CN102307087A - Atomic time signal transmission system and method - Google Patents

Abstract

The invention provides an atomic time signal transmission system and method. In the system, an emitting compensation device at an emission end is used to modulate atomic time signals to be transmitted onto optical signals for transmission by optical fibers and compensate for phase noise introduced by transmitting the atomic time signals in optical fiber links; and a plurality of serially-connected relay compensation transmission devices in each relay end are utilized to further compensate for the phase noise introduced by transmitting the atomic time signals in the optical fiber links, thus locking phases of the atomic time signals transmitted to the far ends at the phase of a reference clock at the emission end. The technical scheme is used for solving the problems of the locking bandwidth limitation and signal attenuation of an over-long base-line atomic time signal transmission loop and improving the transmission distance and transmission accuracy of the atomic time signals greatly.

Description

Atomic time signal transmission system and transmission method

Technical field

The present invention relates to a kind of transmission system and transmission method of atomic time signal.Special, relate to a kind of atomic time signal system for transmitting and method that realizes overlength baseline (distance) through optical fiber.

Background technology

Current, temporal frequency systematic research and application mainly contain 3 general orientation.The one, the preparation in temporal frequency source is used to provide the benchmark of time.The 2nd, the transmission system of temporal frequency has had good a reference source, also need temporal frequency be released accurately.Therefore the quality of temporal frequency transmission system has directly determined the quality of the frequency time signal that user side receives.And this problem is even more important in the transmission of over distance frequency time signal.The 3rd, the reception of frequency time signal, comparative maturity, for example GPS receiver and so on of the technology in this field at present.

For the reference clock that the temporal frequency source is provided, through years of researches in the world, the accuracy of reference clock and stability are very high.For example best in the world atomic clock sky stability can reach 10 at present ^-16Magnitude.For the transmission system of temporal frequency, the transmission of overlength baseline atomic time signal and the synchronous method that adopts mainly contain clock carrying method, satellite and look method (CV), the two-way temporal frequency TRANSFER METHOD of satellite (TWSTFT) etc. altogether at present.Wherein, except the clock carrying method, other several methods all will rely on the transmission of satellite.

But the sky stability of these transmission methods can only reach 10 at present ^-15Magnitude can't satisfy the accurate transmission of frequency time signal and the requirement of comparison.For example, if the best in the world atomic clock signal of transmission, then the stability of transmission system should be superior to the stability (10 of this atomic clock ^-16/ day).

For clock carrying method of the prior art, with a high-precision miniaturization atomic clock C, the time standard at long baseline one end A station is passed to the B station, thereby realize A station and B station synchronously.Basic principle is: at first A station clock and C clock and location, and at a certain coordinate time t ₀,, read the reading τ of A, C clock respectively with A clock and the comparison of C clock _A0And τ _C0The C clock is along known path then Be transported to the B station, compare, read B, the reading τ of C clock with the B clock _B1And τ _C1Like this, coordinate time t ₁Just can be by t ₀, τ _C0, τ _C1With

Derive, again according to the B relation with coordinate time of standing when former, synchronous B station clock.

But, utilize clock carrying method transmission atomic time signal to have following shortcoming.

(1) but because atomic time signal transmitting accuracy directly is subject to the stability of carrying small-sized atomic clock, but and handling process and the systematic error of different location height above sea level to the introducing of carrying small-sized atomic clock, thereby cause the precision of transmission signals lower.

(2) the clock carrying method must be carried to B ground more earlier after the clock comparison on A ground and A ground, compares with the clock on B ground.Thereby can't realize A, measurement simultaneously synchronous between the B two places is compared, and measures comparison thereby cause carrying out real-time continuous.

(3) how the clock carrying method must be transmitted media as the atomic time signal with same clock carrying, so can't between, carry out temporal frequency transmission comparison simultaneously, promptly can't carry out multiple spot simultaneously and compare synchronously.

Also there are the various transmission comparison methods of utilizing satellite to realize atomic time signal transmission in the prior art.As shown in Figure 1, between the ends A station of overlength baseline and the B station, mutual via satellite electromagnetic signals, the propagation delay of measurement electromagnetic wave signal perhaps receives the clock signal from same satellite simultaneously.Through swap data between two stations, just can obtain the relative clock correction between two stations, thereby realize that clock comparison between two stations is with synchronously.

But also there are some shortcomings in existing satellite transmission comparison method.For example, owing to receive the influence of factors such as earth ionosphere and atmosphere disturbance, the sky stability of utilizing satellite to carry out the transmission comparison of atomic time signal can only reach 10 ^-15Magnitude, promptly the precision of this method is low.In addition, owing to carry out time-frequency between A, the B two places when transmitting, A, B two places must be seen same satellite simultaneously.Atomic time signal for the overlength baseline transmits, and between some place, this condition does not possess.That is to say that the actual use of satellite transmission comparison method is subject to satellite coverage, thereby the atomic time signal transmission that is applicable to the overlength baseline that can not be good.

As stated; Existing clock carrying method adopts a miniaturization high accuracy atomic clock to transmit media as the atomic time signal; Existing satellite transmission comparison method is utilized the transmission media of artificial satellite as the atomic time signal, and these transmit media and all there is defective more or less in transmission method.Therefore, be necessary to consider to adopt new transmission media and corresponding transmission system and transmission method, to avoid or to solve the problem that exists in the above-mentioned prior art.

Summary of the invention

There to be the problems referred to above in the present invention in the prior art and to propose in order to solve just.

According to one object of the present invention; A kind of atomic time signal transmission system is provided; This system comprises: the emission compensation arrangement, be used for atomic time signal waiting for transmission is modulated on the light signal with through Optical Fiber Transmission, and the phase noise of compensation atomic time signal introducing when in optical fiber link, transmit; With a plurality of relaying compensation transmitting devices that are connected in series, each said relaying compensation transmitting device is used for further compensating the phase noise that the atomic time signal is introduced when optical fiber link transmits; Wherein, be modulated at the atomic time signal on the light signal through Optical Fiber Transmission between said emission compensation arrangement and a plurality of relaying compensation transmitting device.

According to another object of the present invention, a kind of atomic time method for transmitting signals is provided, this method comprises: receive the atomic time signal as the reference signal that reference clock produces; Atomic time signal waiting for transmission is modulated on the light signal to pass through Optical Fiber Transmission; The phase noise of when transmitting terminal compensation atomic time signal transmits in optical fiber link, introducing; Receive the microwave signal on the light signal that is modulated in the relay, and reproduction phase locking is in the atomic time of reference clock signal from optical fiber link; Atomic time signal waiting for transmission is modulated on the light signal to pass through Optical Fiber Transmission once more; The phase noise of introducing when further the said atomic time signal of compensation transmits in optical fiber link in the relay.

Preferably, the phase noise of when transmitting terminal compensation atomic time signal transmits in optical fiber link, introducing is achieved in that and generates two phase places and the auxiliary compensating signal that is locked in reference clock; Produce the feedback compensation signal that is used for compensating the phase noise that said atomic time signal introduces when optical fiber link transmits based on said auxiliary compensating signal, and this feedback compensation signal is loaded in the atomic time signal waiting for transmission.

The phase noise of introducing when preferably compensation atomic time signal transmits in optical fiber link in the relay is achieved in that and generates two phase places and the auxiliary compensating signal of the relaying that is locked in reference clock; Produce the relaying feedback compensation signal that is used for further compensating the phase noise that said atomic time signal introduces when optical fiber link transmits based on the auxiliary compensating signal of said relaying, and this relaying feedback compensation signal is loaded in the atomic time signal waiting for transmission.

