231 results about "Frequency synthesizer" patented technology

A digital frequency synthesizer includes a delay-locked loop (DLL) that generates time-delayed versions of a reference clock signal, a clock divider that executes an integer-division operation on one delayed clock signal to generate an integer-divided clock signal, and control circuitry that generates fractional data for enabling a fractional division. The digital frequency synthesizer further includes a first clock selector that selects one delayed clock signal as a DLL clock signal based on the fractional data, a delay chain that generates time-delayed versions of the DLL clock signal, and a second clock selector that selects one delayed clock signal as a selected clock signal based on the fractional data. A rising edge of the integer-divided clock signal is adjusted based on the selected clock signal to generate a fractional-divided clock signal that is a fractional-divided version of the reference clock signal.

The invention relates to the field of digital signal processing, in particular to a miniature digital transceiver module which comprises a signal processing board and a power clock board. The signal processing board and the power supply clock board are stacked and interconnected through a high-speed connector; the signal processing board integrates multiple ADC acquisition channels and DAC output channels, and is internally provided with an RFSOC chip to realize multichannel digital down-conversion, waveform generation and signal processing functions. The power supply clock board integrates a power supply conversion module and a clock frequency synthesizer, provides various power supply varieties for the module, and generates a time sequence, a sampling clock and a reference clock. The stacking design of the two board cards forms a high-integration digital transceiver module, thereby saving a large amount of space and improving the system integration. The scheme is obviously superior to a traditional design method in the aspects of volume, power consumption, performance and the like, and is particularly suitable for equipment sensitive to an outer envelope.

The embodiment of the invention provides a rubidium atomic clock based on a velocity grating spectrum and an implementation method, and the method comprises the steps: enabling a multi-frequency coherent laser source to emit a laser signal containing the velocity grating spectrum, and dividing the laser signal into two paths through a polarization splitting prism; the reflected light beam enters the laser frequency stabilization module to realize laser frequency stabilization; a transmission light beam enters the rubidium bubble through the lens group to interact with rubidium atoms; the photoelectric tube detects a transition spectral line, converts the transition spectral line from an optical signal into an electric signal and transmits the electric signal to the lock-in amplifier for demodulation; the integral amplification module converts the demodulated direct-current voltage into linear increasing voltage and transmits the linear increasing voltage to the crystal oscillator; the crystal oscillator generates an initial microwave signal and generates a microwave signal corresponding to the 87Rb atom through the frequency synthesizer; and the phase frequency modulation module modulates the microwave signal to obtain an error signal and transmits the error signal to the microwave resonant cavity so as to adjust the electromagnetic field according to the error signal to stably lock the rubidium atomic clock. The method is used for achieving the effect of improving the stability of the rubidium atomic clock system.

The invention provides a programmable frequency control array radar waveform generation system and method based on an FPGA, and belongs to the technical field of radar systems and digital signal processing. In order to solve the technical problems of complex hardware system, inflexible parameter adjustment and poor multi-channel synchronism of the traditional frequency control array radar, the invention provides an integrated high-performance solution. The system adopts an FPGA (Field Programmable Gate Array) architecture of an integrated processing system (PS) and programmable logic (PL). The method comprises the following steps: a PS end receives waveform control parameters of an upper computer through a communication interface and transmits the waveform control parameters to a PL end; and a plurality of parallel direct digital frequency synthesizer (DDS) modules in the PL end synchronously generate multi-channel digital baseband signals with programmable frequency offset at high precision according to the parameters under the unified driving of the FPGA global clock network. And the digital signal is subjected to digital-to-analog conversion and radio frequency front-end processing to finally form a transmitting wave beam. According to the invention, flexible programmability of parameters is realized by utilizing a PS-PL collaborative architecture, the synchronization precision of multi-channel signals is remarkably improved through a global clock network and a parallel DDS module generated in the FPGA, and meanwhile, the system has the advantages of high integration level and low complexity.

