CN-121984591-A - Radio frequency signal optical fiber synchronous conversion system

CN121984591ACN 121984591 ACN121984591 ACN 121984591ACN-121984591-A

Abstract

The invention provides a radio frequency signal optical fiber synchronous conversion system, and particularly relates to the technical field of signal conversion and transmission. The invention only adopts a single-core stable-phase optical cable to interconnect the central station unit platform and the antenna unit platform, fully utilizes passive optical fiber devices such as an optical wavelength division multiplexer, an optical add/drop multiplexer, an optical circulator and the like, redesigns the optical path structure based on the optical multiplexing technology, and realizes the single-core optical fiber bidirectional transmission of multipath radio frequency signals. And then the reliable phase discrimination control module is matched for monitoring the phase drift of the link in real time, and the phase tracking compensation of the signal is carried out by feeding back the delay quantity of the control light path, so that the stable phase light transmission of the radio frequency signal is realized. Furthermore, the invention greatly simplifies the optical link composition structure under the complex signal transmission condition, the problem of inconsistent phase drift caused by external and self factors of the multi-core optical cable is physically avoided by the single-core optical cable interconnection mode, the signal phase is clamped in real time by combining with the phase monitoring and control, and the signal phase stability of the radio frequency optical transmission link is ensured.

Inventors

SUN LEI
Zhang fangzheng
ZHANG WENBING
ZOU ZHIYONG

Assignees

合肥综合性国家科学中心能源研究院(安徽省能源实验室)
南京航空航天大学

Dates

Publication Date: 20260505
Application Date: 20260116

Claims (10)

