45 results about "Joint frequency" patented technology

The present invention provides an apparatus and method of multiple antenna receiver combining of high data rate wideband packetized wireless communication signals, where the apparatus includes M receive antennas, receiving M high data rate wideband packetized wireless communication signals, where each of the signals includes N frequency bins. The apparatus, in an exemplary embodiment, includes (1) a joint timing recovery units that perform joint coarse signal timing estimation, joint frequency offset estimation, and joint fine timing estimation on each of the signals, (2) M Fast Fourier Transform units (FFTs) that each convert the digital data for each of the M signals into frequency domain information for each of the N received frequencies and that output Q pilots for each of the signals, where Q is a positive integer, and (3) a combiner that weights and combines the outputs of the M FFTs for each of the N received frequencies.

Traditionally, echo cancellation has employed linear adaptive filters to cancel echoes in a two way communication system. The rate of adaptation is often dynamic and varies over time. Disclosed are novel rates of adaptation that perform well in the presence of background noise, during double talk and with echo path changes. Additionally, the echo or residual echo can further be suppressed with non-linear processing performed using joint frequency-time domain processing.

The invention discloses a method and a device for maximum likelihood frequency offset estimation based on a joint pilot frequency. The method and the device are used for reception synchronization of a multi-input multi-output (MIMO)-orthogonal frequency division multiplexing (OFDM) system. The method comprises the following steps: a receiving end preprocesses a corresponding nth transmission pilot symbol matrix D(n), a discrete Fourier transform (DFT) matrix F, and a matrix W(wavy line) composed of the first L columns of the matrix F to obtain a matrix P(n); the receiving end respectively and correspondingly stores a receiving pilot symbol matrix R(n) and the matrix P(n) in first-in-first-out sliding window memories with the length being M; and M frequency offset matrixes are constructed, the receiving pilot symbol matrix R(n) and the matrix P(n) are acquired from the sliding window memories, a likelihood function is calculated according to the receiving pilot symbol matrix R(n), the matrix P(n) and the M frequency offset matrixes, and frequency offset estimation values to be selected are substituted in the likelihood function to obtain a frequency offset estimation value, which makes the accumulation of values of the likelihood function minimum, as the final maximum likelihood frequency offset estimation value.

The invention provides a direct current transmission system and generator set joint frequency modulation starting method. A direct current transmission system and a generator set are started according to the frequency deviation delta f of an alternating-current system to realize joint frequency modulation, wherein the starting comprises the high-frequency starting mode and the low-frequency starting mode; if the frequency deviation delta f is greater than zero, then direct current transmission system and the generator set are started in the high-frequency starting mode; and if the frequency deviation delta f is less than zero, then the direct current transmission system and the generator set are started in the low-frequency starting mode. Compared with the prior art, according to the direct current transmission system and generator set joint frequency modulation starting method provided in the invention, the primary frequency modulation capability of the generator set and the modulation function of the direct current transmission system are utilized comprehensively, the problem that a lot of spare capacity needs to be increased when frequency modulation is performed by only relying on the generator set can be avoided, and at the same time, the power changing amount of the direct current transmission system is limited through coordination frequency control, so frequent switching of the direct-current two-end alternating-current filter can be avoided, so that the economy of the direct current transmission system can be improved.

The invention discloses a multi-machine parallel virtual synchronization control system and method for a cascade energy storage system. According to the three-phase voltage of each cascaded energy storage converter, a grid active power given command, as well as the current power of the thermal power unit, the active power is calculated and obtained; the active power and the active power change aresuperposed to obtain the total active power given value, and then the average modulation voltage and the equalization control voltage components of the power conversion unit are superposed to obtainthe total modulation voltage. finally, the pulse driving signals of each power device are calculated. The invention realizes the high-voltage direct-hanging parallel connection of multiple cascaded energy storage converters to the joint frequency modulation operation of the low-voltage side of the high-power transformer and the thermal power unit of the thermal power plant, and has the advantagesof virtual synchronous friendly operation of multiple machines in parallel, high-capacity, high-efficiency and fast response, bi-directional charge-discharge regulation, highly self-balanced control,high power quality and convenient centralized dispatching frequency modulation.