The invention discloses a fractional frequency division frequency synthesizer with output signal phase synchronization and frequency modulation continuous wave functions, and the basic structure is a charge pump phase-locked loop. Comprising a phase frequency detector, a first charge pump, a second charge pump, a low-pass filter, a voltage-controlled oscillator, a first buffer, a second buffer, a two-frequency divider chain, an IQ undersampling circuit, a local oscillator generator, a programmable multimode frequency divider, a Delta-Sigma modulator (DSM), a first selector, a second selector, a third selector, a tracking phase accumulator, a numerical control oscillator, an accumulation phase difference register and an atan2 logic circuit. The device comprises a main phase control circuit, a phase adjusting circuit, an enabling control circuit, a waveform generator and a serial peripheral interface. The decimal frequency-division frequency synthesizer can be applied to a general-inductance integrated system, ensures that output signals provided by a plurality of decimal frequency-division frequency synthesizers are consistent in phase in a multi-channel radio frequency transceiving system adopting a multi-chip splicing mode, and can also be applied to the general-inductance integrated system as a sensing signal source; and the speed and the distance of an object can be quickly sensed by the high linearity and the quick chirp capability of an output signal. The decimal frequency division frequency synthesizer is applied to a linear frequency modulation continuous wave radar system, initial phase synchronization can be carried out firstly, then frequency continuous modulation is carried out, and measurement errors can be eliminated. In view of functional similarity of partial modules of the synchronous loop and the FMCW loop, such as a phase frequency detector, a charge pump, a voltage-controlled oscillator and the like, the modules can be shared, so that the power consumption and area cost of the system are remarkably reduced.

The invention discloses a deformation rolling stone integrated road slope radar monitoring system and a detection method, and belongs to the field of radar detection, the deformation rolling stone integrated road slope radar monitoring system comprises a signal processing module, a multi-channel radio frequency module and an antenna array module, the multi-channel radio frequency module is connected with the signal processing module through a hardware line, and the antenna array module is connected with the signal processing module. The antenna array module is connected with the multi-channel radio frequency module through a hardware line; the signal processing module comprises a programmable main control chip, a data memory, an analog-to-digital converter and a direct digital frequency synthesizer, a line of the signal processing module is also connected with a camera, and the system also comprises a power supply module for supplying power to the signal processing module, the multi-channel radio frequency module and the camera. According to the deformation and rolling stone integrated road slope radar monitoring system and the detection method, deformation and rolling stone integrated monitoring is realized, two sets of equipment do not need to be arranged, the cost and the arrangement difficulty are reduced, early warning is reliable, the environmental adaptability is high, and the requirement for long-term field road monitoring is met.

The invention relates to the technical field of signal generation, and discloses a signal generation system and method, and the system comprises a first signal generation module; the second signal generation module comprises an analog signal generation unit and a signal copying unit; the signal mixing module comprises an analog frequency mixing unit, a digital frequency mixing unit and a signal switching unit; the output end of the analog signal generation unit is connected with the input end of the analog frequency mixing unit; the first end of the signal copying unit is connected with the clock signal output end of the analog signal generating unit, the second end is connected with the mixing input end of the analog signal generating unit, and the third end is connected with the first end of the signal switching unit; the second end of the signal switching unit is connected with the output end of the analog frequency mixing unit, and the third end is connected with the input end of the digital frequency mixing unit. Therefore, a direct digital frequency synthesizer in the analog signal generation unit is calibrated when the clock signal is switched to, and spurious signals are eliminated based on a calibration result when the clock signal is switched to the analog local oscillator signal.

The invention discloses an intelligent dual-mode radar system based on a terahertz frequency band and an imaging method thereof, and relates to the field of terahertz radars, and the system comprises a transmitting module which supports the dynamic switching of a short-distance high-resolution mode and a long-distance low-power-consumption mode; the receiving module is used for receiving an echo signal reflected by the target of the transmitting module; the frequency synthesizer is used for generating adaptive frequency sweeping bandwidth and frequency sweeping time parameters according to a target distance requirement, and presetting at least two waveform modes; the self-adaptive signal processing unit is used for dynamically adjusting filtering parameters and gains according to a target distance working mode and outputting target imaging data; and the control module is used for realizing parameter configuration and mode switching of dual-mode cooperative work. According to the dual-mode radar collaborative architecture, collaborative work of short-distance high-resolution imaging and long-distance low-power-consumption detection can be achieved, the performance bottleneck of a traditional single-mode radar is solved, and the dual-mode radar collaborative architecture is suitable for efficient target detection and imaging requirements of diversified scenes.

The invention discloses an online cable fault detection device and calibration method based on broadband impedance spectroscopy, belongs to the technical field of cable fault detection, is used for cable fault detection, and comprises a direct digital frequency synthesizer DDS, a micro control unit MCU, an analog-to-digital converter ADC, four low-pass filters, two multipliers and an electromagnetic coupling device. The DDS is respectively connected with the MCU, the first low-pass filter and the second low-pass filter, and the analog-to-digital converter ADC is respectively connected with the MCU, the third low-pass filter and the fourth low-pass filter; the calibration process of the method includes obtaining a measured value of the cable reflection coefficient and a true value of the cable reflection coefficient. According to the invention, cable defects are monitored and positioning is realized during on-line operation of the cable, and the method is suitable for cables of various specifications and three-phase cables, has universality, and reduces the detection difficulty; the broadband impedance spectroscopy measurement precision is improved, the measurement error is reduced, and the cable fault defect positioning precision is improved.

