Abstract: A broadband radio frequency signal optical fiber phase-stable transmission system includes a local end and a remote end connected by a dispersion compensation module and an optical fiber. The local end modulates a first auxiliary signal whose frequency is half of the frequency of the to-be-transmitted signal and a second auxiliary signal whose frequency is 1.5 times the frequency of the to-be-transmitted signal through the optical carrier and filters out a lower sideband to obtain an optical signal containing only the optical carrier, a first signal, and a second signal corresponds to the optical signal of the first-order upper sideband. The optical signal is transmitted to the remote end through the dispersion compensation module and the optical fiber.

Abstract: A phase noise suppression method for a multiple-input multiple-output (MIMO) system with a plurality of co-reference channels includes: dividing the phase noise of each channel in the MIMO system into common phase noise and independent phase noise, and constructing a certain number of joint phase states for the independent phase noise; inserting a pilot sequence into the sent signal based on a preset cycle, obtaining the common phase noise based on the pilot at receiver, and performing compensation; and performing signal demodulation on each joint state of the independent phase noise, and comparing the posterior log likelihood values to select the optimal result to output. The above method can significantly improve the phase noise suppression performance of the MIMO system with a plurality of co-reference channels, thereby providing support for improving the system capacity by using MIMO technology.

Abstract: A co-frequency co-time full duplex (CCFD) signal receiving method includes: taking the sent baseband signal as the self-interference reference signal, reconstructing self-interference, and then performing primary self-interference cancellation on the received signal; processing, by using a timing synchronization loop, the signal after the primary self-interference cancellation, realizing timing recovery at the optimal sampling point of the useful signal through resampling a, and controlling resampling b1 and resampling b2 after performing low-pass filtering on the timing error signal in the timing synchronization loop, to recover the optimal sampling points of the self-interference reference signal and the received signal respectively; and performing joint self-interference cancellation and equalization on the resampled self-interference reference signal and the resampled received signal, and receiving the useful signal through signal demodulation.

Abstract: This application discloses a signal generating method, apparatus, and system. One example method includes: performing cyclic electro-optic modulation on a first signal to generate a first optical frequency comb signal, where the first signal is a signal output by a laser source, the first optical frequency comb signal includes a target spectral component, and a frequency of the target spectral component is equal to a sum of or a difference between a frequency of the first signal and a frequency of a target signal; performing first filtering processing on the first optical frequency comb signal to generate the target spectral component; and generating the target signal based on a heterodyne beat frequency of the first signal and the target spectral component.

Abstract: A co-frequency co-time full duplex (CCFD) signal receiving method includes: taking the sent baseband signal as the self-interference reference signal, reconstructing self-interference, and then performing primary self-interference cancellation on the received signal; processing, by using a timing synchronization loop, the signal after the primary self-interference cancellation, realizing timing recovery at the optimal sampling point of the useful signal through resampling a, and controlling resampling b1 and resampling b2 after performing low-pass filtering on the timing error signal in the timing synchronization loop, to recover the optimal sampling points of the self-interference reference signal and the received signal respectively; and performing joint self-interference cancellation and equalization on the resampled self-interference reference signal and the resampled received signal, and receiving the useful signal through signal demodulation.

Abstract: A phase noise suppression method for a multiple-input multiple-output (MIMO) system with a plurality of co-reference channels includes: dividing the phase noise of each channel in the MIMO system into common phase noise and independent phase noise, and constructing a certain number of joint phase states for the independent phase noise; inserting a pilot sequence into the sent signal based on a preset cycle, obtaining the common phase noise based on the pilot at receiver, and performing compensation; and performing signal demodulation on each joint state of the independent phase noise, and comparing the posterior log likelihood values to select the optimal result to output. The above method can significantly improve the phase noise suppression performance of the MIMO system with a plurality of co-reference channels, thereby providing support for improving the system capacity by using MIMO technology.

