71 results about "Jitter noise" patented technology

A modulation system and method having a high linearity. The system is a PWM modulator or a class D amplifier and includes an integrator, a low pass filter (LPF), a comparator, and an output circuit. The LPF is located before the comparator. Jitter noise produced by the comparator and/or switching noise of the output circuit are removed by feedback to the input. Thus, the linearity of the modulation system is provided.

The invention relates to an intelligent terminal sensing-based highway vehicle lane identification method and system. The method includes the following steps that: a built-in sensor in an intelligent terminal is utilized to acquire data; jitter noise in the data are removed through a low-pass filter; the coordinate system of the intelligent terminal is aligned with the coordinate system of a vehicle; and the lane changing behavior of the current vehicle and the number of lane dividing lines which are crossed by the vehicle in lane changing can be judged according to acceleration information detected by the intelligent terminal. According to the intelligent terminal sensing-based highway vehicle lane identification method and system of the invention, a lane where a vehicle running on a highway is located can be judged through sensing different types of lane changing behaviors.

The invention discloses a digital delay device, which comprises a delay part, a first control logic circuit and an output clock selection circuit, wherein the delay part comprises a first delay circuit and a second delay circuit, which are used for processing digital signals respectively, and the digital signals are differential signals of each other; the first control logic circuit is used for controlling the first and second delay circuits to output a first clock signal and a second clock signal respectively; and the output clock selection circuit is used for outputting a third clock signal according to the first clock signal and/or the second clock signal. The problem that a great number of delay units of a delay chain are required to cause loud clock jitter noise when a digital delay locked loop is required to have maximum delay time in related technologies is solved, and the effect of lowering the clock jitter noise is achieved.

A receiver may include a clock and data recovery circuit, a detection circuit and a sampling clock generator. The clock and data recovery circuit may receive first data and sample the first data to generate recovered data in response to a reception sampling clock signal. The detection circuit may detect a frequency difference between a transmission sampling clock signal and the reception sampling clock signal by comparing the first data and the reception sampling clock signal to generate a frequency difference detection signal. The sampling clock generator may generate the reception sampling clock signal based on the frequency difference detection signal and a first reference clock signal. Therefore, a communication system including the receiver may effectively reduce a jitter noise.

The present invention discloses a novel multi-channel timing recovery scheme that utilizes a shared CORDIC to accurately compute the phase for each tone. Then a hardware-based linear combiner module is used to reconstruct the best phase estimate from multiple phase measurements. The firmware monitors the noise variance for the pilot tones and determines the corresponding weight for each tone to ensure that the minimum phase jitter noise is achieved through the linear combiner. Then a hardware-based second-order timing recovery control loop generates the frequency reference signal for VCXO or DCXO. A single sequentially controlled multiplier is used for all multiplications in the control loop.

The invention discloses a snapshot compact noise immunity type light field imaging full polarization spectrum detection device and method. The device comprises an object lens, a light field modulation unit, a micro-optical array, an area array detector and a data acquisition and processing display system. The object lens, the light field modulation unit, the micro-optical array and the area array detector are arranged in turn along an incident light direction. The light field modulation unit is arranged at the position of the aperture diaphragm of the object lens. The micro-optical array is arranged at the position of the image plane of the object lens. The area array detector is arranged on the rear focal plane of the micro-optical array and connected with the data acquisition and processing display system. The light field modulation unit comprises a polarization modulation module and a spectrum filter array. The device is suitable for detecting all light information of a dynamic or quick change target and can effectively avoid the adverse influence caused by the change of the target, jitter noise or the change of environment and other factors so as to have potential application value in the field of astronomical observation, space exploration, remote sensing of the earth, machine vision and biomedical diagnosis.

