862 results about "Frequency synthesis" patented technology

An all-digital frequency synthesizer architecture is built around a digitally controlled oscillator (DCO) that is tuned in response to a digital tuning word (OTW). In exemplary embodiments: (1) a gain characteristic (K_DCO) of the digitally controlled oscillator can be determined by observing a digital control word before and after a known change (Δf_max) in the oscillating frequency; and (2) a portion (TUNE_TF) of the tuning word can be dithered (1202), and the resultant dithered portion

can then be applied to a control input of switchable devices within the digitally controlled oscillator.

The invention discloses a configurable multi-mode multi-band satellite navigation receiving method and a radio frequency front end module constructed by the method. The front end module can receive signals of satellite navigation and positioning systems such as a global positioning system (GPS), the Big Dipper, a Galileo positioning system and a global navigation satellite system (Glonass), and comprises a configurable low-noise amplifier (LNA) with a buffer and an active balun, a folding passive mixer with a configurable frequency synthesizer, a configurable multi-mode filter, an automatic gain control (AGC) amplifier, a direct-current bias circuit, and a multi-mode multi-band program controlled and coded on-off control word from a receiving system. The radio frequency front end module can meet the requirement of multi-band multi-mode work through the control word programmed by the receiving system, has a simple and reliable structure, does not need complicated time division multiplexing control system and off-chip module, has low cost and high flexibility, and improves the noise performance of the radio frequency front end of the whole receiver and multi-mode multi-band signal processing capacity; and a one-channel signal is input into the module, and the module outputs a two-channel differential signal. The receiver can be used for receiving and processing multi-mode satellite navigation signals asynchronously, and receiving and processing satellite navigation signals with the required mode in different time intervals according to the requirement.

Methods and systems to implement and operate software-defined radios (SDRs). An SDR may be configured to perform a combination of fractional and integer frequency synthesis and direct digital synthesis under control of a digital signal processor, which may provide a set of relatively agile, flexible, low-noise, and low spurious, timing and frequency conversion signals, and which may be used to maintain a transmit path coherent with a receive path. Frequency synthesis may include dithering to provide additional precision. The SDR may include task-specific software-configurable systems to perform tasks in accordance with software-defined parameters or personalities. The SDR may include a hardware interface system to control hardware components, and a host interface system to provide an interface to the SDR with respect to a host system. The SDR may be configured for one or more of communications, navigation, radio science, and sensors.

The invention relates to a multiturn absolute rotary encoder based on a rotary transformer, which is characterized in that: a sensor is displaced by taking the rotary transformer as a shaft angle; a shaft angle decoding circuit can be formed by adopting DSP as a core processor; a sine wave which can be controlled by frequency and phase in the method that the circuit is synthesized by direct digital frequency for the numerical control of an oscillator; and the sine wave is directly taken as an excitation rotary transformer signal via a power amplifier and a filter circuit; the rotary transformer signal is transferred to A/D converter after being run through a matching circuit of electronic transformer; after sampling, digital filtering and digital signal processing, the sine and cosine value for the actual angle of two channels is generated; the angle error change is tracked dynamically by the PI algorithm; the mechanical displacement of the rotating object is converted into digital shaft angle position and speed. The multiturn absolute rotary encoder based on a rotary transformer has the advantages of high tracking speed, high conversion accuracy, high reliability, simple structure, sensitive movement, low environmental condition, strong anti-interference capability, high measuring accuracy and speed voltage output.

In a method and a device for carrying frequency synthesis, in particular in a distance measuring device based on the principle of evaluating the change over time in the phase of an electromagnetic radiation emitted by a radiation source and remitted by an object aimed at, a frequency, which is preferably furnished by a quartz oscillator, is regulated in a ring oscillator with N delay elements (V₁, V₂, V₃, . . . , V_N) to a desired first high frequency (F), which is used as a mixer frequency or as a modulation frequency. The signals at the N delay elements (V₁, V₂, V₃, . . . , V_N) are delivered to a multiplexer, which is switched over with a cadence that is equivalent to 2*N times the frequency of the low-frequency measurement signal to be evaluated to produce a modulation frequency or mixer frequency.