According to atomic time signal transmission system of the present invention and transmission method, can adopt the transmission media of optical fiber as the atomic time signal, be modulated to the atomic time signal on the light signal and pass through Optical Fiber Transmission.In addition, the present invention surveys and compensation technique through implementing phase noise, realizes the compensation to the phase noise of fiber transmission link (especially extra long distance).

Special; Transmission for overlength baseline atomic time signal; The invention provides a kind of method of utilizing a plurality of relay stations to carry out the segmentation phase noise compensation; Solve the problem of overlength baseline atomic time signal transmit ring locking bandwidth constraints and signal attenuation, improved the transmitting accuracy of atomic time signal greatly.

Description of drawings

Fig. 1 has shown the sketch map that utilizes satellite to realize atomic time signal transmission;

Fig. 2 has shown the structural representation of atomic time signal transmission system of the present invention;

Fig. 3 has shown the structural representation of emission compensation arrangement of the present invention;

Fig. 4 has shown the of the present invention first operation principle sketch map than facies unit;

Fig. 5 has shown the structural representation of relaying compensation transmitting device of the present invention;

Fig. 6 has shown the second operation principle sketch map than facies unit of the auxiliary transport part of relaying;

Fig. 7 has shown an example of emission compensation arrangement of the present invention;

Fig. 8 has shown an example of relaying compensation transmitting device of the present invention;

Fig. 9 has shown an example of terminal of the present invention receiving system;

Figure 10 has shown the flow chart of atomic time method for transmitting signals of the present invention.

Embodiment

For making the object of the invention, technical scheme and advantage more cheer and bright, below in conjunction with embodiment and with reference to accompanying drawing, to further explain of the present invention.

Fig. 2 has shown the structural representation of atomic time signal transmission system of the present invention.

As shown in Figure 2, atomic time signal transmission system of the present invention comprises: the emission compensation arrangement, be used for atomic time signal waiting for transmission is modulated on the light signal with through Optical Fiber Transmission, and the phase noise of compensation atomic time signal introducing when in optical fiber link, transmit; A plurality of relaying compensation transmitting devices are used for further compensating the phase noise that the atomic time signal is introduced when optical fiber link transmits.Wherein, be modulated at the atomic time signal on the light signal through Optical Fiber Transmission between said emission compensation arrangement and a plurality of relaying compensation transmitting device.

As shown in Figure 2, the exemplary employing of a plurality of relayings compensation transmitting device of the present invention mode that is connected in series, but be not restricted to this.In practical application, can adopt as required to be connected in parallel and the simultaneous hybrid junction mode of series, parallel, can both be applicable to technical scheme of the present invention, and realize the high accuracy transmission of long baseline atomic time signal.

After through transmission system of the present invention the atomic time signal being transmitted, by a terminal receiving system receive and reproduction phase locking in the atomic time of reference clock signal, and it is converted to corresponding frequencies according to demand, supply the user to use.As shown in Figure 2, this terminal receiving system is connected to last relaying compensation transmitting device of transmission system.

Among the present invention, a relaying compensation transmitting device is set at regular intervals, each relaying compensation transmitting device is connected in series.Spacing distance between adjacent two relayings compensation transmitting device is by design load Δ v=c/ (the 4 π nl) decision of system phase noise compensation loop bandwidth, and wherein c is the light velocity, and l is an optical fiber link length between neighboring devices, and n is an optical fibre refractivity.In a preferred embodiment, this spacing distance is set to about 100 kilometers.

Introduce each part of atomic time signal transmission system of the present invention below respectively.

< emission compensation arrangement >

Fig. 3 has shown the structural representation of emission compensation arrangement of the present invention.

As shown in Figure 3, emission compensation arrangement of the present invention is in the transmitting terminal of atomic time signal transmission system, and it comprises the auxiliary transport part 1 and the first phase noise compensation portion 2.Said auxiliary transport part 1 generates auxiliary compensating signal and outputs to the first phase noise compensation portion, and this auxiliary compensating signal is used for the auxiliary first phase noise compensation portion and produces feedback compensation signal.Specifically; Auxiliary transport part 1 comprises first frequency oscillator F1 and second frequency oscillator F2; It generates the first auxiliary compensating signal and the second auxiliary compensating signal respectively, exports to the first phase noise compensation portion 2 (wherein first than facies unit) and produces feedback compensation signal with auxiliary its.Wherein, the phase locking of this first auxiliary compensating signal and the second auxiliary compensating signal is in reference clock.

The first phase noise compensation portion 2 is used for atomic time signal waiting for transmission is modulated on the light signal with through Optical Fiber Transmission, and produces the feedback compensation signal that is used for compensating the phase noise that said atomic time signal introduces when optical fiber link transmits based on the auxiliary compensating signal that auxiliary transport part generates.

If the benchmark microwave signal of the generation of reference clock does

Ω ₀＝A ₀cos(ω ₀t+φ _ref)

Here, A ₀The amplitude of expression reference clock signal, φ _RefBe the phase place of reference clock signal, ω ₀Frequency for the reference clock signal.Reference clock of the present invention can be any microwave signal source that produces as the atomic time signal of reference signal, and is preferred, can adopt the punctual clock by national reference clock (caesium fountain clock) calibration such as hydrogen clock, caesium clock or rubidium clock.

First frequency oscillator F1 produces the first auxiliary compensating signal of phase locking in reference clock

Ω ₁＝A ₁cos(aω ₀t+aφ _ref)

A wherein ₁The amplitude of the expression first auxiliary compensating signal, a are that arbitrary number (satisfies

Be the arbitrary number of a certain certain number, this certain number by the atomic time signal frequency that will transmit obtain divided by the reference clock signal frequency), can produce the optional frequency microwave signal of phase locking through phase-locked loop and frequency synthesizer in the reference clock signal.

Second frequency oscillator F2 produces the second auxiliary compensating signal of phase locking in reference clock

Ω ₂＝A ₂cos(bω ₀t+bφ _ref)

Wherein A2 representes the amplitude of the second auxiliary compensating signal; B be arbitrary number (satisfy and be the arbitrary number of a certain certain number, this certain number by the atomic time signal frequency that will transmit obtain divided by the reference clock signal frequency).

The present invention is provided with the first phase noise compensation portion 2 in the emission compensation arrangement of transmitting terminal, it comprises that the 3rd frequency oscillator F3, first is than facies unit, first laser, first detector and optical fiber circulator.

Wherein, the 3rd frequency oscillator F3 produces the 3rd microwave signal

${\mathrm{\&Omega;}}_3=A_3\cos (\frac{a+\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="HDA0000073738340000021.png,HDA0000073738340000031.png"\; state="\{\{state\}\}">b</figure-callout>}}{2}{\mathrm{\&omega;}}_{0}t+{\mathrm{\&phi;}}_0)$

Wherein, A ₃The amplitude of representing the 3rd microwave signal, the frequency of this microwave signal does

Phase meter is shown φ ₀, this phase place can be by feedback compensation signal Ω ₈Control is to satisfy certain conditions (seeing below).

First laser is modulated to the 3rd microwave signal on the light signal and exports to optical fiber circulator to get into optical fiber link.Wherein, use microwave signal Ω ₃The mode of modulating first laser is internal modulation or external modulation method.The optical signal transmission of first laser output is to far-end, and said first laser is the laser of output wavelength corresponding to optical fiber communication window wave band.

