270results about How to "Accurate frequency" patented technology

The frequency changes in a bang-bang PLL that are generated using a digital phase detector's up / down signal are initially set to produce a faster pull-in rate and then reduced to produce a slower pull-in rate. The faster pull-in involves relatively large frequency changes and the slower pull-in rate involves smaller frequency changes. The changes in frequency of a bang-bang PLL can be implemented using a step size controller that includes timing control logic and step size logic. The function of the timing control logic is to control the timing of step size changes. The function of the step size logic is to set the step size of the frequency changes that are made by the VCO in response to the pd_up / down signal that is delivered directly to the VCO from the digital phase detector.

A device and method for self-healing control of multi-level power grid system are provided in the present invention. The requirements to be satisfied by the present invention are that: realizing interaction and balance between power supplies and loads; controlling and coordinating cooperation coordination and cooperation between various distributed power supplies, micro-grids in multi-levels and their main grids; automatically distinguishing an on-grid state or an isolated island state of a locale grid; and guaranteeing energy supply to the maximum. The device for self-healing control of multi-level power grid is connected in one or more levels of power grids of the multi-level power grid system, and the device includes: a parameter acquiring and monitoring unit, a central processing unit, a human-machine interface and configuration parameter setting and inputting unit, and a regulating and controlling unit. Using frequency as an information carrier to characterize the connection state and the area coverage and grids levels included in the power system, the device enables the loads and the power supplies in the power grid system to distinguish the states of their localized grids by themselves, and performs to perform automatic switching or regulating according to preset strategies. Using frequency as information tie, the device balances supply and demand of power by self-adjustment between the power supplies and the loads in the system, and guarantees the automatic balance and stabilization of the power grid system both in the on-grid state and in the isolated island state.

A weight vector computing unit derives amounts of phase rotation for a plurality of multicarrier signals, respectively, and rotates the phase of a weight vector. A combining unit weights respectively a plurality of multicarrier signals with the phase-rotated weight vector, combines weighting results, and determines a combined result. A receiving weight vector computing unit remodulates the determined result and derives a first phase difference between the plurality of multicarrier signals and a result of the remodulation. The receiving weight vector computing unit remodulates the values of pilot signals and derives a second phase difference between the plurality of multicarrier signals and a result of the remodulation. Further, the receiving weight vector derives phase rotation amounts based on the first phase difference and the second phase difference.

Provided is a method of estimating a symbol. The method may include deriving phase components of input data, applying a second order differentiation to the phase components to obtain a second order differential phase vector, and estimating symbols corresponding to the input data using the second order differential phase vector.

A clip for use in a cushion for a seat is disclosed. The cushion includes a cushioned pad and a trim cover covering the cushioned pad, the cushioned pad having a recess portion and a wire embedded in the cushioned pad so as to be partially exposed to the recess portion from the cushioned pad, the trim cover having a portion, a longitudinal tensioning cord attached to the portion of the trim cover, a longitudinal bulged member provided along a longitudinal edge portion of the cord, and a laterally elongated through-hole formed in the cord. The clip comprises a frame body having a substantially U-shape in cross-section, the frame body including first and second spaced apart side portions and an intermediate portion interconnecting the side portions, a pair of spaced apart inverted-pawls provided at edges of both ends of the frame body so as to inwardly face each other, a hook portion provided on an outer surface of the intermediate portion, and a stopper piece provided on the first side portion of the frame body so as to stand up from the first side portion and extend beyond a space between the pawls toward the second side portion. The clip is adapted to be hooked between the bulged member and an exposed axial portion of the wire with the frame body receiving the bulged member therein and retainingly holding the bulged member, with the pawls being stoppingly engaged with the bulged member, with the stopper piece being inserted through the through-hole, and with the hook portion being hooked to the exposed axial portion of the wire, whereby the trim cover is tensioned and attached at the portion thereof to the cushioned pad by the clip. A vehicle seat wherein the trim cover is tensioned and attached at the portion thereof to the cushioned pad by a plurality of the clips is also disclosed.

