71results about How to "Low phase noise" patented technology

Provided in the present invention are a channel estimation processing method, apparatus and communication device, wherein a phase compensation processing method comprises: obtaining from various receiving antennae a reception signal of at least one first pilot frequency subcarrier in channel estimation preamble sequences transmitted simultaneously by a plurality of transmitting antennae; according to the reception signal of the at least one first pilot frequency subcarrier, obtaining the phase shift parameters of the various receiving antennae during the reception of the channel estimation preamble sequences, and obtaining a channel estimation matrix during the reception of data symbols; obtaining from the various receiving antennae a reception signal of at least one second pilot frequency subcarrier in the data symbols, the reception signal being obtained by calculation on the basis of non-common source phase noise factors of different receiving antennae, and obtaining the phase shift parameters of the various receiving antennae during the reception of the data symbols; and performing phase compensation on the received data subcarrier according to the phase shift parameters as well as the channel estimation matrix during the reception of the data symbols. The technical solution of the present invention can reduce the influence of phase noise and frequency offset effectively.

The invention relates to a method for synchronizing the time and the frequency of a motor-driven configured bistatic radar. The frequency and the time between a receiving station and a transmitting station of the bistatic radar can be realized by utilizing the characteristics of long-term stability, low phase noise and low stray; when the receiving station and the transmitting station are deployed separately, the real-time statistics of time synchronization errors of the receiving station and the transmitting station are completed on the basis of pulses per second of a navigation satellite; when the time synchronization errors exceed a limit value and the state of the pulses per second of the navigation satellite is normal, time resynchronization between the receiving station and the transmitting station is completed in a navigation satellite time service synchronization mode; the receiving station and the transmitting station enter a timekeeping synchronization state again. The method is applicable to synchronizing the time and the frequency of the motor-driven configured bistatic radar, and has the advantages of short erecting and withdrawing time, high maneuverability, high working stability and the like. Before the receiving station and the transmitting station are deployed separately, the modes of direct time contrast synchronization and long-time autonomous timekeeping maintenance are adopted, and have the advantages of being not limited by the navigation satellite and not impacted by electromagnetic environment in wartime.

The present invention proposes a Ka-band radio frequency modulation system and method, including: a baseband signal processing module, which receives a digital baseband signal, and performs constellation mapping on it according to a corresponding modulation mode, and performs shaping and filtering on the generated constellation mapping symbols Output; the digital-to-analog conversion processing module is connected to the baseband signal processing module to perform digital-to-analog conversion and filtering on the shaped and filtered data signal, and output the analog baseband signal; the carrier source generation module is used to generate and output modulation Carrier signal; quadrature analog modulator, connected to the digital-to-analog conversion processing module and the carrier source generation module, for performing quadrature analog modulation on the analog baseband signal according to the carrier signal, and outputting a modulated radio frequency signal. It solves the problems of poor performance index and flexibility of common modulation systems, and achieves the characteristics of simple circuit, small footprint, low power consumption, excellent modulation performance index, and strong flexibility.

The invention discloses a broadband low-noise frequency modulation signal source. A high-stability clock module has two clock signals as output, the first clock signal as output is directly connected with the reference clock end of a DDS module, and the second clock signal is connected with the input end of a power divider; the power divider divides the second clock signal into haves and respectively outputs the two haves through two output ends, wherein one half is output to a DDS configuration module; the DDS configuration module outputs a configuration signal to the DDS module, the DDS module, after receiving the configuration signal, generates a frequency modulation signal by use of a phase synthesis and table look-up method and outputs the frequency modulation signal through a waveform output end; the waveform output end is respectively connected with a first phase-locked loop circuit and a second phase-locked loop circuit through a low-noise amplifier; output of the first phase-locked loop circuit is taken as an emission local oscillator; and output of the second phase-locked loop circuit is taken as a receiving local oscillator. The signal source provided by the invention can meet the demands for high linearity and low phase noise of a broadband frequency modulation signal source.