The invention discloses a phased array radar and a low-altitude detection radar system, the phased array radar comprises a lower shell and an upper shell which are oppositely arranged in a first direction, the lower shell and the upper shell define a containing cavity, and the containing cavity comprises a first cavity located in the lower shell; the phased array radar further comprises a frequency synthesizer, a signal processing plate, a heat conduction plate, an air cooling mechanism, a plurality of TR assemblies, an antenna and an antenna housing. The frequency synthesizer is arranged in the first cavity. The signal processing plate is arranged in the first cavity and is compactly arranged with the frequency synthesizer in the second direction; the heat conducting plate is arranged in the first cavity and located on the side, facing the upper shell, of the signal processing plate, the heat conducting plate is attached to the frequency synthesizer and the signal processing plate, and a cooling pipe is embedded in the heat conducting plate; the air cooling mechanism is arranged in the containing cavity and used for supplying air to the heat conduction plate so as to cool the heat conduction plate. The antenna housing is arranged on the side, away from the lower shell, of the upper shell so as to cover the TR assembly and the antenna. Through the compact arrangement of the frequency synthesizer and the signal processing board, the size of the phased array radar can be greatly reduced, and the phased array radar is convenient to carry and deploy.

A temperature-control-free double-optical-comb repetition frequency and phase digital locking system comprises a double-optical-comb light source module, a phase digital locking module, a phase setting module, a first controllable direct digital frequency synthesizer and a second controllable direct digital frequency synthesizer, the repetition frequency and phase of the double optical combs are locked through reference signals generated by the controllable direct digital frequency synthesizer, the frequency of the reference signals output by the controllable direct digital frequency synthesizer is adjusted through feedback signals of the first servo controller and the second servo controller when the temperature changes, and frequency and phase locking of the double optical comb optical system is achieved. Reference signal phases generated by the first controllable direct digital frequency synthesizer and the second controllable direct digital frequency synthesizer are controlled through the upper computer, respective control over the two optical comb pulse phases is achieved, a temperature control module is not needed in the system, the complexity of the system is reduced, and the stability and the integration degree of the system are improved.

The invention discloses a high-precision vector regulation and control device and method for a signal generation link, and belongs to the technical field of information. A frequency mixing feedback loop is adopted to replace a traditional ALC detection loop, the amplitude of a signal can be stabilized, the phase of the signal can also be stabilized, and impedance matching of a channel can also be regulated and controlled; a path feedback signal is converted into a digital signal for high-speed transmission, and the ADC, the signal processing module and the DDS are interconnected through a high-speed bus, so that high-speed vector regulation and control can be quickly performed, and the loop control speed is higher; according to the invention, the direct digital frequency synthesizer is in a loop, which means that the amplitude and phase drift in the DDS can also be captured by the loop for correction; according to the method, vector information of the amplitude and phase drift of the channel can be obtained at the same time, so that closed-loop dual control, namely vector control, is carried out, and the purpose of regulating and controlling the amplitude and phase of the signal at the same time is achieved.

The utility model discloses interference source equipment. Comprising a power control subsystem for realizing signal receiving and transmitting and power dynamic management, an intermediate frequency signal processing subsystem for realizing high-speed signal acquisition and playback, a main control subsystem for realizing system control, man-machine interaction and data processing, and an air feed subsystem for realizing radiation and receiving of electromagnetic signals, the power control subsystem comprises a signal receiving module used for receiving and transmitting communication signals, a transmitting channel module and a frequency synthesizer module, and the frequency synthesizer module integrates a voltage-controlled constant-temperature crystal oscillator, provides stable clock signals and simultaneously comprises external reference clock access and Beidou time synchronization; through integration of the power control subsystem, the intermediate frequency signal processing subsystem, the main control subsystem and the air feed subsystem, the volume and the weight are reduced, an individual soldier is convenient to carry, and the strategic significance of the utility model is increased.

