46results about How to "Good autocorrelation properties" patented technology

A radio frequency (RF) motion capture system includes stationary sensor receivers, one or more transmitter marker tags on one or more objects to be tracked within a capture zone, at least one stationary reference tag transmitter, and a processing system for processing the received signals. The individual tags transmit burst of spread-spectrum RF signals. The transmitted signals include a common sync code, and a tag identification code that is unique to each tag. By computing double differences of pseudoranges, clock terms are cancelled out allowing the processing system to precisely determine the location of each tag as it moves through the capture zone without the need to synchronize clocks between sensors and tags. The system can be used for RF match moving.

The invented method includes the following steps: 1). Inputting the selected parameter into high-speed DSP to produce chaos series; 2). Using chaos series to make frequency modulation to obtain chaos radar signal; 3). Dividing chaos radar signal into two lines, one line is passed through modulation unit and transferred to transmitter and transmitted, another line is transferred to pulse compression unit and can be used as reference signal; and 4). Transferring base band signal after the received return signal is down converted to the pulse compression unit to make pulse compression, then outputting said signal for making analysis.

The invention provides a method and an apparatus for restraining cross-correlation interference in GNSS. The invention comprises the following steps: step A, detecting and demodulating a strong signal in a receiving signal; step B, generating a spreading code synchronized to a certain strong signal; step C, carrying out segmentation on the receiving signal according to a certain length; step D, carrying out segmentation on the spreading code that is generated in the step B; step E, generating a set of orthogonal codes such as a Walsh code and a set of orthogonal codes with a certain length, for example, a set of Walsh codes; step F, generating a set of outputs after corresponding multiplication of an output of the step D with an output of the step E; step G, generating a set of outputs after corresponding summation of convolution by an output of the step C with the outputs of the step F; step H, generating a set of outputs after corresponding multiplication of the outputs of the step F with the outputs of the step G; step I, generating an output after accumulation of a set of data referring to the outputs of the step H; step J, carrying out merging of segments on the outputs of the step I and then generating an output. According to the invention, the method has low complexity of algorithm and the apparatus has a good comprehensive property.

The invention belongs to field of communication technique, especially a synchronization method in new wireless mobile communication system which can be used in OFDM modulating system of digital broadcasting TV system, wireless mobile communication system. The invention provides a new OFDM multi-carrier communication system synchronization method whose calculating complexity, performance is perfect. The method uses superposed pseudo-random sequence which possesses perfect relativity to protection band sub carrier, and pseudo-random sequence is distributed with weak energy, and the pseudo-random sequence and local sequence generate synchronization signal on receiving end. The invention is accurate, probability of synchronization is high, and performance of system can not be affected.

The invention relates to an MC-CDMA-based underwater acoustic communication system and a PAPR suppression method, and the method comprises the steps: enabling a transmitting end to code input data after mapping, carrying out the serial-parallel conversion of the input data into q sub-data streams bi, and copying the bit of each sub-data stream bi into Np parts; generating a chaotic sequence according to the number U of subcarriers, and circularly multiplying the chaotic sequence by the basic spread spectrum sequence to generate a chaotic composite spread spectrum sequence C; multiplying each sub-data stream bi by the chaotic composite spread spectrum sequence C, and converting the multiplied sub-data streams bi into time domain signals through IFFT; and calculating the peak-to-average power ratio PAPR of the system according to the frequency band signal after up-conversion sampling. According to the PAPR suppression method disclosed by the invention, by changing the generation mode ofthe spreading code, the chaotic sequence is cyclically multiplied by basic spreading sequences such as an M sequence, a Walsh sequence or a completely complementary CCS sequence to generate a chaoticcomposite spreading sequence, so that the peak-to-average power ratio suppression characteristic of the system is improved. Compared with an amplitude limiting method, the method does not cause in-band distortion and out-of-band leakage. Compared with a probability method, the method is simple in operation mode and low in operation complexity.

The invention discloses an establishment method for a real virtual staggered quadriphase sequence and a sequence set, an MSK/GMSK (Gaussian Minimum Shift Keying) synchronization method and an FBMC (Filter Bank Multicarrier)-OQAM spectrum spread system. The real virtual staggered quadriphase sequence and sequence set are established according to a binary sequence with high autocorrelation. The real virtual staggered quadriphase sequence can be generated by any binary sequence. The cycle of the generated real virtual staggered quadriphase sequence is two times of that of the original binary sequence. The maximum nontrivial autocorrelation function value of the generated real virtual staggered quadriphase sequence is two times of that of the original binary sequence. According to the real virtual staggered quadriphase sequence and sequence set obtained through adoption of above-mentioned establishment method, synchronization of a MSK/GMSK signal is realized; the optimum quadriphase sequence is applied to MSK/GMSK modulation, thereby obtaining the MSK/GMSK signal with an excellent autocorrelation characteristic; and the optimum quadriphase sequence can be applied to synchronization and channel estimation. The established real virtual staggered quadriphase sequence and sequence set also can be used as spectrum spread codes for spreading spectrum, a purpose of reducing a peak-to-average power ratio of an FBMC signal is achieved, a signal transmission rate is improved, and an FBMC-OQAM signal with the excellent autocorrelation characteristic is obtained.

The invention provides a potassium-bismuth titanate piezoelectric ceramic/native copper composite material and a preparation method thereof, relates to a composite material and a preparation method thereof, and aims at solving the problems of poor osteoconduction, single function and high price of the existing bone repair material. The composite material is prepared from potassium-bismuth titanate piezoelectric ceramic powder and native copper powder. The preparation method of the composite material comprises the steps of 1, preparing the potassium-bismuth titanate piezoelectric ceramic powder by a citrate hydrothermal method and then obtaining the potassium-bismuth titanate piezoelectric ceramic powder having the grain sizes ranging from 50nm to 200nm, 2, forging the native copper by a vinegar quenching method to obtain the native copper powder having the grain sizes ranging from 100 microns to 500 microns, and 3, preparing the potassium-bismuth titanate piezoelectric ceramic/native copper composite material through hot pressed sintering. The potassium-bismuth titanate piezoelectric ceramic/native copper composite material is applied to the bone repair field.

