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 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.

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.

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.

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.

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.