13 results about "Raised-cosine filter" patented technology

The application discloses a kind of communication signal parameter blind estimation methods, devices and program products for intelligent instrument, involve signal identification field, to with low complexity calculation cost, accurately estimate the carrier frequency offset value of electromagnetic signal, symbol rate and pulse shaping filter type.The application carries out normalization to received signal, carrier frequency offset rough correction, estimates carrier frequency offset and meets rate, carries out the pre-estimation of pulse shaping filter type from the spectrum diagram of rough correction signal, and, for square root raised cosine filter / Raised cosine filter, first sequentially carrier frequency offset correction is carried out to first signal, based on square root raised cosine filter Matching filter, and based on symbol rate construction constellation diagram, finally according to constellation diagram, distinguish whether square root raised cosine filter or Raised cosine filter.The application realizes comprehensive, accurate, reliable estimation to electromagnetic signal parameter with low calculation complexity, realizes the automation and wisdom of electromagnetic signal measurement.

The invention relates to the technical field of optical communication, in particular to a method for suppressing low-frequency noise, which comprises the following steps: at a transmitting end, converting an input original service signal into a digital signal to obtain a digital signal sequence; using a root raised cosine filter to perform shaping filtering operation on the digital signal sequence after up-sampling, and then performing frequency spectrum inversion operation on the filtered digital signal sequence to obtain an inverted digital signal sequence; in a channel, transmitting the inverted digital signal sequence, and meanwhile, introducing a low-frequency noise signal; and at a receiving end, performing frequency spectrum inversion operation on the digital signal sequence into which the low-frequency noise signal is introduced, and then performing root raised cosine matched filtering and down-sampling operation to obtain and output a final digital signal. No extra device needs to be introduced, so that the cost of a communication system is reduced; the method is low in algorithm complexity, is high in low-frequency noise suppression flexibility, and still has a good suppression effect even for randomly changing low-frequency noise.

The present invention belongs to the field of laser Doppler technology, and specifically relates to a laser communication test system based on code Doppler and a code Doppler generation method thereof, including: S1, parameter initialization; the initialized parameters include the original sampling period, the original symbol rate, the rate offset, the new symbol rate, the number of symbol sampling points, and the code Doppler step amount; S2, using random binary data to generate a binary phase shift keying BPSK signal; S3, shaping filtering the BPSK signal through a square root raised cosine filter; S4, calculating the sampling time index through a time scaling ratio, and judging whether the sampling time index is within a target index range; if so, going to step S5; S5, interpolating and resampling the BPSK signal after shaping filtering based on the sampling time index and the Doppler phase offset. When performing Doppler frequency shift compensation, the present invention realizes the adjustment of the symbol rate through the calculation of the time scaling ratio, and combines interpolation to ensure the accuracy of the signal after resampling.

The invention belongs to the technical field of laser Doppler, and particularly relates to a laser communication test system based on code Doppler and a code Doppler generation method thereof, and the method comprises the steps: S1, initializing parameters; the initialized parameters comprise an original sampling period, an original code element rate, a rate offset, a new code element rate, a symbol sampling point number and a code Doppler stepping amount; s2, generating a binary phase shift keying (BPSK) signal by using the random binary data; s3, performing shaping filtering on the BPSK signal through a square root raised cosine filter; s4, calculating a sampling time index through the time scaling, and judging whether the sampling time index is within the target index range or not; if yes, turning to step S5; and S5, based on the sampling time index and Doppler phase shift, performing interpolation and resampling on the BPSK signal subjected to shaping filtering. When Doppler frequency shift compensation is carried out, the code element rate is adjusted through calculation of the time scaling, and the precision of the signal after resampling is ensured in combination with interpolation.

