7 results about "Instantaneous frequency measurement" patented technology

This invention relates to a radio frequency (RF) link and detection device for passive wireless detection equipment, belonging to the field of wireless detection technology. The RF link includes: a tracking local oscillator link, comprising: an instantaneous frequency measurement receiver and a fast frequency hopping synthesizer connected to it; the instantaneous frequency measurement receiver is used to evaluate the frequency of the incoming signal and determine the instantaneous estimated frequency; the fast frequency hopping synthesizer is used to determine the local oscillator frequency based on the instantaneous estimated frequency and perform local oscillator frequency hopping to generate the local oscillator signal; a receiving link is used to mix the incoming signal and the local oscillator signal, down-converting it to an intermediate frequency (IF) signal; and a processing unit connected to the receiving link is used to sample and process the IF signal to track agile wireless detection equipment. Through the above method, the frequency hopping of agile signals can be effectively addressed, avoiding problems such as IF signal distortion, clutter interference, and signal filtering caused by frequency mismatch in traditional ordinary local oscillators.

A sensor buoy comprising: a buoy casing configured to float on a body of water; an antenna mounted to the buoy casing so as to limit an RF range of view to no more than fifteen kilometers; an instantaneous frequency measurement (IFM) receiver mounted to the buoy casing and communicatively coupled to the antenna; a pulse descriptor word (PDW) generator mounted to the buoy casing and configured to receive an output from the IFM receiver; a processor configured to receive PDWs generated by the PDW generator and to calculate a corresponding pulse repetition interval (PRI); a magnetometer communicatively coupled to the processor; a scheduler communicatively coupled to the processor and configured to control when the sensor buoy transmits information; and a transmitter communicatively coupled to the scheduler and configured to format data from the processor into a correct format and packet structure for transmission.

A monobit analog-digital converter (ADC) system and method are disclosed, the system comprising a front-end signal conditioning system equipped with a programmable attenuator and amplifier for processing analog signals, where the attenuator, which may include a cascade of programmable attenuator cells, is controlled by an attenuation control signal to adjust signal attenuation to cause a signal-to-noise ratio (SNR) in the negative domain, after which an amplifier amplifies the attenuated signal with the suitable SNR, where the amplified signal is then converted to a monobit signal by a monobit ADC, thereby achieving an ADC system that enables conditioning and digitizing of RF signals over a wide range of input signal powers with control over the output spectrum signal power and harmonics to achieve low-power real-time general-purpose broadband blocker detection for adaptive radios and for interference detection, main beam radar signal detection, and instantaneous frequency measurement, among other fields requiring general-purpose blocker identification with low size, weight, power, and cost (SWaP-C).

The application relates to a multi-channel ultra-wideband undersampling instantaneous frequency measurement method, belonging to the technical field of wideband digital radars, and solving the problem of spectrum overlap of multiple signals; for a scheme of multiple channels with different time delays, phase frequency measurement is combined with the remainder theorem to demodulate the frequency of an input signal; for signals near f s / 2, phase frequency measurement is carried out through the time delay difference between different channels to solve the frequency band in a targeted manner; for signals near f s / 2, multi-rate sampling is realized through a time-sharing sampling method, threshold discrimination and parameter matching are carried out on the FFT frequency measurement result through the remainder theorem, and finally, the PDW signal is demodulated, the method does not need to provide a high-speed pseudo-random sequence, has hardware realizability, has the characteristics of small size, no need of channelization, low algorithm implementation complexity, strong robustness and strong demodulation capability compared with the prior art, and can realize high-precision undersampling frequency estimation of radar signals under the index of 0 to 18G instantaneous bandwidth.

The invention relates to a radio frequency link for passive wireless detection equipment and the detection equipment, and belongs to the technical field of wireless detection. The radio frequency link comprises a tracking local oscillator link which comprises an instantaneous frequency measurement receiver and a fast frequency hopping frequency synthesizer which are connected; the instantaneous frequency measurement receiver is used for carrying out frequency evaluation on an incoming wave signal and determining an instantaneous estimation frequency, and the fast frequency hopping frequency synthesizer is used for determining a local oscillation frequency based on the instantaneous estimation frequency, carrying out local oscillation frequency hopping and generating a local oscillation signal; the receiving link is used for performing frequency mixing and down-conversion on the incoming wave signal and the local oscillation signal to obtain an intermediate frequency signal; a processing unit; and the sampling link is connected with the receiving link and is used for sampling the intermediate frequency signal so as to track the agile wireless detection equipment. By means of the mode, frequency hopping of agile signals can be effectively coped, and the problems of intermediate frequency signal distortion, clutter interference, signal filtering and the like caused by frequency mismatching of a traditional common local oscillator are solved.

This invention discloses an ultra-wideband, high-precision instantaneous frequency measurement circuit and method, belonging to the field of frequency measurement technology. It includes a power divider group, multiple frequency measurement channels, an analog switch group, an SP3T switch, a direct digital frequency synthesizer (DDS), and an FPGA. The input RF signal is divided into four channels by the power divider group, corresponding to four frequency measurement channels. Each frequency measurement channel corresponds to a different frequency range, and the channels operate in parallel. Each channel signal is output as an LVTTL level to the FPGA after passing through a detector and comparator. The FPGA determines the frequency range based on the level combination and controls the analog switch and SP3T to select the corresponding channel. The frequency of the signal generated by the DDS is measured by the FPGA, and the input RF signal frequency is calculated inversely based on the division ratio and frequency control word. This invention achieves DC-20GHz ultra-wideband frequency measurement. The measurement speed depends on the DDS frequency switching speed. After the measurement is completed, the power to the divider is turned off to eliminate spurious interference. The circuit structure is simple and low-cost.