31results about How to "Improve phase detection accuracy" patented technology

A radiographic apparatus includes a first grating, a second grating, a scanning unit, and a radiological image detector. The second grating includes a periodic form that has a period which substantially coincides with a pattern period of a radiological image formed a radiation having passed through the first grating. The scanning unit relatively displaces the radiological image and the second grating to a plurality of relative positions at which phase differences between the radiological image and the second grating are different each other. The radiological image detector detects the radiological image masked by the second grating. The scanning unit includes a driving unit that drives one of the first grating and the second grating relatively to the other in a pattern arrangement direction of the radiological image and a plurality of elastic members that has natural frequencies different from each other.

The invention discloses a frequency-locked loop and subcarrier loop united phase discrimination tracking loop which comprises a carrier tracking loop, a subcarrier tracking loop and a spreading code tracking loop. The carrier tracking loop firstly conducts carrier stripping processing on received intermediate-frequency BOC signals, the obtained output signals are used as the input of the subcarrier tracking loop, and multiplied by local cosine and sinusoidal signals generated by a subcarrier numerically controlled oscillator, and the obtained signals are input to the spreading code tracking loop to conduct code phase tracking. Due to the ambiguity problem of binary system offset carrier signal tracking, the united phase discrimination method is adopted in the united tracking loop of the carrier tracking loop and the subcarrier tracking loop so as to solve the problem of phase ambiguity caused by noise when the signal to noise ratio is low. Due to the united phase discrimination method, the phase discrimination precision is improved, and the accurate tracking is achieved.

This invention relates to a high-frequency clock jitter measuring circuit and calibration method thereof, which comprises a first / second oscillation signal unit to generate the first / second oscillation signal with TV1 / TV2 period (TV1 G01R 29 / 02 G01R 23 / 02 G01R 31 / 00 H03K 5 / 19 6 13 4 2006 / 4 / 18 1837835 2006 / 9 / 27 100501423 2009 / 6 / 17 2009 / 6 / 17 2009 / 6 / 17 Peking University Shenzhen Graduate School 518057 Zhang Jingkai Li Chongren Yu Fei Tian Chao guo yan 44223

The invention discloses a clock data recovery circuit with a waveform screening function for a PAM4 receiver and the PAM4 receiver. The clock data recovery circuit for the PAM4 receiver comprises a clock data recovery circuit body with a comparator module and a phase discriminator module, wherein the front end of the phase discriminator module is connected with a waveform screening circuit in series, and the waveform screening circuit is used for selecting symmetrical waveforms in output signals of the comparator module as an output; the PAM4 receiver comprises the clock data recovery circuitfor the PAM4 receiver. The objective of the invention is to solve the problem that the CDR of a PAM4 receiver deteriorates the jitter performance of a recovery clock while improving the phase discrimination density. According to the invention, the waveform screening circuit is added, and the waveform screening circuit selects symmetrical jump edges in the output signals of the three comparators asthe input of the phase discriminator, thereby improving the phase discrimination precision while improving the phase discrimination density, and improving the jitter performance of a CDR recovery clock while guaranteeing the quick locking of a loop.

The invention provides a lead-lag digital phase discriminator structure which is composed of a first signal path, a second signal path and a three-input NAND gate. The first signal path comprises a first D-trigger, a first phase inverter, a first buffer, a first NAND gate, a first digital pulse amplifier and a third D-trigger. The second signal path comprises a second D-trigger, a second phase inverter, a second buffer, a second NAND gate, a second digital pulse amplifier and a fourth D-trigger. The third input end of the three-input NAND gate is connected with an input enabling signal, and the output end is connected with the reset ends of the first and second D-trigger. Effective time of a trigger signal is increased via appropriate additional arrangement of certain logic units and triggers so that lead-lag phase discrimination precision can be greatly enhanced.