The invention relates to the technical field of high-speed data transmission, and provides a coefficient generation method and device of a forming filter, the forming filter, a storage medium and a computer program product. Performing even symmetry conversion and preprocessing on the set parameters to obtain preprocessed parameters; in combination with a Cordic algorithm, the preprocessing parameters are calculated, a first part calculation value, a second part calculation value and a third part calculation value are obtained respectively, and then a final calculation value is obtained through calculation and serves as a calculation value of a half coefficient of the forming filter; and performing folding operation on the calculation value of the half coefficient of the forming filter to obtain a calculation value of the coefficient of the forming filter and outputting the calculation value. According to the scheme, the FPGA design can be adopted, the forming coefficient of the root raised cosine filter is generated in real time based on the Cordic algorithm, ROM storage resources of the FPGA are not occupied, and the flexibility and performance of design of the forming coefficient of the root raised cosine filter are improved.

The application relates to the technical field of optical communication, in particular to a method for suppressing low-frequency noise, which comprises the following steps: at a sending end, converting an input original service signal into a digital signal to obtain a digital signal sequence; performing a shaping filter operation on the up-sampled digital signal sequence by using a root-raised cosine filter, then performing a frequency spectrum inversion operation on the filtered digital signal sequence to obtain an inverted digital signal sequence; in a channel, transmitting the inverted digital signal sequence, and simultaneously introducing a low-frequency noise signal; at a receiving end, performing a frequency spectrum inversion operation on the digital signal sequence with the introduced low-frequency noise signal, then performing a root-raised cosine matching filter operation and a down-sampling operation to obtain and output a final digital signal. The application does not need to introduce additional devices, thereby reducing the cost of a communication system; the algorithm has low complexity, and the flexibility of suppressing the low-frequency noise is high; even if the low-frequency noise is randomly changed, the application still has a good suppression effect.

The invention discloses a communication signal parameter blind estimation method and device for an intelligent instrument and a program product, relates to the field of signal identification, and is used for accurately estimating a carrier frequency deviation value, a symbol rate and a pulse shaping filter type of an electromagnetic signal at low-complexity calculation cost. According to the method, after normalization and carrier frequency offset coarse correction are carried out on the received signal, the carrier frequency offset and the coincidence rate are estimated, pre-estimation of the pulse shaping filter type is carried out through a spectrogram of the coarse correction signal, and the pulse shaping filter type is estimated for a square root raised cosine filter / raised cosine filter. The method comprises the following steps: sequentially carrying out carrier frequency offset correction on a first signal, carrying out matched filtering based on a square root raised cosine filter, constructing a constellation diagram based on a symbol rate, and finally judging whether the filter is a square root raised cosine filter or a raised cosine filter according to the constellation diagram. According to the invention, comprehensive, accurate and reliable estimation of electromagnetic signal parameters is realized with low calculation complexity, and automatic and intelligent electromagnetic signal measurement is realized.

The invention provides a timing estimation method and device, electronic equipment, a storage medium and a product. The method comprises the steps of obtaining a raised cosine filtering peak value, a peak value left-side correlation value and a peak value right-side correlation value; based on the peak value, the peak value left-side correlation value and the peak value right-side correlation value, determining a target loss function and a gradient value corresponding to the target loss function; iteratively decreasing and updating the gradient value based on a preset adjustment step length; and when the updated gradient value meets a target threshold value, determining a timing estimation result. Therefore, compared with an existing estimation method based on quadratic function approximate fitting, the method has the advantages that the target loss function is constructed by directly utilizing the peak value and related value information of the raised cosine filter, continuous optimization is carried out in a gradient descent iteration mode, and estimation can be carried out by fitting the actual characteristics of the impulse response function of the raised cosine filter better.

The present invention discloses a motor fault diagnosis method based on a GR-SWPT wavelet packet algorithm embedded with HD-RCF. When the motor is running stably without load, the vibration signal and stator current signal of the motor in normal state and fault state are collected; the chaotic dynamics roll-off factor β is designed, and a raised cosine filter HD-RCF based on the chaotic dynamics roll-off factor is constructed; the motor fault frequency and bandwidth, upper band limit coefficient and lower band limit coefficient are calculated; the basis function and fixed path method generated by HD-RCF are used to design a stationary wavelet packet decomposition algorithm to realize the extraction of motor fault characteristics; the motor fault is classified and identified by using a selective supervised radial basis classifier, and a two-level distance judgment method is used to determine the cluster center. The present invention can realize the generation of any adjustable wavelet filter through simple parameter setting; in addition, the present invention is completed under low sampling rate conditions, which can reduce the amount of data, is more suitable for forming an online embedded diagnosis system, and can obtain better diagnostic effects.