As shown in Figure 3, the light signal of first laser output is input to an optical fiber circulator, and it is used for emission light and back light are separated.Optical fiber circulator makes modulated light signal enter into optical fiber link through fiber optical circulator and transmits to far-end (relaying compensation transmitting device or terminal receiving system), and makes the light signal that is returned along optical fiber link by far-end export to first detector.In addition; Receive this light signal at the relaying of far-end compensation transmitting device, and the detector through wherein (in vide infra shown in Figure 5 second detector) carries out opto-electronic conversion to this light signal and can obtain the 4th microwave signal (relevant relaying compensates the description of the atomic time signal reproduction portion of transmitting device in vide infra):

${\mathrm{\&Omega;}}_4=A_4\cos (\frac{a+\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="HDA0000073738340000021.png,HDA0000073738340000031.png"\; state="\{\{state\}\}">b</figure-callout>}}{2}{\mathrm{\&omega;}}_{0}t+{\mathrm{\&phi;}}_0+{\mathrm{\&phi;}}_p)$

Wherein, A ₄The amplitude of representing the 4th microwave signal, φ _pBe the phase noise that optical fiber link is introduced, this phase noise receives optical fiber link variation of ambient temperature of living in, the factor affecting such as variation of the suffered mechanical stress of optical fiber (cause like vibration, or the like).

In order to compensate above-mentioned phase noise; The present invention is configured such that the part of the light signal (comprising the microwave signal that is modulated on the light signal) that transfers to far-end returns (description of the atomic time signal reproduction portion of relevant relaying compensation transmitting device in vide infra) along the former road of optical fiber link, and from port 3 outputs of fiber optical circulator.As shown in Figure 3, the port 3 of fiber optical circulator is connected to first detector, and it will be modulated at microwave signal demodulation on the light signal through opto-electronic conversion and come out and export to first and compare facies unit.Thus, this light signal that returns obtains the 5th microwave signal after first detector demodulates

${\mathrm{\&Omega;}}_5=A_5\cos (\frac{a+\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="HDA0000073738340000021.png,HDA0000073738340000031.png"\; state="\{\{state\}\}">b</figure-callout>}}{2}{\mathrm{\&omega;}}_{0}t+{\mathrm{\&phi;}}_0+2{\mathrm{\&phi;}}_p)$

Here, the 5th microwave signal has comprised phase noise 2 φ in the optical fiber link of twice _p, it outputs to first and generates feedback compensation signal with auxiliary first than facies unit than facies unit.

Subsequently, through first the output phase than facies unit FEEDBACK CONTROL the 3rd frequency oscillator F3.Specifically; First said first, second auxiliary compensating signal and the 3rd, the 5th microwave signal that will receive than facies unit carries out than handles mutually to produce feedback compensation signal; And this feedback compensation signal outputed to the 3rd frequency oscillator F3, make in the phase place of the 3rd microwave signal of its output and introduce the phase noise φ that optical fiber link is introduced _pCompensation, thereby make the microwave signal Ω that transfers to far-end ₄Phase locking in the phase place of the reference clock of transmitting terminal, this microwave signal Ω ₄The atomic time signal that will transmit exactly.

Among the present invention, at least one in the frequency oscillator that is adopted is constant temperature VCXO and External Reference phase locking dielectric oscillator or frequency multiplier.

Fig. 4 has shown the of the present invention first operation principle sketch map than facies unit.

among Fig. 4 represents frequency mixer; It makes two input signals do multiplying, thereby makes the frequency of two signals and phase place do signed magnitude arithmetic(al).

Of the present invention first is used for the signal Ω that provides above-mentioned than facies unit ₁, Ω ₂, Ω ₃And Ω ₅Carry out than handling mutually, to obtain the feedback compensation signal Ω of the output phase that is used for FEEDBACK CONTROL the 3rd frequency oscillator F3 ₈Ratio among the present invention is handled mutually and is meant through circuit computing, obtains a signal of telecommunication that comprises specific mathematical relation between several signal phases.Specifically, with microwave signal Ω ₂With Ω ₅Obtain signal behind mixing and the LPF

${\mathrm{\&Omega;}}_6=A_6\cos (\frac{b-a}{2}{\mathrm{\&omega;}}_{0}t+b{\mathrm{\&phi;}}_{\mathrm{ref}}-{\mathrm{\&phi;}}_0-{2\mathrm{\&phi;}}_p)$

With microwave signal Ω ₁With Ω ₃Obtain signal behind mixing and the LPF

${\mathrm{\&Omega;}}_7=A_7\cos (\frac{b-a}{2}{\mathrm{\&omega;}}_{0}t+{\mathrm{\&phi;}}_0-a{\mathrm{\&phi;}}_{\mathrm{ref}})$

Then, with signal Ω ₆With Ω ₇Obtain feedback compensation signal behind mixing and the LPF

Ω ₈＝A ₈cos(aφ _ref+bφ _ref-2φ ₀-2φ _p)

What should explain is that above-mentioned method of work than facies unit only is exemplary, is not construed as limiting the invention, and in fact can also adopt other processing method.For example, can be with Ω ₁And Ω ₂Mixing and high-pass filtering obtain being proportional to cos [(a+b) ω ₀T+ (a+b) φ _Ref] signal, with Ω ₃And Ω ₅Mixing and high-pass filtering obtain being proportional to cos [(a+b) ω ₀T+2 φ ₀+ 2 φ _p] signal, and then these two signal mixings and LPF are obtained feedback compensation signal:

Ω ₈＝A ₈cos(aφ _ref+bφ _ref-2φ ₀-2φ _p)

This feedback compensation signal is used for the output phase φ of feedback compensation the 3rd frequency oscillator F3 ₀, make its phase ₀Satisfy relational expression:

${\mathrm{\&phi;}}_0=\frac{a+\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="HDA0000073738340000021.png,HDA0000073738340000031.png"\; state="\{\{state\}\}">b</figure-callout>}}{2}{\mathrm{\&phi;}}_{\mathrm{ref}}-{\mathrm{\&phi;}}_p+(2n+1)\frac{\mathrm{\&pi;}}{4}$

In the following formula, when system lock, n is a certain constant integer of confirming.

Visible by following formula, after phase compensation, the phase of the 3rd microwave signal of the 3rd frequency oscillator F3 output ₀Be locked in the reference clock phase _RefThe basis on, further introduced the phase noise φ of optical fiber link _p, make it follow the phase noise φ of optical fiber link _pAnd constantly change, realize the phase noise φ that optical fiber link is introduced thus _pDynamic compensation.Therefore, the 3rd microwave signal after compensation can guarantee that the atomic time signal phase that far-end (relaying compensation transmitting device or terminal receiving system) receives can be locked in the reference clock phase _Ref, promptly the relative datum clock is stable.

For example, through servo feedback circuit, can make Ω ₈=0, thus obtain

${\mathrm{a\&phi;}}_{\mathrm{ref}}+b{\mathrm{\&phi;}}_{\mathrm{ref}}-2{\mathrm{\&phi;}}_0-{2\mathrm{\&phi;}}_p=(2n+1)\frac{\mathrm{\&pi;}}{2}$

And then obtain following formula.