The invention provides a general satellite navigation signal interference source and a signal generating method thereof. The general satellite navigation signal interference source is mainly composed of a main control software module, an intermediate frequency interference signal generating module and a radio up-conversion circuit. The method mainly comprises the steps of: according to the control parameters of the interference signal input by users as interference mode, frequency points, bandwidth and power and the like, processing digital frequency synthesis to generate low-intermediate frequency digital signals, processing digital orthogonal up-conversion and D/A conversion for the low-intermediate digital signals, to attain intermediate frequency analogue signal output. The invention utilizes phase lock frequency synthesis theory to generate the local oscillation frequency of corresponding frequency points, mixes the radio frequency local oscillation signal of the local oscillation frequency and the intermediate frequency analogue signals via an orthogonal modulation, processes automatic gain control and accurate power control to output the attained radio frequency interference signals. The invention can simulate the interference condition of a receiver actually receiving satellite signals.

The invention relates to an accessory non-contact power supply type rotary ultrasonic machining device belonging to the technical field of precision machining of hard brittle materials and aiming at promoting a common machine tool to an ultrasonic auxiliary rotary machining machine tool capable of carrying out the precision machining of the hard brittle materials without changing the traditional part of the machine tool. The accessory non-contact power supply type rotary ultrasonic machining device comprises a direct digital frequency synthesis ultrasonic generator with frequency automatic-tracking function, an ultrasonic tool shank with a standard main shaft interface, and an ultrasonic vibration system, wherein the ultrasonic vibration system is integrated in the ultrasonic tool shank on the basis of the ultrasonic tool shank and adopts a non-contact electromagnetic conversion type power supply method; and the ultrasonic tool shank is integrated on a main shaft of the common machine tool through the standard main shaft interface. The invention is mainly used for the design and the manufacture of a precision machining device of the hard brittle materials.

Disclosed herein is a multi-band ZigBee transceiver for supporting IEEE 802.15.4 wireless communications. In the multi-band ZigBee transceiver, a Multi-Mode Modem (MMM) selects any one of a European version standard using 860 MHz band, a US version standard using 920 MHz band, and a worldwide version standard using 2.4 GHz ISM band among IEEE 802.15.4 standards. A frequency synthesizing unit variably adjusts a carrier frequency according to the transmission standard. A transmission unit receives a digital modulated signal, low-pass-filters the digital modulated signal with a bandwidth thereof being variably adjusted, and up-converts the filtered digital modulated signal into an RF modulated signal corresponding to the selected transmission channel. A receiving unit down-converts the RF modulated signal into a BB modulated signal using the carrier frequency, low-pass-filters the BB modulated signal with a bandwidth thereof being variably adjusted according to the selected transmission standard, converts the filtered BB modulated signal into a digital modulated signal, and outputs the digital modulated signal to the MMM. A transmission/reception switch unit outputs the RF modulated signal, input from the transmission unit, to an antenna, or outputs the RF modulated signal, received from the antenna, to the receiving unit.

The invention relates to a configurable frequency synthesis circuit based on a delay locked loop. The circuit comprises the delay locked loop, a frequency synthesizer and a configuring SRAM, wherein, the delay locked loop consists of a phase discriminator, a controller and a variable delay chain; and the frequency synthesizer consists of a frequency doubling synthesizer and a frequency division synthesizer. The phase discriminator receives a reference clock and a feedback clock and outputs comparison signals and locking signals after phase demodulation comparison; the comparison signals and the locking signals are processed by the controller, and the controller outputs control voltage then in order to enable the variable delay chain to generate N phase clocks that are output to the frequency synthesizer; and the frequency doubling synthesizer and the frequency division synthesizer enable the set/reset time of a R/S trigger in the frequency doubling synthesizer to generate frequency doubling clock signals under the control of the configuring SRAM, and lead the set/reset time of the R/S trigger in the frequency division synthesizer to generate frequency division clock signals. The configurable frequency synthesis circuit has simple circuit organization, flexibly changes a frequency synthesis coefficient by changing the code flow value in the embedded configuring SRAM so as to obtain a frequency division coefficient and a frequency doubling coefficient as required, and can be applied to a field programmable logic array.

