73 results about "Amplitude noise" patented technology

The present invention provides an optical filter assembly that reduces the phase and amplitude noise of a detection laser used to detect ultrasonic displacements. The filtered detection laser is directed to the surface of a remote target. Ultrasonic displacements at the surface scatter the filtered detection laser. Collection optics then gather phase modulated light scattered by the surface and direct the phase modulated light to an optical processor to produce a signal representative of the ultrasonic displacements with an improved SNR. Additional processors may determine the structure of the remote target.

Automatic background signal removal for input data, such as for spectrometry data, is provided. Input data includes input pixel points, such as those read by a CCD spectrometer of chromatography device, and intensity values corresponding to the data points. A distribution of changes in the intensity values between the data points is determined, and a noise level is judged by setting a threshold for the distribution. A noise region is identified as a predetermined number of consecutive input points for which the changes in the intensity values are within the noise level. Adjacent noise regions may be connected and the background signal is thus determined and subtracted. A spike noise region may also be identified and filtered, such that a peak obtained from fewer than a second predetermined number of the pixel points is determined as a spike, not a true peak. Non-spike large amplitude noises are optionally filtered.

A regenerator for restoring the originally encoded optical phase of a differential-phase-shift-keyed signal. In an embodiment, the regenerator simultaneously provides limiting amplification and reduces amplitude noise based on a phase-sensitive optical amplifier that combines a weak signal field of a degraded input data with a strong pump field supplied by a local oscillator in a nonlinear interferometer. The two fields interact through degenerate four-wave mixing, and optical energy is transferred from the pump to the signal and vice versa. The phase sensitive nature of the optical gain leads to amplification of a specific phase component of the signal, determined by the input pump-signal phase difference and the incident signal phase is restored to two distinct states, separated by 180° according to the original encoding. Simultaneously, gain saturation of the pump wave by the signal wave results in limiting amplification of the signal wave for removing signal amplitude noise.

The present invention pertains to the field of the design technology of wireless communication system transceiver chip. The characteristics reside in that: the novel back-to-back series connected type MOS varactor adopting the digital signal control forms the main hypercap part of the numerical controlled LC oscillator, and the phase noise converted from the amplitude noise from the oscillator is reduced, and the restraining ability of the oscillator to the noise from the current source is improved, thus, the phase noise of the output signal of the oscillator is finally reduced. The method in the present invention, comparing with the prior method, can improve the performance of the on-piece CMOS oscillator and reduce the power consumption of the oscillator effectively, thus, the method is useful to the reduction of the manufacturing cost and power consumption of the receiver.

The invention relates to a phase difference synchronous measuring device and a phase difference synchronous measuring method for multi-way sine wave signals, and belongs to the technical field of electronic measurement. The device comprises two or more than two signal conditioning circuits, two or more than two analog-to-digital conversion circuits, two or more than two data registers, a sharing logic control circuit, an interface circuit, a computer, a man-machine interface circuit and a clock circuit, and a measured object is phase difference of two or more than two ways of sine wave signals, wherein the number of the signal conditioning circuits, the number of the analog-to-digital conversion circuits and the number of the data registers are the same, and the signal conditioning circuits, the analog-to-digital conversion circuits and the data registers are matched in a one-to-one mode. Due to the adoption of the device and the method, the phase difference of the multi-way sine wave signals can be measured synchronously, the phase resolution is high, a waveform is stable, the multi-way phase synchronism is high, and error influence factors such as sampling clock jitter, channel synchronization error, the stability of channel phase delay, amplitude noise and the like in the conventional phase measuring method are prevented.

The method according to the present invention includes the steps of splitting an optical signal into first and second optical signals, increasing the pulse widths of the first optical signal to obtain waveform shaped light, generating clock pulses according to the second optical signal, and inputting the waveform shaped light and the clock pulses into an optical AND circuit 10 to obtain a converted optical signal. According to the present invention, it is possible to suppress amplitude noise or the like generated in the optical AND circuit due to the jitter or temporal instability of the optical signal and the clock pulses.