The invention discloses a compact field scanning device, solving the problem that a scanning rack of the prior art is big in the measurement error. The compact field scanning device includes a scanning rack and a laser collimator, wherein the scanning rack includes an orientation adjusting mechanism, a pitch adjusting mechanism, a horizontal scanning rack, a vertical scanning rack, and a compensation mechanism; the laser collimator includes a transmitting device and a receiving device; the transmitting device is located at a fixed point above the ground for generating a laser beam parallel toa field plane; the receiving device is fixed at an end portion of a motion tube for receiving the laser beam; after receiving the laser beam, the receiving device detects an offset; and a control unitreceives the offset, and controls the compensation mechanism to reduce the offset. The compact field scanning device can improve the compact field plane wave phase detection accuracy, and can avoid the defects of manual operation, low efficiency, low speed and the like.

The invention relates to a method for detecting vibroseis signal phases based on K-L decomposition. When a vibroseis works, excitation signals of a vibroseis are acquired in real time through a sensor installed on the vibroseis, high random noise of the signals is removed through a K-L decomposer, and the signals are sent to a phase detector and a phase controller respectively to conduct phase detection and phase control on the vibroseis excitation signals. Compared with an existing filtering method, phase information of original signals is not lost in the vibroseis excitation signals extracted by adopting the K-L decomposition method, and the K-L decomposition method especially has the good suppressing effect on signal bands with the high random noise; compared with a self-adaptive filtering method, a mathematic model does not need to support the method for detecting the vibroseis signal phases based on K-L decomposition, and the method can be excellently suitable for unknown coupling model environment; the signals extracted by adopting the K-L decomposition method can truly reflect phase information of the vibroseis excitation signals, the problem of zero point hopping in zero crossing point phase detection is solved, and accuracy of phase detection of the vibroseis excitation signals is improved.

The invention relates to an anti-multipath high-precision code loop phase detection method. The anti-multipath high-precision code loop phase detection method comprises steps that a shift register is constructed, and the shift register is used to generate four different relatively delayed local codes; by using a narrow correlator technology, an integral accumulated value of a same-direction component and an orthogonal component is calculated; a code phase difference is calculated respectively by adopting a non-coherent early minus late amplitude method and a front and back slope method, and the switching of the above mentioned two phase detection methods is carried out according to the phase difference. The anti-multipath high-precision code loop phase detection method is advantageous in that anti-multipath effect and high phase detection result precision are provided; the accurate phase difference is calculated, and the local codes are aligned with received codes more accurately, and therefore the tracking precision of the code loop and a positioning performance of a receiver are improved.

The invention discloses a phase detection method and device, and equipment. The phase detection device comprises a signal processing component, a phase discrimination component and a phase comparison component, wherein the signal processing component is used for obtaining a reference clock signal and an initial phase value thereof; the phase discrimination component is used for obtaining a to-be-detected clock signal and obtaining a first phase difference signal according to the reference clock signal and the to-be-detected clock signal; the phase comparison component is used for obtaining a phase adjustment signal according to the first phase difference signal; the signal processing component is also used for carrying out phase adjustment on the reference clock signal according to the phase adjustment signal so as to reduce the first phase difference signal, accumulating the adjusted phase value so as to obtain a phase cumulative value, and obtaining the phase value of the to-be-measured clock signal according to the phase cumulative value and the initial phase value. In the embodiment of the invention, the phase of the reference clock signal can approach the phase of the to-be-measured clock signal through limited times of processing, so that the clock phase can be measured at high precision and high speed.

The invention discloses a microwave phase discrimination device based on a microwave photon technology, and the device comprises a light source which is used for providing an optical pulse sequence with a femtosecond-order pulse width; a phase discrimination module which is of a Sagnac ring structure in which a DP-DMZM is connected in series in a loop, and is used for modulating phases of two paths of microwave signals of which the frequencies are integral multiples of the repetition frequency of the optical pulse sequence to two orthogonal polarization states of the optical pulse sequence, and enabling forward and reverse propagated modulated optical signals to form interference at an output port of the Sagnac ring structure; a polarization separation module which is used for separating out two orthogonal polarization states in the two paths of optical signals output by the Sagnac ring structure; and a balance detection module which is used for carrying out balance detection on the two paths of separated horizontal polarization state optical signals and the two paths of separated vertical polarization state optical signals respectively to obtain phases of the two paths of microwave signals respectively. The invention further discloses a microwave phase locking device based on the microwave photon technology. According to the invention, the phases of two microwave signals can be independently and accurately detected at the same time, the structure is simple, and the implementation cost is low.

