CN105680970A - Remote optical fibre synchronous system for radio astronomical array and method thereof - Google Patents

Remote optical fibre synchronous system for radio astronomical array and method thereof Download PDF

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CN105680970A
CN105680970A CN201610025611.0A CN201610025611A CN105680970A CN 105680970 A CN105680970 A CN 105680970A CN 201610025611 A CN201610025611 A CN 201610025611A CN 105680970 A CN105680970 A CN 105680970A
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local
clock
remote
module
optical
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CN105680970B (en
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宫新保
秦冕
臧小刚
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上海交通大学
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    • HELECTRICITY
    • H03BASIC ELECTRONIC CIRCUITRY
    • H03LAUTOMATIC CONTROL, STARTING, SYNCHRONISATION, OR STABILISATION OF GENERATORS OF ELECTRONIC OSCILLATIONS OR PULSES
    • H03L7/00Automatic control of frequency or phase; Synchronisation
    • H03L7/06Automatic control of frequency or phase; Synchronisation using a reference signal applied to a frequency- or phase-locked loop
    • H03L7/08Details of the phase-locked loop
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04JMULTIPLEX COMMUNICATION
    • H04J3/00Time-division multiplex systems
    • H04J3/02Details
    • H04J3/06Synchronising arrangements
    • H04J3/0635Clock or time synchronisation in a network
    • H04J3/0638Clock or time synchronisation among nodes; Internode synchronisation
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04JMULTIPLEX COMMUNICATION
    • H04J3/00Time-division multiplex systems
    • H04J3/02Details
    • H04J3/06Synchronising arrangements
    • H04J3/0635Clock or time synchronisation in a network
    • H04J3/0682Clock or time synchronisation in a network by delay compensation, e.g. by compensation of propagation delay or variations thereof, by ranging

Abstract

The invention relates to a remote optical fibre synchronous system for a radio astronomical array and a method thereof. The remote optical fibre synchronous system comprises a local phase-locked control module and a clock purification module, wherein the local phase-locked control module is arranged in a local node; the clock purification module is arranged in a remote node; the remote node and the local node are connected through an optical fibre; the local node inputs a local reference clock and a local optical fibre receiving clock received from the clock purification module into the local phase-locked control module; the local reference clock is controlled to perform phase adjustment through PID, such that a local optical fibre sending clock is obtained; and thus, optical fibre temperature drift compensation is realized. According to the invention, the optical fibre temperature drift compensation is carried out in a digital manner; the remote optical fibre synchronous system has high clock synchronous precision; the clock synchronous precision is up to the pico-second level; the remote optical fibre synchronous system is high in environment adaptive capability and low in cost; the clock information is transmitted in the digital manner; the remote optical fibre synchronous system is high in anti-interference capability and long in transmission distance; transmission of a sampling clock, sampling data and a system control command can be realized only through one optical fibre channel; therefore, high-degree system integration is realized; and the optical fibre wiring complexity is reduced.

Description

射电天文阵列远程光纤同步系统及其方法 Remote Fiber Array radio astronomy synchronization system and method

技术领域 FIELD

[0001] 本发明涉及的是一种低频射电天文望远镜分布天线阵列领域的技术,具体是一种射电天文阵列远程光纤同步系统及其方法。 [0001] The present invention relates to a low-frequency radio telescope technical field of a distributed antenna array, in particular a remote optical fiber array astronomy synchronization system and method shot.

背景技术 Background technique

[0002] 射电天文学的观测对象为广阔宇宙中天体辐射的微弱电磁信号。 [0002] The observation target radio astronomy weak electromagnetic signal is a broad universe objects radiation. 为了提升天文观测的分辨率和灵敏度,需要不断增加射电天文阵列的天线口径。 In order to improve the resolution and sensitivity of astronomical observation, the increasing need for radio astronomy antenna aperture array. 现代射电天文阵列正在向着大规模、长距离、分布式的方向发展,这也对射电天文阵列的远程时钟同步性能提出了更高的要求。 Modern radio astronomy array is toward large-scale, long-distance, distributed direction, which also remote clock synchronization performance radio astronomy array put forward higher requirements. 现代射电天文阵列的时钟同步主要用于射电天文阵列的采样时钟同步,需要在长距离,其距离一般超过1公里的阵元节点之间实现极高的时钟同步精度,通常在皮秒量级,以满足阵元节点之间的采样相干性要求;而且,现代射电天文阵列的阵列规模巨大、阵元节点数量众多,因此需要相对低廉的实现成本。 Modern radio astronomy sampling clock of the clock synchronization array is mainly used for synchronization of the radio astronomy array, achieve high precision clock synchronization between nodes requires array elements in the long distance, which distance is generally more than one kilometer, usually in the order of picoseconds, to meet the requirements of coherence between sampling node array element; Also, a huge array size modern radio astronomy array, the array element number of the number of nodes, it is necessary to achieve relatively low cost.

