49 results about "Amplitude compression" patented technology

The invention relates to an expressway audio vehicle detection device and a method thereof. By the aid of the detection device, a microphone array signal acquisition module acquires an audio signal on a lane, the audio signal is subjected to band-splitting filtering and framing through a signal processing module after being subjected to de-noising processing through a noise suppression module, cross-correlation processing is conducted among sub-band signals, an audio space spectrogram is obtained, a vehicle detection module tracks a track of the maximum value on the audio space spectrogram and judges whether a vehicle passes, and the vehicle type and the vehicle speed are obtained through a vehicle type recognition module and a vehicle speed recognition module if the vehicle passes. The detection method is based on the device, a minimum statistical noise estimation method of the adaptive window length is adopted, the signal which is subjected to noise suppression processing is subjected to band-splitting filtering and framing processing, then cross-correlation processing is conducted among same sub-band signals, cross-correlation results are summed after being subjected to amplitude compression and are unfolded along a timer shaft, and an audio signal space-time spectrum is obtained. The method and the device have the advantages of being low in cost, low in energy consumption,easy to construct, interference resisting, capable of working in all weather and the like.

The invention provides a uniting method of decreasing OFDM signal peak ratio, the method maps base band signal modulated by OFDM selectively, then extent is compressed, signal is expanded on receiving end, and edge information is used to release mapping to recover signal. The invention can make ratio of signal peak power and average power decreased greatly, so peak ratio of signal is restrained, and transmission performance of signal is equal to press-expending method. The invention is easy to realize, and can be used in various communication systems with OFDM to modulate.

A signal processing device includes: a frequency conversion processing unit that sets, as a processing target signal, a section in which a peak signal level exceeds a first threshold in an input sound signal and applies frequency conversion processing to the processing target signal to acquire power levels in respective plural bands; and an amplitude compressing unit that executes, when a power level exceeding a second threshold is present among the power levels in the respective plural bands acquired by the frequency conversion processing unit, amplitude compression processing for compressing a signal level of the processing target signal at a compression ratio at which the peak signal level of the processing target signal falls within the first threshold and, otherwise, prohibits the execution of the amplitude compression processing.

The method comprises: the damaged inputted optical signals are divided into two routes via two output end of optic splitter and coupler; one route of signal is connected to the optic delay line (2) and the non-linear optic signal processor(4); the other route of signal is connected to the optic delay line (3) and the non-linear optic signal processor (5); the non-linear optic signal processor (4) and (5) respectively make phase and amplitude compression for the four phase shift keyed signals orthogonal each other in the angular bisector direction to generate two phase shift keyed signals orthogonal each other; said two route of signals is combined to generate the four phase shift keyed signals via an optical multiplexer. The invention can be used to restore the optical four phase shift keyed signals polluted by noise.

The invention provides a millimeter wave GaN power amplifier radio frequency predistortion linearizer and aims at providing the predistortion linearizer which is simple in structure, low in insertion loss, wide in working frequency band and high in stability and is applicable to a millimeter wave GaN power amplifier. The millimeter wave GaN power amplifier radio frequency predistortion linearizer is realized through the following technical scheme that a radio frequency enters a broadband matching network (5) from a radio frequency input port (1) through an input chip capacitor (3) connected with an input microstrip line (2) and a two-level impedance transformation step (6) connected with an input gold wire (4). A GaN Schottky diode (8) and a tube socket circuit (9) generate a distortion radio frequency signal with expanded amplitude and expanded phase. The distortion radio frequency signal matches amplitude compression and phase compression characteristics of a millimeter wave GaN power. The distortion radio frequency signal is output to a radio frequency output port (22) through the two-level impedance transformation step (17) on the output end of the broadband matching network (5), and an output chip capacitor (20) and an output microstrip line (21) connected with an output matching gold wire (19).