The present invention relates to a variable symbol sampling rate raised cosine filter based on FPGA, comprising L+1 high-speed sampling modules and L address calculation modules, and satisfying N=KL, wherein K is the number of sampling points for each symbol, L represents that the filter cut-off time length is L symbols, and the number of filter coefficients is N+1; the L+1 high-speed sampling modules are sequentially delayed by one clock cycle for sampling, the output ends of the high-speed sampling modules are each connected to a multiplier, the output ends of the multipliers are connected to an adder, the adder performs addition operation on L+1 parallel input signals, and is used to output a raised cosine filter signal; and also comprises L ROM memories, the ROM memories are used to store raised cosine filter coefficients h(n), n=0,1,2...N-1, and each ROM memory is connected to an address calculation module, which is used to calculate the address of the subsequent ROM memory. This scheme can adapt to a variable symbol sampling rate, and the consumed FPGA multiplier resources do not change with the symbol sampling rate.

The invention discloses a modulation and demodulation method for unmanned aerial vehicle communication, which is realized based on a Xilinx Zynq-7000 series FPGA (Field Programmable Gate Array) hardware platform and is suitable for a 50km-level long-distance and high-speed moving scene. A modulation end adopts a 3pi / 8 dynamic phase rotation algorithm to eliminate phase ambiguity, an I / Q signal is generated through an assembly line CORDIC algorithm, a raised cosine filter with a roll-off coefficient of 0.35 is configured, and out-of-band rejection is greater than 45dB. A demodulation end combines an improved Costas ring and a Gardner timing synchronization technology, can realize + / -25kHz frequency offset capture and 0.5-degree RMS phase tracking precision, adopts a normalized LMS equalizer to suppress multipath distortion, and integrates a diversity antenna dynamic switching mechanism. A layered clock architecture and a resource reuse strategy are adopted in the system, logic resource occupation and power consumption are reduced, and 20 / 5MBaud symbol rate dynamic switching is supported. According to actual measurement, the throughput reaches 48.6 Mbps under the transmission distance of 52 km, the end-to-end time delay is smaller than 12.7 ms, the system can adapt to the temperature environment of-40 DEG C to + 85 DEG C and the high-speed moving condition of 200 km / h, frequency hopping anti-interference and error correction capacity is achieved, and the high-reliability communication requirement of the unmanned aerial vehicle in the complex environment is met.

The application discloses a kind of root raised cosine filter-based optical fiber identification method, first utilize optical fiber imaging system to obtain optical fiber image, then adjust to certain width with fiber core width, utilize root raised cosine filter to the optical fiber brightness curve filtering, calculate the height difference, height ratio or width ratio of peak and valley in the filtered optical fiber brightness curve and other characteristic parameters to distinguish four common optical fibers.The application first applies root raised cosine filter in signal processing to optical fiber identification, realizes the wave formation shaping process of optical fiber brightness curve by filter, makes optical fiber brightness curve more standard, more easily extracts the characteristics of optical fiber brightness curve, so as to realize the rapid identification of optical fiber type, and improve the accuracy of optical fiber identification.

A system may include an analog front-end circuit configured to receive signals from an antenna array and a digital circuit coupled to the analog front end. The digital circuit may include a digital beamforming circuit configured to include a Nyquist fractional delay filter that is piecewise continuous in the frequency domain. The Nyquist fractional delay filter may be implemented as a Gaussian Nyquist filter, a generalized raised cosine Nyquist filter, or another Nyquist filter. The fractional delay filter may be critically sampled and evaluated numerically or with a closed-form time-domain expression. The fractional delay filter may be part of a digital beamforming phased array antenna system.