This invention discloses a clock phase-discriminating device and a method for testing the phase difference of a primary signal and a tested signal, in which, the phase signals to be tested expressing the phase difference between the primary signal and the tested signal should be got and the phase-discriminating clock signal numbers contained in the width of the phase signal te be tested should be accumulated to carry out symmetric integration to the continued phase-discriminating clock signals to get numeric quantity integration result of phase-discriminating clock signals and their phase values then to compute the phase width of the phase signal to be tested, which can increase the accuracy for clock phase-discrimination.

The invention relates to a high-speed phase detector, in particular to a high-speed phase detector based on the single-phase-clock dynamic CMOS technology, belonging to the technical field of signal processing and the circuit thereof. Based on the traditional phase detector, a time delay module is added to a feedback loop, so that no dead zone exists when the phase detector is in operation; and ahigh speed D trigger is used for replacing the traditional low speed D trigger, thereby causing the working speed of the phase detector to reach 900 MHz. The phase detector has the advantages of highworking speed, easy manufacture, and no dead zone during the operation, and is especially suitable for precisely differentiating the phase difference of two input signals in a delay-locked loop.

An under-sampling phase detection method and device used in phase laser range finding relate to the field of phase laser range finding. The invention aims to solve the problem that it is difficult toaccurately extract phase information by using the existing phase detection method because of the high frequency and noise of the transmitted signals and the echo signals in the phase laser rangefinder. The method of the invention includes the following steps: transmitted signals and echo signals are under-sampled, and a discrete sequence of the transmitted signals and a discrete sequence of the echo signals are obtained; discrete Fourier transformation is carried out on the two discrete sequences, the maximum values of spectral lines in the two discrete sequences are selected according to theresult of transformation, and the locations of the two groups of spectral lines are determined according to the maximum values of the two groups of spectral lines; and the initial phases of the transmitted signals and the echo signals are calculated according to the locations of the two groups of spectral lines, difference operation is performed on the initial phases of the transmitted signals andthe echo signals, and the difference obtained is the phase detection result. The method and the device are used to extract the phase information of high-frequency signals in a phase laser rangefinder.

The invention relates to a high-speed phase detector, in particular to a high-speed phase detector based on the single-phase-clock dynamic CMOS technology, belonging to the technical field of signal processing and the circuit thereof. Based on the traditional phase detector, a time delay module is added to a feedback loop, so that no dead zone exists when the phase detector is in operation; and a high speed D trigger is used for replacing the traditional low speed D trigger, thereby causing the working speed of the phase detector to reach 900 MHz. The phase detector has the advantages of high working speed, easy manufacture, and no dead zone during the operation, and is especially suitable for precisely differentiating the phase difference of two input signals in a delay-locked loop.

The invention discloses an arrival angle measuring device based on microwave photon auxiliary phase discrimination. The device comprises an antenna array, a light source, a phase discrimination module, a polarization separation module, a balance detection module and a data processing module; the phase discrimination module is of a Sagnac loop structure with a dual-polarization dual-drive Mach-Zehnder modulator connected in series in a loop, and is used for performing phase modulation on the two paths of microwave signals received by the antenna array on two orthogonal polarization states of anoptical pulse sequence respectively, and enabling the modulated optical signals propagating forwards and backwards to form interference at an output port of the Sagnac loop structure; the polarization separation module is used for carrying out polarization state separation; the balance detection module is used for carrying out balance detection on the two paths of separated horizontal polarization state optical signals and two paths of separated vertical polarization state optical signals to respectively obtain phases of microwave signals modulated to a horizontal polarization state and a vertical polarization state; and the data processing module calculates an arrival angle according to the obtained phase information. Compared with the prior art, the device can perform high-precision detection on the arrival angle, and is simple in structure.

