49 results about "Direct digital synthesizer" patented technology

The invention discloses a frequency source synthesis system and method based on a frequency agility radar, and belongs to the technical field of microwave radio frequency, and the method specifically comprises the steps: generating a target clock signal, carrying out the frequency processing of the target clock signal to generate a frequency multiplication signal, and dividing the frequency multiplication signal into two clock signals through a power divider; performing frequency multiplication processing on one path of clock signal, taking the processed signal as a clock reference signal of a direct digital synthesizer, generating an analog signal according to the clock reference signal, and calibrating the analog signal as an output signal; performing frequency multiplication processing on the other path of clock signal, and taking the processed clock signal as a local oscillation signal of the frequency mixer; performing frequency conversion processing to obtain a frequency mixing signal, performing quadruplicated frequency processing on the frequency mixing signal, and calibrating the processed frequency mixing signal as a final output signal; according to the invention, the frequency source has the characteristics of low phase noise, rapid agility, fine resolution and miniaturization at the same time.

The invention discloses a micro meteorological change real-time monitoring method based on a millimeter wave radar, and relates to the technical field of meteorological monitoring. The method comprises the following steps: carrying out dynamic acquisition on millimeter wave radar signals and carrying out coordinate system conversion; converting the converted information into a programmable chirp signal through a DDS (Direct Digital Synthesizer) chip; performing space-time adaptive filtering processing on the received signal to eliminate interference; abnormal phase points are detected, and a dynamic noise base model is established; inputting the preprocessed phase data into a pre-trained DPGN network, and outputting a weather result map; a lightweight engine is deployed at a radar end to process the weather result map; when it is detected that the weather gradient exceeds a threshold value, weather early warning is triggered. The adaptive chirp waveform modulation is adopted, the frequency slope and the pulse width of the radar transmitting signal are dynamically adjusted according to the real-time environmental noise level, the meteorological monitoring sensitivity and the small change detection efficiency are improved, and the environmental noise interference is optimized.

Laser control circuitry is described. In one example, a laser controller integrated circuit (IC) includes first and second input ports, a sideband direct digital synthesizer (DDS) coupled to the first input port and configured to produce a modulation signal and a reference signal based on an input signal received via the first input port, the modulation signal and the reference signal having a same frequency. The laser controller IC further includes a Pound-Drever-Hall frequency-locking control loop coupled to the second input port and to the sideband DDS, and configured to produce a corrected DC bias current signal based on the reference signal and a measurement signal received via the second input port, and a thermal management circuit configured to produce at least one thermal control signal.

The invention discloses a laser control system for a coherent population trapping magnetometer. The laser control system comprises a core control unit, a driving circuit system, a microwave source signal modulation system and an H bridge in bidirectional connection with the core control unit, the driving circuit system comprises a band-gap reference voltage circuit, and the band-gap reference voltage circuit comprises an input end low-power-consumption bias starting circuit and a folding operational amplifier; the core control unit comprises an FPGA (Field Programmable Gate Array) and a temperature control circuit system, and the temperature control circuit system combines an anti-integral saturation algorithm with fuzzy PID (Proportion Integration Differentiation) control and dynamically adjusts PID parameters to realize temperature adjustment; the microwave source signal modulation system comprises an all-digital phase-locked loop, a direct digital synthesizer and a frequency multiplier, and the generation, modulation and amplification of microwave signals are realized through the control of the FPGA. The laser control system is high in microwave source frequency stability and strong in noise suppression capability.

The invention discloses a relay station for digitally locking an optical fiber link and monitoring phase noise in real time, which belongs to the technical field of relay stations for optical fiber optical frequency transmission and comprises a main control circuit, a link locking circuit and a laser locking circuit. The link locking circuit is bidirectionally connected with the main control circuit, the link locking circuit sends a link locking error signal to the main control circuit, and the main control circuit sends a link locking instruction to the link locking circuit; the laser locking circuit is bidirectionally connected with the main control circuit, the laser locking circuit sends a laser locking error signal to the main control circuit, and the main control circuit sends a laser locking instruction to the laser locking circuit; the link locking circuit comprises an optical frequency digital phase-locked loop; and the optical frequency digital phase-locked loop adopts a DDS (Direct Digital Synthesizer) to drive an acousto-optic modulator to adjust the frequency and the phase of an optical frequency signal. An optical frequency digital phase-locked loop is adopted to measure a phase noise power spectrum in real time, link locking can be achieved, and meanwhile whether the power spectrum of a locked signal reaches a theoretical noise suppression limit or not can be judged.