[0003] 远程时钟同步技术被广泛应用于网络传输、通信、射电天文等领域。 [0003] remote clock synchronization network transmission technology is widely used, communication, radio astronomy, and other fields. 不同领域对于时钟同步的精度要求不同,因此采用的技术实现手段也有差异。 Different art for clock synchronization accuracy requirements are different, so the technology employed means are different. 在网络传输领域,时钟同步的精度通常要求不高、一般在毫秒量级,因此主要采用的是基于网络时间协议(Network Time Protocol,NTP)的时钟同步方法。 In the field of network transmission, usually less demanding synchronization clock accuracy, typically in milliseconds, so the main clock synchronization method used is based on the Network Time Protocol (Network Time Protocol, NTP) of. 在通信领域,时钟同步的精度要求一般在几十纳秒量级,因此通常采用基于空域无线的同步方式或基于GPS的时钟同步方式。 In the field of communications, the clock synchronization accuracy requirements are generally in the order of tens of nanoseconds, it is often a synchronized manner based wireless airspace or GPS-based clock synchronization. 而在射电天文领域,为了实现皮秒量级的远程时钟同步精度,目前比较合适的方式是光纤时钟同步技术。 In radio astronomy, remote to the clock synchronization accuracy of picoseconds, the current approach is more appropriate optical clock synchronization. [0004]光纤时钟同步技术,即通过对光纤传输的信号进行时钟恢复,在远程接收端将光纤上传递的时钟信息提取出来,得到与本地同步的时钟信号,实现远程时钟与本地时钟同步。 [0004] The optical clock synchronization, clock recovery by a signal that is transmitted to the optical fiber, the remote receiver will extract the clock information transmitted on the fiber out to obtain a clock signal synchronized with the local, remote and local clock synchronization clock. 由于光纤具有良好的传输特性和低廉的价格,非常适合射电天文望远镜阵列的远距离、 高精度时钟同步。 Since the optical fiber has good transmission characteristics and low price, it is suitable for long distance radio telescope array, high-precision clock synchronization. 但是由于光纤介质受温度变化会发生长度的变化,在光纤较长的情况下, 会使得远程恢复的时钟产生较大的抖动。 However, since the fiber length of the medium changes by temperature changes will occur, in the optical fiber is long, so that the clock will have a greater recovery remote jitter.

[0005] 经过对现有技术的检索发现,LJ Wang等人发表在2012年Nature子刊Scientific Report第二期的论文"Precise and Continuous Time and Frequency Synchronisation at the 5Xl(T19Accuracy Level"提出了在本地节点采用原子钟作为时钟源,将时钟信息以模拟信号的形式通过光纤传输。远程节点将接收到的时钟同步信息反馈给本地节点,本地节点根据反馈的时钟信息对发送时钟进行校正,以补偿光纤长度变化给远程同步时钟带来的抖动。但该方案设备成本高,系统复杂,且传送的时钟信号为模拟信号,需要单独的光纤通路传输。 [0005] After retrieval of the prior art found, LJ Wang et al, Journal of Scientific Report of the second phase of the child in 2012 Nature paper "Precise and Continuous Time and Frequency Synchronisation at the 5Xl (T19Accuracy Level" presented at the local node using atomic clocks as the clock source, the clock information in the form of an analog signal transmitted through the fiber remote node will receive the clock synchronization information back to the local node, the local node corrects the transmission clock according to the clock information is fed back to compensate fiber length variation bring to the remote synchronous clock jitter, but this scheme equipment cost, system complexity, and transmits a clock signal into an analog signal, a separate optical fiber transmission path.

