32 results about "Cosine modulation" patented technology

A non-uniform filter bank is created by joining sections of oversampled uniform filter bands that are based on complex exponential modulation (as opposed to cosine modulation). Each filter bank handles a given, non-overlapping frequency band. The bands are not of uniform bandwidth, and the filters of different banks have different bandwidths. The frequency bands of the different filter banks cover the frequency of interest with gaps in the neighborhoods of the filter band edges. A set of transition filters fills those gaps.

The invention discloses a broadband sub-matrix adaptive beamforming method based on sub-band decomposition, which mainly resolves the problem that computation burden in the prior art is high, and broadband interference signals cannot be processed and suppressed adaptively. The implementation process of the broadband sub-matrix adaptive beamforming method includes steps: 1) dividing a total matrix into a plurality of sub-matrixes, leading the sub-matrixes to be aligned with local beam pointing by the aid of microwave synthesis of a phase shifter, and obtaining sub-matrix synthesis data; 2) selecting a prototype filter and obtaining corrected analyzing and comprehensive filter banks via a cosinusoidal modulation filter bank; 3) under-sampling the sub-matrix synthesis data after the sub-matrix synthesis data pass through the analyzing filter banks, solving an adaptive weight in a narrow band and performing sub-band beamforming in the narrow band; and 4) up-sampling signals after sub-band beamforming, leading the up-sampling signals to pass through the comprehensive filter banks, and summating data of the comprehensive filter banks to obtain data after broadband adaptive beamforming. The broadband sub-matrix adaptive beamforming method has the advantages that the dimension of hardware is small, computation burden is low and broadband interference signals can be suppressed adaptively. In addition, the broadband sub-matrix adaptive beamforming method can be used for adaptive beamforming of a broadband phased array radar.

This invention discloses one parallel module inverter power even current control method and system, wherein, the method comprises the following steps: comparing two inverter modules output values and taking maximum value as even current signal through even bus into other inverter module to control other inverter output value; the control system testing each inverter module DC / DC voltage control circuit output signals through CPU process through connection control bus feedback signals to each inverter module DC / AC to control each inverter module output. The relative system comprises at least two parallel load inverter module, one control system to control sine and cosine modulation signal generator through control bus to output the modulation signal to inverter module to adjust inverter module output.

The invention relates to a signal-digit conversion method for a rotating transformer which is characterized by simultaneously carrying out digitle processing on the signals of the rotating transformers of a plurality of channels and converting a sine modulation signal Vs and a cosine modulation signal Vc outputted by the rotating transformer into a binary digit angle signals by the resolving method of a DSP digital signal processer. The invention consists of signal conditioning circuits, digital integrators, a clock oscillator and the DSP digital signal processer. Each rotating transformer channel is connected with one signal conditioning circuit; each signal conditioning circuit comprises two A / D convertors and a zero-crossing detector; each signal conditioning circuit is connected with one digital integrator; each digital integrator consists of two shift registers, two digital accumulators, two flip-latches and an address encoder. The measuring signal channel qualities of the conversion technology of the invention are more; the signal frequency range is broad; the digital angles are resolved by software, thus reducing the hardware cost, reducing the size and having a high cost performance.

The invention discloses a rotary transformer system and a control method thereof. A digital signal control chip modulates and outputs a sinusoidal excitation signal with preset frequency, the sinusoidal excitation signal is used as rated voltage of a rotary transformer after being conditioned; a zero passage moment of the sinusoidal excitation signal is used as an interrupt signal of the digital signal control chip; a timer of the digital signal control chip starts to count by taking the zero passage moment as a time reference, the digital signal control chip collects an AD sample of a sine and cosine signal of the rotary transformer after 1 / 4 period is delayed; the rotary transformer outputs two sine and cosine modulation and simulation signals; a signal conditioning circuit is used for conditioning the two sine and cosine modulation and simulation signals to obtain the conditioned simulation signals to be transmitted to the digital signal control chip; and the digital signal control chip synchronously samples the conditioned simulation signals to obtain an AD conversion result and output a rotor position angle value. According to the method, a special calculating chip is removed, so that the integration level of a control system is improved, and the cost of the control system is reduced.