The invention provides a vector signal source and a design method thereof, which can be applied to the technical field of communication. The vector signal source comprises: a generation module comprising a plurality of parallel direct digital synthesizers, the generation module being configured to generate a plurality of target digital signals based on drive clock signals corresponding to the plurality of direct digital synthesizers, the driving clock signals respectively corresponding to the plurality of direct digital synthesizers have phase differences relative to each other and are equal in frequency; the conversion module comprises a plurality of digital-to-analog converters electrically connected with the plurality of direct digital synthesizers respectively, and the conversion module is configured to convert the received multiple paths of target digital signals into multiple paths of target analog signals respectively based on sampling clock signals corresponding to the multiple digital-to-analog converters respectively, the sampling clock signals corresponding to the plurality of digital-to-analog converters are synchronized relative to each other; and the synthesis module is configured to integrate the multiple paths of target analog signals according to a time sequence to obtain a target vector signal source.

The invention discloses a DDS (Direct Digital Synthesizer) secure communication middleware implementation method and device. The method comprises the following steps: adding a security detection component and an authentication service component into an original DDS middleware model; performing bidirectional security access authentication between a publisher and a subscriber by using the security detection component; the bidirectional security access authentication comprises authority access control and transmission data encryption; and the authentication service component is utilized to carry out identity authentication on a remote participant. According to the invention, the authenticity, availability and confidentiality of the publishing and subscribing process are realized by comprehensively utilizing the security detection component and the authentication service component. And in combination with a discovery mechanism of the DDS and a QoS negotiation mechanism, custom configuration of a security protection level and an encryption algorithm is realized, and the requirements of flexibility and high efficiency of an upper-layer application are met.

In one example, an RF oscillator system includes a laser source configured to emit laser light, a housing, a crystalline microresonator disposed within the housing, and a photonic integrated circuit disposed within the housing, the photonic integrated circuit including an optical waveguide network and configured to generate a clock signal based on the laser light. The RF oscillator system may further include at least one photonic wirebond configured to couple the laser light between the optical waveguide network and the crystalline microresonator via evanescent coupling; laser control circuitry disposed within the housing and configured to lock a frequency of the laser light to a resonance of the microresonator to generate the clock signal; and a direct digital synthesizer disposed within the housing and configured to produce a tunable oscillator signal based on the clock signal.

This high-frequency signal generation device is provided with: (A) a clock signal generation unit that generates a clock signal using a harmonic component generated by an amplifier having nonlinearity; (B) a direct digital synthesizer (DDS) that generates a frequency signal having a frequency set by the frequency setting data, using the clock signal as a system clock for operating the internal processing; and (C) a frequency-increasing unit that is configured from a non-active frequency multiplier that does not use an active element, and that increases the frequency of the frequency signal generated by the DDS. A clock signal is generated using a harmonic component generated by an amplifier having nonlinearity, and in a frequency variable function, a delay time is shortened to cope with a high speed, and spurious and phase noise are suppressed to cope with a high C / N ratio.

The invention discloses a wire adhesion detection circuit and a metal wire bonding machine, and the circuit comprises a capacitance-resistance oscillation circuit which is connected with a power supply end, a metal wire connection end of a to-be-detected device and a material sheet connection end, and outputs a first oscillation signal according to a preset impedance value and a first impedance value between the metal wire connection end and the material sheet connection end; the waveform processing circuit is connected with the capacitance-resistance oscillation circuit and converts the first oscillation signal into a first square wave signal; the signal processing circuit is connected with the waveform processing circuit, and the wire bonding state, namely the connection state between the metal lead and the material sheet, the connection state between the metal frame on the material sheet and the wafer, is obtained according to the signal parameters of the first square wave signal, so that high-cost devices such as a DDS (Direct Digital Synthesizer), a DAC (Digital-to-Analog Converter), an ADC (Analog-to-Digital Converter) and an RMS-DC converter are completely omitted; the method can be realized only by adopting the capacitance-resistance oscillation circuit, the waveform processing circuit and the signal processing circuit which are low in cost, the hardware cost is reduced, and the detection delay is only one or more cycles of the first square wave signal and is reduced from the millisecond level to the microsecond level.