1. The system is characterized by comprising an uplink transmission and transmission module, an uplink transmission and reception module, a downlink transmission and transmission module, a downlink transmission and reception module, a central station optical path branching module, an antenna unit optical path branching module and a single-core stable-phase optical cable; The uplink transmission transmitting module is used for modulating the uplink input electric signal to obtain a modulated uplink optical signal, and carrying out phase adjustment on the uplink optical signal according to a coupling signal and a coupling feedback signal output by the uplink transmission receiving module; the uplink transmission receiving module is used for receiving the uplink optical signal, performing photoelectric conversion to obtain a demodulated uplink output electric signal, and obtaining a coupling feedback signal according to the uplink output electric signal; the downlink transmission and transmission module is used for modulating the downlink echo electric signal to obtain a modulated downlink optical signal, wherein the downlink echo electric signal comprises the coupling feedback signal; The central station optical path branching module is used for realizing uplink and downlink optical signal branching, wave combination and wave decomposition at the central station platform, the antenna unit optical path branching module is used for realizing uplink and downlink optical signal branching, insertion and reconstruction, wave combination and wave decomposition at the antenna unit platform, and the single-core stable-phase optical cable is used for interconnecting the antenna unit platform and the two ends of the central station platform and providing an optical signal stable-phase bidirectional transmission medium.
2. The system of claim 1, wherein the upstream transmission module comprises a low frequency input signal electro-optical conversion channel; the low-frequency input signal electro-optical conversion channel comprises a low-frequency directional coupler, a direct-tuning laser ITU-C26 and a low-frequency phase demodulation control module; The low-frequency directional coupler is used for carrying out coupling distribution on a low-frequency input signal, a part with larger output power is used as a main output of a direct-pass end, a part with smaller output power is used as a low-frequency coupling signal to be input into the low-frequency phase demodulation control module, the direct-tuning laser ITU-C26 is used for realizing optical modulation of the low-frequency input signal to obtain a low-frequency uplink optical signal, and the low-frequency phase demodulation control module is used for carrying out phase adjustment on the low-frequency uplink optical signal according to the collected low-frequency coupling signal and the low-frequency coupling feedback signal.
3. The system of claim 2, wherein the low frequency phase demodulation control module comprises a first IQ demodulator, a first delay amount control circuit, and a first optical delay unit; The first delay amount control circuit calculates a corresponding delay amount according to the phase difference and feeds back the delay amount to the first optical delayer to perform phase adjustment on the low-frequency uplink optical signal.
4. The system of claim 1, wherein the upstream transmission module comprises a high frequency input signal electro-optical conversion channel; the high-frequency input signal electro-optical conversion channel comprises a high-frequency directional coupler, a direct-tuning laser ITU-C30 and a high-frequency phase discrimination control module; The high-frequency directional coupler is used for carrying out coupling distribution on a high-frequency input signal, a part with larger output power is used as a main output of a direct-current end, a part with smaller output power is used as a high-frequency coupling signal and is input into the high-frequency phase demodulation control module, the direct-tuning laser ITU-C30 is used for realizing optical modulation of the high-frequency input signal to obtain a high-frequency uplink optical signal, and the high-frequency phase demodulation control module is used for carrying out phase adjustment on the high-frequency uplink optical signal according to the collected high-frequency coupling signal and the high-frequency coupling feedback signal.
5. The system of claim 4, wherein the high frequency phase demodulation control module comprises a second IQ demodulator, a second delay amount control circuit and a second optical delay device; The second delay amount control circuit calculates a corresponding delay amount according to the phase difference and feeds back the delay amount to the second optical delayer to perform phase adjustment on the high-frequency uplink optical signal.
6. The system of claim 1, wherein the upstream transmission and reception module comprises a low-frequency output signal photoelectric conversion channel and a high-frequency output signal photoelectric conversion channel; The low-frequency output signal photoelectric conversion channel comprises a low-frequency directional coupler, the low-frequency directional coupler is used for distributing power of the uplink optical signal after photoelectric conversion, the part with larger output power is used as a main output of a direct-current end, the part with smaller output power is used as a secondary output of a coupling end, and the secondary output part is used as a low-frequency coupling feedback signal returned by a link; the high-frequency output signal photoelectric conversion channel comprises a high-frequency directional coupler, the high-frequency directional coupler is used for distributing power to the uplink optical signal after photoelectric conversion, the part with larger output power is used as the main output of the direct-current end, the part with smaller output power is used as the secondary output of the coupling end, and the secondary output part is used as the high-frequency coupling feedback signal returned by the link.
7. The system for optical fiber synchronous conversion of radio frequency signals according to claim 1, wherein the downstream transmission module comprises: The low-frequency coupling feedback signal electro-optical conversion channel is used for performing electro-optical conversion on the low-frequency coupling feedback signal output by the uplink transmission receiving module and sending a downlink optical signal containing the low-frequency coupling feedback signal to the antenna unit optical path branching module; And the high-frequency coupling feedback signal electro-optical conversion channel is used for performing electro-optical conversion on the high-frequency coupling feedback signal output by the uplink transmission and reception module and sending a downlink optical signal containing the high-frequency coupling feedback signal to the antenna unit optical path branching module.
8. The system of claim 1, wherein the central station optical path branching module comprises a first dense wavelength division multiplexer, a second dense wavelength division multiplexer, and a first optical fiber circulator; The first dense wavelength division multiplexer receives the uplink optical signals and completes optical path wave combination division and transmits the uplink optical signals to the first optical fiber circulator, the second dense wavelength division multiplexer receives the downlink optical signals and completes optical path wave separation, and the first optical fiber circulator completes optical path uplink and downlink branches of the bidirectional optical signals.
9. The system of claim 1, wherein the antenna unit optical path branching module comprises a third dense wavelength division multiplexer, an optical add/drop multiplexer, and a second optical fiber circulator; The third dense wavelength division multiplexer is used for receiving the downlink optical signals and outputting the downlink optical signals to the loading port of the optical add/drop multiplexer after the optical path combination wavelength division is completed, the optical add/drop multiplexer is used for downloading two channels C26 and C30 in an uplink optical path, loading the downlink optical path output by the third dense wavelength division multiplexer and realizing the reconstruction of the optical path under the condition of not changing the wavelength channel, and the second optical fiber circulator completes the uplink and downlink branches of the bidirectional optical signals.
10. The system of claim 1, wherein the temperature drift coefficient of the single-core phase-stabilizing optical cable is less than or equal to 15ps/km/°c, and the type of the optical connectors at both ends is FC/APC.