The invention discloses a multi-sensor partial discharge sound signal phase detection circuit. The power output end of a power module is electrically connected with the power end of a control module, the power end of a first sound reproduction module, the power end of a second sound reproduction module, the power end of a third sound reproduction module, the power end of a fourth sound reproduction module, the power end of a fifth sound reproduction module and the power end of a sixth sound reproduction module. The signal transmission end of the first sound reproduction module, the signal transmission end of the second sound reproduction module, the signal transmission end of the third sound reproduction module, the signal transmission end of the fourth sound reproduction module, the signal transmission end of the fifth sound reproduction module and the signal transmission end of the sixth sound reproduction module are electrically connected with the signal transmission end of the control module, and the power supply module comprises +5V and +15V. The first sound reproduction module, the second sound reproduction module, the third sound reproduction module, the fourth sound reproduction module, the fifth sound reproduction module and the sixth sound reproduction module are sequentially distributed in a spherical shape. The detection circuit has the advantages of strong anti-interference performance, accurate measurement and the like.

The invention discloses a microwave phase detection device based on microwave photon technology, comprising: a light source for providing an optical pulse sequence with a pulse width of femtosecond level; The Sagnac ring structure is used to phase-modulate the two microwave signals whose frequency is an integer multiple of the repetition frequency of the optical pulse sequence on the two orthogonal polarization states of the optical pulse sequence, and make the forward and backward modulated optical signals in the Sagnac The output port of the ring structure forms interference; the polarization separation module is used to separate the two orthogonal polarization states of the two optical signals output by the Sagnac ring structure; the balance detection module is used to separate the two separated horizontal and The two vertically polarized optical signals are detected in balance, and the phases of the two microwave signals are respectively obtained. The invention also discloses a microwave phase-locking device based on microwave photon technology. The invention can independently and accurately detect the phases of two microwave signals at the same time, and has simple structure and low implementation cost.

The invention provides an undersampling frequency selection method for improving phase discrimination precision. The undersampling frequency selection method comprises the following steps of setting a to-be-sampled signal parameter, setting an undersampling parameter, sampling according to the relative relationship between the undersampling sampling position and the to-be-sampled signal, and confirming the final undersampling frequency, so that the phase discrimination precision is improved. The set to-be-sampled signal parameters comprise set to-be-sampled signal frequency f. The setting of the undersampling parameters comprises setting an undersampling frequency fs. The undersampling frequency fs can meet the effectiveness of undersampling, n is a positive integer, and f is the frequency of the to-be-sampled signal. By means of the method, the technical problem that in the prior art, due to selection of the undersampling frequency, the phase discrimination precision is poor can be solved.

The invention discloses a clock phase discrimination device and method, which are used for measuring the phase difference between a reference signal and a signal to be measured; both need to obtain a phase signal to be measured that can reflect the phase difference between the reference signal and the signal to be measured. The number of phase detection clock signals that can be accumulatively accommodated within the phase width of the phase signal to be measured; and by symmetrically integrating the continuous phase detection clock signal, the integration result of the digital quantity phase detection clock signal within the phase width of the phase signal to be measured is obtained, and then Obtain the phase value of the phase detection clock signal when the integration result of the phase detection clock signal is obtained; then, calculate the phase of the phase detection signal according to the obtained phase value of the phase detection clock signal and the accumulated number of phase detection clock signals width. The device and method of the invention can significantly improve the precision of clock phase discrimination.

The present invention proposes a combined phase detection and tracking loop of a phase-locked loop and a subcarrier loop, including a carrier tracking loop, a subcarrier tracking loop, and a spread code tracking loop, wherein the carrier tracking loop first conducts a process on the received intermediate frequency BOC signal Carrier stripping processing, the obtained output signal is used as the input of the subcarrier tracking loop, multiplied by the local cosine and sine signals generated by the subcarrier numerical control oscillator, and the obtained signal is input into the spread spectrum code tracking loop for code phase tracking, for binary For the ambiguity problem of offset carrier signal tracking, a joint phase detection method is used in the joint tracking loop of carrier tracking loop and subcarrier tracking loop to solve the phase ambiguity problem caused by noise when the signal-to-noise ratio is low. The method improves the accuracy of phase detection and realizes precise tracking.