The invention belongs to the field of global navigation satellite systems, and discloses a PPP-B2b-based high-precision time service method, which mainly comprises a PPP resolving module, a loop filter and a constant-temperature crystal oscillator + DDS (Direct Digital Synthesizer) combined circuit. The PPP resolving module is equivalent to a phase frequency detector in a delay locking loop, realizes a real-time precise point single positioning function by adopting double-frequency observed quantity and precise correction of a Beidou satellite navigation system, and outputs a precise clock error; a loop filter is equivalent to a loop filter in a carrier ring, a second-order frequency-locked loop is adopted to assist a third-order phase-locked loop structure, and frequency ramp-up excitation can be stably tracked; the combination of the constant-temperature crystal oscillator and the DDS is equivalent to a numerical control oscillator (NCO), and the precise adjustment of the clock frequency can be realized. Compared with a traditional high-precision time service terminal, the high-precision time service terminal does not depend on GPS observed quantity and precise correction information of the internet, a relatively low constant-temperature crystal oscillator instead of an atomic clock is adopted as a clock source, and the quantization error problem of second pulse output is solved.

The invention discloses a laser local oscillation device based on an optical frequency comb and a Brillouin filter, and belongs to the technical field of information transmission and processing. The device comprises a laser, an optical frequency comb generation module, a switch selection module, a frequency reference module, a DDS (Direct Digital Synthesizer) frequency synthesizer, a frequency control module, a Brillouin filter, a coupler, a photoelectric converter, an analog-to-digital converter and a stray filter. The comb spectrum laser with a fixed frequency interval is output, the center frequency of the Brillouin filter is changed by setting the pumping current of the Brillouin filter, so that a required comb spectrum obtains high gain in a passband of the filter, and after stray is filtered out through the stray filter, the laser with the selected comb spectrum frequency is output. The wide-range large-step laser local oscillator has the advantages of being high in response speed, low in cost, good in producibility and high in reliability, is suitable for achieving the wide-range large-step laser local oscillator, and is an important improvement on the prior art.

The utility model discloses a DDS (Direct Digital Synthesizer) signal generator in an MEMS (Micro Electro Mechanical System) gyroscope, which comprises a control module which is formed by connecting more than three DDSs into a signal link in parallel and is used for connecting phase control words and frequency control words into the input ends of the DDSs one by one, each DDS has an initial phase and the frequency control words of the DDSs are kept consistent; each DDS points to and extracts storage data in a generator wave table, and the storage data are fitted into signal data with amplitude control words under the driving of a clock; the clock module is electrically connected with the control module; and a waveform generation module that generates a waveform based on the fitted signal data and outputs a signal through a digital-to-analog converter. By applying the DDS signal generator, the resolution of the DDS and the signal-to-noise ratio of the driving signal are improved, the problem of distortion of the driving signal of the gyroscope at a high sampling rate is solved, and the functions that any waveform is adjustable and the frequency and the phase can be independently configured can be realized.

The invention discloses a linear frequency modulation signal circuit based on a DDS (Direct Digital Synthesizer), and aims to solve the problems that a traditional frequency agility circuit adopts a single-path DDS circuit to output signals, and the frequency agility rate is limited by the performance of the DDS and is generally in a microsecond level. The switch is adopted to control output and switching of the two DDS circuits, when one DDS circuit is outputting a frequency agility signal, the other DDS circuit completes number setting operation, therefore, when the output signal needs to be switched, the working DDS circuit can be immediately closed, the other DDS circuit which completes number setting is switched on, the frequency agility rate is determined by the switching frequency of the switch, and the frequency agility rate of the DDS circuit is determined by the switching frequency of the switch. And the frequency agility rate is increased to 20ns.

