48results 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.

Small radio frequency tags for use in a motion capture system include a power source, circuitry for generating radio frequency identification signals, an antenna for transmitting the signals, and means for automatically activating the tags so that the tags begin transmitting the signals including a tag identification code when a cover is removed. The activation means may include a release strip that, when removed, opens or closes an electrical circuit that activates the tag and also exposes an adhesive covered surface of the tag so that the tag can then be adhered to a clothed or unclothed human body or other object to be tracked. The activation means can also include an optical sensor, an oxygen sensor, or other sensors. The battery and the antenna may be printed or constructed of film, thus allowing the tag to be small, thin, and flexible.

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.

A method for producing frame synchronization in ground digital multimedia television broadcast system, of which the frame synchronization signal is composed of a front synchronization, a PN series and a back synchronization, includes steps as: (1) to create a eight steps m series by Fibonacci type linear feed-back shift register, (2) to select a sixteen steps Wolsch code word by DMB-T network supervisor as a base station (emission station), (3) to expand the sixteen bit Wolsh code to a vector of 256 / 304 / 384 position by duplicating each, "1" and each "0" 16 / 19 / 24 times according to the big or small or front synchronization / back synchronization in PN series, (4) to carry out one position by one position exclusive OR (XOR) to the vector produce by step (2) and the frame synchronization series to be coded to establish the frame synchronization series of Wolsh spread spectrum coding.

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 discloses an anti-active-jamming method in wind profile radar signal detection. The method comprises the following specific steps: firstly constructing a wind profile radar anti-active jamming system which comprises an intra-pulse inter-pulse modulation circuit (3), an intra-pulse inter-pulse demodulation circuit (4), an intra-pulse modulating sequence generating circuit (1), an inter-pulse modulation sequence generating circuit (2), a pulse signal source (5) and a signal processor (10); secondly, generating a modulation sequence by the intra-pulse modulating sequence generatingcircuit (1) and the inter-pulse modulation sequence generating circuit (2); thirdly, modulating an emitting signal by the intra-pulse inter-pulse modulation circuit (3); and fourthly, demodulating and pre-processing an echo signal by the intra-pulse inter-pulse demodulation circuit (4); and therefore, the wind profile radar anti-active jamming method is realized. The anti-active jamming method can effectively resist the external active jamming, improve the detection ability to a target signal and obviously enhance the detection result of the wind profile radar.

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 present invention belongs to the field of satellite navigation system signal, and especially relates to a binary coded symbol modulation method based on a time domain raised cosine pulse. The binary coded symbol modulation method comprises the steps of: first determining the frequency and period of a spreading code and the length of a coded symbol sequence, and selecting the optimal coded symbol sequence through a signal auto-correlation characteristic; performing spread spectrum for a navigation signal by using a pseudo random sequence according to the determined frequency or period of the spreading code and the optimal coded symbol sequence, so as to obtain a spread spectrum signal; performing carrier modulation of an orthogonal branch for an obtained binary coded symbol base-band modulation signal based on a time domain raised cosine pulse, so as to obtain a binary coded symbol modulation signal based on the time domain raised cosine pulse; and re-determining the frequency or period of the spreading code and the length of the coded symbol sequence, and selecting the optimal coded symbol sequence. Compared with a traditional BCS modulation, the modulation signal obtained by the binary coded symbol modulation method of the present invention is faster in power spectrum sidelobe attenuation speed and lower in amplitude, and is higher in energy concentration degree.

Method of synchronising base stations in a mobile radio telecommunication system, characterised in that a first base station transmits a synchronisation sequence having a first sequence followed by a second sequence, the said first and second sequences being obtained from polyphase complementary sequences and in that at least one second base station effects the correlation of the said synchronisation sequence with a replica of the first sequence and a replica of the second sequence, the correlation results then being added in order to provide synchronisation information.

