摘要:
An automatic calibration method for use in an electronic compass. Using the automatic calibration method, the electronic compass automatically calculates and corrects offset and scale values of a geomagnetic signal by detecting one rotation of a geomagnetic axis during a predetermined period of time. The electronic compass calculates an azimuth angle upon receiving geomagnetic data from the geomagnetic sensor, and finds maximum and minimum values of sensor signals of individual axes of the geomagnetic sensor using the received geomagnetic data such that it can correct or calibrate deviation of the azimuth angle. When a time consumed for calibration is the same or shorter than a maximum calibration effective time, the electronic compass determines whether a current state of the detected entry signal indicates a predetermined steady-state flow. If the current state indicates the steady-state flow, at the same time a signal indicative of one rotation of the geomagnetic sensor is received, and the time consumed for calibration is longer than a predetermined minimum calibration effective time, the electronic compass calculates offset and scale values using the maximum and minimum values and stores the calculated offset and scale values.
摘要:
In a signal processor for use in an electronic compass for controlling an offset voltage generated in an analog signal process and automatically controlling an amplification gain, an analog signal processor 52 amplifies signals Sx and Sy, and controls an offset voltage and amplitude A generated during an amplification process. An analog/digital (AD) converter 53 converts analog signals Vadcx and Vadcy from the analog signal processor 52 into a digital signal. A digital signal processor 54 measures a maximum value Vadc—max and a minimum value Vadc—min associated with the digital signal from the AD converter 53, and outputs, to the analog signal processor 52, an offset control signal Soc and a gain control signal Sgc based on the maximum value Vadc—max and minimum value Vadc—min. The signal processor can maintain levels of signals, to be inputted into the AD converter, to be within a reference voltage range.
摘要:
A method of finding a dip angle in a tilt-compensated electronic compass includes the steps of a) setting a predetermined azimuth angle indicative of a horizontal status of a geomagnetic sensor to a reference azimuth angle; b) if the compass is slightly tilted, stepwise-increasing a dip angle within a predetermined dip angle search range, and calculating azimuth angles associated with individual dip angles; c) comparing the calculated azimuth angles with the reference azimuth angle, and finding one azimuth angle, which is closest to the reference azimuth angle, among the calculated azimuth angles; and d) setting the dip angle applied to the closest azimuth angle to a specific dip angle associated with a corresponding azimuth angle, such that a more accurate azimuth angle can be detected by the on the basis of the calculated dip angle.
摘要:
There are provided an apparatus for detecting coordinates, which may detect coordinates corresponding to an event occurring within a region of interest, and a display device, a security device, and an electronic blackboard, each including the same. The apparatus for detecting coordinates, which is provided in at least one side of a touch panel having a preset region of interest being surrounded by a frame having a predetermined length, the apparatus comprising: a light source body providing preset light; a scanner emitting the light provided from the light source body at a preset angle to scan the region of interest, and receiving light reflected by the region of interest; a photo diode receiving reflected light to convert the received reflected light to a voltage value; and a beam splitter transmitting the light provided from the light source body to the scanner via a first path, and transmitting, to the photo diode via a second path, the reflected light received from the scanner.
摘要:
An apparatus and method for orthogonal frequency division multiplexing (OFDM) channel equalization are disclosed. The apparatus includes a compensation value setting unit setting a compensation value in the form of a diagonal matrix by use of a diagonal matrix of diagonal elements extracted from a channel matrix of an OFDM receiver, and a preset divergence suppression value, an initial estimation value calculation unit calculating an initial estimate value by use of a fast Fourier transform (FFT)-processed signal of the OFDM receiver and the compensation value, an equalization unit detecting a transmission signal to be processed by use of the compensation value, the channel matrix and the diagonal matrix, and a symbol decision unit determining a symbol for an adjacent signal of a transmission signal, which is to be processed among a plurality of signals output from the equalization unit, and providing the symbol-determined adjacent signal to the equalization unit.
摘要:
An apparatus and method for orthogonal frequency division multiplexing (OFDM) channel equalization are disclosed. The apparatus includes a compensation value setting unit setting a compensation value in the form of a diagonal matrix by use of a diagonal matrix of diagonal elements extracted from a channel matrix of an OFDM receiver, and a preset divergence suppression value, an initial estimation value calculation unit calculating an initial estimate value by use of a fast Fourier transform (FFT)-processed signal of the OFDM receiver and the compensation value, an equalization unit detecting a transmission signal to be processed by use of the compensation value, the channel matrix and the diagonal matrix, and a symbol decision unit determining a symbol for an adjacent signal of a transmission signal, which is to be processed among a plurality of signals output from the equalization unit, and providing the symbol-determined adjacent signal to the equalization unit.