The invention relates to the technical field of automotive electronics and communication, and provides a DDS (Direct Digital Synthesizer)-based safety vehicle-mounted communication method, which comprises the following steps of: dividing whole vehicle data into non-safety data, periodic safety data and non-periodic safety data; establishing a communication channel for each type of data; for a non-periodic transmission channel, a special protection scheme is adopted, and a communication failure mode is detected: a sender configures a life cycle for data, and after the data is sent, the life cycle is monitored; when the data is discarded due to exceeding the life cycle, the sender updates the life overrun state; the receiver replies based on an ACK / NACK mechanism, and the sender updates the service life overrun state when the time is out and the confirmation is not carried out; arranging a monitor at a receiver, and detecting a communication failure event of data loss when the monitor monitors a service life overrun state; when a communication failure is detected, the communication management middleware notifies the security application. The invention aims to solve the problems that data protection is not distinguished and non-periodic data cannot be effectively detected in an existing scheme.

The present application relates to a kind of multi-mode noise interference signal generation method, belong to signal interference technical field, solve the problem that existing cannot dynamically flexibly generate the interference signal of multiple modulation modes and the high development complexity.For method includes: according to noise kind and interference mode, obtain first noise sequence, second noise sequence, third noise sequence, noise interference bandwidth and center frequency;Carrier signal is generated based on center frequency;First noise sequence and noise interference bandwidth are passed into first multiplier, then the output result and carrier signal are passed into adder, and first complex signal is output by direct digital synthesizer;First complex signal and second noise sequence are passed into complex multiplier, and second complex signal is output;Second complex signal and third noise sequence are passed into second multiplier, and noise interference signal is output.The generation of multi-mode noise interference signal dynamically flexibly is realized.

This invention discloses a segmented quadrupole system incorporating phase control, comprising a segmented quadrupole structure, a direct digital synthesizer, a first phase shifting device, a second phase shifting device, a first radio frequency high voltage output device, and a second radio frequency high voltage output device. Compared to traditional quadrupole systems that increase radio frequency high voltage and frequency, this invention achieves high resolution while reducing electrical noise and power loss in the radio frequency system and improving power supply control accuracy, as it eliminates the need to increase high voltage and frequency. This results in higher instrument reliability while maintaining high resolution. By dividing the long quadrupole into multiple short segments—at least one first quadrupole and at least one second quadrupole—the manufacturing precision requirements for single-segment quadrupole electrodes are effectively reduced, simplifying the manufacturing process, improving overall mechanical stability, and minimizing the impact of thermal deformation and mechanical vibration on mass spectrometer performance.

The invention discloses a baseband digital modulation device and method based on an FPGA (Field Programmable Gate Array) and a DDS (Direct Digital Synthesizer), relates to the technical field of telemetering systems, and aims to solve the problem of high signal sidelobe energy caused by adopting 2FSK (Frequency Shift Keying) modulation in the prior art. The device comprises an FPGA (Field Programmable Gate Array) and a DDS (Direct Digital Synthesizer), and the FPGA comprises a pre-modulation filtering module which is configured to convert a PCM (Pulse Code Modulation) signal input into the FPGA into a bipolar signal and perform pre-modulation filtering on the bipolar signal; a phase calculation module; the DDS configuration module is configured to configure a register and an interface signal of the DDS, so that the DDS works in a quadrature modulation mode. According to the method, 2FSK modulation is replaced by quadrature modulation, so that the signal sidelobe energy is effectively reduced, and the telemetering baseband signal finally output by the DDS has better out-of-band rejection capability.

The invention discloses a low-speed speed measurement method for a sine frequency modulation Doppler radar, and mainly solves the problems that the existing debugging test is complicated, and the speed measurement cannot be carried out due to easy lock losing during low-speed flight. The implementation scheme comprises the following steps: determining side frequency times, a modulation index and a modulation frequency; a DDS is used for digitally synthesizing a sine frequency modulation signal, the sine frequency modulation signal is mixed with a local oscillator signal generated by a PLL to generate a radio frequency sine frequency modulation signal, and the radio frequency sine frequency modulation signal is transmitted to specific four directions in turn according to a period; performing phase shifting and frequency mixing on a coupling signal of the echo signal and the transmitting signal, performing down-conversion to a base band, and performing band-pass filtering to obtain a side frequency component containing a Doppler frequency spectrum; carrying out IQ demodulation on the side frequency component and IQ two-path coherent reference signals thereof to obtain an IQ signal of a Doppler spectrum; and calculating the IQ signal of the Doppler frequency to obtain the speed information of the aerial carrier. The method greatly reduces the isolation index requirement of the receiving / transmitting antenna of the Doppler radar, improves the speed measurement capability of the Doppler radar during low-altitude low-speed flight, and can be used for airborne Doppler radars.