The invention relates to a phase noise optimization compensation method for a CO-OFDM system. By reducing the constraint conditions of a phase noise spectrum structure, an optimization algorithm can effectively compensate the residual amplitude noise after channel equalization regardless of whether the channel estimation is accurate or not, so that the final phase noise estimation accuracy is obviously better than other phase noise estimation algorithms, and a breakthrough phase noise compensation effect is also achieved. According to the scheme of the invention, a phase noise dimensionality reduction model is applied, and the computational complexity of the phase noise optimization method is completely tolerable for the CO-OFDM system. The scheme of the invention can greatly promote the application of the CO-OFDM system in a long-distance access network and a metropolitan area network.

The invention discloses a non-contact breathing detection method and a device thereof. The method comprises the following steps: a receiving device R receives a radio frequency signal from a sending device T, and the receiving device R includes two or more receiving antennas; by aiming at the channel state information CSI corresponding to the radio frequency signals received by any two receiving antennas, a ratio of the two is taken, and a new channel state information of each subcarrier is constructed, which can eliminate phase offset and amplitude noise; an optimal breath detection characteristic of each subcarrier is determined according to new channel state information in a window of a period time; According to the optimal respiratory detection characteristics of the plurality of subcarriers, and the fusion calculation is performed to obtain the respiratory rate of a detection target. By adopting the technical scheme of the invention, a sensing range of the respiratory detection can be greatly expanded, and the method has the technical advantages of non-intrusiveness, convenience and low cost.

The invention discloses an acoustic vector array wideband direction finding method based on a sparse decomposition theory, and relates to a direction finding technique and implementation method for target broadband continuous spectrum noise in the acoustic vector sensor array detection field. The sparsification idea is introduced to an acoustic vector array direction finding system; a combined sparse constraint is established according to frequency point components in broadband continuous spectrum noise signal bandwidth; and finally, a unified airspace sparse decomposition form is obtained, thereby realizing direction finding of the broadband continuous spectrum noise. According to the method, a relatively-sharp spectrum peak and a low-amplitude noise floor can be formed; when the number of array snapshots is small, the method is stable in performance and can distinguish coherent signal sources; and when the target DOA (direction of arrival) approaches to the array axial direction, the phenomenon of noise floor fluctuations occurring under the condition of low signal-to-noise ratio of a conventional beam forming (CBF) method and a minimum variance distortionless response (MVDR) method does not exist.

The embodiment of the invention provides a carrier phase recovery method and device based on a Kalman filtering algorithm. The method comprises the following steps: performing carrier phase estimation on a 16QAM (Quadrature Amplitude Modulation) signal through a carrier phase estimation algorithm, and obtaining a first phase estimation value; performing phase recovery on the 16QAM signal according to the first phase estimation value, and obtaining the 16QAM signal after the first recovery; performing phase estimation on the recovered 16QAM signal through the Kalman filtering algorithm, and obtaining a second phase estimation value; and performing phase recovery on the recovered 16QAM signal according to the second estimation value, and obtaining the 16QAM signal after the second recovery. By using the carrier phase recovery method and the device based on the Kalman filtering algorithm provided by the embodiment of the invention, the error of phase estimation in the Kalman filtering algorithm is effectively reduced, and the influence of phase noise and amplitude noise is removed more accurately.

A driver circuit for a laser diode provides drive signals to the electrodes of the laser diode based on a pulsed input signal. An input receives the pulsed input signal and launches it into an amplification stage which preferably includes dual amplifiers, a buffering stage and a biasing stage. The output of the laser diode is an optical signal that reproduces the pulsed input signal with high fidelity and low amplitude noise. In one embodiment, the input separates the pulsed input signal into two signal components, launched in respective inverting and non-inverting branches which each include successive amplification, buffering and biasing stages.

