374 results about "Linear variation" patented technology

A circuit for controlling an LED with temperature compensation is employed in the LED-based system. The circuit of the invention linearly controls luminance and color of the LED according to temperature change and more precisely compensates for temperature-related variations in LED properties. Also, the circuit saves the cost of the product due to no requirement of a microprocessor. In the circuit, a waveform generator generates a sawtooth wave for Pulse Width Modulation (PWM) control. A temperature detector detects a voltage via a resistance value which is linearly variable according to changes in an ambient temperature. A PWM controller compares the sawtooth wave from the wave generator with the detection voltage from the temperature detector and generates a PWM voltage having a duty determined by the comparison result.

A differential compression method and computer program product combines hash value techniques and suffix array techniques. The invention finds the best matches for every offset of the version file, with respect to a certain granularity and above a certain length threshold. The invention has two variations depending on block size choice. If the block size is kept fixed, the compression performance of the invention is similar to that of the greedy algorithm, without the expensive space and time requirements. If the block size is varied linearly with the reference file size, the invention can run in linear-time and constant-space. It has been shown empirically that the invention performs better than certain known differential compression algorithms in terms of compression and speed.

An integrated device includes a voltage mode transmit driver for matching an output impedance to an output transmission line based on a binary code, an input termination module configured for matching an input impedance to an input transmission line based on an input impedance calibration value using thermometer-based decoding. The voltage mode transmit driver includes, for each differential output signal, a resistor network circuit having pull-up circuits and pull-down circuits for changing the voltage on the differential output signal, and having binary weighted resistance values relative to each other. The input termination module includes pull-up circuits and pull-down circuits having inverse hyperbolic resistance values relative to each other, and using thermometer-based decoding to ensure a linear change in input impedance during transitions in the input impedance calibration value. A calibration circuit generates the binary code and the input impedance calibration value based on replicas of the pull-up and pull-down circuits.

Alternate layers of wide band gap and narrow band gaps of different kinds of semiconductors are used to form multiple channels of a FET. The channels are doped or formed as 2-DEG / 2-DHG in narrow band semiconductor by charge supply layer in the wide band gap semiconductor. The different kinds of semiconductors form heterojunctions to confine the electrons / holes in separate thin spikes layers. A number of spikes (3-10 nm thick) of different doped or 2-DEG / 2-DHG concentrations in various channels can result in overall electron concentration gradient such as a 1 / x3 electron / hole concentrations profile. Such an electron / hole concentration gradient can result in a linear variation of drain current with voltage to obtain a wide dynamic range.

A circuit for controlling an LED with temperature compensation is employed in the LED-based system. The circuit of the invention linearly controls luminance and color of the LED according to temperature change and more precisely compensates for temperature-related variations in LED properties. Also, the circuit saves the cost of the product due to no requirement of a microprocessor. In the circuit, a waveform generator generates a sawtooth wave for Pulse Width Modulation (PWM) control. A temperature detector detects a voltage via a resistance value which is linearly variable according to changes in an ambient temperature. A PWM controller compares the sawtooth wave from the wave generator with the detection voltage from the temperature detector and generates a PWM voltage having a duty determined by the comparison result.

The invention discloses a method for classifying and compensating nonlinear variation of core boards for manufacturing multilayer circuit boards, which comprises the following steps of: A. classifying factors affecting the deformation of core board materials; B. designing a test pattern on an inner negative film; C. measuring the distance of the test pattern on the inner negative film; D. transferring the test pattern on the inner negative film to an inner core board; E. blackening and browning multiple layers of circuit boards; F. laminating the circuit boards, and measuring the distance of the test pattern on the inner core board after the lamination; G. calculating the expansion and shrinkage distance of the inner core board of the multilayer circuit boards; H. creating a compensation database in accordance with the classification of the step A, and optimizing the design dimension of the inner core board of the multilayer circuit boards. By using the technical scheme described in the invention, problems of deviation between layers and out-of-tolerance of expansion and shrinkage dimension appear during the lamination of the multilayer circuit boards can be solved, the dimension accuracy of the finished product and alignment accuracy between core board layers are improved, and the reliability of the product is improved.