The invention belongs to the field of 3D contour measurement on object surface. The main technical features comprise: (1) projecting gratings with different frequencies to the object surface to obtain multiple phase diagrams; (2) unwrapping the phase diagrams with frequency synthesis method to obtain high-precision unwrapped phase; (3) matting corresponding points to external polar line with the unwrapped phase and calculating 3D contour of the object surface; and (4) in order to make the calculation result more reliable, using modulation degree as reliable reference of phase unwrapping and masking the phase with modulation degree less than the set threshold. The invention has the advantages of simple structure, non-contact, high precision, high speed, and easy implementation.

A frequency synthesis/multiplication circuit and method for multiplying the frequency of a reference signal. In one embodiment, multiple versions of the reference signal are generated having different phases relative to one another, and these multiple versions are combined to form an output signal having a frequency that is a multiple of the frequency of the reference signal.

A frequency synthesizer IC is disclosed that includes a variable delay circuit, a fractional-N phase locked loop circuit, and a feedback loop. The variable delay circuit is electrically coupled to the input of the fractional-N phase locked loop circuit. The feedback loop couples a first control signal from the fractional-N phase locked loop to the variable delay circuit. The variable delay circuit generates a reference signal that has a phase delay that varies in accordance with a second control signal and a first control signal. The fractional-N phase locked loop circuit is operable upon receiving the reference signal to generate the first control signal, the second control signal, and an output signal having a frequency that is a non-integer product of the reference signal.

The invention relates to a frequency combination-based optical frequency domain reflection method and system. According to the frequency combination-based optical frequency domain reflection method and system, electro-optic modulation and acousto-optic modulation are performed on local light, so that optical pulses can be obtained; the optical pulses, adopted as detection pulse optical signals, are inputted into a test optical fiber; coupling and frequency beating are performed on obtained Rayleigh backscattered optical signals and the local light; obtained optical signals are subjected to photoelectric conversion and demodulation; and therefore, an optical frequency reflectometer can be obtained. According to the electro-optic modulation, single-frequency signals are adopted to perform modulation. According to the acousto-optic modulation, pulse signals are adopted to perform modulation. A plurality of frequency components of optical combed signals obtained through the electro-optic modulation are simultaneously subjected to frequency sweeping, so that optical pulses can be obtained. The frequency combination-based optical frequency domain reflection method and system have the advantages of large detection range, high spatial resolution, low hardware cost and low software complexity.

The invention relates to a two-way ranging and time comparison processing terminal which is characterized in that: the processing terminal comprises a frequency benchmark, a radio frequency front end, a noise source, a frequency synthesis, a transmitting channel, a receiving channel, a medium frequency signal processor, a machine case, a display and control system, a power source distributor and a LAN switching module, wherein the configuration of the entire processing terminal is a 4U machine case postnotal plate joint interconnecting structure fastened by a standard machine cabinet; the frequency benchmark, the transmitting channel, the receiving channel, the medium frequency signal processor and the power source distributor are arranged inside a standard 4U machine case; the display and control system, which is realized through the configuration of an external notebook computer and display and control software, is in interaction with the outside through the LAN switching module. The entire processing terminal has simple equipment and high integration level; communication, ranging and time comparison are completed inside a unified channel, thereby saving frequency band resource; a pseudo code ranging system is adopted to ensure high ranging precision; moreover, the processing terminal, which has the functions of simulating dynamic state and time delay inside the transmitting channel, is used to realize the quantitative detection of the performance of a receiving terminal.