The invention discloses a motor rotor position collection method and system. The method comprises the following steps: acquiring a rotary transformer excitation signal, a sine modulation signal and acosine modulation signal output by a rotary transformer on a motor shaft, and a preset demodulation signal; performing phase compensation on a preset demodulation signal according to the rotary transformer excitation signal, the sine modulation signal and the cosine modulation signal to generate a demodulation signal; performing phase-sensitive demodulation processing on the sine modulation signaland the cosine modulation signal by using the demodulation signal to generate a sine low-frequency envelope signal and a cosine low-frequency envelope signal; and decoding the sine low-frequency envelope signal and the cosine low-frequency envelope signal by using a phase-locked loop to generate a motor rotor decoding angle. The phase-sensitive demodulation method and the phase-locked loop are used for tracking the position of the motor rotor in real time, accurate position information is provided for motor driving, the decoding precision is improved, and the decoding speed is increased; phase compensation is performed on the preset demodulation signal so that the situation of failure of the method caused by phase lag can be avoided.

The invention discloses a method for preparing a super-thick and high-toughness TiN film. The method for preparing the TiN film comprises the steps that 1, a metal filtered cathodic vacuum arc (FCVA) deposition system is adopted, and the surface of a workpiece is cleaned through high-energy large-beam metal ion beams; 2, a layer of metal 'pinning layer' capable of improving the film base binding force is injected into the surface of the workpiece through a metal vapor vacuum arc (MEVVA) ion source method; 3, on the metal 'pinning layer', the gas inlet quantity is subjected to sine or cosine modulation and deposition through a filtered cathodic vacuum arc (FCVA) deposition method, and thus the super-hard good-toughness thick TiN film layer is obtained; and 4, the modulation period is repeated till the total thickness of the TiN film is 10-30 microns. By means of the method for preparing the super-thick and high-toughness TiN film, the TiN film deposited on the workpiece has very good toughness and very high microhardness.

The invention discloses a reorganizable filter bank of a digital hearing aid based on nonlinear transformation and a design method. The reorganizable filter bank comprises a shielding module and a passband forming module which are connected in sequence, wherein the shielding module is used for extracting a low-frequency passband and a high-frequency passband of a mapping frequency space, the passband forming module is used for transforming a low-pass FIR filter into an even filter bank through disperse cosine modulation and mapping the even filter bank into an uneven filter bank through a nonlinear transformation, and the passband forming module can generate four different subband distribution schemes through changing of values of set parameters. The reorganizable filter bank and the design method have the advantages that the four different subband distribution schemes can be provided under the situation that the basic structure is not changed by adjusting control parameters based on the combination of the cosine modulation filter bank and the nonlinear transformation, and thus amplification compensation is flexibly conducted on voices. Compared with a previous design method, the design method has good compatibility and low group delay.

A non-uniform filter bank is created by joining sections of oversampled uniform filter bands that are based on complex exponential modulation (as opposed to cosine modulation). Each filter bank handles a given, non-overlapping frequency band. The bands are not of uniform bandwidth, and the filters of different banks have different bandwidths. The frequency bands of the different filter banks cover the frequency of interest with gaps in the neighborhoods of the filter band edges. A set of transition filters fills those gaps.

The invention provides a modulation laser ranging method for underwater ranging, relating to the technical field of underwater detection. The method comprises specific steps that a light emitter emitsGaussian pulse, performs cosine modulation on the Gaussian pulse, adjusts pulse width, modulation frequency and modulation depth and other parameters, and selects a proper parameter according to actually detected seawater depth; and modulated Gaussian pulse passes a transfer medium and then arrives at a target, is reflected by the target and returns through the same medium, an echo signal is received by a high-speed detector, the modulated signal is extracted and undergoes microwave signal treatment, and a treatment result peak is corresponding to target distance information. The method solves problems of low signal to noise ratio of an underwater signal, poor target contrast, short distance measurement range and low accuracy caused by underwater backward scattering. The method effectively suppresses underwater backward scattering, improves signal to noise ratio of the signal greatly, is suitable for various complex underwater environments, and improves underwater distance measurementaccuracy and prolongs distance measurement range.

The invention discloses a method for testing conversion precision of a resolver-to-digital converter. The method comprises the following steps of simulating a sinusoidal modulation signal, a cosine modulation signal and a reference signal of a resolver by using a waveform generator, and inputting the signals to a tested resolver-to-digital converter; and capturing an output digital signal of the tested resolver-to-digital converter, and utilizing a traditional ADC static parameter testing method to solve the output digital signal of the tested resolver-to-digital converter in order to obtain atest result. According to the method, sine and cosine angle modulation output signals and the reference signal of the resolver are simulated through any waveform generator and are input to the testedresolver-to-digital converter, and a set of corresponding solving methods for the precision of an output conversion angle of the resolver-to-digital converter are used, the accurate testing of the conversion precision of the resolver-to-digital converter is achieved, and a testing process is efficient and reliable.