An optically pumped tunable VCSEL swept source module has a VCSEL and a pump, which produces light to pump the VSCEL, wherein the pump is geometrically isolated from the VCSEL. In different embodiments, the pump is geometrically isolated by defocusing light from the pump in front of the VCSEL, behind the VCSEL, and / or by coupling the light from the pump at an angle with respect to the VCSEL. In the last case, angle is usually less than 88 degrees. There are further strategies for attacking pump noise problems. Pump feedback can be reduced through (1) Faraday isolation and (2) geometric isolation. Single frequency pump lasers (Distributed feedback lasers (DFB), distributed Bragg reflector lasers (DBR), Fabry-Perot (FP) lasers, discrete mode lasers, volume Bragg grating (VBG) stabilized lasers can eliminate wavelength jitter and amplitude noise that accompanies mode hopping.

The invention discloses a state observer of a complex dynamic network. Signal transmission between a monitored network and the state observer can be influenced by channel noise, the noise is suppressed by an integral observer, integral modeling is conducted on measuring signals of the complex dynamic network, the measuring signals after integral serve as control signals of an estimator so as to build an observer model; a norm controlling gain design of the observer of the complex dynamic network is given according to Lyapunov stability theory and linear matrix inequality, the norm is expressed by the linear matrix inequality so as to estimate the state of the complex dynamic network efficiently. The invention further discloses a state estimation method of the complex dynamic network based on the state observer. According to the state observer and the state estimation method of the complex dynamic network, state errors can be restrained to a low-amplitude noise range, and therefore accurate estimation of all nodes in the complex dynamic network is achieved.

The invention discloses a design method for reducing crosstalk influence between high-speed differential pairs. Polarity of the parts, in front and rear of DC (direct current) coupling capacitors, of differential pair lines is reversed; crosstalk positive and negative amplitude noises of far ends are mutually stacked; differential overall noise is weakened. Theoretical analysis and simulation verification show that the design method has the effect of improving crosstalk quality of high-speed signals on high-density layout PCBs (printed circuit boards); by the use of the design method, development cost of products can be lowered, product quality is stable, and the products are more competitive in the market.

The disclosed testing device for laser phase noise comprises: a phase noise conversion device with two polarization beam-splitting lens (1) and (3), and an atom gas chamber or molecule gas chamber (2). Wherein, coupling two beam linear polarization light by (1) to spread into (2), converting the phase noise into amplitude noise by electromagnetic induced coherence effect, using (3) to divide the detecting light and coupling light, and using a balance zero-beat system to detect the outgoing noise. This invention simplifies device fit to mobile and wide application.

The method of sweep frequency source with restorable phase information belongs to metric testing field. It takes advantage of Hilert transform to restore its lost phase information on the basis of sweep frequency source calibrating method of broadband sampling oscilloscope, thus reconstructs step response of oscilloscope. In this method, sweep frequency source (1) outputs adjusted constant amplitude sine-wave sweep signal, oscilloscope (2) receives amplitude-frequency response of oscilloscope, then it finished the process of data in computer process (3). The processing step includes: preprocess of data of amplitude-frequency through widening frequency-field window and adding certain-amplitude noise to data of prolongation; then, it restores the phase with Hilbert transform in order to receive intact data including amplitude-frequency and phase-frequency response.

The invention discloses an inductor-capacitor (LC) oscillator with basically constant variable capacitance in an oscillation period. The LC oscillator comprises a resonance network consisting of an inductor L and a self-adaptive compensation variable capacitor, a complementary cross-coupling negative resistance amplifier and a bias current source, wherein the variable capacitor is a self-adaptive compensation varactor (AC-Varactor). By dynamically compensating the variable capacitance of the AC-Varactor, variable capacitance variation caused by amplitude variation of output waveform is avoided, and frequency modulation caused by the amplitude variation is avoided, so that phase noise performance deterioration caused by amplitude noise is minimized. The LC oscillator overcomes the defects that in one oscillation period, the variable capacitance can change the oscillation frequency along with the change of voltage at two ends, and the oscillator phase noise performance is decreased by an amplitude modulation to frequency modulation (AM-FM) process; and the LC oscillator with the basically constant variable capacitance in the oscillation period has good phase noise performance and can be widely applied to wireless communication systems.

