75 results about "Nonlinear modulation" patented technology

A two-mode demodulating apparatus for use in a radio terminal in a mobile communication system has a linear reception demodulating circuit and a non-linear reception demodulating circuit which can be selectively operated by selecting a mode. The non-linear reception demodulating circuit has a second frequency converting unit for frequency-converting a received signal into a low-frequency signal, a variable-band filtering unit for allowing a signal in a desired band contained in an output of the second frequency converting unit to pass therethrough, and a non-linear reception demodulating process unit for performing a non-linear reception demodulating process on an output from the filtering unit, thereby receiving and demodulating a linear modulated wave and a non-linear modulated wave while suppressing increases of the circuit scale and the power consumption, and generalizing a hardware structure for an applied non-linear modulating system.

A analog/digital modulation type discrimination circuit 1 discriminates whether a reception signal is an analog modulation type, a linear modulation type or a non-linear modulation type by digital modulation type. In case where the reception signal is discriminated to be the analog modulation type, an analog modulation type discrimination circuit 2 discriminates whether it is an AM signal or an FM signal among the analog modulation type. In case where the reception signal is discriminated to be the linear modulation type by digital modulation type, a linear modulation type discrimination circuit 3 discriminates whether it is a BPSK signal, a QPSK signal, a π/4-shift QPSK signal, an 8-PSK signal, an M-ary PSK signal of multi-level exceeding 8-levels, a 16 QAM signal or a n M-ary QAM signal of multi-level exceeding 16-levels among the linear modulation type by digital modulation type. In case where the reception signal is discriminated to be the non-linear modulation type by the digital modulation type a non-linear modulation type discrimination circuit 4 discriminates whether it is an M-ary FSK signal, a 2-FSK signal, an MSK signal or a GMSK signal among the non-linear modulation type by the digital modulation type.

A multiband and multimode transmitter circuit (200) includes two separate oscillators, such as at least a first oscillator circuit (60), a second oscillator circuit (62), a corresponding first signal processing circuit (64), and second signal processing circuit (66) to produce a first output frequency signal (78) defined within the first or second band of frequencies in response to a transmitter input signal (46). Each oscillator and corresponding signal processing circuit (64, 66) may be optimized for the lowest power consumption while meeting the noise performance criteria in each of the multiple frequency bands. The multiband and multimode transmitter circuit (200) may produce the transmitter output signal (36) with either linear modulation or nonlinear modulation and at a first band or second band frequencies.

Space time transmit diversity (9, 14, 17, 19) is applied at the block level to an original block of bits (12) in order to reduce the effects of fading in wireless communication systems that use nonlinear modulation schemes (13, 33). At the receiving end, fading parameters (α₁, α₂) are estimated (α_E1, α_E2) and the properties of complex conjugates are utilized (28, 29, 201, 202) to produce a result (r₁, r₂) that is representative of the original block of bits.

A transmitter includes a dual mode modulator and an amplifier coupled to the dual mode modulator. The dual mode modulator implements a linear modulation scheme during a first mode of the modulator to produce a variable envelope modulated signal. The dual mode modulator implements a non-linear modulation scheme during a second mode of the modulator to produce a constant envelope modulated signal. The amplifier is biased as a linear amplifier during the first mode of the modulator and is biased as a non-linear amplifier during the second mode of the modulator. A feed-forward connection between the dual mode modulator and the amplifier is used to indicate a change in modulation mode and to adjust the bias of the amplifier. A power of the constant envelope modulated signal is increased such that an operating point of the amplifier remains substantially constant during the first and second modes of the modulator.

A digital control apparatus for a switching DC-DC converter includes at least one power transistor and is able to provide a regulated output voltage on a load. The apparatus includes digital control having a reference digital input signal and provides a modulating signal to a PWM device to which is input the modulating signal and which provides an output square wave signal for driving the power transistor of the DC-DC converter such that there is non-linear modulation only when the value of a signal on the load is lower or higher than a prefixed value range.

The invention provides a synchronous rectification control circuit and method. The synchronous rectification control circuit comprises an output detection unit, an error amplifying unit, a logic control unit and a driving circuit unit; the output detection unit is connected between the output positive end of a main power unit and the first input end of the error amplifying unit; the output end ofthe error amplifying unit is connected with the first input end of the logic control unit; the first output end and the second output end of the logic control unit are connected with the first input end and the second input end of the driving circuit unit respectively; the first output end and the second output end of the driving circuit unit are connected with gates of switching tubes M1 and M2 respectively; the third output end of the driving circuit unit is connected with the drain of the switching tube M1 and the source of the switching tube M2 respectively; the synchronous rectification control circuit also comprises an input detection unit and a nonlinear modulation unit; the output end of the input detection unit is connected with the input end of the nonlinear modulation unit; andthe output end of the nonlinear modulation unit is connected with the second input end of the logic control unit.