Among the present invention, with respect to the phase locking of transmitting terminal reference clock, be not strict with its phase place and be equal to the transmitting terminal phase place as long as realize the receiving terminal microwave signal phase.Therefore; In order to express easily, in preferred implementation of the present invention, can omit the atomic time signal (the 4th microwave signal) that fixing phase difference item

transfers to far-end (relaying compensation transmitting device or terminal receiving system) like this does

${\mathrm{\&Omega;}}_4=A_4\cos (\frac{a+\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="HDA0000073738340000021.png,HDA0000073738340000031.png"\; state="\{\{state\}\}">b</figure-callout>}}{2}{\mathrm{\&omega;}}_{0}t+{\mathrm{\&phi;}}_0+{\mathrm{\&phi;}}_p)$

$=A_4\cos [\frac{a+\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="HDA0000073738340000021.png,HDA0000073738340000031.png"\; state="\{\{state\}\}">b</figure-callout>}}{2}{\mathrm{\&omega;}}_{0}t+\frac{a+\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="HDA0000073738340000021.png,HDA0000073738340000031.png"\; state="\{\{state\}\}">b</figure-callout>}}{2}{\mathrm{\&phi;}}_{\mathrm{ref}}]$

Visible by following formula, the phase locking of atomic time signal that is transferred to far-end (relaying compensation transmitting device or terminal receiving system) is in the phase of reference clock _RefLike this, just be equivalent to obtain the atomic time signal identical, thereby realized the very atomic time signal transmission passage of clean (noise is very low) with transmitting terminal reference clock quality at user side (relaying compensation transmitting device or terminal receiving system).

As stated; In a preferred embodiment of the invention; The emission compensation arrangement adopts first frequency oscillator F1 and second frequency oscillator F2 auxiliary the produce feedback compensation signal of two phase lockings in reference clock; Realization is to the phase compensation of the atomic time signal that will transmit, and makes the phase locking of the atomic time signal that transfers to far-end (relaying compensation transmitting device and terminal receiving system) in the phase place of reference clock.

The phase place of the above-mentioned first auxiliary compensating signal and the second auxiliary compensating signal be the transmitting terminal reference clock phase place (a+b) doubly.But the present invention is not restricted to this, also can be other proportional relation, and the skew (promptly having a constant term on above-mentioned equality the right) of a fixed value is perhaps arranged on the basis that is directly proportional.That is to say,, just can guarantee the phase place and the phase place that is locked in the transmitting terminal reference clock of two auxiliary compensating signals as long as make the phase place of two auxiliary compensating signals and linear with the phase place of transmitting terminal reference clock.

Further; The present invention can also be set to the frequency of two auxiliary compensating signals that first frequency oscillator F1 and second frequency oscillator F2 produce and be any multiple, phase place and the phase place that is locked in reference clock of the atomic time signal frequency

transmitted.As long as promptly make two auxiliary compensating signals frequency and with the proportional relation of frequency of the atomic time signal that is transmitted, the phase place of two auxiliary compensating signals gets final product with the phase place that is locked in the transmitting terminal reference clock.

For example, with the frequency of two auxiliary compensating signals be ξ (a+b) ω ₀, phase place is an example with being locked in the transmitting terminal reference clock.Shown in Fig. 4 (b), first than facies unit in, will can obtain being proportional to cos [ξ (a+b) ω from two auxiliary compensating signal mixing and the high-pass filtering of first frequency oscillator F1 and second frequency oscillator F2 ₀T+ ξ (a+b) φ _Ref] signal (with Ω ₁₀Expression), can find out that this signal frequency is ξ/2 times of the atomic time signal frequency transmitted, phase locking is in transmitting terminal reference clock phase place; With Ω ₃And Ω ₅Mixing and high-pass filtering obtain being proportional to cos [(a+b) ω ₀T+2 φ ₀+ 2 φ _p] signal, then this signal is carried out frequency multiplication computing (among the figure * ξ represent ξ frequency multiplication computing doubly), obtain being proportional to cos [ξ (a+b) ω ₀T+2 ξ (φ ₀+ φ _p)] signal (with Ω ₁₁Expression); With Ω ₁₀With Ω ₁₁Mixing and LPF can obtain being proportional to cos [ξ (a+b) φ _Ref-2 ξ (φ ₀+ φ _p)] signal (with Ω ₁₂Expression); Like this with Ω ₁₂Come the output phase φ of feedback compensation the 3rd frequency oscillator F3 as feedback compensation signal ₀, its phase place is satisfied

Statement for ease is here equally with the fixed skew item

Omit.

As stated; Transmission system of the present invention is come the phase noise in the compensated fiber transmission link through the phase place (its phase place is followed the optical fiber link noise in continuous variation) of dynamic compensation the 3rd frequency oscillator F3; Thereby the atomic time signal phase that guarantees far-end (relaying compensation transmitting device or terminal receiving system) can be locked in reference clock, and promptly the relative datum clock is stable.

< relaying compensation transmitting device >

Fig. 5 has shown the structural representation of relaying compensation transmitting device of the present invention.

As previously mentioned; Be provided with a plurality of relaying compensation transmitting devices that are connected in series in the atomic time signal transmission system of the present invention, it is mainly used in the phase noise of introducing when further compensation atomic time signal transmits in optical fiber link (n relaying compensation transmitting device to the n+1 relaying compensation transmitting device).Optional; Relaying compensation transmitting device also has following action: (1) receives the microwave signal on the light signal that is modulated at from optical fiber link; And reappear phase locking in the atomic time of reference clock signal, supply the relay to use, and play the effect of compensation atomic time signal transmission attenuation; (2) solve because the problem of the compensation loop that time delay the caused locking bandwidth constraints of atomic time signal long-distance transmission.

As shown in Figure 5; Relaying compensation transmitting device of the present invention comprises the atomic time signal reproduction A of portion, the auxiliary transport part B of relaying and second C of phase noise compensation portion, is respectively applied for to realize that reproduction phase locking is in the atomic time of reference clock signal, relay transmission, these three functions of phase noise compensation.

The atomic time signal reproduction A of portion comprises second detector and the 4th frequency oscillator, and it receives the microwave signal on the light signal that is modulated at from optical fiber link, and reproduction phase locking is in the atomic time of reference clock signal.As shown in Figure 5, (add on it and carry aforesaid the 4th microwave signal Ω from the light signal of optical fiber link ₄) get into fiber optical circulator by port 2, from port 3 outputs, again by one-to-two fiber coupler FC separated into two parts.Wherein, a part is from port one input optical fibre circulator, and gets into optical fiber link once more from port 2, returns along the former road of optical fiber link, and another part is imported second detector.

Second detector will be modulated at the 4th microwave signal Ω on the light signal through opto-electronic conversion ₄Demodulation is come out, and obtains the 4th microwave signal of phase stabilization

${\mathrm{\&Omega;}}_4=A_4\cos [\frac{a+\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="HDA0000073738340000021.png,HDA0000073738340000031.png"\; state="\{\{state\}\}">b</figure-callout>}}{2}{\mathrm{\&omega;}}_{0}t+\frac{a+\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="HDA0000073738340000021.png,HDA0000073738340000031.png"\; state="\{\{state\}\}">b</figure-callout>}}{2}{\mathrm{\&phi;}}_{\mathrm{ref}}]$

Then, second detector offers the 4th frequency oscillator T with the 4th microwave signal ₁, its generated frequency is equaled and phase locking in the microwave signal of the 4th microwave signal:

${\mathrm{\&Omega;}}_{\mathrm{<figure-callout\; id="1"\; label="T"\; filenames="HDA0000073738340000021.png"\; state="\{\{state\}\}">T</figure-callout>}1}=A_{\mathrm{<figure-callout\; id="1"\; label="T"\; filenames="HDA0000073738340000021.png"\; state="\{\{state\}\}">T</figure-callout>}1}\cos [\frac{a+\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="HDA0000073738340000021.png,HDA0000073738340000031.png"\; state="\{\{state\}\}">b</figure-callout>}}{2}{\mathrm{\&omega;}}_{0}t+\frac{a+\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="HDA0000073738340000021.png,HDA0000073738340000031.png"\; state="\{\{state\}\}">b</figure-callout>}}{2}{\mathrm{\&phi;}}_{\mathrm{ref}}]$

In the following formula, a, b are that arbitrary number (satisfies

Be the arbitrary number of a certain certain number, this certain number by the atomic time signal frequency that will transmit obtain divided by the reference clock signal frequency), φ _RefBe reference clock signal phase, ω ₀Be the frequency of reference clock, A _T1The amplitude of representing this signal.Statement is omitted fixed skew item here equally for ease.Like this, just reappear phase locking, thereby played the effect of compensation atomic time signal transmission attenuation in the atomic time of reference clock signal in the relay.

