by using a WDR process. The method includes: receiving a long exposure image and a short exposure image having different exposure times; detecting a motion artifact area that may be occur when the long exposure image and the short exposure image are fused; generating a non-linear gain control short exposure image by non-linearly adjusting a gain of the short exposure image such that a luminance component of the short exposure image corresponds to a luminance component of the long exposure image; compensating for motion in the non-linear gain control exposure image based on the detected motion artifact area; and fusing the non-linear gain control short exposure image and the long exposure image to output an image to which a WDR process is performed.

A system and method for controlling a digital pulse-width modulated power converter achieves a fast large-signal transient response while maintaining a slow response near the steady-state operating point in order to assure stability and to reduce the system's susceptibility to noise. Digital output error samples are processed through a gain scheduling block that applies a non-linear gain function to produce a weak loop response when the system is near its steady-state equilibrium point and a strong loop response when large transients are encountered. The resulting system maintains a fast transient response to large error signals while reducing noise and loop jittering and assuring loop stability.

The invention discloses an all-fiber scroll optical laser based on the orbital angular momentum mode resonance, which has a ring cavity structure, and comprises a narrow linewidth pump laser, an optical amplifier, an orbital angular momentum mode generator, a first polarization controller, an optical fiber ring, an optical fiber coupler, a second polarization controller and a scroll optical fiber.The orbital angular momentum mode generator converts the fundamental transverse mode of a single-mode optical fiber into the orbital angular momentum mode of a specific topological charge in a vortexoptical fiber. The fiber coupler can realize the directional coupling of the orbital angular momentum mode in one scroll fiber to the orbital angular momentum mode in another scroll fiber. Vortex optical fiber is a kind of optical fiber which supports orbital angular momentum mode stable transmission. Based on Brillouin nonlinear gain of vortex fiber in ring cavity, the resonant amplification oforbital angular momentum mode in cavity is realized and vortex laser is output. The invention adopts an all-optical fiber structure, has good output vortex laser stability, narrow line width and highorbital angular momentum mode purity.

The invention provides a molecular beam epitaxy (MBE) growing method of a high-speed vertical-cavity surface-emitting laser. The method comprises the steps that deoxidation pretreatment is conducted on a GaAs substrate, and epitaxial growth of a GaAs buffer layer, a lower DBR, an active region, an oxidation confinement layer and an upper DBR is sequentially achieved; in the growth process, the active region is clamped between the upper DBR and the lower DBR, and a delta-doping method is adopted by the potential barrier middle position of the active region, wherein a doping source adopts carbon (C), and growth is stopped for a period of time under the protection of As after delta-doping is completed. By means of the method, the technical problems of reducing a threshold, increasing differential gain and reducing nonlinear gain compression are solved, and the good effects of reducing optical losses, decreasing line width and increasing output power and intrinsic bandwidth are achieved.

A method for displaying a gain control interface having a gain level display with non-linear gain levels. The gain level display has a first end having an associated first pixel offset value and a second end having an associated second pixel offset value. A range of pixel offset values span from the first pixel offset value through the second pixel offset value. The method includes receiving a plurality of pixel offset values in the range of pixel offset values, calculating a gain level value for each of the plurality of pixel offset values (whereby a difference between two pixel offset values of two gain level values having a gain level difference is not equal to a difference of two pixel offset values of any other two gain level values having the same gain level difference), and mapping a gain level value to a pixel offset value.

The invention relates to a design method for derivative controlling the gain switching ratio of an aerocraft pose dynamics simplified model, which adopts a nonlinear gain switching PD controlling scheme and allows two PD subcontrollers (a rapid PD subcontroller and a heavy damping subcontroller) designed with different parameters and complementary performance cooperatively function by stages according to switching rules designed. Meanwhile, on the basis of the guarantee of stability of an enclosed ring controlling system in the large, the step response of the system with no overshoot is realized, and the adjusting time of the step response is flexibly adjusted to meet the design requirements of rapidity. The technical scheme of the designing method comprises that: a first step, the structure of the enclosed ring controlling system is designed; a second step, a gain switching strategy section is designed; a third step: the gain parameters of two PD subcontrollers are designed; a fourth step: the rapidity of the step response is inspected and adjusted; a fifth step: the stability of an enclosed ring controlling system in the large is validated; a sixth step: the design is finished.

Certain embodiments relate to and involve producing broadband phase-locked frequency combs in the near-infrared and mid-infrared spectral ranges. One such embodiment is directed to a system, with a pump laser and an optical parametric oscillator (OPO) resonator, that is configured to produce broad-bandwidth frequency combs in the near-infrared and mid-infrared frequency ranges. The pump laser is configured to produce femtosecond pulses of light having a pulse repetition rate. The optical parametric oscillator (OPO) resonator that is coupled to the pump laser for facilitating synchronous OPO pumping by matching a roundtrip time of the pulses of light within the OPO resonator with the pulse repetition rate of the pump laser. Among other more specific aspects, the OPO resonator can include a nonlinear optical gain element to provide broad-bandwidth parametric amplification, and optical elements to direct the pulses of light from the femtosecond laser to the nonlinear gain element and to direct subharmonic frequencies of the light out of the optical cavity.