The invention relates to an anti-multipath high-precision code loop phase detection method. The anti-multipath high-precision code loop phase detection method comprises steps that a shift register is constructed, and the shift register is used to generate four different relatively delayed local codes; by using a narrow correlator technology, an integral accumulated value of a same-direction component and an orthogonal component is calculated; a code phase difference is calculated respectively by adopting a non-coherent early minus late amplitude method and a front and back slope method, and the switching of the above mentioned two phase detection methods is carried out according to the phase difference. The anti-multipath high-precision code loop phase detection method is advantageous in that anti-multipath effect and high phase detection result precision are provided; the accurate phase difference is calculated, and the local codes are aligned with received codes more accurately, and therefore the tracking precision of the code loop and a positioning performance of a receiver are improved.

This invention relates to a high-frequency clock jitter measuring circuit and calibration method thereof, which comprises a first / second oscillation signal unit to generate the first / second oscillation signal with TV1 / TV2 period (TV1 G01R 29 / 02 G01R 23 / 02 G01R 31 / 00 H03K 5 / 19 6 13 4 2006 / 4 / 18 1837835 2006 / 9 / 27 100501423 2009 / 6 / 17 2009 / 6 / 17 2009 / 6 / 17 Peking University Shenzhen Graduate School 518057 Zhang Jingkai Li Chongren Yu Fei Tian Chao guo yan 44223

The invention relates to the technology of ultrasonic power supplies and provides constant-power power supply with a high power factor and fast response to reduce system complexity and improve detection precision. To this end, the invention provides a constant-power driving power supply based on an ARM and a multiplier and a driving method, The constant-power driving power supply comprises a firstpart which is a driving circuit including a DDS chip, an integrated PWM wave control chip and an inversion amplification circuit; a second part which is a sampling matching circuit; a third part which is a signal conditioning circuit; and a fourth part which is a micro-control module formed by an ARM microprocessor and achieving constant-power control by adjusting the frequency and the duty ratioof a PWM wave. The invention is mainly applied to the design and manufacture of ultrasonic power supplies.

The invention relates to the field of signal demodulation, in particular to a digital FM signal demodulator with instant AGC. The digital FM signal demodulator with instant AGC aims to solve the existing technical problems. Through real-time modulation on signal quantization amplitude by means of the instant AGC, the digital FM signal demodulator solves the problem that demodulation is high in error rate due to small FM signal quantization amplitude, and increases the accurate rate of demodulation. The digital FM signal demodulator with instant AGC comprises an ADC unit, an orthorhombic dual-channel digital downconversion unit, an extraction and filtration unit, an instant AGC unit and the like. Intermediate frequency signals generated by a signal generator are input into the ADC unit and quantized into digital signals through the ADC unit, and then the digital signals pass through the orthorhombic dual-channel digital downconversion unit, the extraction and filtration unit, the instant AGC unit and the like in sequence, wherein the instant AGC unit increases the number of quantization significance bits of I(n) and Q(n) signals to the value of the most significant bit allowed by a CORDIC module by detecting the number of quantization sign bits of the I(n) and Q(n) signals, and the error rate of demodulation is lowered effectively.

The invention provides a clock phase discrimination method and device, and the method comprises the steps: generating a plurality of output clocks, determining a target output clock with the smallestphase deviation value with a reference clock from the plurality of output clocks, and recording a first deviation value between the target output clock and a to-be-discriminated phase clock; in two adjacent clock periods, sampling the target output clock according to the reference clock, and determining whether the target output clock is aligned with the reference clock or not according to a sampling result; if the target output clock is not aligned with the reference clock, adjusting the phase of the target output clock according to a preset phase value, sampling and judging again until it isdetermined that the target output clock is aligned with the reference clock, and recording a second deviation value between the adjusted target output clock and the target output clock; and if so, compensating the to-be-discriminated phase clock according to the first deviation value and the second deviation value. By applying the embodiment of the invention, the phase discrimination precision can be improved.