A frequency synthesiser (100) has a first variable frequency oscillator (10) for generating a first oscillator signal having a frequency responsive to a first control signal, a second variable frequency oscillator (50) for generating a second oscillator signal having a frequency responsive to a second control signal, and a phase reference generator (40) for generating a phase reference signal. There is a phase difference generator (30) for generating a phase difference signal indicative of the phase difference between the sum of the phases of the first and second oscillator signals and the phase of the phase reference signal. A controller (60) responsive to the phase difference signal generates the first and second control signals. At least one of the first and second control signal are determined dependent on a value of the phase difference signal, and at least one of them are determined dependent on a further characteristic of a signal, the further characteristic being supplementary to the effect of any dithering introduced into the frequency synthesiser (100).

A fractional-N frequency synthesizer includes a voltage-controlled oscillator, a dual-modulus divider which divides an output frequency of the voltage-controlled oscillator according to a fractional control input, and a phase comparator which compares a phase of an output of the dual-modulus divider with a phase of a reference frequency, where an output of the phase comparator controls an input of the voltage-controlled oscillator. The synthesizer further includes a sigma-delta modulator which has a single-bit output, and a bit converter which converts the single-bit output of the sigma-delta modulator to the fractional control input applied to the dual-modulus divider.

Described herein is a method and system of distributed acoustic sensing, such as in an urban or metropolitan area involving a dedicated and established fibre optic communications network including a data centre. In general, the disclosed method and system includes the steps of (a) selecting an optical fibre cable installation having a path extending across a selected geographical area, the optical fibre cable installation including a bundle of optical fibres and forming part of a fibre-optic communications network, (b) determining characteristics associated with the optical fibre and / or the selected optical fibre installation, (c) transmitting outgoing light in the optical fibre, (d) receiving reflected light back scattered along the optical fibre, and (e) based on the reflected light and the determined characteristics, generating an alert signal representative of an acoustic event. The disclosed method and system may be useful in the detection of acoustic events near or within the selected geographical area.

The invention discloses a method for network voltage amplitude, frequency and phase angle detection based on the one-phase phase-locked loop algorithm. According to the method, accurate amplitude, frequency and phase angle detection is achieved when direct current offset and harmonic waves exist in a one-phase power grid. The method comprises the steps that a network voltage signal is acquired and transmitted to a delay phase-shifting module; the delay phase-shifting module receives a network voltage frequency value obtained from the last cycle at the same time and outputs a network voltage delay signal; subtraction is carried out on the acquired network voltage signal and the network voltage delay signal to obtain a result, and the result is divided by 2 to obtain a network voltage signal free of direct current offset; the network voltage signal free of direct current offset is taken as an input signal of an enhanced phase-locked loop, and then the network voltage amplitude value, frequency value and phase angle value of the cycle are obtained. The method for network voltage amplitude, frequency and phase angle detection based on the one-phase phase-locked loop algorithm is suitable for the field of conversion of electrical energy.

A frequency offset correction value estimation section (21) receives a signal including a predetermined fixed pattern from a transmission side, thereafter, selects a combination of fixed patterns used in a process of estimating a frequency offset is selected depending on the state of a channel, and an estimation result of the frequency offset calculated by the combination of the fixed patterns is output as a correction value of a determined frequency offset. A frequency offset correction section (22) receives the received signal obtained after the correction is performed for correcting a frequency offset of the received signal on the basis of the correction value, and an equalizer (23) demodulates the received signal by using a predetermined algorithm.

The invention provides a method and device for planning frequency and scrambling codes. The method comprises the following steps of: acquiring network parameter information and sweep frequency data in a planning region; constructing an interference matrix according to the network parameter information and the sweep frequency data, wherein the interference matrix comprises a same-frequency interference matrix and a scrambling code correlation matrix; distributing frequencies for each cell in the planning region according to the same-frequency interference matrix, and distributing scrambling codes for each cell in the planning region according to the scrambling code correlation matrix. By applying the scheme of the invention, the accuracy of frequency and scrambling code planning can be improved, namely, a frequency and scrambling code distribution mode with optimal overall interference level of the network can be acquired, so that the network quality and the user experience can be improved.