[0006] 中国专利文献号CN104917582A,公开日为2015年09月16日,公开了一种高精度时钟分发和相位自动补偿系统及其相位调节方法,该系统包括时钟分发模块Master和多个前端电子学节点Slave,Master采用光纤将时钟分发给多个Slave,其中:Master通过光纤将时钟发送到Slave,Slave接收到时钟后通过光纤将时钟重新传回到Master,Master对时钟的往返时间之和进行动态测量得到时钟的上下延时,并将测量结果发送到Slave,Sla Ve根据测量结果对接收到的时钟进行动态相位调节,使Slave与Master保持相位同步。 [0006] Chinese Patent Document No. CN104917582A, publication date September 16, 2015, discloses a precision clock distribution system, and automatically compensate for phase and phase adjustment method, the system includes a clock distribution module and a plurality of front-end electronics Master Learn node Slave, Master using a plurality of optical fibers distributed clock Slave, wherein: Master clock transmission through the optical fiber to the Slave, the Slave receives the optical clock by the clock back to re-Master, Master of the round trip time of the clock and be dynamic measured vertical clock delay, and transmits the measurement result to the Slave, Sla Ve measurement result received clock dynamic phase adjustment so that the Master Slave holding phase synchronization. 但该技术所能达到的同步精度在几十皮秒量级,无法满足射电天文阵列的采样时钟同步的精度要求。 However, this technology can achieve synchronization precision in the order of tens of picoseconds, can not satisfy the sampling clock of the radio astronomy array of synchronization accuracy.

发明内容 SUMMARY

[0007] 本发明针对现有技术存在的上述不足,提出一种射电天文阵列远程光纤同步系统及其方法。 [0007] The present invention addresses the above shortcomings of the prior art, to provide a synchronous optical astronomy array system and method for remote radio.

[0008] 本发明是通过以下技术方案实现的: [0008] The present invention is achieved by the following technical solutions:

[0009] 本发明涉及一种射电天文阵列远程光纤同步系统,包括:设置于本地节点的本地锁相控制模块和设置于远程节点的时钟净化模块,其中:远程节点和本地节点通过光纤相连,本地节点将本地参考时钟和从时钟净化模块接收到的本地光纤接收时钟输入本地锁相控制模块,通过PID控制本地参考时钟进行相位调整得到本地光纤发送时钟。 [0009] The present invention relates to a radio astronomy array of optical remote synchronization system, comprising: a lock is provided to the local control module and disposed in a remote node of the local node clock cleaning module, wherein: the remote node and the local node is connected through an optical fiber, local local clock reference node and received from the local clock cleaning module to a clock input receiving the local optical phase lock control module, the local phase adjustment to obtain an optical fiber transmission clock PID control local reference clock.

[0010] 所述的本地锁相控制模块包括:第一滤波器、第二滤波器、鉴相器、模数转换器(ADC)、数字信号处理单元和直接数字频率合成器(DDS),其中:第二滤波器、鉴相器、ADC、 DDS和数字信号处理单元依次串联成环路,第一滤波器两端与鉴相器和本地光纤接收模块相连,DDS连有本地光纤发送模块。 [0010] The local phase lock control module comprises: a first filter, a second filter, phase detector, analog to digital converter (the ADC), a digital signal processing unit and a direct digital frequency synthesizer (the DDS), wherein : a second filter, phase detector, ADC, DDS, and the digital signal processing unit into a loop in series, a first filter connected to both ends of the phase detector and a local optical receiver module, the DDS has a local optical transmission module is connected.

[0011] [0011]

Figure CN105680970AD00041

其中u(n)为PID输出控制量,e (η)为PID输入量,KP为比例系数,Ki为积分系数,Kd为微分系数。 Where u (n) is the output of PID control amount, e (η) for the input PID, KP is the proportional coefficient, Ki is the integral coefficient, Kd is the differential coefficient.

[0012] 所述的远程节点设有远程光纤发送模块和远程光纤接收模块,该远程光纤发送模块与时钟净化模块和本地光纤接收模块相连,该远程光纤接收模块与时钟净化模块和本地光纤发送模块相连。 [0012] The remote node with remote fiber optic transmission optical receiver module and a remote module, the remote module is connected to the optical fiber transmission clock cleaning module and a local optical receiving module, optical receiving module and the remote module and the local clock purification fiber transmission module connected.

[0013] 所述的数字信号处理单元和ADC由现场可编程门阵列(FPGA)实现,本地光纤接收模块和本地光纤发送模块由FPGA的高速串行收发器(GTX)实现。 Digital signal processing unit [0013] and the ADC is implemented by a field programmable gate array (FPGA), a local optical receiver module and the optical transmission module is implemented by a local high-speed serial transceivers FPGA (GTX).