A DC / DC converter has: a soft-start circuit generating a soft-start input voltage increasing gradually; an error amplifier generating an error signal by comparing an output voltage or a feedback voltage with a reference voltage or the soft-start input voltage, whichever is lower; a variable current generator generating a variable current proportional to the soft-start input voltage or a soft-start output voltage; a constant current source generating a bias current; an oscillator generating a rectangular-wave signal whose frequency varies linearly with a soft-start current which is the sum of the variable current and the bias current; a slope circuit generating a slope signal based on the rectangular-wave signal; a PWM comparator generating a PWM signal based on the error signal and the slope signal; and a control circuit switching transistors alternately based on the PWM signal. Through switching operation of the transistors, an input voltage is converted into the output voltage.

The invention relates to a three-phase sinusoidal voltage control driving system for a permanent magnet synchronous motor, in particular to a Hall position sensor-based position estimation and compensation method for the permanent magnet synchronous motor. The method comprises the following steps of: driving the permanent magnet synchronous motor to rotate at constant speed in a VVVF manner by a controller, and detecting a position signal transmitted back by a Hall sensor to obtain the distribution proportion of six position intervals under an electrical angle of 360 degrees; obtaining a position interval with a calculation number i according to the distribution proportion, and estimating a correction coefficient V[i] of an angle change value; and correcting T in an angle estimation formula 60*t / T to finally obtain a corrected angle estimation formula 60*t / (V[i]*T), wherein i is the number of the position interval, and V[i]*T in the corrected angle estimation formula is time actually required by the rotation of the motor by the position interval with the number i. A position angle change value calculated according to the formula in the interval always changes linearly within 0 to 60 degrees regardless of an electrical angle actually corresponding to the position interval.

Alternate layers of wide band gap and narrow band gaps of different kinds of semiconductors are used to form multiple channels of a FET. The channels are doped or formed as 2-DEG / 2-DHG in narrow band semiconductor by charge supply layer in the wide band gap semiconductor. The different kinds of semiconductors form heterojunctions to confine the electrons / holes in separate thin spikes layers. A number of spikes (3–10 nm thick) of different doped or 2-DEG / 2-DHG concentrations in various channels can result in overall electron concentration gradient such as a 1 / x3 electron / hole concentrations profile. Such an electron / hole concentration gradient can result in a linear variation of drain current with voltage to obtain a wide dynamic range.

A sprayable coating composition for a bare portion of an optical fiber that includes a refractive index grating having a characteristic wavelength response. A coating composition comprises a curable composition having a viscosity from about 0.05 Pa-sec to about 0.30 Pa-sec for spray application to cover the bare portion of the optical fiber, to protect the refractive index grating. A photoinitiator reacts with actinic radiation in the presence of oxygen to cure the curable composition covering the bare portion of the optical fiber. The characteristic wavelength response of the grating exhibits substantially linear variation between a lower limit of temperature and an upper limit of temperature when the curable composition has a glass transition temperature either above the upper limit of temperature or less than about 30° C. above the lower limit of temperature.

An object of the present invention is to enable the detection of a mixture ratio indicating the mixture state of a plurality of objects, such as a background image and a moving object image. A normal-equation adder 541 extracts mixed pixel data according to a motion, and also extracts background pixel data corresponding to the mixed pixel data so as to generate relational expressions for a designated pixel. A normal-equation calculator 542 detects the mixture ratio indicating the mixture state of the objects based on the relational expressions. The normal-equation adder 541 generates the plurality of relational expressions based on a first approximation in which foreground object components change substantially linearly, and a second approximation in which the mixture ratio changes substantially linearly. The present invention is applicable to a signal processing apparatus for processing images.

