44 results about "Digital radio frequency memory" patented technology

The invention discloses an object indication radar object simulator which is mainly applied to simulating radar reflection echoes of a missile type object and an airplane type object in a real state close to reality. The object indication radar object simulator comprises an emission antenna, an emission front end, a radiation pulse generation unit, a high precision reference source and C-wave band agility frequency source, a comprehensive control unit, a digital radio frequency memory unit, a receiving front end and a receiving antenna. Radar signals, after being converted down to an intermediate frequency through the receiving front end, penetrate into the radio frequency memory unit and are stored there, the comprehensive control unit performs control according to an object batch, a speed and distance information which are to be simulated, the radio frequency memory unit generates intermediate frequency signals of object echoes, then the radiation pulse generation unit and the emission front end simulate magnitude information and Doppler information of the echoes, and final, the emission antenna performs emission. The stimulator can simulate radar echo information of a real object and is mainly applied to dynamic object simulation, outfield test simulation, integrated practice and testing of a radar system.

The invention discloses a radar signal processing system based on DRFM (Digital Radio-Frequency Memory) technology and a dense target jamming generation method. A transmitting and receiving antenna receives a radar transmitting pulse, and an L-waveband microwave transmitting and receiving assembly carries out down conversion processing on a radar signal; a wideband digital radio frequency memory in a signal processing unit receives an intermediate frequency signal, and high-speed sampling and memory are carried out; an FPGA-based signal processor carries out piecewise superposition on the stored data, and an analog echo signal covering a radar detection distance range is generated; an all-digital single-sideband modulator carries out Doppler frequency shift on the echo signal; and an FPGA-based timing controller converts the echo signal through frequency shift into an intermediate frequency output signal. Delayed superposition forwarding increases the number and the density of false targets, dense target jamming approximate to noise can be realized, and functions of the DRFM, control and management and the like can be effectively realized.

System that measures absolute or additive phase noise includes a power divider for dividing an input RF signal, a local oscillator, two mixers, each arranged in a path of a respective signal component from the power divider and receiving input from the power divider and local oscillator, two digital radio frequency memories, each associated with a respective mixer and receiving an input signal therefrom, and a digital signal processor that receives signals from the digital radio frequency memories and outputs a digital data stream indicative of measured phase noise. For absolute phase noise measurement, phase noise of the input RF signal is provided. For additive phase noise measurement, a unit under test is arranged in one of the paths between the power divider and the mixer. The system may be interposed between a radar transmitter of a radar environment simulator and a radar receiver coupled to a radar target display.

The invention discloses a digital radio frequency memory based on analogue demodulation/modulation. The digital radio frequency memory is provided with an FPGA (Field Programmable Gate Array), a FLASH, an RAM (Random Access Memory), A/Ds (Analog to Digital) and D/As (Digital to Analog) of a line I and a line Q, and a low pass filter, wherein the FLASH and the RAM are respectively connected with the FPGA through data lines; the A/D and the D/A of the line I and the line Q are respectively connected with the FPGA through data lines; the low pass filter is respectively connected with the D/As of the line I and the line Q. According to the digital radio frequency memory disclosed by the invention, the bandwidth which is better than 400MHz and the dynamic state which is better than 40dB are realized and the digital radio frequency memory can be applicable to radar signals of various systems; the digital radio frequency memory has the capability of improving the quality of a copying signal through using a sample screening technology and a sample frequency spectrum purification technology; a coherent interference signal can be generated through carrying out multi-pulse tracking and stable tracking on a target signal and an output signal can be subjected to normalization and peak-to-average ratio improvement treatment; the efficiency of interference is greatly improved and the digital radio frequency memory can be widely applied to various types of radar jammers.

The invention discloses a linear frequency modulation continuous wave system based on chaotic coding frequency agility and an application method thereof. The system comprises a detector front-end module which transmits a chaotic coding continuous wave frequency modulation detection signal after up-conversion and also receives a target intermediate frequency signal outputted after down-conversion of echoes; a DDS-based signal generator which is used for outputting control word DDS frequency agility linear frequency modulation continuous wave signals through the FPGA; and a digital radio frequency memory (DRFM) which is used for storing, copying, modulating and forwarding the intercepted signal, wherein the deception interference signals have great interference effect for the linear frequency modulation continuous waves. The linear frequency modulation continuous wave are optimized by using the sensitivity, the randomness and great auto-correlation and cross-correlation of the initial value of chaotic coding from the waveform design perspective, chaotic coding frequency hopping is performed on the frequency modulation center frequency and the law of agility is difficult to be intercepted by the enemy so that the anti-deception interference can be realized. The anti-interference capacity of the self-detector can be enhanced from the waveform design perspective and the system has important meaning for the field of short range detection.

A vehicular programmable transceiver includes a digital radio frequency memory (DRFM) having at least one register configured to sample and hold a radio frequency input signal in response to a clock signal and to generate an output signal having a carrier frequency generated in response to the sampled and held input signal.