The invention relates to a lens and a design method thereof and particularly relates to a free-form surface progressive multi-focus-point lens and a design method thereof. The free-form surface progressive multi-focus-point lens disclosed by the invention adopts an expanded axial symmetry quadric surface formula to establish an initial facial form; and a quadric surface coefficient and a curvature parameter of each point on the surface are iterated and optimized to obtain the final facial form and the optical property. According to the free-form surface progressive multi-focus-point lens and the design method thereof, an image astigmatism region is greatly compressed, the maximum astigmatism value is reduced, the astigmatism distribution is softer, the width of a channel is increased, an effective vision range of the lens is obviously increased, and the comfortable degree of a wearer can be effectively improved; and the luminosity degree can be increased to be more than +0.03D. The lens is especially suitable for a presbyopia ametropia patient more sensitive to an image difference.

The invention discloses a loaded angle radial logarithmic zigzag line micro-strip slow-wave structure based on a photonic band gap structure, and belongs to the field of radial beam traveling wave tube slow-wave systems. The structure solves the technical problems that electron beams are deviated from radial tracks caused by an electric field formed by charge accumulation existing on a dielectric substrate, the damage of the micro-strip slow-wave structure and the deviation of the electron beams from effective interaction areas are possibly caused to cause the reduction of traveling wave tube efficiency, and the size of the traveling wave tube slow-wave system is decreased along with the increase of work efficiency and then the size of an electron beam passage is greatly reduced due to a size sharing effect so as to cause the increase of process cost and the reduction of performance and stability. The structure mainly comprises a dielectric substrate, angle radial logarithmic micro-strip zigzag lines, a photonic band gap structure and side micro-strip lines. The structure is used for a wave injection interaction system of radial beam traveling wave tubes.

A method of crest factor reduction using amplitude compression for multi carrier signals. Major elements of the inter-modulation distortion caused by amplitude suppression are removed to be outside of the desired signal band, and the peak amplitude is compressed, thus producing a signal with lower peak to average ratio for a required maximum error vector magnitude.

This invention provides a method for reducing peak balance power ratio in a low complicated OFDM communication system, which compresses the amplitude of the base band signals modulated by the OFDM and expands the received signals at the receiving end to resume signals, which can reduce the ratio of the signal peak power and the mean power to suppress the peak and mean power ratio of the system and neglect the influence of signals used in various communication systems modulated by the OFDM.

A signal processor for GPS or other GNSS radiolocalization systems, includes a RAM pre-correlation buffer which is filled in sync with the code NCO, thus all sample alignment in the buffer is fixed The device further includes an amplitude compressor to limit the size of the buffer memory and is optimized to provide data to the following DFT unit in small bursts that can be processed in real time without the need for intermediate buffers. Thanks to these features the processor limits the amount of fast intermediate memories, is simpler and has lowerpower consumption.

Systems and methods for amplitude compressing a digital signal. An input signal is divided into frames having a first and second sets of samples. The samples in the second set are also in a subsequent frame. Peak values are determined for the first and second sets. One or more slopes are calculated based on the peak values. The slopes are used to define a scale factor which is applied to the first set to produce the output signal. For example, if the first peak value exceeds an amplitude threshold, first and last samples in the first set to exceed the amplitude threshold are found. Slopes are calculated for each of three regions of the first set demarcated by the first and last samples. In each region a slope is selected. These slopes along with an initial scale factor are used to calculate the scale factor.

The invention relates to a filter-based electromagnetic transient state simulation method and system. The method comprises, through a group of simulative filter circuits, simulating a plurality of groups of LCC (leadless chip carrier) converter station alternate current filters of the same kind to the simulative filter circuits, and through a parameter setting method, simulating the switch operation of the LCC converter station alternate current filters, wherein the parameter setting method is a method in which the electromagnetic transient state equivalent computing circuit of the filter circuits in real time corrects a historical current source. By compressing a dozen of alternate current filters of a practical LCC converter station into a plurality of types for simulation in an electromagnetic transient state program, the filter-based electromagnetic transient state simulation method and system can greatly reduce the number of electrical nodes and elements of a direct current powertransmission electromagnetic model, accelerate simulative models, and meanwhile have no loss in the filtering effects of the filters or the simulation precision of dynamic switching processes, therebyhaving high practical promotion values.