Systems, devices, processors, and methods are described for joint detection of frequency and unique word (UW) location(s) for burst transmissions. Embodiments receive a wireless signal. Frequency detection is performed, resulting in multiple possible frequency correlation peaks. A subset of the correlation peaks are each used to perform trial frequency corrections, thereby generating a set of trial sequences. A UW correlation is performed on each of the trial sequences to generate a maximum UW correlation value for each trial sequence. The UW correlation value and the frequency correlation peak value are weighted and combined to generate a joint detection correlation value. The trial sequence having largest joint detection correlation value may indicate the correct transmission frequency and UW location. The jointly detected information may then be used to identify the frequency and start time of the burst transmission, which may then be demodulated, decoded, etc. to recover its payload data.

The invention discloses a joint frequency modulation control strategy for improving a frequency of an AC / DC grid-connected system in a wind power plant. The joint frequency modulation control strategyproposes a method employing energy storage and flexible DC additional control to participate in system frequency adjustment for improving main grid frequency, and comprises the steps of: firstly, adding flexible DC frequency additional control based on wind power plant frequency variation into a flexible DC converter station at the wind power plant side, and preferentially improving the frequencyproperty of the wind power plant by utilizing the features of high transmission power and capability of short-time overload operation of flexible DC power transmission; and secondly, parallelly connecting an energy storage system on a DC line between the wind power plate and a main grid by means of a current converter, and compensating for the frequency deterioration effect of the DC additional control at the wind power plant on the main grid. The joint frequency modulation control strategy preferentially improves the frequency properties of the wind power plant, ensures the safe operation ofthe wind power plant, and improves the frequency properties of the main grid.

The invention discloses an electric press plier which comprises a shell, wherein a switch is arranged on the shell, the inside of the lower end of the shell is provided with a power supply and a circuit control device, the inside of the upper end of the shell is provide with a motor and a speed reducer, a drive gear is arranged on an output shaft of the speed reducer and mutually matched with a driven gear fixedly arranged on a screw barrel, the screw barrel is sleeved on a screw in the shell and mutually and helically matched with the screw, a knocking block is arranged on the screw, the shell is internally and respectively provided with a front stroke switch and a rear stroke switch which are mutually matched with the knocking block, a digital display device is arranged on the rear end of the shell, and the front end of the screw is mutually matched with a plier assembly arranged at the front end of the shell. The invention has the advantages of avoidance of structural defects of hydraulic compression joint, convenience for compression joint, small volume, light weight, convenience for carrying, high automation, convenience for use and management because the compression joint frequency is measured by a control system and displayed by the digital display device, and the like.

Systems, devices, processors, and methods are described for joint detection of frequency and unique word (UW) location(s) for burst transmissions. Embodiments receive a wireless signal. Frequency detection is performed, resulting in multiple possible frequency correlation peaks. A subset of the correlation peaks are each used to perform trial frequency corrections, thereby generating a set of trial sequences. A UW correlation is performed on each of the trial sequences to generate a maximum UW correlation value for each trial sequence. The UW correlation value and the frequency correlation peak value are weighted and combined to generate a joint detection correlation value. The trial sequence having largest joint detection correlation value may indicate the correct transmission frequency and UW location. The jointly detected information may then be used to identify the frequency and start time of the burst transmission, which may then be demodulated, decoded, etc. to recover its payload data.

The invention provides a joint frequency offset estimation method and a joint frequency offset estimation system. The joint frequency offset estimation method comprises the following steps: S1, compensating a frequency offset estimation value using SSB or TRS; S2, after the compensated signal is subjected to intermediate processing, a channel estimation module being executed; S3, executing an MIMOdetection module on a result after channel estimation; S4, performing frequency offset attempt on a result after MIMO detection; S5, storing the signals modulated by the sending end, and taking the stored signals modulated by the sending end as entry data of a frequency offset attempt module; and S6, acquiring the MIMO detection signal after frequency offset adjustment. The SSB and TRS referencesignals are periodic reference signals, a certain error exists in frequency offset estimation, frequency offset attempt is introduced into the detection module to perform joint frequency offset estimation, and the precision of frequency offset estimation is further improved.