A method and apparatus for frequency-updating for procedure inlining. The frequency-updating scheme assumes the call graph of a program has no cycles. It keeps the frequency for each procedure as accurate as that before inlining. Using the present invention, the runtime performance of a source program by a compiler is improved. A source program is analyzed to generate a call graph of the source program, wherein each of the procedures has a first known execution frequency. The call graph is used in conjunction with inlining plans by an inlining algorithm to generate an inlined version of the source program wherein selected call sites have been inlined. An updated execution frequency is generated for each of the procedures and the updated execution frequency for each of the procedures is used to generate optimized executable code for the source program. In various embodiments of the invention, heuristics can be used to calculate cost / benefit ratios for calls in the procedures of the source program to generate a ranking of the call sites and to select calls in the subroutines for inlining. The selected calls are inlined until a predetermined resource limit has been reached. An updated execution frequency is computed each time any of the call sites is inlined. In an embodiment of the invention, the updated execution frequency of the procedures determined by proportional adjustment, wherein the ratio between a procedure's frequency and its statement frequency remains unchanged.

An OFDM receiver configured for measuring frequency error based on comparing prescribed pilot tones from a prescribed group of consecutive symbols in a received OFDM signal. A complex conjugate generator is configured for generating complex conjugates of the prescribed pilot tones of a first subgroup of the consecutive symbols. A multiplier is configured for generating a complex pilot product, for each symbol subgroup position, by multiplying the pilot tones of a second subgroup symbol at the corresponding symbol subgroup position with the respective complex conjugates of the first subgroup symbol at the corresponding symbol subgroup position. A complex summation circuit sums the complex pilot products of the symbol subgroup positions to obtain an accumulated complex value. A error calculator calculates the frequency error from the accumulated complex value for use in correcting frequency offset.

The present invention relates to a method and apparatus for correcting frequency offset of a local oscillator in a direct sequence spread spectrum receiver such as UMTS. Received signals comprise a plurality of sequential slots of data. At least one of these includes synchronization data. A correlation is performed between this received data and a locally stored synchronization code. Subsequently, the received data is phase adjusted and a further correlation performed between the phase adjusted data and the locally stored synchronization code. The strongest correlation peak is then determined and a phase offset to be applied to the local oscillator is estimated from the phase adjustment required to produce the strongest peak. This is subsequently applied to the local oscillator.

The invention discloses a real-time calibration and frequency measurement method for time base frequency and a device thereof, wherein the method comprises the following steps: 1) calibration step: a frequency measurement device acquires an external high-accuracy standard-frequency signal with Fs of given frequency as a calibration signal; the actual frequency value measured by the frequency measurement device is Fs'; a calibration factor K which is equal to Fs / Fs' is calculated and stored, and the calibration factor K can not be updated until the next calibration step is finished; 2) measurement step: the frequency of the unknown signal measured by the frequency measurement device is Fx', and the calculated and revised frequency value of the unknown signal Fx is equal to K * Fx'; 3) the process returns to step 1). The method and the device can ensure that, the time base frequency can be as accurate as 5E-10 and the second gate time frequency measurement can be as accurate as 1E-9 when measuring frequency and the accuracy of the measured frequency can be determined, thereby solving the problems of undetermined frequency timing base frequency accuracy, low precision, and the like of the prior art.

Provided are an orthogonal frequency division multiple assess (OFDMA) system and a method for controlling frequency offsets of subscribers in uplink communication. The OFDMA system solves a problem that the system performance is deteriorated in uplink communications because subscriber stations have different carrier frequency offsets. Each subscriber station compensates for a frequency offset thereof in response to a frequency offset control signal provided by a base station and then transmits an uplink frame to the base station. The base station compensates for an average frequency offset using the uplink frame, which has a small frequency offset shift because each subscriber station compensates for the frequency offset thereof previously, and thus the frequency offset of each subscriber station can be correctly compensated to prevent inter-carrier interference.