Abstract: The device of the disclosure provides an optical frequency comb frequency multiplication link to generate millimeter wave signals. The device of the disclosure also provides a local oscillator and a delay compensation link to eliminate the influence of the phase noise of the local oscillator on the test system. The local oscillator signal is down-converted in the optical carrier radio frequency link to obtain an intermediate frequency signal. The intermediate frequency signal is then down-converted with the local oscillator signal and the millimeter wave signal twice to cancel the influence of the microwave mixer noise on the test system. At last, by detecting the output low-frequency signal noise, the ultra-low phase noise level of the millimeter wave signal can be accurately obtained.

Abstract: A measurement device for polarization-maintaining optical fiber spindle difference delay is provided. The measurement device comprises a polarization-maintaining fiber (PM) Sagnac interferometer, a signal generator, a microwave detector, a microprocessor. The PM Sagnac interferometer comprises a laser, a photoelectric modulator, and a PM fiber coupler that are connected in sequence. The PM Sagnac interferometer further comprises an optical fiber interface J1 and an optical fiber interface J2 arranged at the two output ends of the PM fiber coupler, a PM fiber to be measured located between the fiber interface J1 and the fiber interface J2, and a photodetector arranged at the other output end of the PM fiber coupler.

Abstract: A measurement device for polarization-maintaining optical fiber spindle difference delay is provided. The measurement device comprises a polarization-maintaining fiber (PM) Sagnac interferometer, a signal generator, a microwave detector, a microprocessor. The PM Sagnac interferometer comprises a laser, a photoelectric modulator, and a PM fiber coupler that are connected in sequence. The PM Sagnac interferometer further comprises an optical fiber interface J1 and an optical fiber interface J2 arranged at the two output ends of the PM fiber coupler, a PM fiber to be measured located between the fiber interface J1 and the fiber interface J2, and a photodetector arranged at the other output end of the PM fiber coupler.

Abstract: A frequency chirp correction method for the photonic time-stretch system comprises acquiring the stretching signal, i.e. acquiring the time-domain data after the time-domain stretching. First, the time-domain data of the stretching signal is Fourier transformed to obtain the spectral distribution. The spectral distribution is then convoluted with the first frequency-domain correction factor, and then multiplied with the second frequency-domain correction factor to obtain the modified frequency spectrum. Finally, the modified frequency spectrum is performed by the inverse Fourier transform to obtain the time-domain signal after the frequency chirp correction.

Abstract: A photonic radio-frequency receiver with mirror frequency suppression function, in which a single modulator is utilized to form a photoelectric oscillator so as to generate high-quality and low-phase-noise optically generated local oscillators, without the need for an external local oscillator source, and at the same time, another radio-frequency port is used as a radio-frequency signal input port, thereby allowing a compact structure. By properly setting a bias point for the two-electrode modulator and orthogonally synthesizing two branches of intermediate frequency signals respectively generated by the upper and lower sideband beat frequencies of the modulated optical signal, the photonic radio-frequency receiver realizes the functions of receiving radio-frequency signals and suppressing mirror frequency signals. The present disclosure can realize a photonic mirror-frequency suppression receiver.

Abstract: A frequency chirp correction method for the photonic time-stretch system comprises acquiring the stretching signal, i.e. acquiring the time-domain data after the time-domain stretching. First, the time-domain data of the stretching signal is Fourier transformed to obtain the spectral distribution. The spectral distribution is then convoluted with the first frequency-domain correction factor, and then multiplied with the second frequency-domain correction factor to obtain the modified frequency spectrum. Finally, the modified frequency spectrum is performed by the inverse Fourier transform to obtain the time-domain signal after the frequency chirp correction.

Abstract: A photonic radio-frequency receiver with mirror frequency suppression function, in which a single modulator is utilized to form a photoelectric oscillator so as to generate high-quality and low-phase-noise optically generated local oscillators, without the need for an external local oscillator source, and at the same time, another radio-frequency port is used as a radio-frequency signal input port, thereby allowing a compact structure. By properly setting a bias point for the two-electrode modulator and orthogonally synthesizing two branches of intermediate frequency signals respectively generated by the upper and lower sideband beat frequencies of the modulated optical signal, the photonic radio-frequency receiver realizes the functions of receiving radio-frequency signals and suppressing mirror frequency signals. The present disclosure can realize a photonic mirror-frequency suppression receiver.