The invention discloses a differential detection device for a coherent layout imprisoned magneto-optic effect. The differential detection device comprises a bias coupler, a laser, a solenoid, alkali metal atomic vapor bubbles, a polarization beam splitting crystal, a photoelectric cell and a second photoelectric cell. The invention also discloses a differential detection method for the coherent layout imprisoned magneto-optic effect. According to the method, differential detection is performed on a laser signal obtained after linearly polarized light and atoms are mutually interacted in a magnetic field; through the scheme, common-mode noises which are associated with laser amplitude noises and frequency noises can be inhibited, so that the signal-to-noise ratio of the signal is improved; therefore, the stability of the output frequency of a coherent layout imprisoned atomic clock is improved. A passive coherent layout imprisoned atomic clock realized by adopting the scheme has the advantages of simple structure, low cost, small size and the like, and is suitable for realizing small and micro atomic clocks. The invention also discloses the differential detection method for the coherent layout imprisoned magneto-optic effect.

An optical signal regeneration technique includes receiving optical symbols in a phase-modulation format. The received symbols are converted to symbols in a phase / amplitude-modulation format. A first amplitude regeneration, which involves reduction of amplitude noise, is applied to a first symbol pair. A modulation format conversion is performed on the optical signal in the phase / amplitude modulation format after the first amplitude regeneration. A second amplitude regeneration is applied to a second symbol pair, wherein the first and second symbol pairs differ from one another in respect of at least one different feature, which is selected from a group that includes a different nominal phase value assigned to the symbols of the symbol pair and a different temporal distance between the symbols of a symbol pair.

A multistage system and method for estimating respiration parameters from an acoustic signal. At a first stage, the method and system detect and isolate portions of the signal that exhibit long-term, moderate amplitude noise by analyzing cumulative energies in the signal, and portions of the signal that exhibit short-term, high amplitude noise by analyzing peak energies in the signal. At a second stage, the method and system filter heart sound from the signal energy envelope by applying an adaptive filter that minimizes the loss of respiration sound. At a third stage, the system and method isolate respiration phases in the signal by identifying trends in the energy envelope. Once respiration phases are isolated, these phases are used to estimate respiration parameters, such as respiration rate and I / E ratio.

A method for determining the phase and / or amplitude noise spectrum of a digitally modulated input signal. The method for determining a phase-noise spectrum comprises generating real complex samples, by digitally sampling a phase component and phase quadrature component of the input signal in baseband, determining ideal complex samples from generated real samples, establishing complex quotients from the real and ideal complex samples, generating modified complex quotients by assigning the value 1 to the complex quotients, and subjecting the modified complex quotients to a Fourier transform. The invention also concerns a similar method for determining the amplitude noise spectrum of the digitally modulated input signal.

The invention relates to the communication filed, in particular to a method, a device, a base station and terminal equipment for obtaining the signal noise ratio and the amplitude noise ratio, and for simplifying the process of obtaining the SNR and the ANR. The invention conducts linear joint detection on the received data, and obtains the SNR or the ANR of the data according to the result of the linear joint detection; and estimates the corresponding ANR according to the SNR and the algorithm type of the linear joint detection; or estimates the corresponding SNR according to the ANR and the algorithm type thereof, thus, the technical proposal of the invention only needs to obtain one of the SNR value or the ANR value, according to the value, the other value can be estimated; while obtaining the two values simultaneously is not needed, so that the amount of corresponding operation is reduced, the processes of obtaining the SNR and the ANR are simplified, and the load of the corresponding device is lowered.