Optional, as shown in Figure 5, atomic time signal reproduction portion also comprises the divider " ÷ " that is connected to the 4th frequency oscillator output, its microwave signal with the output of the 4th frequency oscillator is removed to corresponding frequencies, supplies the user of relay to use.

In addition;

expression frequency mixer between second detector and the 4th frequency oscillator T1; It is used to make two input signals to do multiplying, though the frequency of two signals and phase place do add, subtraction.

The auxiliary transport part B of relaying is used for the relay transmission of atomic time signal; It generates the auxiliary compensating signal of relaying and outputs to second C of phase noise compensation portion in the relay; The auxiliary compensating signal of this relaying is used for the auxiliary second phase noise compensation portion and produces the relaying feedback compensation signal, the phase noise of introducing when transmitting in optical fiber link further to compensate the atomic time signal in this relay.

As shown in Figure 5, the auxiliary transport part B of relaying comprises the 5th frequency oscillator T2, and the 6th frequency oscillator T3 and second compares facies unit.Wherein frequency oscillator T2, T3 produce auxiliary compensating signal of first relaying and the auxiliary compensating signal of second relaying respectively, export to second C of phase noise compensation portion (wherein the 3rd than facies unit) and produce relaying feedback compensation signal with auxiliary its.

The 5th frequency oscillator T2 produces the auxiliary compensating signal of first relaying:

Ω _T2＝A _T2cos(ω _T2t+φ _T2)

Wherein, A _T2, ω _T2, φ _T2Amplitude, frequency and the phase place of difference expression signal.

The 6th frequency oscillator T3 produces the auxiliary compensating signal of second relaying:

Ω _T3＝A _T3cos(ω _T3t+φ _T3)

Wherein, A _T3, ω _T3, φ _T3Amplitude, frequency and the phase place of difference expression signal.

In a preferred embodiment, be set to one of them frequency in the auxiliary compensating signal of above-mentioned two relayings be lower than the atomic time signal that transmits in the optical fiber link frequency

another be higher than transmission atomic time signal frequency but both frequency with satisfy equality:

ω _T2+ω _T3＝(a+b)ω ₀

The frequency of auxiliary compensating signal of above-mentioned first relaying and the auxiliary compensating signal of second relaying and 2 times of frequency that are the atomic time signal that transmits in the optical fiber link.But the present invention is not restricted to this, also can be other proportionate relationship.That is to say, if make the auxiliary compensating signal of two relayings frequency and with the proportional relation of frequency of the atomic time signal that is transmitted.

Further, through the phase place of the second auxiliary compensating signal of second relaying that produce than facies unit FEEDBACK CONTROL the 6th frequency oscillator T3, make the auxiliary compensating signal of two relayings that frequency oscillator T2 and T3 produce phase place and satisfy equality:

φ _T2+φ _T3＝(a+b)φ _ref

The phase place of auxiliary compensating signal of above-mentioned first relaying and the auxiliary compensating signal of second relaying be the transmitting terminal reference clock phase place (a+b) doubly.But the present invention is not restricted to this, also can be other proportional relation, and the skew (promptly having a constant term on above-mentioned equality the right) of a fixed value is perhaps arranged on the basis that is directly proportional.That is to say,, just can guarantee the phase place of the auxiliary compensating signal of two relayings and be locked in the phase place of transmitting terminal reference clock as long as make the phase place of the auxiliary compensating signal of two relayings and linear with the phase place of transmitting terminal reference clock.

Fig. 6 has shown the second operation principle sketch map than facies unit of the auxiliary transport part of relaying.

As shown in Figure 6, the auxiliary transport part of relaying second than the microwave signal Ω of facies unit with input _T1, relaying is assisted compensating signal Ω _T2And Ω _T3Carry out than handling mutually, to obtain the compensating signal Ω of the output phase that is used for FEEDBACK CONTROL the 6th frequency oscillator T3 _T7Specifically, with microwave signal Ω _T1With signal Ω _T2Obtain signal behind mixing and the LPF

${\mathrm{\&Omega;}}_{T5}=A_{T5}\cos [(\frac{a+\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="HDA0000073738340000021.png,HDA0000073738340000031.png"\; state="\{\{state\}\}">b</figure-callout>}}{2}{\mathrm{\&omega;}}_0-{\mathrm{\&omega;}}_{T2})t+\frac{a+\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="HDA0000073738340000021.png,HDA0000073738340000031.png"\; state="\{\{state\}\}">b</figure-callout>}}{2}{\mathrm{\&phi;}}_{\mathrm{ref}}-{\mathrm{\&phi;}}_{T2}]$

With microwave signal Ω _T1With signal Ω _T3Obtain signal behind mixing and the LPF

${\mathrm{\&Omega;}}_{T6}=A_{T6}\cos [({\mathrm{\&omega;}}_{T3}-\frac{a<figure-callout\; id="2"\; label="+\; b"\; filenames="HDA0000073738340000021.png,HDA0000073738340000031.png"\; state="\{\{state\}\}">+</figure-callout>b}{2}{\mathrm{\&omega;}}_0)t+{\mathrm{\&phi;}}_{T3}-\frac{a<figure-callout\; id="2"\; label="+\; b"\; filenames="HDA0000073738340000021.png,HDA0000073738340000031.png"\; state="\{\{state\}\}">+</figure-callout>b}{2}{\mathrm{\&phi;}}_{\mathrm{ref}}]$

With signal Ω _T5With Ω _T6Can be compensated signal behind mixing and the LPF

Ω _T7＝A _T7cos{[(a+b)ω ₀-(ω _T2+ω _T3)]t+(a+b)φ _ref-(φ _T2+φ _T3)}

＝A _T7cos[(a+b)φ _ref-(φ _T2+φ _T3)]

It should be noted that the of the present invention above-mentioned second realization principle than facies unit only is exemplary, and is not construed as limiting the invention, in fact, can also adopt other similarly to realize principle.For example, can be with Ω _T1Frequency multiplication obtains being proportional to cos [(a+b) ω ₀T+ (a+b) φ _Ref] signal, with Ω _T2And Ω _T3Mixing and high-pass filtering obtain being proportional to cos [(ω _T2+ ω _T3) t+ φ _T2+ φ _T3] signal, then these two signal mixings and LPF are obtained signal

Ω _T7＝A _T7cos[(a+b)φ _ref-(φ _T2+φ _T3)]。

Above-mentioned compensating signal is used for the phase place of the auxiliary compensating signal of second relaying of FEEDBACK CONTROL the 6th frequency oscillator T3 generation, and its phase place is satisfied

φ _T3＝(a+b)φ _ref-φ _T2

And then obtain

φ _T2+φ _T3＝(a+b)φ _ref

Wherein, φ _RefPhase place for the signal of transmitting terminal reference clock.Statement is omitted fixed skew item

here equally for ease.