The invention aims at achieving the technical purpose of providing a phase-coherent accumulation detection method for a high-speed high maneuvering target. The method includes the steps that firstly, Keystone conversion is used for compensating for the distance moving of the target within a distance unit; secondly, the speed multiple of the target is obtained through traverse searching and is used for compensating for the distance moving of the target on distance units (the number of the distance units can be seen in the specifications), and therefore after the distance moving of the target is corrected, a target echo envelope peak value with the distance moving compensated for can be within one distance unit; thirdly, two-dimensional traverse searching is then used for estimating the radial acceleration and the acceleration rate of change of the target, Doppler moving of the target can be compensated for and eliminated, and the phase of echoes is in linear variation; finally, effective accumulation of energy of the target is achieved through the FFT.

A current regulator includes a first current source to provide a reference current varying with a dimming step, and a second current source to generate a drive current for a white LED according to the reference current. The reference current and the dimming step have a relationship identical to or approximating a relationship between luminance and lightness perceived by human eyes. Thus, the white LED is controlled to have a linear variation of the luminance perceived by human eyes when the dimming step is changed.

The invention discloses an electrocardiogram R wave detection method. The method comprises the following steps: filtering an input electrocardiogram signal by a band pass filter, and performing phase compensation; performing differential processing; performing data reduction on a differential signal by adopting linear variation; performing Shannon energy conversion by using a formula d(n)*d(n)*log(d(n)*d(n)); filtering by using an average filter, and performing phase compensation; detecting a maximum point and a minimum point, eliminating a fault R point, and correcting a falsely eliminated point to obtain a position of approximate R wave; and searching the position of true R in a range of periphery of the position of the approximate R wave + / - 25 points. By using the method, the problems of time delay and asystole detection unavailability in the conventional R wave detection method can be solved, and the method can be used for analyzing real-time electrocardiogram to reduce time delay and reduce required memory space, so that the accuracy rate is improved.

An audio communications system has an acoustic echo cancellation (AEC) module. The AEC module receives a digital signal sent to a loudspeaker and a digital signal received from a microphone. The signal received from the microphone contains an echo of the signal played through the loudspeaker. The loudspeaker signal is processed by an audio generation module (AGM) that models substantially nonlinear distortions that can occur while producing the signal played through the loudspeaker. The AGM includes a modeling path comprised of one or more distortion modules. Each distortion module receives digital samples as input, modifies the samples to model a form of distortion, and outputs the modified samples. The output of the AGM is provided to an acoustic echo estimation (AEE) module that uses adaptive algorithms to compensate for substantially linear changes in the echo characteristics of the environment in which the loudspeaker and microphone are located.

The invention discloses a variable gain amplifier (VGA) for linearity optimization at low gain, belonging to the technical field of analogue integrated circuits. The variable gain amplifier adopts pseudo-indexes to approximately realize linear variation by decibel. The variable gain amplifier is formed by a variable transconductance array, a bias current array, a digital control circuit, a transistor variable load connected with a diode, and a common-mode feedback circuit. The VGA realizes the variable gain of the VGA through changing the bias current of the variable transconductance and the variable load and realizes the linearity optimization when the gain of the VGA is low. Since the bias current of the variable transconductance array is very small at low gain, the variation of the width-to-length ratio effective value of the variable transconductance array does not have great impacts on the overall power consumption of the VGA. A circuit structure can be realized by using a CMOS technology.

Methods and apparatuses are disclosed for generating a temperature independent current limit. The value of the temperature independent current limit may be determined based in part on an error signal representative of a difference between an actual output value and a desired output value of a power converter. When the error signal is below a lower threshold voltage, the temperature independent current limit may be set to a first value. When the error signal is above an upper threshold voltage, the temperature independent current limit may be set to a second, higher value. When the error signal is between the lower threshold voltage and the upper threshold voltage, the temperature independent current limit may change linearly with the error signal. The error signal may be adjusted to compensate for changes in the system caused by a change in temperature.