The present disclosure provides an apparatus for wireless communications. The apparatus includes one or more processors; a transmit path coupled to the one or more processors comprising: a first frequency synthesizer configured to consume a first amount of power, wherein the first frequency synthesizer is configured to feed a first local oscillator (LO) signal that comprises a first frequency tone with a first phase noise profile; and a feedback receive path selectively coupled to the transmit path comprising: a second frequency synthesizer configured to consume a second amount of power less than the first amount of power, wherein: the second frequency synthesizer is configured to feed a second LO signal that comprises a second frequency tone with a second phase noise profile; the second frequency tone is offset from the first frequency tone; and the second phase noise profile comprises a wider phase profile than the first phase noise profile.

The invention discloses a broadband LFM signal array beamforming method and system thereof, belonging to the technical field of radar signal processing. The method comprises: antenna array elements of M channels receive radar echoes and receive the same mixing signal sent from the same digital frequency synthesizer; digitally mix the radar echo and the mixing signal of the first channel, filter out high-frequency components, and perform AD sampling on the mixing signal as a reference signal; digitally mix the mixing signal and the radar echo of the mth channel, perform low-pass filtering, and perform AD sampling to obtain a sampled signal m; input a mixing compensation signal into the mth channel, perform secondary digital mixing on the sampled signal m and the mixing compensation signal to obtain a secondary mixing signal m; apply a delay signal to each secondary mixing signal m to perform delay compensation, so that the output signal of the mth channel is equal to the reference signal; and accumulate the output signals of the M channels to obtain a de-skewed array beam.

This invention discloses a multi-level collaborative SAW exhaled breath detection system and method based on a large language model, belonging to the field of SAW detection technology. The system includes a precision RF excitation control layer, an IoT gateway layer, and a cloud-based AI analysis layer. Data interaction between the three layers is achieved through a heterogeneous communication protocol stack. The precision RF excitation control layer includes a microcontroller, a DDS frequency synthesizer, and an SAW resonator; the microcontroller has a built-in pre-verification module. The IoT gateway layer includes a dual-core processor, a wireless communication module, and an I / O interface. 2 The system features an S-channel audio interface and a dual-core processor with a heterogeneous architecture. The cloud-based AI analysis layer includes speech recognition services, large language model inference services, a utility function definition library submodule, and a command string generation submodule. The system has an end-to-end device-level mapping channel from user speech to the DDS frequency synthesizer's frequency tuning word register. This invention lowers the operational threshold for precision SAW inspection and adapts to on-site inspection scenarios.

The application discloses a microwave photon frequency hopping signal generation device and method based on an optical switch and belongs to the technical field of optical communication. The application is composed of a light source, a beam splitter, an optical frequency comb generator, an electro-optical frequency shifter, an acousto-optic modulator, a digital frequency synthesizer, a filter array, a signal control unit, an electrically controlled high-speed optical switch, a beam combiner and a photoelectric detector. The application separates optical frequency comb teeth by using an ultra-narrow bandwidth optical filter, selects and opens the frequency hopping signal generated by the local light beat frequency through the optical switch, and can generate a high-speed high-order high-stability frequency hopping signal compared with the prior art.

The present application relates to a frequency synthesizer with dynamically selected level shifting of an oscillating output signal. An oscillator circuit powered by a source voltage generates an oscillating output signal. The oscillating output signal is level shifted and applied to a first input of a multiplexer. A second input of the multiplexer receives the oscillating output signal. The multiplexer selects one of the oscillating output signal and the level shifted oscillating output signal to output as a selected oscillating output signal in response to a selection signal. A lock loop circuit controls a frequency of the oscillating output signal based on the selected oscillating output signal and a reference oscillating signal. The selection signal also selects one of the source voltage of the oscillator circuit and a reference voltage as an error amplifier reference voltage for a voltage regulator circuit that generates a first supply voltage.

The invention discloses an anti-interference radio frequency transceiving assembly which comprises a plurality of B1 low-noise amplification units, a B1 array antenna, a plurality of B3 low-noise amplification units, a B3 down-converter, a BDS B1 / GPS L1 down-converter, a first frequency synthesizer, a second frequency synthesizer, a crosslinking equipment digital signal processing board, a BDS B1 / GPS L1 up-converter, a B3 up-converter, a B2B low-noise amplifier unit and an S low-noise amplification unit. And the first triplexer is in data connection with the L power amplifier unit, the B2B, S and L three-in-one antenna array, the first directional coupler and the first logarithmic detector. According to the invention, electromagnetic wave signals of multiple paths of B3 and multiple paths of BDS B1 / GPS L1 are converted into electric signals, and the signals are filtered and amplified, so that amplitude-phase consistency is satisfied. And performing up-conversion on the analog intermediate frequency signal processed by the cross-linked digital signal processing board to output BDS B3 and BDS B1 / GPS L1 radio frequency signals. And the short message integrated service digital network can be realized.