Systems and methods that provide clock jitter compensation architectures that improve the performance of direct radio frequency (RF) receivers by injecting a calibration tone into the received radio frequency (RF) signals in order to help identify and then compensate for the clock jitter noise. After injecting the tone, the jitter noise going through the direct RF bandpass sampling receiver is estimated using a narrow bandwidth filter, and the received signals are further processed and demodulated depending on the Nyquist zone of the received signal. The relative modulation factor for the modulation is computed and then applied to the Nyquist zone to de jitter that particular Nyquist zone.

In an embodiment, a delta-sigma modulator is constructed from one or more stages of a first order low-pass filter, which has a modest gain compared to the integrator used in other embodiments of delta-sigma modulators. Delta-sigma modulators can be converted into low-pass filter based delta-sigma modulators according to an embodiment of the invention by replacing the ideal integrator building block with a first order low-pass filter and adjusting other loop parameters, such as gain factors, accordingly. In an embodiment, a dithering technique to suppress spurious tones can be used with the low-pass filter based, ideal integrator based, or near ideal integrator based delta-sigma modulator. In another embodiment, a noise cancellation technique can also be used to cancel the dithering noise.

The invention discloses a wide band induction heating power supply based on resonance frequency tracking. The wide band induction heating power supply comprises a rectifier filter circuit, a full-bridge inverter circuit, an impedance matching transformer, a resonant circuit, a zero-crossing comparing circuit, a full-digital frequency tracking controller and a full-bridge driving circuit; the full-digital frequency tracking controller is composed of a digital phase discriminator, a digital filter and a digital oscillator; the digital phase discriminator is composed of a shaping filter and a phase comparator; and the digital oscillator is composed of a phase difference frequency word controller, a reference frequency word controller, a phase angle threshold controller, a frequency word controller and a direct digital synthesizer. The wide band induction heating power supply adopts the full-digital frequency tracking controller and has the characteristics of quick resonance frequency search, wide frequency band and high precision; and the wide band induction heating power supply adopts the shaping filter to conduct shaping on signals representing the load voltage and the current phase, the influence of high-frequency jitter noise on the phase comparator is reduced, and the anti-jamming ability of a system is enhanced.

The invention relates to the technical field of antennas, and particularly relates to a helicopter conformal omnidirectional short wave antenna for helicopter short wave radio communication. The conformal omnidirectional short wave antenna for helicopter short wave radio communication is composed of an antenna radiator (1) and a cable assembly (2), wherein the antenna radiator (1) and the cable assembly (2) are welded as a whole by a core wire, and a bottom feed mode is adopted. The conformal omnidirectional short wave antenna for helicopter short wave radio communication is characterized in that the conformal antenna technology is adopted, the antenna radiator (1) is mounted on the inner surface of a non-metallic and non-carbon fiber skin of the helicopter, the antenna radiator (1) has three sections, and the three sections are connected into a Z type with the consistent shape with the inner surface of the skin of the helicopter through fasteners. The antennas has better performance, and also has the advantages of simple layout, large radiation elevation angle, no jitter noise, no wire breaking phenomenon and no freezing phenomenon.

The invention provides a pulse modulation signal carrier frequency measuring system. The system comprises a front-end circuit, a high-speed acquisition card and a host computer, the front-end circuitis used for performing frequency mixing on a tested signal and a local carrier and outputting a pulse modulation intermediate frequency carrier signal to the high-speed acquisition card, the high-speed acquisition card is used for converting the acquired modulation pulse intermediate frequency carrier signal to a digital signal and transmitting the digital signal to the host computer, and the hostcomputer is used for performing a frequency measuring algorithm based on zero passage judgment and cycle counting on the acquired digital signal. According to the system, the measurement of the carrier frequency of the pulse modulation signal is realized on the host computer so that the overall architecture of the device for realizing the algorithm is more software-based, the design thought of software radio is satisfied, the hardware design is simplified, the hardware architecture is more universal, the design of the software algorithm of the host computer is more flexible, and the influenceof signal jitter noise on a measuring result in a signal frequency measuring process is optimized; and the precision of frequency measurement is improved by employing a cycle measuring method, zero passage detection and linear interpolation.