A control circuit for a DC/DC converter has a linear-control loop, which receives a quantity to be controlled and a first reference quantity, and generates a modulation value. A nonlinear modulation unit is activated in presence of a variation of the quantity to be controlled higher than a preset intervention threshold and modifies in a nonlinear way the reference quantity supplied to the linear-control loop. In the case of large variation and of preset sign of the quantity to be controlled, the linear-control loop is deactivated, a signal for switching-off of the DC/DC converter is initially generated, and then a false steady-state-modulation value is supplied to the DC/DC converter.

The invention discloses a method and a device for detecting sea abnormal wave. The method comprises the following steps: an environmental sea surface model where the wave to be detected and a Bragg short wave coexist is formed; the solution of the Bragg short wave under the nonlinear modulation of the wave to be detected is worked out; radar scattering sections of the wave to be detected of a resolution cell and the environmental sea surface echo are calculated and compared; if the radar scattering section ratio of the wave to be detected and the environmental sea surface echo is less than a threshold, the wave to be detected is determined as an abnormal wave. The method and the device can detect the abnormal wave on the sea surface and reduce the hidden safety trouble of maritime sailing and maritime platform.

A structure and a manufacturing method of a terahertz cascaded traveling-wave tube (TWT) frequency multiplier belong to the field of vacuum electron devices. Among a slow wave structure part and a collector outputted by the TWT, at least one to M N harmonic systems (wherein M and N are to 2, 3...) are cascaded. Design is performed as per steps, and the high-frequency system of the traveling-wave tube controls harmonic information in an electron beam after interaction; and the cascaded harmonic systems realize harmonic wave power maximization and frequency response optimization and output harmonic waves as practical information. On the basis of the nonlinear modulation of electromagnetic wave to the electron beam, the harmonic information in the electron beam is optimized after interaction of the traveling-wave tube, and full energy exchange is performed by utilizing the cascaded harmonic systems so as to realize frequency multiplication amplification and output.

The invention is suitable for the field of internet communication, and discloses a graphic processing unit (GPU)-based low-luminance image enhancement method. According to the method, a model is programmed by using a compute unified device architecture (CUDA). The method comprises the following steps of: acquiring red green blue (RGB) channel data of an original image and size information of the original image; initializing a GPU, namely determining the thread number of executing a Kernel function according to the size of the original image; starting the Kernel function to solve a luminance component of the original image, and performing image enhancement processing on the original luminance component, wherein the luminance component processing comprises the non-linear modulation and contrast enhancement of the luminance component; starting the Kernel function, restoring the color of the image, returning a calculation result to a central processing unit (CPU) end, and saving as a picture; and releasing a GPU video memory. By the method, the self-adaption regulation of the image luminance is realized, and the contrast enhancement is performed by a high-dimensional space image geometric method, so that a halation phenomenon is avoided; and particularly, acceleration is performed by using the GPU, so that the processing speed is improved effectively.

Methods, apparatus, and systems are provided for remoteable communication systems. More particularly, the inventions of this system include a remoteable or distributed communications system having a plurality of front ends located remotely from a base station. Each front end includes a receive side subsystem with an HTS filter, a non-linear modulator, and may also include a low noise amplifier coupled to the non-linear modulator. The non-linear modulator modulates a RF signal in light prior to transport via an optical transmission path to the base station. Because the modulator is placed in the front end, no down conversion is required prior to transport of a received signal.

The invention discloses a local edge feature integration-based target object contour extraction method. The method comprises the steps of firstly performing filtration processing on an input original image by adopting a group of Gabor filter banks different in direction to obtain a directional information graph and a corresponding energy distribution image; and secondly dividing an image region into a central region and a peripheral region according to processed pixel point coordinates, and designing a peripheral center action mechanism based on a directional distribution difference, so that the robust contour extraction method is realized through flexible local edge feature integration, wherein the peripheral region consists of a plurality of sub-regions capable of independently perceiving local features and performing nonlinear modulation in response to the central region. According to the contour extraction method, feature integration parameters can be adaptively calculated according to a context relationship in a large-range region where pixels are located, and the robustness and validity of contour extraction of target objects in complex scenes can be effectively improved.

A phase-locked loop control system and method are described. Present invention phase-locked loop control systems and methods facilitate control of phase-lock loop operations. In one embodiment, phase-lock loop control systems and methods are utilized in the implementation of a modulated frequency synthesizer for facilitating efficient frequency spreading over a designated spectrum. It is appreciated that present invention embodiments can have a variety of implementations and can be compatible with vector accumulation. For example, a phase-locked loop control system or method can facilitate generation of a variety of modulation patterns, including but not necessarily limited to linear or non-linear modulation, standard or non-standard modulation, etc.

A ladar system with phase correction. The novel ladar system includes optics for receiving a first signal that is a reflected version of a transmitted laser signal, an optical delay line for providing a second signal that is a delayed version of the transmitted laser signal, and a mechanism for mixing the first signal with the second signal. The second signal is delayed by a time T_D that reduces a relative time difference between the first and second signals such that phase errors caused by laser transmitter instabilities and nonlinear modulation are less than a predetermined level.