The invention discloses a calibration method of a time division-synchronization code division multiple access (TD-SCDMA) terminal, which increases terminal calibration speed and enhances terminal calibration accuracy. The technical scheme comprises three aspects, namely automatic frequency control calibration, automatic gain control calibration and automatic power control calibration, wherein the automatic frequency control calibration comprises the following steps of: under the fixed input signal power of a signal source, changing a control word; demodulating to acquire data of a plurality of frames; calculating frequency information; and performing linear variation to acquire a step change value and an automatic frequency control initial value; the automatic gain control calibration comprise the following steps of: under the fixed input signal power of the signal source, changing the control word to acquire a plurality of groups of receiving signal intensity values, a gain value of a fixed gain module and a gain slope of a variable gain module; calculating input signal power and a gain value and combining automatic gain calibration tables; and the automatic power control calibration comprises the following steps of: transmitting a power list by gradually increasing or decreasing control words at a fixed periodic interval by using the terminal; acquiring data by using a frequency spectrograph; and selecting a power value and a control word.

The invention includes radar level-sensing device, feeding equipment and control system. The control system includes system for automatic controlling speed of feeding equipment of round roller, and system for automatic controlling extent of opening of assistant gate. The radar level-sensing device is installed in front of the feeding equipment. Measuring direction of the radar level-sensing device is faced to the feed opening of feeding equipment with nine rollers. When height of materiel measured by radar is in trend of linear variation, computer is connected to the radar level-sensing device directly. Using PACTware software to setup control value, the invention carried out real time control through automatic feeding method including longitudinal and lateral feeding methods. Features are: in high real-time, little investment about 1 / 10 investment of current automatic feeding equipment, and good reliability.

An analog variable gain amplifier (VGA) adjusting a signal level of a mobile communication system is provided. More particularly, design of a VGA using an operational transconductance amplifier (OTA) having a wide linear input / output range is disclosed. The VGA includes two double-differential-pair OTAs and feedback resistors. A first differential input of a first double differential pair OTA receives an input signal from the forward stage, and a second differential input is negatively fed back through a differential output and a passive resistor. An input in which a first block of the connection structure and first and second differential inputs of a second double differential pair OTA are connected receives an output signal of the first block stage. The output is negatively fed back in series through a variable resistor whose resistance varies exponentially with an adjustment voltage from outside. According to the VGA, it is possible to provide a characteristic of linear variation of gain on a logarithmic scale with respect to a control voltage with a simple and inexpensive constitution. In addition, the VGA can be designed for a low pass filter having a conventional OTA used for a core circuit, and has a simple circuit structure. Therefore, the VGA is convenient for high integration and low-power design, and thus is appropriate for a terminal chip and so forth.

A method and apparatus for a fast and automatic setting of the phase locked loop (PLL) output frequency that significantly improves linearity, locking range as well as spectrum purity, jitter and phase noise performances is disclosed. In one embodiment, a PLL frequency synthesizer is disclosed having a reconfigurable voltage controlled oscillator VCO with three modes of operation: a Linear-High-gain, Zero-gain, and Low-gain mode. During a first tuning operation, the VCO work in a linear high gain mode, enabling a totally analogue self-calibration of the PLL over a wide frequency tuning range and with a fast settling time. During this operation the control voltage at the input of the VCO is varied by the PLL until the appropriate output frequency is found. A method for providing a linear variation of the frequency over all the voltage tuning range during this mode is disclosed. When the loop is locked, the VCO is automatically switched to the Zero-gain mode while keeping its frequency unchanged. Its sensitivity to the noise in the control path is then practically eliminated and its phase noise performances significantly improved. If the frequency error and phase noise are sufficiently small for the considered application the tuning is stopped. If the error and phase noise are not sufficiently small the VCO is switched again to Low-gain mode and fine-tuning adjustment of the output frequency is achieved.

A DC supply slugging circuit includes a transistor switch and a switch control circuit connected between the grating and the drain of the switch and connected with the input supply, said switch control circuit adjusts the character of the junction capacitance between the grating and the drain of the switch to be expressed as linearity so that the voltage of the source and drain changes in linearity, which can realize that the output slugging voltage changes in fixed tilted ratio and the change is controlled and the instant striking current can be controlled accurately.