The invention provides a transformer zero-sequence overcurrent protection method based on a phase-space distribution gravity center magnitude change of zero-sequence current. The method comprises thesteps of obtaining a zero-sequence current sequence I0 measured by a neutral line current transformer (TA) of a transformer at a certain sampling rate; judging whether a zero-sequence current amplitude is greater than a zero-sequence overcurrent protection action setting value or not, if so, starting a novel method provided by the invention, or else, continuously discriminating an inequality; carrying out normalization processing on the zero-sequence current, extracting a maximum value and a minimum value of the current within a determined time window, carrying out amplitude compression on various points in the sequence on the basis of the maximum value and the minimum value and obtaining the normalized zero-sequence current sequence, thereby making various points in the current sequence fall in a change range of [-1, 1]; carrying out phase-space reconstruction on the normalized zero-sequence current sequence I0' and obtaining a gravity center sequence G and a distance sequence R froma gravity center to an original point after a criterion is started; and judging a formula that R is greater than Rset is true or not. According to the method provided by the invention, zero-sequence overcurrent protection misoperation caused by excitation inrush current and restorative inrush current generated during no-load closing and external fault removal can be effectively prevented.

The invention discloses a high-magnification compact telescopic sight optical system. The high-magnification compact telescopic sight optical system comprises an objective lens group, a focusing lensgroup, a field lens, a relay lens group, a dividing plate and an eyepiece group which are arranged on the same optical axis, infinite parallel light passes through a chromatic aberration correction objective lens group from the object surface to form converging light, a primary inverted image point is converged through the focusing lens group, the height of beams is greatly compressed by formed divergent light passing through a high-focal-power field lens, the converging light is formed again, through the relay lens group, an image converged to a dividing line of the dividing plate forms a secondary erect image point, and finally, human eyes observe scenes being subjected to angular magnification through a wide-view-field eyepiece group in the structural form of an Elfer eyepiece. According to the high-magnification compact telescopic sight optical system, an inner focusing structural form is adopted, the sealing performance is very good, close observation can be achieved, a replication system is avoided, the optical axis consistency of the dividing plate is very high, a positive real image is directly formed for the human eyes, the ability to collect light energy is high, and themagnifying power is high.

The invention relates to a microgrid short-term load prediction method which comprises the following steps: S1, acquiring load historical data, and carrying out data quality improvement on a singularvalue interval by adopting cubic spline difference values; S2, establishing a gray variation coefficient model based on amplitude compression, and introducing an improved human body comfort index as an influence factor in the modeling process; S3, calculating a prediction parameter sequence of the cumulative variation coefficient sequence and the mutational variation coefficient sequence; S4, optimizing the prediction parameter sequence by using a genetic simulated annealing algorithm to obtain an optimal matching parameter; S5, reconstructing an optimal matching parameter to obtain an optimalvariable coefficient sequence; and S6, carrying out reverse solving to obtain a load prediction value, and controlling the working state of the distributed power supply. Compared with the prior art,the method has the advantages that the air quality condition is introduced into the human body comfort index, the gray variation coefficient model is established, solving is carried out based on the genetic simulated annealing algorithm, the prediction speed is high, and the prediction precision is high.

The invention provides a method for eliminating reverberation. According to the method and system for eliminating the reverberation, speech time-frequency probability detection with respect to a speech signal is introduced in the reverberation eliminating process, calculation is performed to obtain the speech time-frequency probability of the speech signal, and adaptive updating adjustment operation is carried out on a filter used in the reverberation eliminating process according to the speech time-frequency probability, so that the updating error probability of the filter can be effectivelyreduced, the calculation frequency of the filter can be reduced, the calculation amount of reverberation eliminating can be reduced and greatly compressed, and the applicability of a reverberation eliminating algorithm to different types of processors can be improved.