The invention provides a synchronous sequence sending method, and a synchronous detection method and apparatus. The sending method comprises the following steps: setting a target synchronous sequencewith good autocorrelation property, wherein at least a segment of sequence intercepted on the time domain or the frequency domain of the target synchronous sequence is a sub-synchronous sequence, thesub-synchronous sequence has good autocorrelation property, and the sub-synchronous sequences have good cross-correlation property; and sending the target synchronous sequence to a terminal. In the synchronous sequence sending method provided by the embodiment of the invention, for terminals with different bandwidths or terminals with different carrier intervals, after a base station side sends the same target synchronous sequence, the terminals can intercept the corresponding sub-synchronous sequences according to own requirements to perform synchronous detection, thereby not only ensuring the synchronous detection accuracy, but also improving the application range of the target synchronous sequence.

The invention discloses a synchronous data acquisition system and acquisition method based on LabVIEW and a sound card. The acquisition system comprises a LabVIEW upper-layer controller, the sound card, a loudspeaker, and a sound sensor, the sound card is connected with the LabVIEW upper-layer controller, the loudspeaker, and the sound sensor, the LabVIEW upper-layer controller generates a coding signal, an analog-to-digital converter for controlling the sound card transmits the data in a sound wave manner, the loudspeaker increases the amplitude of the sound wave signal, the sound sensor receives the echo sound signal and attenuates the amplitude to a certain value, and the LabVIEW upper-layer controller controls the analog-to-digital converter of the sound card to read the echo data and display the data after real-time processing. The most critical synchronization control technology is adopted in the data acquisition process to replace an expensive data acquisition device, the cost is low, the operation is simple, the versatility is high, and the acquisition system and acquisition method have wide application prospects in the fields of industrial automation, and test and measurement.

The invention relates to a voice data processing method for synchronizing information source voice data before vocoders. The method is characterized in that a manner of combining a pseudorandom sequence SYN1 and a single tone sequence SYN2 is used, and accurate synchronization of voice sample data of a circuit domain is realized. At an encoding end, L1+L2 original voice data are replaced with the sequences SYN1 and SYN2 respectively; at a decoding end, a coarse synchronization position is determined by solving the correlation peak of the SYN1, and an accurate synchronization position is determined by searching the cross-correlation peak of the SYN2. During mobile voice encryption communication, the lengths of the frames of various vocoders are different, the lengths and the starting points of information source encrypted frames and the vocoder frames are different, the truncation alignment deviation effect can be produced, the effect shows that the synchronous position might be leading or lagging, and thereby the voice encryption communication quality is affected directly. According to the method, the problem of the truncation alignment deviation effect is effectively solved, and the effect is remarkable.

The invention discloses an intelligent pipeline positioning device based on a coded signal. The device comprises a signal transmitter and a signal receiver. The signal transmitter comprises an encoder, a signal amplifier and an audio oscillator. The signal receiver comprises a vibration signal sensor, an analog-to-digital converter and a signal processor. An encodable signal with moderate frequency and outstanding autocorrelation characteristics is finally converted into a sound wave signal by means of a power amplifier, by controlling parameters such as the frequency of the encodable signal,the receiver can perform accurate analysis by means of various post-processing methods, information implied in the received signal can be extracted more easily, and technicians can judge the signal transmitted by the transmitter more reliably by means of a related analysis method more conveniently. According to the device, the signal propagation distance is greatly improved, and the accuracy and reliability of data interpretation by the technicians are improved.

The invention provides a waveform design method of an expanding zero-correlation zone; the method includes steps of forming a zero-correlation sequence by applying an initial regular base sequence generating method, introducing a spread spectrum radar polyphase code sequence to perform Kronecher multiplication with the zero-correlation sequence, so that the final sequence has quasi-perfect self-correlation property and perfect cross-correlation property within a certain zone, and has a larger zero correlation zone; thereby effectively reducing the mutual influence of the echo of adjacent distance units and improving the target detecting precision.

The invention discloses a selecting method of synchronization codes for a mobile communication synchronization system. The method selects binary codes with zero correlation window as the synchronization codes for a mobile communication synchronization system, i.e. selects binary codes whose periodic autocorrelation and periodic cross-correlation have the zero correlation window, or whose aperiodic autocorrelation and aperiodic cross-correlation have the zero correlation window; and for former transmitting the synchronization codes uses cyclic and continuous mode and for later a guard period is added to each synchronization code for transmitting. A width of the zero correlation window is determined to be greater than time delay spread of a multipath signal. Using the method, the selected synchronization codes can implement more accurate synchronization.

The invention discloses a primary synchronization signal generation method and device, and a computer readable storage medium. The method comprises the steps: acquiring ZC sequences corresponding to three root indexes, wherein the three ZC sequences have the same length; carrying out the discrete Fourier transform on the three ZC sequences to obtain frequency domain sequences in one-to-one correspondence with the three ZC sequences; respectively expanding the three frequency domain sequences to obtain expanded sequences in one-to-one correspondence with the frequency domain sequences; carryingout the inverse discrete Fourier transform on the three extended sequences to obtain time domain sequences in one-to-one correspondence with the extended sequences; and combining the three time domain sequences to obtain a main synchronization signal. The main synchronization signal generated by the scheme can balance the autocorrelation performance and the frequency offset resisting performance,and the time-frequency synchronization between the user terminal and the base station can be realized quickly.