The invention provides an optical frequency comb generation device with the comb tooth frequency interval capable of being scanned. A signal generator form two output ends through a microwave power distributor, wherein the first output end is connected with a photoelectric phase modulator after passing through a first broadband microwave power amplifier, the second output end is connected with a photoelectric intensity modulator after sequentially passing through an adjustable microwave delay line and a second broadband microwave power amplifier, a continuous wave laser carries out output sequentially through the photoelectric phase modulator and the photoelectric intensity modulator , the photoelectric phase modulator and the photoelectric intensity modulator are cascaded, and the photoelectric intensity modulator has direct-current bias. The invention further provides an optical frequency comb generation method. According to the optical frequency comb generation device and method, broadband continuous frequency scanning and accurate arbitrary adjustment of the comb tooth frequency interval are achieved, a generated optical frequency comb is stable in phase, frequency and central wavelength, and tunable, the device is simple in scheme, and low in cost, and the optical frequency comb generation device and method meet the requirement for application in the fields such as the optical measurement field, the laser radar field, the laser spectroscopy field, the optical fiber sensing field, the optical communication field and the microwave photonics field.

The invention provides an excitation control device of a brushless doubly-fed motor independent power generation system and belongs to a power generation control device for a brushless doubly-fed motor. According to the technical scheme of the invention, the defects in the prior art that, an existing scalar control method is poor in dynamic performance and a conventional bisynchronous rotating reference frame is complicated in vector control, high in cost and low in efficiency can be overcome. According to the technical scheme of the invention, the device comprises a PW voltage magnitude controller, a PW voltage frequency controller, a CW current vector controller, an LC filter, a rotating speed calculator, a CW current frequency feed-forward amount calculator, a PW voltage phase-locked loop and a PW current converter. The CW current vector controller of a brushless doubly-fed motor is adopted as an inner ring, while the PW voltage magnitude controller and the PW voltage frequency controller of the brushless doubly-fed motor are adopted as an outer ring. In this way, the PW voltage magnitude and the PW voltage frequency are independently controlled. Meanwhile, a cross feed-forward compensation mechanism is adopted in the CW current vector controller, so that the device is faster in response rate and better in stability precision. The constant-frequency and constant-voltage generating function of the brushless doubly-fed motor independent power generation system in the speed-varying and load-varying condition is realized.

The invention discloses a color identification system and method. The color identification system comprises a white color light source module, a color collecting module, a single-chip microcomputer and an LCD displayer. The white color light source module comprises a white color light source and a sealing channel connected with the white color light source, and the light of the white color light source is irradiated on an object to be detected after passing through the sealing channel. The color collecting module comprises a color sensor and a condensing lens, the condensing lens is mounted in front of the color sensor, and the light reflected by the object to be detected is collected by the color sensor through the condensing lens. The color sensor converts collected light signals into digital signals and sends the digital signals to the single-chip microcomputer to carry out data processing, and HIS values and RGB values of different color modes are obtained and sent to the LCD displayer to carry out data display. The color identification system is simple in structure, low in achieving cost, high in precision, and suitable for personal use.

A plasma based deposition process to deposit thin film on the inner surfaces of the shaped objects such as plastic or metallic object like bottles, hollow tubes etc. at room temperature has been developed. In present invention uniform hydrogenated amorphous carbon (also called Diamond-Like Carbon, DLC) films on inner surfaces of plastic bottles is successfully deposited. Applications of such product include entire food and drug industries. There is a huge demand of polyethylene terephthalate (PET) or polyethylene naphthalate (PEN)) bottles, meant for the storage of potable water, carbonated soft drinks, wines, medicines etc. However, the higher cost prohibits their wide, spread use. The cheaper alternative is to use plastic bottles inside coated with chemically inert material such as Diamond-Like Carbon (DLC) will be commercially viable. Inventor process can be scaled up for mass production. This process can also be used for coating on inner surface of metallic cane or tube with a carbide forming interlayer (like hydrogenated amorphous silicon) to get the DLC films with better adhesion to inner surface of metals.

Position detection of a medical device is prevented from being impossible even when the frequency characteristic of a magnetic induction coil is varied in accordance with the state of an external magnetic field for guiding the medical device. A medical device position detecting system is a medical device position detecting system which is inserted into the body of a subject and guided by an external magnetic field, and it is equipped with a resonance circuit that is mounted in the medical device, contains a magnetic induction coil having a magnetic material inside and generates an alternate magnetic field, an alternate magnetic field detecting device that is disposed at the outside of an operation region of the medical device and detects the alternate magnetic field generated by the magnetic induction coil, a position information calculator for calculating position information of the medical device on the basis of the detected alternate magnetic field, and a frequency setting unit for setting at least one of the frequency of the alternate magnetic field detected by the alternate magnetic field detecting device and the frequency of the alternate magnetic field generated by the magnetic induction coil on the basis of at least one of the intensity and direction of an external magnetic field at the position of the magnetic induction coil.