[0014] 所述的时钟净化模块将接收到的时钟信息进行消抖处理得到远程同步时钟,并反馈回本地节点。 [0014] The cleaning module clock to the clock information received debounces remote process to obtain the synchronous clock, and fed back to the local node.

[0015] 本发明涉及一种利用上述射电天文阵列远程光纤同步系统进行温漂补偿的方法, 包括以下步骤: [0015] The present invention relates to a method for compensating for temperature drift radio astronomy array using the remote synchronous optical fiber system, comprising the steps of:

[0016] 步骤1、本地参考时钟和本地光纤接收时钟分别经过滤波器,然后经过鉴相器进行鉴相; [0016] Step 1, the local reference clock and the local clock respectively, after receiving fiber filter and then through the phase detector for phase;

[0017] 步骤2、将鉴相结果通过低速的模数转换器进行数字化,输入到数字信号处理单元,通过PID控制算法处理,得到相位补偿控制量; [0017] Step 2, the results of phase by low-speed analog-digital input to the digital signal processing unit, the processing by the PID control algorithm, to obtain a phase compensation control amount;

[0018] 步骤3、将相位补偿控制量输入DDS,对本地参考时钟进行相位调整,获得本地光纤发送时钟,实现光纤温漂补偿。 [0018] Step 3, the phase compensation control input the DDS, the local reference clock to adjust the phase, to obtain an optical fiber local transmission clocks, temperature drift compensation to achieve fiber. 技术效果 Technical effect

[0019] 与现有技术相比,本发明通过数字化方式进行光纤温漂补偿,具有时钟同步精度高,达到皮秒量级,环境适应能力强,成本低廉,采用数字化方式传输时钟信息,抗干扰能力强,传输距离长,只需一路光纤通路就可以实现采样时钟、采样数据、系统控制指令的传输, 从而实现了高度的系统集成,降低了光纤布线的复杂度。 [0019] Compared with the prior art, the present invention is an optical fiber temperature drift is compensated for by digitally with high precision clock synchronization, to picoseconds, environmental adaptability, low cost, the digitization and transmission of clock information, interference ability, long transmission distance, only require a single optical fiber can be achieved via a sampling clock, the sampling data, a control command transmission system in order to achieve a high degree of system integration, reducing the complexity of fiber cabling.

附图说明 BRIEF DESCRIPTION

[0020] 图1为本发明原理结构不意图; [0020] FIG. 1 is not intended that the present invention, the principles of the structure;

[0021] 图2为本发明实现结构示意图; [0021] Fig 2 a schematic view of the structure of the present invention is implemented;

[0022] 图3为无温漂补偿时本地采样信号和远程采样信号的相位差变化曲线示意图; [0022] FIG. 3 is a schematic phase drift compensation curve without local and remote sampling signal sampled signal;

[0023] 图4为经温漂补偿后本地采样信号和远程采样信号的相位差变化曲线示意图。 [0023] FIG. 4 is a schematic graph after drift compensated local and remote sampling signal sampled signal phase difference.

具体实施方式 Detailed ways

[0024]下面对本发明的实施例作详细说明,本实施例在以本发明技术方案为前提下进行实施,给出了详细的实施方式和具体的操作过程,但本发明的保护范围不限于下述的实施例。 [0024] Hereinafter, embodiments of the present invention will be described in detail, the present embodiments In order aspect of the present invention is a premise is given and the specific operation detailed embodiments, but the scope of the present invention is not limited to the Example embodiments described below. 实施例1 Example 1

[0025] 如图1所示,本实施例包括:设置于本地节点的本地锁相控制模块和设置于远程节点的时钟净化模块,其中:远程节点和本地节点通过光纤相连,本地节点将本地参考时钟和从时钟净化模块接收到的本地光纤接收时钟输入本地锁相控制模块,通过PID控制本地参考时钟进行相位调整得到本地光纤发送时钟,从而实现光纤温漂补偿。 [0025] 1, the present embodiment includes: disposed in the local node's local control module and a phase-locked clock cleaning module provided in a remote node, wherein: the remote node and the local node is connected through an optical fiber, the local reference local node clock received from the clock cleaning module to a local input fiber receives the local clock phase lock control module, the PID control is performed by the local reference clock phase adjustment to obtain the local clock transmission fiber, the optical fiber in order to achieve drift compensation.