A method of processing an audio signal is disclosed. The present invention includes receiving, by an audio processing apparatus, an input signal; receiving user gain input; generating a linear gain factor and a non-linear gain factor using the user gain input; modifying the non-linear gain factor using absolute threshold of hearing and power of the input signal to generate a modified non-linear gain factor; and, applying the linear gain factor and the modified non-linear gain factor to the audio signal.

The invention discloses a Coriolis mass flow meter cloud transmission digital signal processing device and method. The device comprises a Coriolis mass flow meter, wherein the Coriolis mass flow meter is provided with two magnetoelectricity sensors, a driver and a constant flow source, the two magnetoelectricity sensors transmit collected signals to a differential amplification circuit corresponding to the magnetoelectricity sensors, the differential amplification circuit transmits processed signals to a DSP through an AD sampling circuit corresponding to the differential amplification circuit, and the driver is in communicating connection with the DSP through a feedback type digital driving module. According to the method, digital driving is conducted by means of the feedback type non-linear gain control algorithm fast and stably, frequency is tracked with the Newton LMS algorithm in an adaptive mode timely and accurately with the accuracy capable of reaching 0.01%, and the accuracy of calculation of phase difference achieved by means of the DTFT algorithm with a temperature compensation function can reach the 0.02% industrial level. Therefore, the digital signal processing algorithm is a Coriolis mass flow meter signal processing method with high accuracy and strong timeliness.

A control section for a current resonant converter section controls a DC output voltage of a current resonant converter section to settle to a target voltage by varying a resonant period between predetermined two resonant periods based on an error signal between the DC output voltage and the target voltage. A gain converter is provided in a preceding stage of a frequency generator for generating a square waveform signal with a duty ratio of 50% and the gain converter has a setting of a nonlinear gain characteristic that cancels nonlinearity in the input-output characteristics of the current resonant converter section. The nonlinear gain characteristic can be a characteristic of continuous gain conversion or discrete gain conversion.

An optical filter for correcting non-linear gains across a wavelength band includes a first layer having a first layer thickness according to the formula: first layer thickness=mlambd / (4nfirst), where m is an odd multiple integer, lambd is the central wavelength of the wavelength band, and nfirst is the refractive index of the first layer, and a second layer having a second layer thickness according to the formula: second layer thickness=lambd / (4nsecond), where lambd is the central wavelength of the wavelength band, and nsecond is the refractive index of the second layer. The optical filter introduces an insertion loss for wavelengths in a wavelength band of optical fiber transmission having an insertion loss curve approximating a quadratic shape in the wavelength band and having a maximum insertion loss at a central wavelength of the wavelength band.

The invention relates to an NSST domain flotation froth image enhancement and denoising method based on a quantum harmony search fuzzy set. The NSST domain flotation froth image enhancement and denoising method comprises the steps: carrying out NSST decomposition on a flotation froth image, and obtaining a low-frequency sub-band image and multi-scale high-frequency sub-bands; performing quantum harmony search fuzzy set enhancement on the low-frequency sub-band image; secondly, for the multi-scale high-frequency sub-bands, removing a noise coefficient by combining an improved BayesShrink thresholding and scale correlation, and enhancing an edge coefficient and a texture coefficient through a nonlinear gain function; and finally, performing NSST reconstruction on coefficients of the processed low-frequency sub-band and each high-frequency sub-band to obtain an enhanced de-noised image. According to the NSST domain flotation froth image enhancement and denoising method, the brightness, the contrast and the definition of the froth image can be improved, and the froth edge is obviously enhanced while noise is effectively inhibited, and more texture details are reserved, and subsequent processing such as froth segmentation and edge detection is facilitated.

The invention discloses an inner-cavity single-resonance optical parametric oscillator of a fiber laser pump. A pump source emits single-mode gain optical fiber to absorb pump light in a band, and after being focused by a coupling lens and passing through a dichroic mirror, the pump light enters the single-mode gain optical fiber. After the single-mode gain optical fiber absorbs the pump light, population inversion is formed, and laser oscillation is formed in a laser resonance cavity which is composed of a laser fully-reflecting mirror, the dichroic mirror and an SRO output mirror. A non-linear crystal is arranged in the resonance cavity of an optical fiber laser device, and nonlinear gain is provided. Signal light oscillation is formed in an SRO resonance cavity which is composed of the SRO output mirror and the SRO fully-reflecting mirror and is output by the SRO output mirror. According to the inner-cavity single-resonance optical parametric oscillator of the fiber laser pump, the single-mode optical fiber laser device is used as the pump light of an inner-cavity SRO, the pump source of the SRO is forced to operate in a fundamental transverse mode through the structural features of the single-mode gain optical fiber, and therefore the problems that since the heat effect in a traditional inner-cavity SRO causes degradation of the quality of a pump light beam and the degradation is difficult to compensate, the conversion efficiency of the SRO and the quality of the output light beam are influenced are solved.