An all-digital frequency synthesizer architecture is built around a digitally controlled oscillator (DCO) that is tuned in response to a digital tuning word (OTW). In exemplary embodiments: (1) a gain characteristic (K_DCO) of the digitally controlled oscillator can be determined by observing a digital control word before and after a known change (Δf_max) in the oscillating frequency; (2) a portion (TUNE_TF) of the tuning word can be dithered (1202), and the resultant dithered portion (d_k^TF) can then be applied to a control input of switchable devices within the digitally controlled oscillator; and (3) a non-linear differential term (187, 331) can be used to expedite correction of the digitally controlled oscillator when large phase error changes (335) occur.

The invention relates to a modular generation method for a multi-waveform radar signal, which belongs to the technical field of radar frequency synthesis and is applied to the design of a direct digital frequency synthesis (DDS)-based frequency synthesizer. A multi-waveform radar signal module consists of modular software, a field programmable gate array (FPGA) and DDS chips. The modular software comprises a man-machine interactive interface and a modular serial port timing module, wherein the man-machine interactive interface performs relevant operation and storage of control parameters and waveform data of the DDS chips and performs data communication with the FPGA; and the modular serial port timing module generates modular serial port control timing which is suitable for the DDS series chips and completes data acquisition and updating by computer communication. The FPGA is provided with a random-access memory (RAM), a universal asynchronous receiver/transmitter (UART) and a DDS control module, and realizes the functions of data communication with a computer and the storage of the control parameters and waveform data of the DDS chips and DDS chip control. The DDS chips output various signals set by the parameters under the control of the FPGA. The modular software developed by the method configures different DDS chips, so various radar signals of point frequency, linear frequency modulation, nonlinear frequency modulation and phase encoding can be generated, and the software supports on-line programming and the real-time updating of the control parameters and waveform data of the DDS chips.

A frequency synthesiser (100) has a first variable frequency oscillator (10) for generating a first oscillator signal having a frequency responsive to a first control signal, a second variable frequency oscillator (50) for generating a second oscillator signal having a frequency responsive to a second control signal, and a phase reference generator (40) for generating a phase reference signal. There is a phase difference generator (30) for generating a phase difference signal indicative of the phase difference between the sum of the phases of the first and second oscillator signals and the phase of the phase reference signal. A controller (60) responsive to the phase difference signal generates the first and second control signals. At least one of the first and second control signal are determined dependent on a value of the phase difference signal, and at least one of them are determined dependent on a further characteristic of a signal, the further characteristic being supplementary to the effect of any dithering introduced into the frequency synthesiser (100).

Disclosed is a frequency modulator and method for directly modulating voltage-controlled oscillator (VCO) with self-adapting gain control. The invention exploits double-point modulation structure to control the input of VCO; and exploits the property of phase-lock loop to the narrow band tracking property of VCO to get carrier wave signal; getting frequency modulation signal by modulating VCO with digital self-adapting gain control loop. The inventive structure has the advantages of exploiting phase-lock loop frequency synthesizer to getting carrier wave frequency, and of be able to modulating high speed wide band input signal.

A method and apparatus improves the stability and noise performance of frequency synthesis and synchronization circuits. A cancellation circuit provides an error signal that is a measure of integrated quantization error in a delta-sigma modulator that controls the ratiometric division factor in a fractional-N phase-lock loop (PLL). The error signal is fed to the loop filter of the phase-lock loop as a correction signal via a differentiator (high-pass filter). The high pass filter removes substantially all in-band components from the cancellation signal, which reduces the linearity requirement on the cancellation signal path. The cancellation signal can be tapped from an internal numerical integrator of the delta-sigma modulator that is then converted to an analog signal, that is then filtered and combined with the phase comparator output in the loop filter.

A DPC (200) that includes: a frequency source (20); a delay-locked loop (220) for receiving a clock signal and generating a plurality of phase-shifted clock signals; a control device (280) having a DPS (282) and a DAC (284) for receiving an input signal identifying a desired frequency for a synthesized signal; a selection circuit (270) for receiving the plurality of phase-shifted clock signals, selecting a sequence of the phase-shifted clock signals and outputting a coarse synthesized signal; a variable delay cell (290) having a first input coupled to the selection circuit to receive the coarse synthesized signal and a second input coupled to the control device for receiving a fine tune adjustment signal to modify the coarse synthesized signal to generate the synthesized signal (292) having substantially the desired frequency. The DPC further includes training apparatus for calibrating the DPC.