The invention discloses a design method for a perfect reconstruction filter group based on frequency curling and cosine modulation. The filter group comprises three frequency curling modules. One module is used for mapping a uniform subband into a new frequency domain generation passband. The second and the third modules are used for mapping an original masking filter into a target masking filter. Therefore, no matter there are how many possible passband generation modules, only the two original filters need to be designed, so that system complexity is greatly reduced, and meanwhile flexibility is improved. The problem about the relation between frequency curling parameters of the passband generation module and the masking filter module is solved, parameter values of the all-pass system under various conditions are pre-designed in a unified manner, and then any scheme can be directly achieved via the method of changing the parameter value without changing a system structure.

The invention discloses a filter bank multi-carrier sub-band filter, and particularly relates to the field of filter bank multi-carriers, the filter bank multi-carrier sub-band filter comprises an analysis filter bank, a comprehensive filter bank and a sub-band processor, one M-channel cosine modulation filter bank comprises M branches, an input signal is decomposed into M sub-bands by the analysis filter bank, wherein the sub-bands have the same bandwidth and sampling factor; the analysis filter bank divides an original signal into a series of sub-band signals, the standard center frequency [omega]m = 2[pi]n / M and the same bandwidth 2[pi] / M are achieved, m = 1 to M-1, and the comprehensive filter bank eliminates aliasing components of all sub-bands to achieve complete reconstruction. According to the method, the complexity in the filtering calculation process is reduced, so that the filter bank multicarrier can quickly filter the multicarrier signal, and the filtering efficiency in the filter bank multicarrier is improved.

The invention provides a prototype filter generation method and device, a channelization method and a spaceborne communication device, and the prototype filter generation method comprises the steps: determining a parameter optimization cost function of a prototype filter of a cosine modulation filter bank based on an aliasing distortion error model of the cosine modulation filter bank with any channel number, wherein the parameter optimization cost function enables the generated ultra-high-order prototype filter to meet an approximate perfect reconstruction condition; performing global iterative optimization on the parameter optimization cost function until the fitness of the optimal solution obtained by the current round of optimization reaches a preset threshold; and performing local optimization of a parameter optimization cost function by taking the optimal solution as an initial value to obtain filter parameters of the prototype filter. According to the method, out-of-band leakageand spectrum aliasing distortion between adjacent sub-bands and non-adjacent sub-bands are suppressed, the calculation complexity of solving a mass parameter planning problem is reduced, and the generation efficiency of the ultra-high-order prototype filter is improved.

The invention provides a clean in-phase layer selection in-core selective coherence spectrum method. A modified perfect echo module is used for achieving coherent transfer between the same phases, unwanted signals are removed in combination with selective pulses and phase removing gradients, only J coupling modulation signals generated when t1 and t2 are modulated by cosine functions of an excitation core and an observation core are finally reserved, and the signal strength is affected by a delta value. The two-dimensional J coupling modulation of the excitation core and the observation core presents an in-phase square in a spectrogram, the coupling information of the observation core and other cores is embodied on the lateral offset of the square, and the coupling information of the excitation core and other cores is embodied on the longitudinal offset of the square at present, and the modulation causing transverse and longitudinal offset is cosine modulation, so that the property that the spectral peak is in-phase is not influenced.

The invention relates to a lissajous device based on the optical crystal refractive index profile electro-optical modulation principle. The lissajous device comprises a laser device, a beam collimator, an electro-optical modulation unit and a CCD image sensor, KTN crystal is processed into a cuboid structure, metal plate electrodes are prepared through a coating technology, the two pairs of plate electrodes are arranged on the side face of the crystal, each pair of plate electrodes is connected with an external modulation voltage source, and sine and cosine modulation is carried out on each modulation voltage source; after an incident beam is modulated through the KTN crystal, and emergent beam track is received by the CCD image sensor. The device has the advantages of adopting single beam operation, dispensing with a folded path and being free of mechanical vibration, low in space loss, large in frequency dynamic modulation range, capable of being manipulated at high accuracy, high in device integration level and stability and capable of modulating the beam in a multi-direction mode.