The invention provides a design method of an ultra-low phase noise frequency synthesizer based on regenerative frequency division. The design method comprises the following steps: step 1, enabling a source frequency to generate a multiple frequency through a frequency multiplier; step 2, inputting the multiple frequency into a two-way power divider, and generating an excessive frequency 1 through a phase-locked loop 1 by one path of output of the two-way power divider; the other path of output of the two-way power divider generates an excessive frequency 2 through a phase-locked loop 2; 3, the transition frequency 1 passes through a digital frequency divider and a regeneration frequency divider in sequence to generate transition frequency 3; and step 4, inputting the transition frequency 2 and the transition frequency 3 into a frequency mixer for frequency mixing, and then processing through a filter and an amplifier again to generate a target frequency. When the circuit topology and the transition frequency are designed, how to reduce the phase noise index is considered. According to the design method, the low-phase noise characteristic of the regenerative frequency divider is fully utilized.

The invention belongs to the technical field of radars, and relates to a complete polarization continuous wave rain detection radar system and method, and the system is fixedly installed on the ground and comprises a two-dimensional servo turntable, a transmitting and receiving antenna and a processing case. The transmitting antenna and the receiving antenna are respectively arranged on two sides of the two-dimensional servo turntable and carry out azimuth rotation and pitch angle adjustment along with the two-dimensional servo turntable. The transmitting antenna simultaneously transmits horizontal / vertical polarization signals, and the receiving antenna simultaneously receives dual-polarization echo signals. In the processing case, a transmitting assembly is connected with a transmitting antenna, and the excitation signal is radiated through the transmitting antenna after being amplified; the receiving component is connected with a receiving antenna and is used for performing low-noise amplification, down-conversion and the like on the echo signal; the frequency synthesizer board card generates a linear frequency modulation continuous wave excitation signal; the acquisition processing board card carries out AD sampling, pulse compression, clutter suppression, echo parameter estimation and other processing on the echo signal so as to realize raindrop characteristic analysis.

According to a first aspect of the present disclosure, there is provided a radar apparatus comprising: a plurality of receiver channels; a plurality of mixers, wherein each of the receiver channels comprises one of the mixers; a first frequency synthesizer configured to generate a chirp signal; at least one test tone generator configured to generate a test tone signal having a constant frequency; wherein the mixer is configured to be fed with the chirp signal and the test tone signal. According to a second aspect of the present disclosure, a corresponding method of operating a radar apparatus is conceived.

The present application relates to a kind of complex waveform generating device of anti-active jamming, belong to radar detection guidance and electronic countermeasure technical field, solve the problem that the existing radar main signal is higher in the probability of being detected and intercepted by jammer.One kind of complex waveform generating device of anti-active jamming, including control unit, direct digital frequency synthesizer and signal output unit, the control unit is connected with signal output unit by direct digital frequency synthesizer.The complex waveform generating device of anti-active jamming of the present application, the complex waveform main signal of emission and cover signal random arrangement, cover signal generation time, pulse width, signal bandwidth, emission frequency point, frequency modulation slope and signal number are random, difficult to predict.The signal output by complex waveform generating device is more difficult to distinguish, greatly reduce the probability of main signal interception and the difficulty of correct implementation of jammer, increase the means and strategy of anti-jamming, improve the performance of radar anti-jamming and radar tracking stability.

In one example, the system includes a phase-locked loop (100) comprising a charge pump (104) coupled to a phase frequency detector (102), a low-pass filter (106) coupled to the charge pump, and a VCO (108) coupled to the low-pass filter, wherein the charge pump is configured to provide a charge pump current (126) to the low-pass filter. The system also includes a current source (114) configured to provide a bias current (130) to the charge pump. The system includes a first bias compensation circuit (116) configured to increase the bias current (130) in response to a control voltage (128) supplied to the VCO being within a first range. The system also includes a second bias compensation circuit (116) configured to decrease the bias current (130) in response to a control voltage (128) supplied to the VCO being within a second range.