The invention discloses an active camouflage protection method and device based on multiple phase sectionalized modulation radar interference. According to the invention, image blocks with the number, the position, the area and the brightness being controllable are generated on a synthetic aperture radar image to cover a target image and peripheral background image through controlling characteristics of an interference signal so as to achieve a camouflage purpose. The method disclosed by the invention is processing performed on two dimensions; received signals are uniformly-spaced pulse signals; when the maximum length of subsection signals is less than the pulse width of the received signals, the subsection is a short subsection which is interference for the distance dimension; and when the minimum length of the subsection signals is greater than a pulse repetition period of the received signals, the subsection is a long subsection which is interference for the Doppler dimension. The active camouflage protection device comprises a controller and a digital radio frequency memory DRFM, wherein the controller and the digital radio frequency memory DRFM are connected in series, and the controller controls a sectionalizing mode and a modulation phase value of radar signals; and the DRFM acquires one-dimensional interference signals and two-dimensional interference signals according to the sectionalizing mode and the modulation phase value.

A digital radio frequency memory (DFRM) which converts an incoming analog radio frequency signal to a fourteen bit digital signal allowing for digital signal processing and then retransmitted as an analog RF signal. The DFRM provides a time delay for RF signals by storing the signal. The DFRM also changes the signal frequency in the range of plus or minus 100,000 KHz which places a doppler on the signal. The signal phase is changed in a range of 0 to 359 degrees by the DFRM.

The invention discloses a radar signal emission method for resisting radio frequency storage forwarding interference, which utilizes the digit radio frequency storage forwarding work principle and combines with the bandwidth advantage of the radar broadband signal work. The radar emits the broadband signal, which covers a plurality of digital channelization investigation channels of a jammer, increases the accuracy recognition and jamming difficulty of the jammer on the radar signal through actively optimizing the signal waveform in the broadband, causes the fact that the jammer only interferes parts of the frequency part and reduces the adverse affect brought by the jammer. The radar on a reception terminal firstly performs spectral analysis on the received radar echo to determine whether the radar receives the radio frequency storage forwarding interference, if the radar is found to be interfered, the removal of the interference frequency band can be performed during the pulse pressure, and the signal of the rest part which is not interfered is utilized to perform the object detection.

The invention discloses a two GHz bandwidth digital radio frequency memorizer and a storage method. The memorizer comprises a broadband analog/digital converter (ADC), a radio frequency processing field-programmable gate array (FPGA) and a storage pool. The radio frequency FPGA comprises a serial/parallel converting unit. The ADC is connected with the input end of the serial/parallel converting unit, and the output end of the serial/parallel converting unit is connected with the storage pool. The two GHz bandwidth digital radio frequency memorizer and the storage method are mainly used in the technical field of radar radio frequency emulation and have the capability of collecting and playing back high-speed data, the functions of data collecting, storing, transmitting, playing back and the like can be achieved flexibly, the problem that an existing DRFM system bandwidth is not enough can be solved, and the capability and speed of radio frequency signal storing are improved.

The invention provides a digital radio frequency memory board. An analog/digital converter module for the digital radio frequency memory board is used for acquiring an external analog signal at a high speed, converting the external analog signal into a digital signal and transmitting the digital signal to a first field programmable gate array (FPGA) module, wherein the first FPGA module is used for performing primary programmable processing on the digital signal and transmitting the digital signal to a second FPGA module; the second FPGA module is used for performing secondary programmable processing on data and finally transmitting the data to a digital/analog converter module; the digital/analog converter module is used for converting the digital signal into an analog signal at a high speed and outputting the analog signal; a first static random access memory (SRAM) module is connected with the first FPGA module and is used for caching data of the first FPGA module; and a second SRAM module is connected with the second FPGA module and is used for caching data of the second FPGA module. The digital radio frequency memory board has high-speed data acquisition and playback capacity, and the functions of data acquisition, storage, transmission and playback can be flexibly realized.

The invention relates to the technical field of target simulating, and discloses a projectile echo simulating device and method for an emplacement reconnaissance and fire-directing radar. The simulating device comprises a lifting device, a transverse moving device, a servo and synchronous control device, a digital radio frequency memory microwave delay circuit, a transceiving antenna and a microwave cable. The transverse moving device is horizontally arranged at the upper portion of the lifting device. The transceiving antenna is installed on the transverse moving device and can horizontally move under the control of the transverse moving device. The digital radio frequency memory microwave delay circuit is connected with the transceiving antenna through the microwave cable. The lifting device, the transverse moving device and the digital radio frequency memory microwave delay circuit are connected with the servo and synchronous control device through signals. By means of the projectile echo simulating device and method for the emplacement reconnaissance and fire-directing radar, the problem is solved that the emplacement reconnaissance and fire-directing radar is difficult to train and organize and high in training cost, and meanwhile the problem is solved that projectile trajectory echoes simulated by a simulating device in an existing emplacement reconnaissance and fire-directing radar are unreal.

The invention provides a jammer for resisting a pulse Doppler radar and a jamming method of the jammer and belongs to the technical field of electronic countermeasures. The jammer comprises a receiving antenna, a receiving front end, a coupler, a receiving channel, a digital radio frequency memory, a transmitting channel, a digital control attenuator, a power amplifier, a transmitting antenna, a single-bit receiver, an interference controller, a DDS signal generator, an interference controller and a local oscillator. According to the jammer, a broad pulse coverage jamming method is carried out on a pulse Doppler radar under a low repetition frequency characteristic, a Doppler false target jamming method is carried out on a pulse Doppler radar under a medium-high repetition frequency characteristic, jamming signals and radar signals are coherent, coherent processing gains of the radar signals can be obtained, the jammer has the characteristics of high interference efficiency, good interference effectiveness and the like.