A pulser / receiver for generating and receiving ultrasonic pulses in the form of chirps, for use by an ultrasonic transducer. The pulser has a transmit path having a direct digital synthesizer operable to generate a chirp signal; a converter operable to convert the chirp signal to a transmit signal having a single ended voltage, a voltage amplifier and a power amplifier. Switches deliver the transmit signal to the transducer in a transmit mode but isolate the transmit path in a receive mode. The transmit signal and the received signal are both delivered to a switch, which sends the transmit signal through an attenuator but bypasses the attenuator in receive mode. Both the attenuated transmit signal and the receive signal are then ready for arrival time processing by a matched filter.

The invention provides an AD9361-based radio interference signal generation method, which is characterized in that a baseband interference signal is generated in an FPGA (Field Programmable Gate Array) through the function configuration of a multi-path parallel DDS (Direct Digital Synthesizer) and an upper computer, the baseband interference signal and a local oscillator signal are mixed through the configuration of AD9361, and then the interference signal is output in a radio frequency manner, and the AD9361-based radio interference signal generation method has four interference modes, the interference modes comprise a single-tone interference mode, a frequency sweeping interference mode, a frequency hopping interference mode and a suppression interference mode. According to the invention, target interference capability of multiple frequency bands and multiple communication systems can be realized, and the effect of changing flexibility into controllability is achieved; according to AD9361 configuration, effective power control can be utilized to the maximum extent, and the output management capability of the system is improved.

The invention discloses a method for upgrading and transforming an analog simulation system based on point-to-point communication, which comprises the following steps of: upgrading a communication protocol, forming communication middleware by establishing a DDS (Direct Digital Synthesizer) information warehouse and packaging a communication data interface in an original system, and establishing connection between operating console software and the DDS information warehouse through the communication middleware, completing data subscription and distribution; the method comprises the following steps: transforming data sending ends of software in an original system, only reserving a sending end generated by a data source and ignoring a forwarding data link among the software through data interface arrangement and transmission process tracing, then calling a corresponding data distribution interface function of communication middleware to replace an original sending end module, and uploading data to a communication bus; each software receiving end in an original system is transformed, each software subscribes to a data interface which needs to be received, then a corresponding data receiving interface function of communication middleware is called to replace an original TCP receiving end module, and needed data is obtained from a communication bus.

An antenna circuit for a drilling system beacon. The circuit includes a carrier direct digital synthesizer (“DDS”) and a communication DDS that generate respective signals used to drive an antenna and produce a beacon signal having both carrier and communication components. To obtain an accurate indication of carrier amplitude for feedback control, the beacon signal is synchronously mixed with the carrier DDS signal using an analog switch or similar mixer. The resulting mixed signal contains sum and difference components that are passed through a lowpass filter to remove contributions from the communication component. The filtered output provides a direct current (“DC”) value representative only of the carrier amplitude, enabling a processor to regulate drive parameters without contamination from communication signals.

A DDS circuit includes a phase accumulator circuit. The phase accumulator circuit includes a clock input being configured to receive a clock signal. The phase accumulator circuit includes a frequency tuning register configured to receive a frequency tuning word (FTW), and a phase shift register configured to receive a phase shift word (PSW). The phase accumulator circuit also includes a phase increment sub-circuit configured to increment a phase signal output by the phase accumulator circuit by a predetermined phase increment based on the clock signal and / or based on the FTW. The phase accumulator circuit further includes a feedback path configured to feed back the phase signal to the phase increment sub-circuit. The phase accumulator circuit further includes a phase correction sub-circuit configured to adapt the phase signal fed back to the phase increment sub-circuit based on the phase shift word.

A signal synthesizer circuit includes a clock source, a direct digital synthesizer (DDS) circuit, signal paths, and an output. The clock source generates or receives a clock signal having a predefined frequency. The DDS circuit generates a DDS signal. A first signal path is connected to the DDS circuit to receive the DDS signal and includes a multiplier circuit that multiplies a frequency of the DDS signal by a multiplication factor, obtaining a frequency-multiplied DDS signal. A second signal path is connected to the clock source to receive the clock signal and includes a mixer circuit that receives the clock signal and the frequency-multiplied DDS signal. The mixer circuit mixes the clock signal with the frequency-multiplied DDS signal, obtaining a mixed DDS signal. A frequency of the mixed DDS signal corresponds to the sum of frequencies of the clock signal and the frequency-multiplied DDS signal.