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 mechanical resonant frequency feature obtaining method for an alternating current servo system based on a pseudorandom sequence code, belonging to the technical field of frequency feature obtaining of an alternating current servo system, and solves the problem that the mechanical resonant feature obtained by sweeping frequency under an open loop cannot effectively and accurately obtain the frequency feature of low frequency. The method comprises the following steps of firstly obtaining an n-order primitive polynomial; combining an initial n-order sequence of a binary m sequence by the coefficients of the n-order primitive polynomial, multiplying a feedback shift register and the initial n-order sequence and accumulating and summing, performing feedback calculation after the accumulated value takes 2 as a base number and is subjected to modulo operation, and finally obtaining 2<n> binary m sequences; converting the m sequences into a current value sequence as the given current under the speed open loop of the alternating current servo system; and respectively performing fast Fourier transform for the current value sequence and an acquired motor rotary speed sequence, performing mathematic operation for the converted results, and obtaining a Bode diagraph of the open loop alternating current system. The method provided by the invention can be used for obtaining the mechanical resonant frequency feature of the alternating current servo system.

The invention discloses a single-station full-duplex communication sensing integrated signal design and processing method, and the method comprises the following steps: designing relevant parameters of a sent signal according to sensing performance indexes, such as maximum unambiguous distance, resolution and the like; enabling the communication-sensing integrated transmitter to not only perform low-rate information transmission by using the radar signal subjected to slow time coding modulation, but also transmit a communication signal by using radar echo waiting time, so the spectrum efficiency is improved; enabling the communication receiver to receive and demodulate the radar signal and the communication signal; and enabling the radar receiver to receive signal echoes and sense the distance and the speed of a target through self-interference elimination and radar signal processing. According to the method, the problems of low communication rate, reduced sensing performance, existence of a distance blind area and the like in communication and sensing integration can be solved, and the target detection probability and the system communication efficiency are improved while the sensing precision is ensured by comprehensively utilizing the excellent self-correlation characteristic of the radar signal and the high spectrum efficiency of the communication signal.

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 discloses a multi-user multicarrier short wave modulation method based on sparse codebook spreading. The invention belongs to the field of wireless mobile communication. The invention provides a multicarrier modulation scheme based on sparse codebook spreading for a scene in which multiple users simultaneously communicate in short wave sharing frequency bands, comprising the following step of: generating a sparse codebook conforming to a certain conditions to generate a sparse spreading sequence of each symbol of each user I / Q branch to complete the sparse spreading of the symbol. According to the multi-user multicarrier short wave modulation method based on sparse codebook spreading, the problem that multi-user interference and analog narrow-band interference exist simultaneously in short-wave sharing channels can be effectively solved.

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 a Doppler inhibition method based on a constructed complementary code pair. The Doppler inhibition method comprises the following steps of selecting the complementary code pair with proper length as an optimal code as required; generating a constructed code pair corresponding to the optimal code; taking the constructed complementary code pair as a phase modulation signal; respectively processing two impulse sequences at a receiving end to eliminate the Doppler influence; respectively carrying out matched filtering; finally improving main sidelobe ratio by utilizing complementary characteristics between the two sequences. With the adoption of the Doppler inhibition method based on the constructed complementary code pair, not only can the Doppler influence be completely eliminated, but also better self-correlated characteristics can be acquired.

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 voice data processing method for vocoder forward information source voice data synchronization. The method comprises: a coding step includes: a pre device receives one group of to-be-transmitted audio data; and SYN1 and SYN2 are established and are used for replacing unencrypted audio data in the to-be-transmitted audio data. A decoding step includes: a maximum correlation value of a pseudorandom sequence is calculated; if the maximum correlation value of the pseudorandom sequence is larger than or equal to a random sequence threshold value, SYN1 existence in the audio data is determined and the position of the SYN1 is determined; a maximum correlation value of a single-tone sequence is calculated; if the maximum correlation value of the single-tone sequence is larger than or equal to a single-tone sequence threshold value, a precise tracking effective mark is calculated; and if the precise tracking effective mark is equal to 1, SYN2 existence in the audio data is determined and the position of the SYN2 is determined. Therefore, fidelity of audio data transmission is improved and the interference on the audio data during transmission can be prevented.