It is thus clear that, the phase place of the auxiliary compensating signals of two relayings and linear with the phase place of reference clock, thus can be locked in the phase place (promptly keeping synchronously) of reference clock with reference clock.

As stated, the auxiliary transport part B of relaying of the present invention produces the auxiliary compensating signal of two relayings, and these two signals phase place separately directly is not locked in the reference clock phase place of transmitting terminal, but both phase places and the phase place that is locked in the transmitting terminal reference clock.

Can know by the aforementioned atomic time signal phase noise compensation principle that is in the emission compensation arrangement of transmitting terminal, the frequency of two auxiliary compensating signals and with optical fiber link in the proportional relation of frequency, phase place and the phase place that is locked in reference clock of the atomic time signal that transmits.In like manner; For (relaying compensation transmitting device) continues the atomic time signal to next relay (or receiving terminal) transmission in the relay; The frequency of the auxiliary compensating signals of two relayings and with optical fiber link in the proportional relation of frequency, phase place and the phase place that is locked in reference clock of the atomic time signal that transmits.Therefore, the atomic time signal that in the optical fiber link of relay, transmits is the same with transmitting terminal, all is the signal of phase locking in reference clock.

The principle of second C of phase noise compensation portion of relaying compensation transmitting device and the phase noise compensation principle of transmitting terminal are similar; Be used for atomic time signal waiting for transmission is modulated on the light signal with through Optical Fiber Transmission, and produce the relaying feedback compensation signal that is used for further compensating the phase noise that said atomic time signal introduces when optical fiber link transmits based on the auxiliary compensating signal of relaying that the auxiliary transport part B of relaying generates.As shown in Figure 5, second C of phase noise compensation portion comprises the 3rd than facies unit, the 7th frequency oscillator, second laser, the 3rd detector and optical fiber circulator.

The 7th frequency oscillator produces frequency

Phase place is φ ₁Microwave signal

${\mathrm{\&Omega;}}_{T4}=A_{T4}\cos (\frac{a+\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="HDA0000073738340000021.png,HDA0000073738340000031.png"\; state="\{\{state\}\}">b</figure-callout>}}{2}{\mathrm{\&omega;}}_{0}t+{\mathrm{\&phi;}}_1)$

Second laser is with this microwave signal Ω _T4Be modulated on the light signal and export to optical fiber circulator to get into optical fiber link.The mode of wherein, modulating second laser is internal modulation or external modulation method.This modulated laser signal is input to optical fiber link, makes the signal (not shown) that transfers to far-end become

${\mathrm{\&Omega;}}_{T8}=A_{T8}\cos (\frac{a+\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="HDA0000073738340000021.png,HDA0000073738340000031.png"\; state="\{\{state\}\}">b</figure-callout>}}{2}{\mathrm{\&omega;}}_{0}t+{\mathrm{\&phi;}}_1+{\mathrm{\&phi;}}_{p1})$

This transfers to the microwave signal Ω of far-end _T8The 4th microwave signal Ω with the front ₄Similar, as in optical fiber link, to transmit exactly atomic time signal.Here, far-end refer to the atomic time signal be transferred to next relay or receiving terminal.φ wherein _P1The phase noise of introducing when in the corresponding optical fiber link in this relay, transmitting for the atomic time signal, optical fiber circulator will transfer to the part of the light signal of far-end and return along the former road of optical fiber link, and this light signal that returns obtains microwave signal through the 3rd detector

${\mathrm{\&Omega;}}_{T9}=A_{T9}\cos (\frac{a+\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="HDA0000073738340000021.png,HDA0000073738340000031.png"\; state="\{\{state\}\}">b</figure-callout>}}{2}{\mathrm{\&omega;}}_{0}t+{\mathrm{\&phi;}}_1+{2\mathrm{\&phi;}}_{p1})$

Signal Ω _T9Phase noise 2 φ in the optical fiber link of twice have been comprised _P1, it outputs to the 3rd and generates relaying feedback compensation signal with the auxiliary the 3rd than facies unit than facies unit.

Subsequently, produce the output phase of relaying feedback compensation signal than facies unit, make and introduce the phase noise φ that optical fiber link is introduced in its phase place with FEEDBACK CONTROL the 7th frequency oscillator through the 3rd _P1Compensation, thereby make the microwave signal Ω that transfers to far-end _T8Phase place satisfy following formula:

${\mathrm{\&phi;}}_1+{\mathrm{\&phi;}}_{\mathrm{<figure-callout\; id="1"\; label="p"\; filenames="HDA0000073738340000021.png"\; state="\{\{state\}\}">p</figure-callout>}1}=\frac{a+\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="HDA0000073738340000021.png,HDA0000073738340000031.png"\; state="\{\{state\}\}">b</figure-callout>}}{2}{\mathrm{\&phi;}}_{\mathrm{ref}}$

Thus it is clear that, transfer to the microwave signal Ω of far-end _T8Phase locking in the reference clock of transmitting terminal, this microwave signal Ω _T8The atomic time signal that will transmit exactly.

The 3rd is similar than facies unit with aforesaid first than the principle of facies unit, with microwave signal Ω _T3With Ω _T9Mixing and LPF obtain signal

${\mathrm{\&Omega;}}_{\mathrm{<figure-callout\; id="10"\; label="T"\; filenames="HDA0000073738340000061.png"\; state="\{\{state\}\}">T</figure-callout>}10}=A_{\mathrm{<figure-callout\; id="10"\; label="T"\; filenames="HDA0000073738340000061.png"\; state="\{\{state\}\}">T</figure-callout>}10}\cos [({\mathrm{\&omega;}}_{T3}-\frac{a<figure-callout\; id="2"\; label="+\; b"\; filenames="HDA0000073738340000021.png,HDA0000073738340000031.png"\; state="\{\{state\}\}">+</figure-callout>b}{2}{\mathrm{\&omega;}}_0)t+{\mathrm{\&phi;}}_{T3}-{\mathrm{\&phi;}}_1-2{\mathrm{\&phi;}}_{p1}]$

With microwave signal Ω _T2With Ω _T4Mixing and LPF obtain signal

${\mathrm{\&Omega;}}_{T11}=A_{T11}\cos [(\frac{a+\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="HDA0000073738340000021.png,HDA0000073738340000031.png"\; state="\{\{state\}\}">b</figure-callout>}}{2}{\mathrm{\&omega;}}_0-{\mathrm{\&omega;}}_{T2})t+{\mathrm{\&phi;}}_1-{\mathrm{\&phi;}}_{T2}\mathrm{}]$

With signal Ω _T10With Ω _T11Mixing and LPF obtain signal

Ω _T12＝A _T12cos(φ _T2+φ _T3-2φ ₁-2φ _p1)

Then, with Ω _T12Ratio is amplified the output phase of back as relaying feedback compensation signal FEEDBACK CONTROL the 7th frequency oscillator, makes its phase ₁Satisfy relational expression:

${\mathrm{\&phi;}}_1+{\mathrm{\&phi;}}_{\mathrm{<figure-callout\; id="1"\; label="p"\; filenames="HDA0000073738340000021.png"\; state="\{\{state\}\}">p</figure-callout>}1}=\frac{{\mathrm{\&phi;}}_{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="HDA0000073738340000021.png,HDA0000073738340000031.png"\; state="\{\{state\}\}">T</figure-callout>}2}+{\mathrm{\&phi;}}_{\mathrm{<figure-callout\; id="3"\; label="T"\; filenames="HDA0000073738340000021.png,HDA0000073738340000061.png"\; state="\{\{state\}\}">T</figure-callout>}3}}{2}=\frac{a+\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="HDA0000073738340000021.png,HDA0000073738340000031.png"\; state="\{\{state\}\}">b</figure-callout>}}{2}{\mathrm{\&phi;}}_{\mathrm{ref}}$

Promptly ${\mathrm{\&phi;}}_1=\frac{a+\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="HDA0000073738340000021.png,HDA0000073738340000031.png"\; state="\{\{state\}\}">b</figure-callout>}}{2}{\mathrm{\&phi;}}_{\mathrm{ref}}-{\mathrm{\&phi;}}_{\mathrm{<figure-callout\; id="1"\; label="p"\; filenames="HDA0000073738340000021.png"\; state="\{\{state\}\}">p</figure-callout>}1}$

Visible by following formula, similar with the 3rd frequency oscillator of front, after phase compensation, the phase of the microwave signal of the 7th frequency oscillator output ₁Be locked in the reference clock phase _RefThe basis on, further introduced the phase noise φ of optical fiber link _P1, make it follow the phase noise φ of optical fiber link _P1And constantly change, realize the phase noise φ that optical fiber link is introduced thus _pDynamic compensation.Therefore, the microwave signal of the 7th frequency oscillator output can guarantee that after compensation the atomic time signal phase that far-end (relaying compensation transmitting device or terminal receiving system) receives can be locked in the reference clock phase _Ref, promptly the relative datum clock is stable.

Accordingly, transfer to the microwave signal Ω of far-end _T8For

${\mathrm{\&Omega;}}_{T8}=A_{T8}\cos (\frac{a+\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="HDA0000073738340000021.png,HDA0000073738340000031.png"\; state="\{\{state\}\}">b</figure-callout>}}{2}{\mathrm{\&omega;}}_{0}t+{\mathrm{\&phi;}}_1+{\mathrm{\&phi;}}_{p1})$

$=A_{T8}\cos (\frac{a+\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="HDA0000073738340000021.png,HDA0000073738340000031.png"\; state="\{\{state\}\}">b</figure-callout>}}{2}{\mathrm{\&omega;}}_{0}t+\frac{a+\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="HDA0000073738340000021.png,HDA0000073738340000031.png"\; state="\{\{state\}\}">b</figure-callout>}}{2}{\mathrm{\&phi;}}_{\mathrm{ref}})$

Visible by following formula, microwave signal Ω _T8Frequency and the 4th microwave signal Ω of phase place and front ₄Identical.Therefore, the phase place that is transferred to the microwave signal of far-end through relaying compensation transmitting device transmission continued of the present invention still is locked in the fixed phase φ of reference clock _RefLike this; Microwave signal through user side is obtained (hundreds of and even several thousand kilometers outside) phase locking is in the phase place of transmitting terminal reference clock; Just be equivalent to obtain the atomic time signal identical, thereby realized the very atomic time signal transmission passage of clean (noise is very low) with transmitting terminal reference clock quality at receiving terminal.

As stated; Transmission system of the present invention compensates the phase noise in the transmission link through the phase place (its phase place is followed the optical fiber link noise in continuous variation) that constantly compensates the 7th frequency oscillator T4 in the relay; Make the atomic time signal phase that transfers to far-end (follow-up relaying compensation transmitting device or terminal receiving system) be locked in reference clock, promptly the relative datum clock is stable.

Similarly, first more identical than in facies unit and the aforesaid atomic time signal emission compensation arrangement of the 3rd among second C of phase noise compensation portion than the structure and the principle of facies unit, and implementation method is not limited to a kind of.

In addition, at least one is constant temperature VCXO and External Reference phase locking dielectric oscillator or frequency multiplier in the frequency oscillator of using among the present invention.

It should be noted that processing such as mixing, frequency multiplication, LPF and high-pass filtering that ratio facies unit among the present invention is realized belong to technology well-known to those having ordinary skill in the art, so not at the row of discussion of the present invention.

< preferred embodiment >

Introduce a preferred embodiment of atomic time signal transmission system of the present invention below.

Fig. 7 has shown an example of emission compensation arrangement of the present invention.

In the embodiment shown in fig. 7, be that the atomic time signal of 9.1GHz is an example with the transmission frequency, but be not restricted to this that situation of other transmission frequencies is similar.

The emission compensation arrangement of present embodiment comprises the auxiliary transport part 100 and the first phase noise compensation portion 200, introduces the structure and the working method of each part below respectively.

One, auxiliary transport part

100 are auxiliary transport part, are used to produce frequency and are 9.0GHz and 9.2GHz and phase locking in the auxiliary compensating signal of reference clock.Here, reference clock for example adopts the hydrogen clock of caesium fountain clock calibration, but is not restricted to this, and the reference clock of existing other type also can be applicable to the present invention in the prior art.

As shown in Figure 7, auxiliary transport part 100 is exemplary comprises following assembly.101 with 107:100MHz constant temperature VCXO (VCXO); 102: External Reference phase locking dielectric oscillator (DRO), input reference frequency 100MHz, output frequency of oscillation 9.0GHz; 103: one minute three microwave power divider of phase equilibrium; 104: the microwave frequency divider; Division factor 90 removes the frequency of 9.0GHz signal to 100MHz; 105 and 112: the rf frequency frequency mixer, the LO of this frequency mixer and RF end frequency cover 100MHz, and IF end frequency is initial from DC; 106 and 113: proportional integral servo circuit (Servo), its responsive bandwidth should be greater than 1kHz; 108: External Reference phase locking dielectric oscillator (DRO), input reference frequency 100MHz, output frequency of oscillation 9.2GHz; 109: phase equilibrium one-to-two microwave power divider; 110: microwave frequency frequency mixer, this frequency mixer get LO and RF end frequency covers 9.0-9.2GHz, and IF end frequency covers DC to 200MHz; 111: the rf frequency divider, division factor 2 removes the frequency of 200MHz signal to 100MHz.

In the present embodiment, the producing method of the auxiliary compensating signal of 9.0GHz is following: 101 produce the 100MHz radiofrequency signal, are input to 102 External Reference signal input part.102 through its inner Phaselocked Circuit, and output phase is locked in 101 9.0GHz microwave signal.103 divide 102 output signal that success rate equates, the three equal parts of phase equilibrium.104 will be wherein the frequency of one road 9.0GHz signal divided by 90, obtain the radiofrequency signal output of 100MHz.105 with 104 output signal with (transport to 105 LO end from the signal of hydrogen clock from the 100MHz signal mixing of hydrogen clock; Transport to 105 RF end from 104 signal); The IF end output signal that obtains is as feedback compensation signal input 106; Carry out transporting to 101 voltage controling end after proportional integral amplifies through 106, the phase place of FEEDBACK CONTROL 101 output signals, thus obtain a phase locking in the auxiliary compensating signal of the 9.0GHz of hydrogen clock.