[0026] 所述的本地锁相控制模块包括:第一滤波器、第二滤波器、鉴相器、模数转换器(ADC)、数字信号处理单元和直接数字频率合成器(DDS),其中:第二滤波器、鉴相器、ADC、 DDS和数字信号处理单元依次串联成环路,第一滤波器两端与鉴相器和本地光纤接收模块相连,DDS连有本地光纤发送模块。 [0026] The local phase lock control module comprises: a first filter, a second filter, phase detector, analog to digital converter (the ADC), a digital signal processing unit and a direct digital frequency synthesizer (the DDS), wherein : a second filter, phase detector, ADC, DDS, and the digital signal processing unit into a loop in series, a first filter connected to both ends of the phase detector and a local optical receiver module, the DDS has a local optical transmission module is connected.

[0027] 所述的远程节点设有远程光纤发送模块和远程光纤接收模块,该远程光纤发送模块与时钟净化模块和本地光纤接收模块相连,该远程光纤接收模块与时钟净化模块和本地光纤发送模块相连。 [0027] The remote node with remote fiber optic transmission optical receiver module and a remote module, the remote module is connected to the optical fiber transmission clock cleaning module and a local optical receiving module, optical receiving module and the remote module and the local clock purification fiber transmission module connected.

[0028] 所述的本地节点将本地参考时钟作为变频采样单元的变频采样时钟,采用现场可编程门阵列(FPGA)作为核心器件,而远程同步时钟作为远程节点的变频采样单元的变频采样时钟,实现本地节点和远程节点的相干采集。 Local node [0028] the local frequency reference clock as a sampling clock frequency of the sampling unit, field programmable gate array (FPGA) as the core components, and remote synchronization clock as the sampling frequency conversion unit of the remote node sampling clock frequency, achieve coherent collection of local and remote nodes.

[0029]所述的本地节点通过本地光纤接收模块,接收远程节点反馈的时钟信息,从而获得本地光纤接收时钟。 [0029] The local node over a local fiber optic means for receiving information of the remote node feedback clock, thereby obtaining an optical fiber local reception clock. 将本地参考时钟和本地光纤接收时钟输入到本地锁相控制模块,处理后得到本地光纤发送时钟,将本地光纤发送时钟输出到本地光纤发送模块中,通过光纤传送到远程节点。 The local reference clock and a local clock input receiving the local optical phase lock control module, the optical fiber obtained after processing the local transmit clock, local clock to the local optical transmission fiber transmitting module transmits to the remote node via the optical fiber.

[0030] 所述的远程节点通过远程光纤接收模块,获得本地节点发送的时钟信息,通过时钟净化模块进行消抖处理,得到远程同步时钟,将远程同步时钟发送到远程光纤发送模块中,通过光纤反馈回本地节点。 [0030] The remote node via a remote fiber optic receiving module to obtain clock information transmitted by the local node, the processing performed by the debounce clock cleaning module, to obtain remote synchronization clock, to transmit to the remote fiber remote synchronization clock transmission module, through fiber optics feedback back to the local node.

[0031] 如图2所示,所述的本地光纤接收模块和本地光纤发送模块采用FPGA的高速串行收发器(GTX)。 [0031] As shown, the local optical receiver module and the local optical transmission module uses the high-speed serial transceivers FPGA (GTX) 2. 远程节点也采用GTX作为远程光纤接收模块和远程光纤发送模块,通过GTX的时钟数据恢复单元(CDR)提取出时钟信息。 GTX remote node also used as a remote optical fiber transmission receiver module and a remote module, extracts the clock information recovery unit (CDR) via a clock data GTX.

[0032] 所述的本地参考时钟的相位为與。 Phase of the local reference clock [0032] according to the. ,远程同步时钟的参考相位为I,本地光纤发送时钟的参考相位为约,本地光纤接收时钟为界。 , Remote synchronization clock reference phase as I, the optical fiber transmission local clock reference phase about the local optical receiver clock is bounded. 本地节点到远程节点的光纤路径上的时钟相位差为Af,该Δ切会随着光纤长度变化而发生变化,从而导致接收端的时钟抖动。 Clock on the optical fiber path of the local node to the remote node the phase difference of Af, will change as the Δ cut fiber length changes occur, thereby causing the receiver clock jitter. 假设发送链路和接收链路的光纤长度相等,则有: Assumed to be equal transmission link and receiving link of fiber length, there are:

Figure CN105680970AD00061

[0033] 所述的远程同步时钟由于温漂引起光纤长度变化而产生抖动,为保证死《和<1的相参性不受Δρ变化的影响,令氣=仏,则有:的-札二凡-約,其中科-¾为本地光纤接收时钟和本地参考时钟的相位差,% -釣为本地光纤发送时钟和本地参考时钟相位差。 [0033] Since the remote synchronous clock drift due to changes in fiber length and jitter, to ensure the death "and impact <1 is not coherent Δρ of change, so that Fo = gas, there are: - the two Sapporo where - about which the subjects received -¾ local reference clock and a clock phase for the local fiber,% - fishing local transmit clock and the local clock reference optical retardation. 只要令其相等就可以补偿由于温漂引入的光纤长度变化给远程同步时钟带来的抖动。 So that it can be equal, as long as the jitter introduced due to fiber length variations drift remote synchronization clock to bring compensation. 温漂补偿方法包括以下步骤: Drift compensation method comprising the steps of:

[0034] 步骤1、本地光纤接收时钟和本地参考时钟分别经过第一滤波器和第二滤波器,然后通过鉴相器进行鉴相; [0034] Step 1, an optical fiber local reference clock and the local clock respectively received through the first and second filters, and then phase by phase detector;

[0035]步骤2、将鉴相结果通过低速的ADC进行数字化,输入到数字信号处理单元通过PID 算法对信号进行处理,得到相位补偿控制量; [0035] Step 2, the results of phase digitized by the ADC is a low speed, the input to the digital signal processing unit for processing the signal through the PID algorithm to obtain the phase compensation control amount;

[0036]步骤3、将相位补偿控制量输入DDS,对本地参考时钟进行相位调整,获得本地光纤发送时钟,实现光纤温漂补偿。 [0036] Step 3, the phase compensation control input the DDS, the local reference clock to adjust the phase, to obtain an optical fiber local transmission clocks, temperature drift compensation to achieve fiber.

[0037]所述的第一滤波器和第二滤波器为窄带带通滤波器,以滤掉鉴相频率之外的频率分量,降低鉴相误差。 [0037] The first and second filters to narrow band pass filter to filter off frequency components beyond the frequency phase, reducing the phase error.

[0038] 本实施例中的低速ADC采用FPGA内部的通用ADC,即XADC实现,通过PID控制算法处理,得到相位补偿控制量。 [0038] In the present embodiment, the low-speed ADC using a common ADC inside the FPGA, i.e. XADC achieved by the PID control algorithm to give the phase compensation control amount. 根据得到的相位补偿控制量,通过FPGA对DDS进行控制、调整本地光纤发送时钟的相位,从而实现温漂补偿。 The amount of phase compensation control obtained by the control FPGA of the DDS, the phase adjustment of the local clock of the optical fiber transmission, thereby achieving compensation for temperature drift.

[0039] [0039]

Figure CN105680970AD00062

,其中:u(n)为PID输出控制量,e(n)为PID输入量(即数字化的鉴相结果),KP为比例系数,L为积分系数,Kd为微分系数。 Wherein: u (n) is the output of PID control amount, e (n) is the input PID (i.e., digitized phase results), KP is a proportionality coefficient, L is the integral coefficient, for the Kd of the differential coefficient.

[0040] 本实施例在PID控制之前,优选对e(n)进行数字低通滤波,从而滤掉鉴相结果的高频噪声,保证e(n)的稳定性;对于比例系数KP,积分系数L和微分系数Kd的设置,可以进行分段处理,即在不同的输入量e(n)的取值范围内设置不同的比例系数、积分系数和微分系数值,从而提高PID输出的相位控制的性能。 [0040] In the present embodiment, prior to PID control, preferably of e (n) is digitally low-pass filtered to filter out high frequency phase noise results, ensure the stability of e (n); for the proportional coefficient KP, the integral coefficient L and the differential coefficient Kd is provided, the segmentation process can be performed, i.e., a different set of proportional gain, integral gain and derivative coefficient values ​​in different input amounts e (n) in the range, thereby improving the phase control output of the PID performance.