A video decoder (52, 152) including a digital-control oscillator (DCO) (60, 160) is disclosed. The DCO (60, 160) includes a first flying-adder frequency synthesis circuit (74S) that measures an input signal frequency, such as the horizontal sync frequency of an input video signal. A frequency control word (FREQ) is generated in response to this input signal frequency, and is applied to a second flying-adder frequency synthesis circuit (74), which in turn selects the appropriate phases for leading and trailing edges of the output clock signal (PIX_CLK). Phase tuning of the output clock signal (PIX_CLK) can be effected by using an alternate flying-adder frequency synthesis circuit (74′) architecture, in combination with a phase signal (PH) generated by a digital controller (61). Multiple phase-tuned sample clocks (PIX_CLK_A, PIX_CLK_B, PIX_CLK_C) can be similarly generated from multiple flying-adder frequency synthesis circuits (174A, 174B, 174C), each controlled by the frequency control word (FREQ) and a corresponding phase signal (PHA, PHB, PHC). Video mode control logic (65, 165) can also be implemented by way of a similar DCO architecture. The DCO (60) may be used to generate a clock signal at a large frequency multiple relative to the input signal, outside of the video decoder context.

A communication semiconductor integrated circuit has an oscillator circuit forming part of a transmission PLL circuit fabricated on a single semiconductor chip together with an oscillator circuit forming part of a reception PLL circuit and an oscillator circuit for an intermediate frequency. The oscillator circuit forming part of the transmission PLL circuit is configured to be operable in a plurality of bands. A circuit for measuring the oscillating frequency of the oscillator circuit forming part of the transmission PLL circuit is also used for measuring the oscillating frequency of the oscillator circuit forming part of the reception PLL circuit or for measuring the oscillating frequency of the oscillator circuit for the intermediate frequency.

Using frequency characteristics determined for individual ones of a plurality of analyzed bands of a predetermined audio frequency range with frequency resolution that becomes finer in order of lowering frequencies of the analyzed bands, a synthesized band is set for each one or for each plurality of the analyzed bands, and then a time-axial response waveform is determined for each of the synthesized bands. The response waveforms of the synthesized bands are then added together to thereby provide a response waveform for the whole of the audio frequency range.

An image processing apparatus is provided with a halftone frequency determining section for determining a halftone frequency of an image data consisting of plural color components. The halftone frequency determining section is provided with a flat halftone discriminating section for extracting information of density distribution per segment block, and discriminating, based on the information of density distribution, whether or not the segment block is a flat halftone region in which density transition is low; a threshold value determining section for determining a threshold value by using an adjusting value that is predetermined in accordance with a reading property of the image reading apparatus with respect to respective color components, the threshold value being for use in extraction of the binary data of the pixel density; a maximum transition number averaging section for averaging the transition numbers of the binary data, the transition numbers being worked out by using the threshold value; and a halftone frequency estimating section for estimating the halftone frequency, based on the average. With this arrangement, it is possible to realize an image processing apparatus capable of performing highly accurate halftone frequency determination even for composite color halftone.

A frequency hopping signal receiving system comprising: a receiver for extracting discrete-time samples from the signal; a memory connected to the receiver for storing the extracted discrete-time samples from the signal; at least one processor operatively connected to the memory for: determining a state-space vector that captures relevant information to describe the dynamics of the signal; selecting a parameter to represent the probability of hopping associated with the signal; generating particle filters to estimate unknown parameters in the state-space vector based upon the extracted discrete-time samples by generating random particles that approximate the filtering distribution having importance weights; specifying the importance function in closed-form in a convenient mixture representation, which enables drawing particles and updating the importance weights; constructing an estimator to generate hop particles based upon observing at least one sample hop and then evaluating the estimator using a conditional expected value; using a spectrogram to generate particles in conjunction with an importance function; and estimating the hop frequency, hop time, and amplitude parameters, and a method thereof.