A transmitter including a frequency synthesizer with a voltage-controlled oscillator that provides an oscillating signal, a programmable delay circuit that delays the oscillating signal to provide a delayed oscillating signal, a power amplifier that is configured to amplify the delayed oscillating signal for transmission sufficient to produce interference, and a delay controller that programs the delay circuit with a delay time that reduces interference caused by coupling from the power amplifier to the voltage-controlled oscillator. The delay circuit may be programmed to reduce control voltage change of the voltage-controlled oscillator as a function of delay change, and / or to reduce phase noise degradation at an output of the transmitter as a function of delay change. The delay may be adjusted based on detected operating temperature. A calibration value may be determined at a calibration frequency, in which a frequency offset may be determined based on a selected channel frequency.

The invention relates to the technical field of frequency synthesizers, and discloses a controllable phase frequency detector, a phase-locked loop and communication equipment. The controllable phase frequency detector comprises a phase detection core circuit, a switching power supply circuit, a clock selection circuit and a control circuit. The clock selection circuit selects one of a reference clock signal and a feedback clock signal to output a gating clock signal according to an input clock selection signal. After the enable signal is valid, the control circuit responds to the first valid clock edge of the gating clock signal and controls the switching power supply circuit to be switched on so as to supply power to the phase detection core circuit. The circuit can be started under a controllable preset initial phase, and the initial output state of the circuit only depends on the setting of a clock selection signal and is irrelevant to the actual phase relation when an input clock is powered on. When the charge pump is used for a phase-locked loop, the locking time can be effectively shortened, the overvoltage risk caused by long-time charging of the charge pump is avoided, and the performance and reliability of the phase-locked loop are improved.

A frequency synthesizer includes a voltage controlled oscillator, an analog-to-digital converter, a first processing unit and a second processing unit, an adder, a digital-to-analog converter, a monitoring unit, and a switching unit. The first processing unit and a second processing unit output a first digital signal and a second digital signal for frequency adjustment corresponding to a phase difference, respectively. The adder outputs an addition signal obtained by adding the output from the first processing unit to the output from the second processing unit to a downstream stage. The switching unit switches a first state in which only the first digital signal among the first digital signal and the second digital signal is supplied to the adder to a second state in which the second digital signal and the first digital signal as a fixed value are each supplied to the adder, based on a parameter.

The invention relates to an electric control phase shifting device for quantum homodyne detection and a phase shifting regulation and control method of the electric control phase shifting device. The electric control phase shifting device comprises a first beam splitting piece, a first interference arm, a second interference arm and a second beam splitting piece. After input signal light to be measured is split into two beams of signal light through a first beam splitting piece, one beam of signal light passes through a first interference arm to obtain signal light subjected to phase shift / frequency shift, and the other beam of signal light passes through a second interference arm to obtain signal light not subjected to phase shift / frequency shift; the signal light subjected to phase shift / frequency shift and the signal light not subjected to phase shift / frequency shift are respectively input into a second beam splitter and then are divided into two paths to be output; the optical phase shift of the electric control phase shifter is adjusted by adjusting and changing the frequency difference delta fs generated by the first interference arm to the signal light; by means of the characteristic that the frequency shift amount of the acousto-optic crystal is controlled by the driving frequency and in combination with the fine frequency adjustment capability of the digital frequency synthesizer, high-precision frequency control over the optical phase shift amount is achieved.

A fractional frequency synthesizer, a fractional PLL, and a method for generating a fractional frequency signal based on a reference signal are provided. An example fractional frequency synthesizer includes a multi-phase clock generator configured to generate a clock vector comprising a plurality of clock signals, each oscillating according to a fractional frequency in relation to the reference frequency and each clock signal offset by a phase offset. The fractional frequency synthesizer includes multi-phase divider circuitry configured to select a clock signal from the clock vector to generate a fractional frequency feedback signal. An accumulator configured to increment a count and a rollover detector configured to determine a rollover value associated with a rollover event on the accumulator are further included. A clock signal is selected based on the rollover value and the fractional frequency feedback signal is generated based at least in part on the selected clock signal.

This invention discloses a phase-amplitude conversion method and apparatus for a direct digital frequency synthesizer. The method includes the following steps: receiving an input phase word; performing trigone normalization on a subdivided phase field based on a trigone control field in the input phase word; using the first field of the normalized subdivided phase field as an index to look up a table, retrieving the initial sine and initial cosine values ​​corresponding to the index from a preset lookup table to obtain a coarse rotation result; generating a rotation code based on the second field of the normalized subdivided phase field; performing rotation correction on the coarse rotation result based on the rotation code to obtain a fine rotation result; and restoring the trigone control field to the final fine rotation result to obtain the final sine and cosine amplitude values. This invention can meet the high-precision requirements of phase-amplitude conversion while reducing storage requirements.