A test data generator, test system and method thereof are provided. In the example method, parallel test data may be received at a first data rate. The received parallel test data may be converted into serial test data at a second data rate. Noise (e.g., jitter noise, level noise, etc.) may be selectively inserted into the converted serial test data. The noise inserted into the serial test data, which may be configured to operate at a higher data rate than the parallel test data, may allow a device to be tested with higher data-rate test data. The example method may be performed by the example test data generator and/or by the example test system.

Disclosed is an apparatus for generating a stable clock signal having a Long term jitter noise removed therefrom. In a mobile communication terminal having a power management chip for converting a sinusoidal wave oscillated in a crystal into a clock signal of square wave, the sinusoidal wave is converted into a square wave clock signal by the stabilized driving power having no alternating current components, and thus a power noise of the square wave clock signal is removed. Then, the square wave clock signal having the power noise removed therefrom is outputted after a predetermined delay time. Accordingly, it is possible to supply the clock signal having the Long term jitter noise removed therefrom and synchronized to each device in the mobile communication terminal.

The invention relates to the technical field of detection of a moving target in a low-quality video, and especially puts forward a video foreground detection method by use of a VIBE (Visual Background Extractor) law. According to the method, a VIBE model is adopted, the R value is expressed in Rn, the value of Rn is related to the human eye resolution threshold and the jitter noise inhibition threshold H(noise) in an interval, and the relation is Rn=k*delta s(n)+H(noise), wherein n is the grey value [0, 255], k is a gray threshold system [2, 4], and H(noise) is the gray value jitter noise threshold in each gray interval. According to the invention, improvement is made based on the shortcomings of a VIBE model method, and a video foreground detection method which enables a background image to be generated and increases the ability to distinguish close gray scales is put forward.

A helicopter antenna is characterized in that the antenna is of a 'Z'-shaped tube shape, a spiral radiator is disposed inside the antenna, and the working frequency band of the antenna is 2MHz-30MHz. The helicopter antenna has the advantages that on the basis of guaranteeing the performance of the antenna, the length of the antenna is reduced, the directivity angle of the antenna is increased, jitter noise and wire fracture are reduced, and influence of freezing on the antenna is reduced.

The device provides a snapshot compact channel modulation optical field imaging full polarization spectrum detection device and method. The device comprises an objective lens, an optical field modulation unit, a micro optical array, a surface array detector and a data acquisition and processing display system. The objective lens, the optical field modulation unit, the micro optical array and the surface array detector are successively arranged along the incident light direction. The optical field modulation unit is arranged at the position of the aperture stop of the objective lens. The micro optical array is arranged on the image plane position of the objective lens. The surface array detector is placed on the back focal plane of the micro optical array and is connected with the data acquisition and processing display system. The device provided by the invention is suitable for detecting the all-optical information of a dynamic or fast-changing target, can effectively avoid the negative influence caused by the target change, the jitter noise, the environment change or other factor, and has a potential application value in astronomical observation, space exploration, earth remote sensing, machine vision, biomedical diagnosis and other fields.

The embodiment of the invention discloses a blood vessel image processing method and device, an apparatus and a storage medium, and the method comprises the steps: obtaining a blood vessel longitudinal cutting image which comprises a first initial image comprising the upper wall of a blood vessel and a second initial image comprising the lower wall of the blood vessel; determining each turning point in the edge curve of the upper wall of the blood vessel in the first initial image, and smoothing the edge curve according to the position relation between the turning points to obtain a first reference image; rotating the first reference image to enable the target starting point and the target ending point of the edge curve of the first reference image to be correspondingly overlapped with theinitial starting point and the initial ending point of the edge curve in the first initial image respectively; and obtaining a target image according to the rotated first reference image and the second initial image. According to the technical scheme provided by the embodiment of the invention, under the condition that the overall posture of the original blood vessel is kept, jitter noise causedby respiratory heartbeat is removed, and the credibility of the diagnosis result obtained based on the blood vessel image is improved.