Disclosed is a direct digital chirp synthesizer for generating a chirped optical frequency comb that includes: a direct digital synthesizer that receives a repetition frequency signal from a delay generator, receives a clock frequency from a frequency converter, produces a radiofrequency chirp waveform based on the repetition frequency signal and the clock frequency, and communicates the radiofrequency chirp waveform; and an electro optic modulator in electrical communication with the direct digital synthesizer and that receives the radiofrequency chirp waveform from the direct digital synthesizer, receives laser light, and produces the chirped optical frequency comb from the laser light based on the radiofrequency chirp waveform.

The present invention discloses a laser control system for a coherent population trapping magnetometer. The system comprises a core control unit, a drive circuit system, a microwave source signal modulation system, and an H-bridge bidirectionally connected to the core control unit. The drive circuit system includes a bandgap reference voltage circuit, which includes an input low-power bias startup circuit and a folding operational amplifier. The core control unit includes an FPGA and a temperature control circuit system, which uses an anti-integration windup algorithm combined with fuzzy PID control to dynamically adjust PID parameters to achieve temperature regulation. The microwave source signal modulation system includes a fully digital phase-locked loop, a direct digital synthesizer, and a frequency multiplier. The FPGA controls the generation, modulation, and amplification of microwave signals. The laser control system of the present invention has high microwave source frequency stability and strong noise suppression capabilities.

The invention provides a cloud edge collaborative data distribution method and system. Relates to a digital information transmission method and system. The method comprises the following steps: acquiring a service priority of to-be-distributed data; when the service priority is a high priority, routing the data to be distributed to a DDS (Direct Digital Synthesizer) transmission channel; adjusting the QoS strategy of the DDS transmission channel based on the current network state of the edge node; and distributing the data to be distributed through a DDS transmission channel according to the adjusted QoS strategy. When the service priority is a low priority, routing the data to be distributed to an MQTT transmission channel; and transmitting the to-be-distributed data to a cloud end in a zero analysis mode.

The invention, which relates to the technical field of the precision measuring instrument, discloses a low-temperature-drift digital phase-locked eddy current sensor circuit comprising an MCU, an excitation signal generation module, an AC bridge module, and a high-speed precision ADC sampling module. The excitation signal generation module generates a high-stability 50kHz sine wave excitation signal through high-precision DAC and DMA transmission by adopting a DDS (Direct Digital Synthesizer) mode; the AC bridge module suppresses common-mode interference caused by probe temperature excursion by using a reference coil; the high-speed precise ADC sampling module is used for synchronously digitizing bridge output and excitation signals; the temperature compensation module performs real-time software compensation on the residual temperature excursion through an integrated digital temperature sensor and a pre-calibrated polynomial model; a digital phase-locked demodulation algorithm is realized in the MCU, and a displacement related amplitude is accurately extracted through digital multiplication and low-pass filtering. The circuit fundamentally inhibits temperature drift from hardware and software levels, and realizes high-precision and high-stability eddy current displacement measurement.

The invention discloses a video SAR (Synthetic Aperture Radar) real-time imaging processing system, method and equipment based on mercuric chloride NPU (Network Processing Unit) cluster and FPGA (Field Programmable Gate Array) isomerism, and belongs to the field of radar imaging and signal processing, the system comprises a DDS (Direct Digital Synthesizer) signal generation module, a digital-to-analog conversion module, a signal acquisition module, a data processing module and a data storage module; according to the method, generation and acquisition of a linear frequency modulation signal, digital down-conversion processing and data communication between mercuric chloride NPU clusters are completed through an FPGA based on the system, realization of an RD algorithm and an MD algorithm which can be subjected to parallel calculation is implemented on the mercuric chloride NPU clusters, and through pipeline scheduling and task parallelization, the mercuric chloride NPU clusters are subjected to parallel calculation. The full-process processing from signal generation and acquisition, preprocessing to an imaging algorithm is realized by adopting a pipeline processing mode, and high-frame-rate video SAR real-time imaging processing is realized; the equipment is used for implementing the method. The invention has the advantages of short development period, small volume, low power consumption and low cost.