The invention discloses a frequency synthesizer and a frequency synthesis method. The frequency synthesizer comprises: a large-stepping phase lock loop and a direct digital frequency synthesizer, an orthogonal mixer and a tracking phase lock loop. The orthogonal mixer is connected with the large-stepping phase lock loop and the digital frequency synthesizer respectively for mixing the frequency generated by the large-stepping phase lock loop and the low frequency generated by the direct digital frequency synthesizer to generate a single-sideband single tone; the tracking phase lock loop is connected with the orthogonal mixer for receiving the single-sideband single tone output by the orthogonal mixer and filtering the sideband leakage and oscillation leakage of the signal. The invention provides a frequency synthesizer with wide band width, small stepping, low stray and low noise and a frequency synthesis method. The invention has simple hardware structure and is easy to accomplish.

The invention relates to an amplitude-phase correction device of digital T/R modules of a phased array radar and correction methods thereof, and belongs to the technical field of amplitude-phase correction of the digital T/R modules. The amplitude-phase correction device is composed of a monitoring computer, a resource management computer, a frequency source and the like. The frequency source receives transmitting excitation coupling signals output by the digital T/R modules through array panel monitoring network. The monitoring computer sends amplitude-phase correction instructions to the frequency source and the digital T/R modules through the resource management computer and the array panel monitoring network, and the frequency source and a digital beam forming DBF extension receive correction data. Hardware of the frequency source includes a field-programmable gate array (FPGA) and a direct digital frequency synthesizer (DDS). 9 steps of the amplitude-phase transmitting correctionmethod and 8 steps of the amplitude-phase receiving correction method are adopted to realize automatic switching of frequency points and channels as well as automatic calculation of compensation values to generate the correction instructions, sub-millisecond correction reduces errors, the correction efficiency is high, the effect of temperature drift due to long time correction is avoided, and thehigh-efficiency operation of the digital T/R modules is ensured.

Brushless Multiphase Self-Commutation Control (or BMSCC), also known as Real Time Emulation Control (or RTLC), is a contact-less means for powering any electric apparatus with “conditioned” or “re-fabricated” multiphase electrical excitation that is synchronized to the movement of the electric apparatus. BMSCC inherently phase-locks the frequency of excitation to any speed or position of the electric apparatus being controlled by a natural electromagnetic processing means and as a result, the BMSCC is an Electromagnetic Self-Commutator. BMSCC should never be confused with any derivative of Field Oriented Control, which is the other means of conditioning speed-synchronized electrical excitation by iteratively performing “speed-variant-to-speed-invariant” transformations and frequency synthesis by the unnatural processing means of an electronic computer. The control flexibility of BMSCC realizes additional synergistic or complementary electric apparatus inventions as shown in the illustration.

The invention relates to a millimeter-wave imaging system for the omni-directional scanning of a single antenna array. The millimeter-wave imaging system comprises an antenna array disc bracket, a sliding rail, a drive disc, two metal struts, a servo control module, a frequency synthesis module, a transmitting module, a transmitting antenna array, a receiving antenna array, a receiving module, a delay module, a signal processing module and a display control modules, wherein the servo control module controls a drive shaft of a motor to rotate at a sinusoidal velocity, and controls and detects the rotation angle of the antenna array disc bracket, so that the antenna array disc bracket rotates at an angle of 0-300 degrees; the transmitting antenna arrays radiate radio-frequency signals to the surface of a target, and after being reflected by the surface of the target, the radio-frequency signals are received by the receiving antenna arrays; echo signals are processed by the receiving module so as to form intermediate-frequency echo signals, and then the intermediate-frequency echo signals are sent to the signal processing module; and the intermediate-frequency echo signals are performed three-dimensional imaging processing in the signal processing module so as to obtain three-dimensional image data, and then the three-dimensional image data is transmitted to the display control module. The system provided by the invention has the advantages of simple design, low cost, high image quality, high resolution and short imaging time.