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373 results about "Linear variation" patented technology

Method for classifying and compensating nonlinear variation of core boards for manufacturing multilayer circuit boards

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.
Owner:ZHUZHOU CSR TIMES ELECTRIC CO LTD

Hall position sensor-based position estimation and compensation method for permanent magnet synchronous motor

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.
Owner:DONGFANG ELECTRIC CORP LTD

Calibration method of time division-synchronization code division multiple access (TD-SCDMA) terminal

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.
Owner:SPREADTRUM COMM (SHANGHAI) CO LTD

Variable gain amplifier and variable gain amplifier module

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.
Owner:ELECTRONICS & TELECOMM RES INST

Analogue self-calibration method and apparatus for low noise, fast and wide-locking range phase locked loop

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.
Owner:MARVELL ASIA PTE LTD

Sound volume regulating method

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.
Owner:HISENSE BROADBAND MULTIMEDIA TECH BVI
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