The present invention provides a synchronization sequence transmission method, synchronization detection method and device. The transmission method includes: setting a target synchronization sequence with good autocorrelation characteristics; wherein, intercepting in the time domain or frequency domain of the target synchronization sequence The obtained at least one sequence is a sub-synchronization sequence, the sub-synchronization sequence has good autocorrelation characteristics and the sub-synchronization sequences have good cross-correlation characteristics; the target synchronization sequence is sent to the terminal; the embodiment of the present invention For terminals with different bandwidths or different carrier intervals, after the base station sends the same target synchronization sequence, the terminal can intercept the corresponding sub-synchronization sequence according to its own needs for synchronization detection, which not only ensures the accuracy of synchronization detection, but also improves the target Scope of application of the synchronization sequence.

The invention discloses a frequency domain arrival detection method of an orthogonal frequency division multiplexing system. A frequency domain synchronous transmitting unit adopts two frequency domain pseudorandom sequences with identical length but different phases, a zero is respectively compensated to each pseudorandom sequence to obtain a pseudorandom expanded sequence, then rapid Fourier inverse transformation operation is carried out on the pseudorandom expanded sequences to obtain time domain sequences, and then the two time domain sequences are cascaded to obtain a synchronous pilot training sequence. A frequency domain synchronous receiving unit adopts a time window with a length being identical to that of one pseudorandom expanded sequence, rapid Fourier transformation operation is carried out on data inside the window, then the data is correlated with a known local pseudorandom expanded sequence after being subjected to peak clipping and amplitude limitation processing, and the signal arrival is judged by utilizing excellent autocorrelation property of the pseudorandom sequence and simultaneously considering a threshold and position-based detection method. Due to the adoption of the frequency domain arrival detection method of the orthogonal frequency division multiplexing system, interference of a single tone, narrow band and the like can be effectively resisted, and reliable signal arrival detection can also be realized under a severe channel condition.

The invention discloses an MMC-based pseudo-random code fault location method and system. The method includes: generating an m-sequence signal composed of 0 and 1; and modulating and controlling the MMC through the m-sequence signal, and the symbols 0 and 1 correspond respectively to The MMC phase unit sub-modules are put into different quantities, thereby controlling the MMC DC side voltage to follow the m-sequence signal to switch between two levels; the MMC DC side voltage propagates along the DC line, and when encountering a fault point, the refraction of the traveling wave occurs, The generated reflected wave returns to the MMC terminal, and the delay time between the DC side voltage signal of the MMC and the reflected wave signal is calculated by the cross-correlation function; the distance between the fault point and the MMC terminal is calculated according to the delay time. The invention successfully eliminates the contradiction between the power and the pulse width of the transmitted signal when the pulse reflection method is used for fault detection and positioning, and improves the fault positioning accuracy.

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 high-speed burst signal synchronization and equalization device and method, and relates to the technical field of optical access. The device includes an equalizer, a time synchronizer and an equalization controller. The equalizer receives the uplink burst signal, and under the control of the equalizer controller, transmits the calculated equalized output to the time synchronizer in the blind equalization mode or the training equalization mode. Wherein, the PSBu data pattern of the uplink burst signal includes two parts, A+ and A-, which are negatively correlated. The time synchronizer finds the uplink burst signal based on the PSBu data mode, performs boundary identification, and feeds back to the equalizer controller. The equalization controller controls the equalizer to switch between the blind equalization mode and the training equalization mode according to the preset equalization control state machine according to the feedback. The present invention effectively combines the advantages of the two equalization modes, not only can efficiently equalize but also effectively guarantee the payload bandwidth of the system, and can also improve the quality of synchronization and training to meet the actual application requirements.

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.