System for improving time signal distortion

Abstract

This invention discloses a system for improving time signal distortion, belonging to the field of high-precision time-frequency transmission technology. It includes an optical transmitting unit, an active compensation module, an optical splitter unit, and an optical receiving unit; wherein multiple sets of the active compensation module, optical splitter unit, and optical receiving unit are provided, and they correspond one-to-one. For networked time-frequency transmission systems in aerospace telemetry and control and distributed radar fields, during the transmission of time signals, due to the large number of distribution nodes, the transmitted optical signal needs to be amplified. This amplification process can cause instability such as jitter and signal distortion in the time signal. The method of this invention for improving time signal distortion during fiber optic time signal transmission has the advantages of simple system design, a one-time solution, no real-time operation required, and automatic correction of the distortion of the time pulse signal caused by the optical amplifier during optical transmission amplification.

Description

Technical Field

[0001] This invention relates to the field of high-precision time and frequency transmission technology, and more specifically, to the transmission of high-precision time synchronization signals and frequency standard transmission between distributed telemetry and control stations and distributed radar systems in the aerospace telemetry and control field. Background Technology

[0002] In the field of aerospace telemetry and control, distributed measurement systems such as short baseline interferometry (CEI), uplink and downlink antenna arrays, and distributed radar systems all include time-frequency distribution subsystems to distribute the central frequency and time reference signals to various measurement stations. These systems require not only high long-term and short-term stability of the frequency standards at each measurement station, but also high-precision synchronization of the frequency and time standards between the various measurement stations. For distributed systems, the distance between the central control room and the measurement stations can be several kilometers, and for CEI, the distance between different stations can be hundreds of kilometers. Transmitting frequency standards over such long distances using cables would result in excessive loss, making it virtually impossible. Optical fiber transmission has advantages such as low loss, superior communication performance and stability, simple distribution design, and long-distance transmission with repeater capability. In engineering, optical fiber is generally buried underground to transmit high-precision time and frequency signals, which meets the needs of the aerospace telemetry and control field for high-precision coherent transmission technology and high-precision time delay measurement technology. However, in actual engineering, due to the limited seed light power of fiber lasers and the large number of distributions, the single-channel optical transmission power is low, and amplifiers are needed to amplify the optical information of each channel. After the time pulse signal passes through the optical amplifier, the pulse waveform will be distorted or the time signal will jitter. Therefore, it is necessary to consider the shaping of the time pulse signal. Summary of the Invention

[0003] The purpose of this invention is to propose a method to improve the time signal distortion system during fiber optic time signal transmission. This method features a simple system design, requiring only one design and no real-time operation, and automatically corrects the distortion of the time signal caused by the optical amplifier during optical transmission and amplification. It is particularly suitable for systems requiring fiber optic transmission, such as antenna array systems, networked distribution and transmission systems, and long-distance transmission of time and frequency standard signals in connection unit interferometers (CEIs).

[0004] The objective of this invention is achieved through the following technical solution:

[0005] A system for improving time signal distortion includes an optical transmitting unit, an active compensation module, an optical splitter unit, and an optical receiving unit; wherein, the active compensation module, the optical splitter unit, and the optical receiving unit are provided in multiple groups, and each group of active compensation module, optical splitter unit, and optical receiving unit corresponds one-to-one;

[0006] The optical emission unit includes an electro-optical conversion module I, an optical amplifier I, a wavelength division multiplexer I, a 1×N optical splitter and a laser I;

[0007] The clock signal is first modulated onto laser carriers of different wavelengths by the electro-optic conversion module I of the optical transmitter unit, and then sent to the optical amplifier I for amplification; at the same time, the continuous light output by the laser I is sent to the optical amplifier I, and the signal after the optical amplifier is sent to the wavelength division multiplexer to combine the optical signals of different wavelengths into one optical signal; the optical signal of the wavelength division multiplexer is sent to the 1×N optical splitter.