The invention relates to a method for detecting vibroseis signal phases based on K-L decomposition. When a vibroseis works, excitation signals of a vibroseis are acquired in real time through a sensor installed on the vibroseis, high random noise of the signals is removed through a K-L decomposer, and the signals are sent to a phase detector and a phase controller respectively to conduct phase detection and phase control on the vibroseis excitation signals. Compared with an existing filtering method, phase information of original signals is not lost in the vibroseis excitation signals extracted by adopting the K-L decomposition method, and the K-L decomposition method especially has the good suppressing effect on signal bands with the high random noise; compared with a self-adaptive filtering method, a mathematic model does not need to support the method for detecting the vibroseis signal phases based on K-L decomposition, and the method can be excellently suitable for unknown coupling model environment; the signals extracted by adopting the K-L decomposition method can truly reflect phase information of the vibroseis excitation signals, the problem of zero point hopping in zero crossing point phase detection is solved, and accuracy of phase detection of the vibroseis excitation signals is improved.

The invention discloses a digital phase detector for GPS taming crystal oscillator, comprising: a 2N frequency divider for obtaining a square wave pulse signal with a cycle of 2N seconds by dividing the frequency of the 1Hz PPS signal output by the GPS module; High and low level pulse width counters for wide counting; the input is connected to the externally provided frequency lock enable signal, connected to GPS and frequency-divided OCXO clock to output the second pulse clock of the internal second pulse signal; input the internal second pulse signal and GPS module output PPS signal, count the time difference between the rising edges, and output the phase difference counter clock of the phase difference count value; it is used to realize the OCXO crystal oscillator tracking the frequency of the GPS PPS signal, and simultaneously output the frequency value and the frequency count value latch of the phase error value register and a phase error value latch. The invention is convenient for timing design, and avoids the fuzzy problem of leading and lagging initial phase errors. The frequency and phase measuring counter adopts a serial counter scheme, so that the counting clock frequency is not affected by the number of counting digits.

The invention relates to a clock in a digital circuit, and discloses a digital phase detector, so that the phase detection accuracy can be improved under the same frequency phase detection clock. This digital phase detector includes: a delay module, which is used to generate a plurality of phase detection clock signals with different phases according to a phase detection clock signal; The phase detection clock signals of the phases are counted separately, and the total phase detection count value is saved for external use.

The invention relates to a vibroseis phase-locked control system which is formed by that a main control unit is respectively connected with a phase-locked control unit and a signal acquisition and output unit which is connected with a vibroseis module. A K-L decomposition filter is realized in an FPGA chip through programming, the influence of an external electromagnetic interference noise on a phase-locked loop is avoided, the anti noise performance of the system is raised, the zero phase shifting filtering of a vibroseis feedback signal is realized, the problems of feedback signal phase detection time offset and zero jump are solved, thus the phase detection accuracy is improved significantly, and the phase accuracy of a phase-locked loop output signal is increased. At the same time, according to the system, a standard signal is generated by a direct frequency synthesizer (DDS), and compared with the existing analog phase-locked loop control scheme, according to the phase control scheme with the combination of the direct frequency synthesizer and digital phase-locked loop technology, the speed of vibroseis phase-locked control is greatly improved.

The invention provides a lead-lag digital phase discriminator structure which is composed of a first signal path, a second signal path and a three-input NAND gate. The first signal path comprises a first D-trigger, a first phase inverter, a first buffer, a first NAND gate, a first digital pulse amplifier and a third D-trigger. The second signal path comprises a second D-trigger, a second phase inverter, a second buffer, a second NAND gate, a second digital pulse amplifier and a fourth D-trigger. The third input end of the three-input NAND gate is connected with an input enabling signal, and the output end is connected with the reset ends of the first and second D-trigger. Effective time of a trigger signal is increased via appropriate additional arrangement of certain logic units and triggers so that lead-lag phase discrimination precision can be greatly enhanced.