[0041] 所述的本地节点和远程节点的采样模块采用零中频的结构,选取200m长的光纤进行测试,其中变频本振为2400MHz,采样时钟为50MHz正交采样,采样输入信号为2401MHz的正弦信号。 [0041] The local and remote nodes sampling module uses zero-IF architecture, 200m length of fiber selected for testing, wherein the local oscillator frequency of 2400MHz, the sampling clock of 50MHz quadrature sampling, the sampling of the input signal is sinusoidal 2401MHz signal. 通过对光纤进行均匀加热、然后自然冷却的方式模拟环境温度变化。 By way of the optical fiber temperature uniform heating, and then naturally cooled simulated environment. 测试分析方法为控制本地节点和远程节点同步对输入信号进行采样,每隔15s进行采样一次,并将采样结果缓存,然后对本地采样信号和远程采样信号分别进行FFT分析,利用FFT结果计算本地采样信号和远程采样信号的相位差,根据这一结果计算出本地参考时钟和远程同步时钟之间的抖动。 Test analysis method of synchronizing an input signal to control the local and remote nodes sampling, sampling once every 15s, and the sampling results cache, then the local and remote sampled signal sampled signals are subjected to FFT analysis to calculate the local sample using FFT result sampling the phase difference signal and a remote signal, it calculates the jitter between the reference clock and the local clock according to the results remote synchronization.

[0042] 如图3所示,当不进行温漂补偿时,由于光纤长短变化,远程节点采样信号相对本地节点的采样信号相位差如图所示。 [0042] 3, when the temperature drift compensation is not performed, since the fiber length variation, the remote node sampling signal relative to the local node sampling signal phase shown in FIG. 折算到时间单位后,远程同步时钟相对于本地参考时钟的抖动峰峰值为289.84ps,远程同步时钟相对本地参考时钟的抖动均方根值为60.34ps。 After converted to time units, remote synchronization clock relative to the local reference clock jitter peak value 289.84ps, remote synchronization clock relative to the rms jitter 60.34ps local reference clock.

[0043] 如图4所示,同样的测试条件下,采用温漂补偿时,远程节点采用信号相对于本地节点采样信号相位差如图所示。 [0043] As shown, under the same test conditions, when using the drift compensation, the remote node using the signal relative to the local node sampling signal phase shown in FIG. 4. 折算到时间单位后,远程同步时钟相对于本地参考时钟的抖动峰值为22.70ps,远程同步时钟相对于本地参考时钟的抖动均方根值为3.94ps。 After converted to time units, remote synchronization clock relative to the local reference clock jitter peaking is 22.70ps, remote synchronization clock jitter RMS value relative to the local reference clock 3.94ps. 从结果可以得出,本法明的温漂补偿系统及温漂补偿方法可以大大降低远程同步时钟的抖动,提高远程同步时钟的同步精度。 Can be deduced from the results of the next Act drift compensation system and drift compensation method can significantly reduce the remote synchronous clock jitter and improve remote synchronous clock synchronization accuracy.

[0044] 与现有技术相比,本发明的技术效果包括: [0044] Compared with the prior art, the technical effect of the present invention comprises:

[0045] 1)同步精度高、成本相对低廉,本发明采用的基于滤波器、鉴相器、DDS的数字化光纤温漂补偿方案,具有较高的时钟同步精度;经过测试,时钟同步精度小于5ps,可以满足射电天文阵列的采样时钟同步要求。 High [0045] 1) the synchronization precision, relatively low cost, the present invention employs fiber-based digital filter drift compensation scheme, the phase detector, the DDS has a higher clock synchronization accuracy; tested, the clock synchronization accuracy of less than 5ps , radio astronomy array satisfy a sampling clock synchronization requirements. 此外,相比高精度的模拟光学控制方法,成本大大降低, 比较适合射电天文阵列的大规模布阵要求; Further, compared to the analog high-precision optical control method, greatly reduce the cost, it is suitable for large-scale radio astronomy claim manoeuvering array;

[0046] 2)集成度高,本发明可以通过一路光纤通路完成采样时钟、采样数据、系统控制指令的传输,从而实现了数据采集、传输系统的高度集成,进一步降低了成本,非常适合于大规模射电天文阵列的分布式米集系统; [0046] 2) high integration, the present invention can be accomplished through one optical fiber path sampling clock, the sampling data, the system of the transmission control instruction, whereby data collection, highly integrated transmission system, further reducing cost, very suitable for large distributed meter scale collection system is an array of radio astronomy;

[0047] 3)环境适应能力强,本发明具有良好的温漂补偿能力,可以适应各种极端的户外环境,适合射电天文阵列布阵范围广、背景环境复杂的应用特点。 Strong [0047] 3) environmental adaptability, the present invention has a good ability to compensate temperature drift, can adapt to extreme outdoor environment for radio astronomy array manoeuvering wide range, complex context of application characteristics.