Description

Radio frequency signal optical fiber synchronous conversion system Technical Field The invention belongs to the technical field of signal transmission, and particularly relates to a radio frequency signal optical fiber synchronous conversion system. Background Compared with the traditional coaxial cable, the optical transmission assembly using the optical fiber as a transmission medium is applied to a distributed radar system, and has the advantages of long transmission distance, high working frequency, large communication capacity, electromagnetic interference resistance, light weight and the like, and is widely valued and applied. The existing optical transmission assembly is mostly based on digital optical communication technology, and complex clock recovery and judgment circuits are required to be configured during receiving, so that the power consumption and design difficulty of an antenna platform are increased. Radio frequency optical transmission is a branch of optical communication technology, essentially belongs to the field of analog communication, realizes distortion-free linear transparent transmission of radio frequency signals, and has obvious advantages of volume and power consumption compared with digital optical transmission. The existing method for designing the link structure of the radio frequency optical transmission assembly also preferably utilizes the technologies of optical multiplexing, phase control and the like, but is mostly multi-path point-to-point unidirectional straight-through, and the phase consistency of signals is indirectly realized by utilizing phase discrimination and independent electric control optical delay between adjacent links at a receiving end. The method is not suitable for single-fiber stable-phase bidirectional transmission application occasions with both transmission and reception, and cannot meet the application requirements of accurate radio frequency standard such as target ranging. Disclosure of Invention In order to solve the technical problems, the invention provides a radio frequency signal optical fiber synchronous conversion system so as to realize the bidirectional and stable phase transmission of single-core optical fibers of multiple paths of radio frequency signals. The first aspect discloses a radio frequency signal optical fiber synchronous conversion system, which comprises an uplink transmission transmitting module, an uplink transmission receiving module, a downlink transmission transmitting module, a downlink transmission receiving module, a central station optical path branching module, an antenna unit optical path branching module and a single-core stable-phase optical cable; The system comprises an uplink transmission and transmission module, a downlink transmission and transmission module, a central station optical path branching module, an antenna unit optical path branching module, a single-core stable phase optical cable and an antenna unit optical cable, wherein the uplink transmission and transmission module is used for modulating an uplink input electric signal to obtain a modulated uplink optical signal, carrying out phase adjustment on the uplink optical signal according to a coupling signal and a coupling feedback signal output by the uplink transmission and reception module, the uplink transmission and reception module is used for receiving the uplink optical signal, carrying out photoelectric conversion on the uplink optical signal to obtain a demodulated uplink output electric signal, the antenna unit optical path branching module is used for realizing uplink and downlink optical signal branching, branching and reconstruction, wave combination and wave division at the antenna unit platform, the downlink echo electric signal is modulated by the downlink transmission and transmission module, the downlink echo electric signal comprises the coupling feedback signal, the downlink transmission and reception module is used for receiving the downlink optical signal, the downlink optical signal is subjected to photoelectric conversion to obtain a demodulated downlink output electric signal, and the central station optical path branching module is used for realizing uplink and downlink optical signal branching, wave combination and wave division at the central station platform, and the antenna unit optical path branching module is used for realizing uplink optical signal branching, wave combination and reconstruction, wave combination and wave division at the antenna unit platform, and the two-phase stable signal transmission platform are provided by the two-way medium. As a possible implementation mode, the uplink transmission module comprises a low-frequency input signal electro-optical conversion channel, wherein the low-frequency input signal electro-optical conversion channel comprises a low-frequency directional coupler, a direct-tuning laser ITU-C26 and a low-frequency phase demodulation control module, the low-frequency di