The invention discloses a linear slowly-changed memristor and a preparation method therefor. According to the memristor, a diffusion modulation layer which has a modulation effect on ion diffusion rate is inserted in the interface between an electrode and a resistive switching material. Different modulation effects on the formation of conductive thin wires of the memristor and the ion diffusion rate in the fusing place can be achieved through the inserted diffusion modulation layer, so that the optimization on the memristor characteristic can be realized, and the device can present the characteristics of continuous and linear changes of the resistance value and closer approach to biological synapse; meanwhile, the device has the advantages of low power consumption and compatibility between the preparation process and the conventional CMOS process; and therefore, the linear slowly-changed memristor is of great significance to the final implementation of neural network computing hardware.

An ethanol sensor based on a zinc oxide nanometer structure and a preparing method thereof are provided. The ethanol sensor comprises two electrode groups forming an interdigitated electrode and a zinc oxide nanometer film on at least one side surface of the interdigitated electrode. The zinc oxide nanometer film is formed by zinc oxide nanowires having a hexagonal wurtzite crystal phase. The two electrode groups of the interdigitated electrode are not conducted and form signal output ends of the ethanol sensor. The ethanol sensor can sense resistance reduction on the zinc oxide surface caused by ethanol absorption. The responsivity of the ethanol sensor is in approximate linear variation with the concentration of added ethanol gas in the environment.

The invention relates to a current regulator and a control method thereof. The current regulator comprises a current source and an intensity controller. The invention has the following characteristics: the current source can provide a driving current which is in direct proportion to ((L plus a) divided by b) n, wherein L is intensity; a, b and n are constants; the intensity controller determines the value of L and is used for generating a current to drive a white LED; and as the relation curve between the current and light-regulating steps is equal to or approximates to the relation curve between the brightness in the human eyes and the intensity, when the light-regulating steps are changed, the human eyes can observe that the brightness of the white LED is linearly changed.

The invention discloses a sound volume adjusting method, aiming at solving the problem of swiftly changed volume when changing a channel, in particular to the following steps: firstly determining a reference volume; secondly determining the volume adjusting coefficients of each set of program according to the reference volume; then utilizing the volume adjusting coefficients to adjust the current volume to get an actual outputted volume value and control a terminal receiving device to output an audio signal according to the actual outputted volume value. Meanwhile, in order to ensure that the actual outputted volume value varies linearly when the volume value gradually increases and reduces from 0 to 100 step by step, the invention also sets a volume adjusting correcting curve. The invention determines the curve slope of each section of curve through selecting a correcting node and measuring a correcting reference value and then gets a volume correcting value through carrying through linear correction on the current volume through a volume correcting function; therefore, when users and assembly line workers adjust the program volume, the invention can ensure that the increasing and reducing on the acoustical volume is linearly changed, thus effectively improving the listening effect of a terminal receiving device.

The invention provides a charge pump circuit used for a charge pump phase-locked loop, and belongs to the technical field of electronics. The charge pump circuit comprises a charge and discharge unit, a first complementary circuit unit, a first operational amplifier unit, a phase inverter unit, a second complementary circuit unit, a current mirror unit and a second operational amplifier unit. According to the charge pump circuit, the problems of charge and discharge current matching and charge sharing of an existing charge pump circuit are resolved, the two complementary circuit units and the two operational amplifier units are used, the two complementary circuit units achieve forward and reverse complementation for the charge and discharge unit, charge currents and discharge currents for capacitors keep constant, therefore the problem of charge and discharge current changing is resolved, capacitor voltage linear variation of a charge pump is achieved, and charging and discharging for the capacitors can be accurately controlled. The charge pump circuit is simple in structure, easy to integrate, high in charge and discharge current source matching precision, and suitable for being used in low voltage and low power consumption.

The invention relates to a method for generating a color chart, a color chart and a printer. The method is provided for generating a color chart for a printer, which color chart comprises a pluralityof elements. The method comprises obtaining reference color data representing colors output by the printer, when the printer is in a reference state. Further, comparison color data representing colorsoutput by the printer, when the printer is in another state is obtained. Differences in color between corresponding elements of the reference color data and the comparison color data are determined and at least one region of the output color space of the printer is classified as a linear region in which the differences vary substantially linearly. The method includes selecting colors of the elements of the color chart on the basis of the linear region.