Claims (6)

1. 一种射电天文阵列远程光纤同步系统,其特征在于,包括:设置于本地节点的本地锁相控制模块和设置于远程节点的时钟净化模块,其中:远程节点和本地节点通过光纤相连, 本地节点将本地参考时钟和从时钟净化模块接收到的本地光纤接收时钟输入本地锁相控制模块,通过PID控制本地参考时钟进行相位调整得到本地光纤发送时钟; 所述的本地锁相控制模块包括:第一滤波器、第二滤波器、鉴相器、ADC、数字信号处理单元和DDS,其中:第二滤波器、鉴相器、ADC、DDS和数字信号处理单元依次串联成环路,第一滤波器两端与鉴相器和本地光纤接收模块相连,DDS连有本地光纤发送模块。 An array of radio astronomy remote synchronous optical system, characterized by comprising: setting a local node on the local control module and a lock disposed in the remote node clock cleaning module, wherein: the remote node and the local node is connected through an optical fiber, local local clock reference node and received from the local clock cleaning module to a clock input receiving the local optical phase lock control module, the local phase adjustment to obtain an optical fiber transmission clock PID control local reference clock; the phase locked local control module comprises: a first a filter, a second filter, a phase detector, ADC, digital signal processing unit and the DDS, wherein: the second filter, phase detector, ADC, the DDS and the digital signal processing unit into a loop in series, a first filter with both ends of the phase detector and a local optical receiver module is connected, DDS has a local optical transmission module is connected.
2. 根据权利要求1所述的射电天文阵列远程光纤同步系统,其特征是,所述的PID控制 2. Remote Fiber Array radio astronomy synchronization system according to claim 1, characterized in that the PID control
Figure CN105680970AC00021
,其中u(n)为PID输出控制量,e(n)为PID输入量, KP为比例系数,I为积分系数,Kd为微分系数。 , Where u (n) is the output of PID control amount, e (n) is the input PID, KP is a proportionality factor, I is the integral coefficient, Kd of the differential coefficient is.
3. 根据权利要求1所述的射电天文阵列远程光纤同步系统,其特征是,所述的远程节点设有远程光纤发送模块和远程光纤接收模块,该远程光纤发送模块与时钟净化模块和本地光纤接收模块相连,该远程光纤接收模块与时钟净化模块和本地光纤发送模块相连。 3. The radio astronomy array of optical remote synchronization system according to claim 1, wherein said remote node is provided with the remote fiber optical transmission module and a remote receiver module, the optical transmission module and the remote module and the local optical clock Purification receiving module is connected, the remote optical receiving module and a cleaning module and a clock module connected to the local transmission fiber.
4. 根据权利要求3所述的射电天文阵列远程光纤同步系统,其特征是,所述的数字信号处理单元和ADC由FPGA实现,本地光纤接收模块和本地光纤发送模块由FPGA的GTX实现。 4. The radio astronomy array of optical remote synchronization system according to claim 3, wherein said ADC and the digital signal processing unit is realized by the FPGA, the local receiving module and a local fiber optical transmission module is implemented by the GTX FPGA.
5. 根据权利要求4所述的射电天文阵列远程光纤同步系统,其特征是,所述的时钟净化模块将接收到的时钟信息进行消抖处理得到远程同步时钟,并反馈回本地节点。 The radio astronomy array of optical remote synchronization system according to claim 4, wherein said clock cleaning module clock information received debounces a remote process to obtain the synchronous clock, and fed back to the local node.
6. -种利用上述任一权利要求所述的射电天文阵列远程光纤同步系统进行温漂补偿的方法,其特征在于,包括以下步骤: 步骤1、本地参考时钟和本地光纤接收时钟分别经过滤波器,然后经过鉴相器进行鉴相; 步骤2、将鉴相结果通过低速的模数转换器进行数字化,输入到数字信号处理单元,通过PID控制算法处理,得到相位补偿控制量; 步骤3、将相位补偿控制量输入DDS,对本地参考时钟进行相位调整,获得本地光纤发送时钟,实现光纤温漂补偿。 6. - The method of any preceding claim using a kind of radio astronomy array of optical remote synchronization drift compensation system, characterized by comprising the following steps: Step 1, the local reference clock and the local clock respectively, after receiving fiber filter and then through the phase detector for phase; step 2, the results digitized phase by low-speed analog to digital converter, the input to the digital signal processing unit, the processing by the PID control algorithm, to obtain a phase compensation control amount; step 3, the DDS phase compensation control input, the local reference clock to adjust the phase, to obtain an optical fiber local transmission clocks, temperature drift compensation to achieve fiber.
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