[0008] The N optical signals after being split by the 1×N optical splitter are sent to their respective optical splitting units through the corresponding active compensation modules.

[0009] The optical splitting unit includes a wavelength division multiplexer II, a laser II, an optical amplifier II, a wavelength division multiplexer III, and a 1×M optical splitter.

[0010] After receiving the signal, the optical splitter unit first performs wavelength division multiplexing (WDM) by wavelength division multiplexer II, and then each wavelength signal is amplified by its respective optical amplifier. At the same time, the continuous light output from laser II is sent to optical amplifier II, and the jitter of the 1PPS pulse signal is suppressed by nonlinear effect. Then it is sent to wavelength division multiplexer III for multiplexing, and the multiplexed optical signal is split by 1×M optical splitter.

[0011] The M optical signals output by the optical splitter are transmitted via optical fibers to the optical receiving units of each node.

[0012] The optical receiving unit includes a wavelength division multiplexer IV and a photoelectric conversion module II;

[0013] The signal split by the 1×M optical splitter passes sequentially through wavelength division multiplexer IV and photoelectric conversion module II to recover the clock signal that synchronizes each node.

[0014] Furthermore, the active compensation module is used to maintain the consistency of link latency.

[0015] Furthermore, the 1PPS clock signal of the optical emitting unit is modulated onto the C32 wavelength and amplified by optical amplifier I. At the same time, a continuous laser output from a laser I with a wavelength of 1520nm is sent to optical amplifier I to suppress the jitter of the 1PPS pulse signal through nonlinear effects.

[0016] Furthermore, the optical amplifier II of the optical splitter unit amplifies the 1PPS optical signal, and at the same time sends a continuous laser output from a laser II with a wavelength of 1520nm into the optical amplifier II, suppressing the jitter of the 1PPS pulse signal through nonlinear effects.

[0017] Compared with the prior art, the advantages of the present invention are:

[0018] 1. This invention proposes a method to improve time signal distortion during fiber optic time signal transmission. It does not require synchronous triggering or other control, and can achieve stable amplification and transmission of 1PPS signal upon power-on. It can realize network-distributed fiber optic time signal transmission with highly stable time stamp transmission over distances ranging from several kilometers to tens of kilometers. At the same time, it can achieve network distribution and maintain the synchronization and stability of the time signal transmitted to the remote end.

[0019] 2. The method of the present invention for improving time signal distortion during optical fiber time signal transmission has the advantages of simple design and permanent solution.

[0020] 3. The present invention provides a method for improving time signal distortion during fiber optic time signal transmission. Because the added laser signal is outside the bandwidth of the wavelength division multiplexer, it will not cause other interference to the system, thereby improving the stability of the system. Attached Figure Description

[0021] Figure 1 This is a principle block diagram of an embodiment of the present invention. Detailed Implementation

[0022] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and examples.

[0023] The following is a brief description of this embodiment, which is specifically as follows:

[0024] A system for improving time signal distortion during fiber optic time signal transmission includes the following processes:

[0025] Reference Figure 1 The clock signals, such as 1PPS, are first modulated onto laser carriers of different wavelengths by the electro-optic modulator in the optical transmitting unit, and then sent to their respective optical amplifiers for amplification. In order to prevent jitter of the time signal, the continuous light output from one laser 1 is sent to optical amplifier I. The signal after passing through optical amplifier I is then sent to dense wavelength division multiplexer I to combine the optical signals of different wavelengths into one optical signal.

[0026] After passing through wavelength division multiplexer I, the optical signal is sent to 1*N optical splitter.

[0027] The N optical signals after being split from 1 to N are sent to their respective optical splitting units at the remote end via their respective optical cables and active compensation modules.

[0028] After receiving the signal, the optical splitter unit first performs wavelength division multiplexing (WDM) by wavelength division multiplexer II. Then, each wavelength signal is amplified by its own optical amplifier and sent to wavelength division multiplexer III for multiplexing. The combined optical signal then passes through a 1*M optical splitter.