A method for cancellation of amplitude modulation noise using feedforward or feedback topologies. The method is adaptable to cancel amplitude modulation noise (contamination) of an input signal, including: receiving an input signal including an amplitude modulation noise signal; demodulating the amplitude modulation noise signal to generate a baseband amplitude modulation noise signal; signal processing the baseband amplitude modulation noise signal to generate a amplitude re-modulation signal; and re-modulating the input signal based on the amplitude re-modulation signal to generate an output signal, the output signal having less amplitude modulation noise than the input signal. In a feedforward embodiment, the methodology includes: signal processing the baseband amplitude modulation noise signal based on signal inversion to generate the amplitude re-modulation signal; and feeding forward the amplitude re-modulation signal to re-modulate the amplitude re-modulation signal with the input signal. In a feedback embodiment, the methodology includes: receiving the input signal in a gain controlled amplifier, generating a gain-controlled output signal; detecting the amplitude of the amplitude noise modulation signal in the gain-controlled output signal to generate a feedback amplitude noise signal; integrating the feedback amplitude noise signal to generate a gain control signal; and adjusting the gain controlled amplifier based on the gain control signal, such that the gain-controlled output signal has less amplitude modulation noise than the input signal.

A method for determining jitter and noise of an input signal. The method includes acquiring one or more uncorrelated waveform records by an acquisition unit of a test and measurement instrument, determining a correlated waveform from the acquired waveform(s), dividing the correlated waveform into unit intervals, dividing an uncorrelated waveform into unit intervals, measuring a timing displacement (t 1 ) between the correlated waveform and the uncorrelated waveform for each unit interval to form an apparent-jitter array ([t 1 ]), measuring a voltage displacement (V 1 ) between the correlated waveform and the uncorrelated waveform for reach unit interval to form an apparent-noise array ([V 1 ]), calculating a horizontal shift (t s ) between the correlated waveform and the uncorrelated waveform for each unit interval to form a compensated edge time array ([t s ]), and calculating a vertical shift (V s ) between the correlated waveform and the uncorrelated waveform for each unit interval to form a compensated amplitude voltage array ([V s ]).

A unique optical encoder is employed that utilizes an optical phase modulator, in which an arbitrary phase shift can be realized. The phase modulator is driven by an electrical signal, where the voltage amplitude is proportional to a desired arbitrary phase shift. However, any amplitude noise or poor rise and fall times of the driving voltage translates directly into phase errors. These problems are eliminated by employing a digital phase switch. One encoder, in accordance with the invention, employs an optical phase modulator that can switch the optical phase in a binary manner, wherein the two phase states of the modulator can be chosen to differ by any desired arbitrary angle depending on the splitting ratio of the optical signal to be modulated.

The embodiment of the invention provides a light intensity detection unit and a light intensity detector, as well as a detection method and display device thereof, relates to the technical field of display, and aims to solve the problem of reduced detection accuracy due to poor amplitude noise resistance in the process of collecting the amplitude of a photoelectric current signal generated by a photosensitive device. The light intensity detection unit comprises a first reverser, a second reverser, a third reverser, a photosensitive device and an energy storage module, wherein the first reverser is used for respectively outputting voltage of a first voltage terminal and voltage of a second voltage terminal to the energy storage module under control of the signal input end of the light intensity detection unit; the second reverser and the third reverser are used for controlling the photo-current generated by the photosensitive device to output along the first direction and the second direction; and the energy storage module is used for controlling the voltage of the signal output end of the light intensity detection unit by voltage storage or voltage release.

The present invention is a method for reducing phase noise in oscillator signals. For example, the oscillator may be a low phase noise MEMS-based oscillator and may include a resonator (ex.—a MEMS resonator). Further, the resonator of the oscillator may be operated near a bifurcation point. Still further, the MEMS resonator may be parametrically pumped in such a way so as to redistribute the quadrature signal noise (ex.—phase noise) to in-phase noise (ex.—amplitude noise).