The present invention provides a contour detection method based on a non-classical receptive field and linear nonlinear modulation. The method comprises: A, inputting an image to be detected through gray processing; B, performing Gabor filtering of the image to be detected to obtain the Gabor energy value of each direction of each pixel point; C, constructing X-cell and Y-cell simulation models in a retina ganglion cell; D, calculating and obtaining stimulating response of each central neuron through the non-classical receptive field corresponding to the X cell; E, calculating and obtaining the stimulating response of each central neuron through the non-classical receptive field corresponding to the Y cell; F, respectively calculating the stimulating response of central neurons of the X cell and the Y cell through the combined modulation of the classical receptive field and the non-classical receptive field, and performing addition of the stimulating response of central neurons of the X cell and the Y cell to take as a corresponding contour value; and G performing processing of the contour values of each pixel point to obtain a final contour value. The contour detection method based on the non-classical receptive field and the linear nonlinear modulation overcomes the defect that the contour recognition rate is low in the prior art, and has good simulation effect and high contour recognition rate.

The invention provides a low frequency broadening non-linear feedback control apparatus and a method thereof. The apparatus is characterized in that: a receiving module receives an input signal and transmits the input signal to a non-linear control module; the non-linear control module carries out non-linear modulation on a signal input by the receiving module, transmits a modulated signal to a reference output module, and combined with a feedback signal output by a feedback control module, the non-linear control module carries out non-linear modulation and transmits a modulated signal to the reference output module; the reference output module computes difference between the modulated signal and a reference signal, and determines whether the modulated signal satisfies an expected requirement or not, if so, the modulated signal is output as an output signal, if not, the modulated signal is transmitted to the feedback control module. Through the non-linear control module and the feedback control module, the input signal output various orders of harmonic waves of a plurality of frequency components, amplitude is restricted, line spectrum is broadened, and under an effect of an appropriate parameter, reduction of input line spectrum energy is realized.

The invention provides an on-chip integrated transceiver matching network and method suitable for constant envelope non-linear modulation. The method comprises the following steps that: when a chip isin a receiving state, a first toggle switch is switched on, so that no signal connection exists between a transmitting end TX of an on-chip transmitting circuit and a port of an off-chip antenna, a second toggle switch is switched off, and a signal of an antenna port is transmitted to a receiving end RX of an on-chip receiving circuit through an antenna matching network and an on-chip transformer; and in a transmitting state, the first toggle switch is switched off, so that the signal of the transmitting end TX is transmitted to the antenna port through an output bandpass filter network, thesecond toggle switch is switched on, and the on-chip transformer is short-circuited and connected to GND. The on-chip integrated transceiver matching network can be designed and implemented on an integrated circuit silicon chip. In addition to the antenna, additional matching devices are not needed off the chip; a large number of high-order harmonic components generated when a constant envelope non-linear modulation signal is transmitted can be filtered out; band-pass selection for a required frequency band is provided during inputting; and static charge discharge protection for the antenna end of the chip is formed by on-chip inductance.

There is provided a modulation profile generator and spread spectrum clock generator including the modulation profile generator. The modulation profile generator includes an input signal generator that generates an input signal; a function calculator that outputs a function calculation result in the form of a square root graph by using the input signal as an input of a function; and a profile generator that generates a non-linear modulation profile based on the function calculation result. As a result, it is possible to effectively reduce electromagnetic interference.

The invention discloses a carrier modulation nonlinear ultrasonic guided wave damage detection method, comprising the following steps: selecting a high-low frequency component according to frequency response characteristic of a detection object, and performing delayed time processing on the high-low frequency component and combining with a low frequency component to form a modulated carrier signal; performing signal acquisition by adopting a single excitation-single reception mode, exciting the modulated carrier signal containing a high frequency component and the low frequency signal by virtue of a single-excitation transducer, generating nonlinear modulation effect by the carrier signal by virtue of interaction with damage during propagation, and acquiring by a reception transducer by virtue of a transmission method; according to arrival time of the high frequency component and time when an end surface reflects an echo, intercepting the signal and analyzing, performing filtering andnormalization processing on the signal, then decomposing a received signal by adopting an empirical mode decomposition method, and according to decomposed IMF frequency spectrum information, selectingIMF components containing a base frequency and a nonlinear frequency component and performing signal reconstruction; and extracting a difference frequency component of a high-frequency modulation sidelobe and a low-frequency modulation sidelobe, namely a nonlinear component, calculating a nonlinear coefficient, and evaluating material damage degree by taking a nonlinear coefficient of zero damageas a benchmark.

The invention discloses an optical frequency comb signal generating device and method. The light source area of an electro-absorption modulated laser is non-linearly modulated by the modulation area of the electro-absorption modulated laser, so that optical pulse signals are outputted; the repetition frequency of the optical pulse signals is equal to the frequency of a microwave signal source; thehigh-order sideband of integral multiples of the frequency of the microwave signal source is enhanced and expanded by a cascaded four-wave mixing effect of a non-linear semiconductor optical amplifier; and finally, an optical frequency comb is outputted. The optical frequency comb signal generating device is simple in structure and can be integrated; and optical frequency comb signals generated by the device are wide in frequency spectrum and have a large number of comb teeth.