[0029] The M optical signals output by the optical splitter unit are transmitted to the optical receiving units of each node via optical fibers. After passing through the wavelength division multiplexer IV and the photoelectric conversion module II, the clock signals such as 1PPS that are synchronized between each node are recovered.

[0030] The 1PPS signal from the optical emitting unit is modulated onto the C32 wavelength and amplified by optical amplifier I. At the same time, a continuous laser output from a laser I with a wavelength of 1520nm is sent to optical amplifier I to suppress the jitter of the 1PPS pulse signal through nonlinear effects.

[0031] The optical amplifier II of the optical splitter unit amplifies the 1PPS optical signal and simultaneously sends a continuous laser output from a laser II with a wavelength of 1520nm into the optical amplifier II.

[0032] In actual engineering, the optical splitter N=8 in the optical transmitting unit and the optical splitter M=32 in the optical splitting unit; in this embodiment, signal 2 is a frequency signal.

Claims

1. A system for improving time signal distortion, characterized in that, It includes an optical transmitting unit, an active compensation module, an optical splitter unit, and an optical receiving unit; among which, there are multiple sets of active compensation modules, optical splitter units, and optical receiving units, and each set of active compensation modules, optical splitter units, and optical receiving units corresponds one-to-one; The optical emission unit includes an electro-optical conversion module I, an optical amplifier I, a wavelength division multiplexer I, a 1×N optical splitter and a laser I; The clock signal is first modulated onto laser carriers of different wavelengths by the electro-optic conversion module I of the optical transmitter unit, and then sent to the optical amplifier I for amplification; at the same time, the continuous light output by the laser I is sent to the optical amplifier I, and the signal after passing through the optical amplifier I is then sent to the wavelength division multiplexer I to combine the optical signals of different wavelengths into one optical signal; the optical signal of the wavelength division multiplexer I is sent to the 1×N optical splitter. The N optical signals after being split by the 1×N optical splitter are sent to their respective optical splitting units through the corresponding active compensation modules. The optical splitting unit includes a wavelength division multiplexer II, a laser II, an optical amplifier II, a wavelength division multiplexer III, and a 1×M optical splitter. After receiving the signal, the optical splitter unit first performs wavelength division multiplexing (WDM) by wavelength division multiplexer II, and then each wavelength signal is amplified by its respective optical amplifier II. At the same time, the continuous light output from laser II is sent to optical amplifier II to suppress the jitter of the 1PPS pulse signal through nonlinear effect. Then it is sent to wavelength division multiplexer III for multiplexing, and the multiplexed optical signal is split by 1×M optical splitter. The M optical signals output by the optical splitter are transmitted via optical fibers to the optical receiving units of each node. The optical receiving unit includes a wavelength division multiplexer IV and a photoelectric conversion module II; The signals split by the 1×M optical splitter are sequentially passed through wavelength division multiplexer IV and photoelectric conversion module II to recover the clock signals that synchronize the nodes.

2. The system for improving time signal distortion according to claim 1, characterized in that, The active compensation module is used to maintain the consistency of link latency.

3. The system for improving time signal distortion according to claim 1, characterized in that, The 1PPS clock signal of the optical emitting unit is modulated onto the C32 wavelength and amplified by optical amplifier I. At the same time, a continuous laser output from a laser I with a wavelength of 1520nm is sent to optical amplifier I to suppress the jitter of the 1PPS pulse signal through nonlinear effects.

4. The system for improving time signal distortion according to claim 3, characterized in that, The optical amplifier II of the optical splitter unit amplifies the 1PPS optical signal, and at the same time sends the continuous laser output from a laser II with a wavelength of 1520nm into the optical amplifier II to suppress the jitter of the 1PPS pulse signal through nonlinear effects.

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