The invention relates to a radar communication countermeasure integration design based on microwave photonics. The radar communication countermeasure integration design comprises a system light source, an emitting and receiving end adjustable filtering module, an any waveform generating module, an emitting and receiving end modulator module, a light power amplifier module, a system time delay module, an emitting and receiving end end-detection module, a microwave antenna module, a passage receiving/direct collection receiving module, a microprocessor module and the like. The system can realize the function switching of three kinds of information systems of radar detection, digital communication and electronic countermeasure through parameter configuration and chip configuration; through the any waveform generating module, analog signals or digital signals used for three kinds of systems can be generated; the system comprises an emitting loop and a receiving loop; the emitting loop and the receiving loop use identical light sources, so that the system coherence is ensured; meanwhile, the microwave signals are processed in the photonic filed, so that the advantages of high bandwidth and low noise performance are realized. The system can realize the functional integration of the information system; the environment adaptability and reconfigurability of the system can be improved; the system can be widely used in the information technology fields such as ultra-wide band radar, digital communication and electronic countermeasure.

The invention relates to a frequency agility synthesis method compatible with microwave large band width and mid-frequency small step and a device thereof. The invention is characterized in that direct simulation type frequency synthesis, direct digital frequency synthesis, and DSP(digital signal processor) technology are combined to perform frequency synthesis, so as to make the best of the advantages of the mentioned technologies, avoid technical defects, realize the optimization of all technical indexes of the frequency synthesizer, has a better expandability on the design of frequency band width and at the same time is compatible with large band width microwave frequency agility and mid-frequency small stepping frequency agility signal functions.

The invention belongs to the technical field of synchronous comprehensive design for radar distributed waveform generation, and particularly relates to an online synchronous regulating circuit and method for use in distributed waveform generation. A main control terminal completes controlled communication with a waveform generation part in a receiving-transmitting assembly, and setting and adjustment of relevant parameters such as the leading edge and lagging edge of waveform output and initial frequency are realized according to a preset communication protocol. The online synchronous regulating circuit has the advantages of low cost, convenience and rapidness in operation, high accuracy, simple structure and easiness in integration.

The invention discloses an ionospheric scintillation monitoring system based on Beidou navigation, comprising: an antenna for receiving Beidou satellite signals, and transmitting the Beidou satellite signals to the receiver for processing; and carrier phase φ information are transmitted to the computer; the computer includes a data acquisition and analysis module and a system display module, and the data analysis module processes the satellite signal strength SI and carrier phase φ information output by the hardware, and performs data display through the system display module. Beneficial effects: this embodiment adopts an internal crystal oscillator source, which has stable frequency and low phase noise, and has strong anti-interference ability. The computer directly outputs the signal strength SI and carrier phase φ information of the satellite signal, which can be used to calculate the scintillation of the ionosphere, which is more convenient, simple, stable and reliable than the original equipment.

The invention discloses a C wave band voltage-controlled oscillator. The C wave band voltage-controlled oscillator comprises a load circuit for changing the resonant frequency, a transistor circuit for enabling the whole circuit to oscillate, a terminal circuit for meeting the oscillation condition, a first match circuit and a second match circuit. The load circuit is connected with the transistor circuit through the first match circuit, and the transistor circuit is connected with the terminal circuit through the second match circuit. According to the voltage-controlled oscillator with the center frequency being any frequency point in a C wave band, the circuit is simple in structural design, cost is low, the requirement for the machining precision is not high, high cost performance is achieved, and the C wave band voltage-controlled oscillator has the advantages of being low in phase noise, wide in tuning range, good in linearity, high in output power, stable in in-band power and the like.

The invention discloses a 0-18 GHz ultra wide band frequency sweep source and relates to the technical field of microwave. The 0-18 GHz ultra wide band frequency sweep source comprises a reference source module, a first filtering module and a second filtering module, wherein the reference source module generates any point frequency or linear frequency modulation signal of 0-1.4 GHz by using a high-speed DDS technology, and uses an ultra-wideband low-noise PLL technology integrated with a VCO generating a 8.6-15GHz ultra-wideband frequency hopping high local oscillation signal with low phase noise and low stray and other y point frequency local oscillation and excitation signals. Compared with a direct synthesis technology, the frequency sweep source has the advantages that the size can beeffectively reduced, through careful design of a frequency conversion scheme and application of two filtering modules to a broadband switch filtering technology, the frequency sweep source can achieveultra wide band through a simplified structure, and the size requirement is met while the performance index is met.