An audio signal processing apparatus and an audio signal processing method thereof are provided. The audio signal processing apparatus is configured to receive an audio signal and divide the audio signal into a plurality of frames. The audio signal processing apparatus is also configured to apply Fourier Transform on each of the frames to obtain a plurality of acoustic spectra. The audio signal processing apparatus is also configured to apply Fourier Transform again on each of component combinations corresponding to respective acoustic frequencies in these acoustic spectra to obtain a two-dimensional joint frequency spectrum. The two-dimensional joint frequency spectrum has an acoustic frequency dimension and a modulation frequency dimension. The audio signal processing apparatus is also configured to calculate at least one feature of the audio signal according to the two-dimensional joint frequency spectrum.

The invention relates to the technical field of Internet advertising and particularly to an advertising method for real-time joint frequency control in combination with conventional advertising based on redirection. The method comprises the following steps: S101, real-time data acquisition; S102, user information recording; S103, activity monitoring data analysis; S104: advertising activity integration; and S105, joint activity adjustment. The method associates a conventional advertising activity with an Internet programmed advertising activity, optimizes advertising activities in real time, reduces the number of unnecessary non-TA exposure times, can improve the click rate and conversion rate of the activities, and makes the activities highly efficient. Customers can obtain the data of the activities anytime and can modify advertising strategy in real time.

An audio signal processing apparatus and an audio signal processing method thereof are provided. The audio signal processing apparatus is configured to receive an audio signal and divide the audio signal into a plurality of frames. The audio signal processing apparatus is also configured to apply Fourier Transform on each of the frames to obtain a plurality of acoustic spectra. The audio signal processing apparatus is also configured to apply Fourier Transform again on each of component combinations corresponding to respective acoustic frequencies in these acoustic spectra to obtain a two-dimensional joint frequency spectrum. The two-dimensional joint frequency spectrum has an acoustic frequency dimension and a modulation frequency dimension. The audio signal processing apparatus is also configured to calculate at least one feature of the audio signal according to the two-dimensional joint frequency spectrum.

The invention discloses a symmetrical frame-based carrier synchronization method. The method comprises steps: 1, a pilot block and a data block are generated; 2, a data frame structure is set; 3, signals are sent at a sending end; 4, joint frequency phase offset estimation is carried out at a receiving end; 5, frequency phase offset correction signals are demodulated; and 6, Turbo code decoding is carried out. Defects that frequency offset estimation and phase offset estimation cannot be decoupled in the prior art, and influences on error code performance by large residual frequency offset cannot be effectively solved are overcome, and through arranging the symmetrical data frame structure, the problem of coupling the frequency offset estimation and the phase offset estimation in the case of joint frequency phase estimation can be solved, and the influences on the estimation performance by the large frequency offset can be reduced; and defects that the bit error rate for decoding is influenced as influences of phase offset cannot be cancelled in the case of frequency offset estimation are also overcome, and through carrying out Turbo code decoding on signals after demodulation of the symmetrical frames, the outputted code is obtained, and the bit error rate for decoding is reduced.

The invention discloses an electric press plier which comprises a shell, wherein a switch is arranged on the shell, the inside of the lower end of the shell is provided with a power supply and a circuit control device, the inside of the upper end of the shell is provide with a motor and a speed reducer, a drive gear is arranged on an output shaft of the speed reducer and mutually matched with a driven gear fixedly arranged on a screw barrel, the screw barrel is sleeved on a screw in the shell and mutually and helically matched with the screw, a knocking block is arranged on the screw, the shell is internally and respectively provided with a front stroke switch and a rear stroke switch which are mutually matched with the knocking block, a digital display device is arranged on the rear end of the shell, and the front end of the screw is mutually matched with a plier assembly arranged at the front end of the shell. The invention has the advantages of avoidance of structural defects of hydraulic compression joint, convenience for compression joint, small volume, light weight, convenience for carrying, high automation, convenience for use and management because the compression joint frequency is measured by a control system and displayed by the digital display device, and the like.