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.

The present invention provides an airflow control loop that uses averaged airflow measurements without the problems that are normally encountered with averaging measurements, such as the delay introduced into the airflow control loop. This is accomplished, in the present invention, through a predictive control scheme. The predictive control scheme of the airflow control loop calculates the damper sensitivity, calculates the damper runtime needed to achieve setpoint, and then runs the damper for the determined period of time. In addition to the unique airflow control loop used to maintain the constant airflow into the room, the present invention also implements a digital form of proportional, integral, and derivative (PID) control to maintain the room temperature. The digital form of PID control uses non-linear gains which vary according to how far the measured temperature is from setpoint.

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.

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.

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.

The present invention relates to a lineariser for use with an amplifier. The lineariser comprises an input means and an output means. Input matching means are provided to receive an input signal. A transistor is provided, said transistor being arranged to operate substantially close to a switched on condition. The transistor is arranged to apply a non-linear gain to said input signal. The output means output the non-linear gain signal to said amplifier. The lineariser may be used with a RF power amplifier. The lineariser may be used in elements of a communication system.

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 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.

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.

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 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.

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.