The invention provides an ultra-narrow-linewidth nonlinear gain amplification multi-wavelength fiber laser, belongs to the technical field of photoelectric information and aims at solving the problem that an existing multi-wavelength fiber laser is large in output laser linewidth, complicated in system and poor in stability. The technical scheme is that light emitted by a high-power narrow-linewidthBrillouin pump is irradiated into a port a of an input / output circulator, and a port b of the input / output circulator is connected with a port j of a second coupler. A port m of the second coupler is connected with a polarization controller, and a port k and a port n are respectively connected with a port I and a port o of a single mode fiber. The polarization controller is connected with a reflection circulator. The other two ports of the reflection circulator are connected. A port c of the input / output circulator is connected with an Er-doped fiber, the Er-doped fiber is further connected with a first coupler, and the other two ports of the first coupler are connected. A port d of the input / output circulator is an output port. The ultra-narrow-linewidth nonlinear gain amplification multi-wavelength fiber laser has wide application prospect in the fields of dense wavelength division multiplexing optical communication systems, distributed optical fiber sensing and microwave photonics.

The invention discloses a hypersonic flight vehicle angle-of-attack observation method based on nonlinear gain. An angle-of-attack observation system is constructed by measuring the trajectory inclination angle of a hypersonic flight vehicle and the attitude angular rate of the flight vehicle. According to the error between the trajectory inclination angle and the trajectory inclination angle estimate and the error between the attitude angular rate and the attitude angular rate estimate, a nonlinear variable-gain error law is constructed to adjust the observed value of the angle of attack. The force and moment of the vehicle are estimated according to the observed value of the angle of attack to provide force and moment information for the observation system, and thus, the actual value of the angle of attack can be accurately estimated according to the observed value of the angle of attack. The method is different from the general vehicle angle-of-attack observation method in that there is no need to measure the height and speed of a flight vehicle and the observation system needs less information. Moreover, because of the variable-gain error adjustment law, the response of angle-of-attack observation is very quick, and the accuracy is high.

The present invention provides methods, systems, computer program products, and devices for renewable energy site power limit control that address conditions of plant saturation and loop delay. In an exemplary embodiment, power limit control of the present invention is broken into two levels of control: a site-wide real power limit control that produces a single site-wide command, SitePlimCom, for all inverters, and inverter-level power limit control that outputs a command, Inv[x].PlimCom[k], for individual inverters. In some embodiments, the invention has one or more of the following features: an integrator with nonlinear gains, limit based anti-windup, a power limit control term based on the sum of both integrator and feed-forward terms, and an inverter-level controller designed to meet slew rate and site power overshoot constraints. The invention can be used at any renewable energy site employing inverters wherein improved dynamic control performance is needed, including solar, wind, and tidal energy sites.

The invention relates to a nonlinear gain voltage conversion device for converting analog voltage output from an analog voltage source, comprising a gain determination module, a voltage selection module and a voltage output module; wherein, the gain determination module comprises an analog-digital converter coupled with the analog voltage source and a gain selector coupled with the analog-digital converter; the gain determination module is used to determine the output gain; the voltage selection module is coupled with the analog voltage source and the analog-digital converter to select a DC voltage from a plurality of DC voltages and output the DC voltage. The voltage output module is used to output the amplified results of the DC voltage output by the voltage selection module according to the output gain determined by the gain selector.

The invention provides a parameter estimation method for a low signal-to-noise ratio signal, which comprises the following steps of: processing a to-be-detected noisy signal by using a nonlinear stochastic resonance method, transferring noise energy to signal energy, and effectively recovering signal waveform information. The proposed segmented bistable stochastic resonance solves the classical stochastic resonance nonlinear gain problem, realizes the amplitude linear gain, and solves the amplitude gain coefficient. The signal frequency and amplitude information submerged by noise can be effectively extracted, the signal frequency and amplitude information can be accurately estimated in a low signal to noise ratio environment, and the method is a signal parameter estimation method which isremarkable in anti-noise effect and has good estimation performance.

A method and a device may be provided. The device may include a non-linear amplifying circuit arranged to apply a non-linear gain function on an analog signal to provide an amplified signal; an input circuit, arranged to clip I channel and Q channel digital input signals supplied from a digital transmitter, to provide clipped I-channel and Q-channel digital signals; a pre-distortion circuit, arranged to pre distort the clipped I channel and Q channel digital signals such as to at least partially compensate for a non linearity of the non linear gain function, to provide pre-distorted I-channel and Q-channel digital signals; a mixed signal circuit for converting the pre-distorted I-channel and Q-channel digital signals to the analog signal; a reconstruction circuit, arranged to receive at least a portion of the amplified signal and to generate reconstructed I-channel and Q-channel signals; and a control circuit, arranged to: calculate an error attribute based on (a) the clipped I-channel and Q-channel digital signals, and (b) the reconstructed digital I-channel and Q-channel signals; and to affect at least one operational parameter of the non-linear amplifying circuit in response to the error attribute.