The producing method of the auxiliary compensating signal of 9.2GHz is following in the present embodiment: 107 produce the 100MHz radiofrequency signal, are input to 108 External Reference signal input part.108 through its inner Phaselocked Circuit, and output phase is locked in 107 9.2GHz microwave signal.109 divide 102 output signal that success rate equates, two equal portions of phase equilibrium.110 incite somebody to action wherein one road 9.2GHz signal and the signal mixing of coming from the auxiliary compensating signal of 9.0GHz, obtain the radiofrequency signal of 200MHz at 110 IF end.111 with the 200MHz signal divided by 2 obtain 100MHz radiofrequency signal.112 with 111 output signal with (transport to 112 LO end from the signal of hydrogen clock from the 100MHz signal mixing of hydrogen clock; Transport to 112 RF end from 111 signal); The IF end output signal that obtains is as feedback compensation signal input 113; Carry out transporting to 107 voltage controling end after proportional integral amplifies through 113, the phase place of FEEDBACK CONTROL 107 output signals, thus obtain a phase locking in the auxiliary compensating signal of the 9.2GHz of hydrogen clock.

Two, phase noise compensation portion

200 is the first phase noise compensation portion, and being used for 9.1GHz microwave signal waiting for transmission is modulated to wavelength is 1550nm laser, gets into the optical fiber link transmission.And the phase noise of detection and compensated fiber transmission link.

As shown in Figure 7, the first phase noise compensation portion 200 comprises following assembly: 201:100MHz constant temperature VCXO (VCXO); 202: External Reference phase locking dielectric oscillator (DRO), its input reference frequency 100MHz, output frequency of oscillation 9.1GHz; 203: phase equilibrium one-to-two microwave power divider; 204: the low phase noise microwave power amplifier, its operating frequency range covers 9.1GHz, about gain 10dB, P _1dBAbout output 20dBm; 205:1550nm electro-absorption modulation semiconductor laser is about power output-3dBm; 206: semi-conductor optical amplifier (SOA), its working range covers 1550nm, and gain is greater than 10dB, about saturated output 7dBm.Here also can use the identical erbium-doped fiber amplifier of index (EDFA) to replace SOA; 207: fiber optical circulator, can only can only export by port 3 by the light of port 2 incidents by port 2 outputs by the light of port one incident; 208: semi-conductor optical amplifier (SOA), its working range should cover 1550nm, and gain 20-30dB is about saturated output 7dBm.Here also can use the identical erbium-doped fiber amplifier of index (EDFA) to replace SOA; 209: high speed photodetector, its operation wavelength should cover 1550nm, and the 3dB responsive bandwidth should be higher than 10GHz; 210: the low phase noise microwave power amplifier, its operating frequency range covers 9.1GHz, about gain 33dB, P _1dBOutput 10-13dBm; 211,212: the microwave frequency frequency mixer, frequency mixer LO and RF end frequency cover 9.0-9.2GHz, and IF end frequency covers DC to 200MHz; 213: the rf frequency frequency mixer, frequency mixer LO and RF end frequency must cover 100MHz, and IF end frequency must be initial from DC; 214: proportional integral servo circuit (Servo), its responsive bandwidth should be greater than 1kHz.

The concrete working method of the first phase noise compensation portion 200 is following.201 produce the 100MHz radiofrequency signal, are input to 202 External Reference signal input part.202 through its inner Phaselocked Circuit, and output phase is locked in 201 9.1GHz microwave signal.203 divide 202 output signal that success rate equates, two equal portions of phase equilibrium, and one the tunnel inputs to 204.204 with the power amplification of 9.1GHz microwave signal to 20dBm, input to 205 electro-absorption modulation port then, realize the Modulation and Amplitude Modulation of 205 output 1550nm laser is promptly realized the electric light transfer process to 9.1GHz microwave signal to be passed.After amplifying through 206,205 output light obtain the output light of about 7dBm, as the carrier wave light field of atomic time optical fiber transmission.The light signal of 206 outputs is coupled to 207 port one, and light signal will enter into optical fiber link from port 2 through circulator 207.Light signal is passed to the user side of far-end through optical fiber link, has 90% light signal to return (related content that sees relaying compensation transmitting device for details) in former road from user side along optical fiber, and by port 3 outputs of circulator 207.The light signal of output is coupled to high speed photodetector 209 after amplifying through 208.209 realize the opto-electronic conversion to the back light signal, are the microwave signal of 9.1GHz by its microwave output port output frequency.After this microwave signal is amplified through 210, with from 109 road 9.2GHz microwave signal through 211 mixing (microwave signal from 109 connects 211 LO port, and the signal from 210 connects 211 RF port), the IF 211 holds the radiofrequency signal that obtains 100MHz.9.0GHz microwave signal from 103 with from 203 9.1GHz microwave signal through 212 mixing (microwave signal from 103 connects 212 LO port, and the signal from 203 connects 212 RF port), obtain the radiofrequency signal of 100MHz at 212 IF port.With this signal with from 211 100MHz signal through 213 mixing; The IF end output signal that obtains is as feedback compensation signal input 214; Undertaken transporting to 201 voltage controling end after proportional integral amplifies by 214; The phase place of FEEDBACK CONTROL 201 output signals, thus realize compensation to whole optical fiber link transmission noise, promptly guarantee to obtain the 9.1GHz microwave signal of phase locking in hydrogen clock frequency reference source at far-end (receiving terminal).

It should be noted that the reference clock in the above-mentioned practical implementation example is not limited only to the hydrogen clock of caesium fountain clock calibration, also can be any punctual clock by the calibration of caesium fountain clock, for example: caesium clock, rubidium clock etc.

Parts 101 and 102,107 and 108, and 201 and 202 form three frequency oscillators respectively.Here the implementation that adds DRO with VCXO is an example, but is not limited thereto method.Other phase places can may be used to this by the frequency oscillator of external voltage control.For example: VCXO adds frequency multiplier.

Parts 101 and 102, and the frequency of 107 and 108 two frequency oscillators forming respectively is not only limited to 9.0GHz and 9.2GHz.According to transmission principle of the present invention, any can with the frequency that phase locking produces in the frequency oscillator of reference clock.

The frequency of the frequency oscillator that parts 201 and 202 are formed is not only limited to 9.1GHz.Its frequency be two auxiliary compensating signal frequencies and half the.

Parts 205 are not only limited to the electro-absorption modulation semiconductor laser of wavelength 1550nm.The window wave band of the corresponding optical fiber communication of its wavelength for example is 840nm, 1310nm, 1550nm.Modulator approach is not only limited to electro-absorption modulation, and other can with internal modulation and external modulation method that transmission frequency is modulated on the laser.

Parts 206 and 208 are not only limited to SOA or EDFA, can be other laser amplifiers yet, and operation wavelength is corresponding with selected transmission optical maser wavelength.

Other devices of using in the present embodiment (103-106,109-113,203,204,207,209-214 etc.) parameter all is the optimized choice of being done according to the 9.1GHz atomic time signal of present embodiment transmission.In transmission during other frequencies, the parameter of each device of optimized choice as the case may be.

Fig. 8 has shown an example of relaying compensation transmitting device of the present invention.

The relaying compensation transmitting device of present embodiment comprises atomic time signal reproduction portion 400, the auxiliary transport part 500 of relaying and the second phase noise compensation portion 300, introduces the structure and the working method of each part below respectively

One, atomic time signal reproduction portion

400 is atomic time signal reproduction portion, is used to receive the microwave signal on the light signal that is modulated at from optical fiber link, and reproduction phase locking is in the atomic time of reference clock signal.Optional, through transfer process under the frequency, obtain phase locking and supply the user to use in the 100MHz of reference clock (or 10MHz) microwave signal.

As shown in Figure 8, atomic time signal reproduction portion 400 is exemplary comprises following assembly: 401: fiber optical circulator, the light of its port 2 incidents can only be by port 3 outputs, can only be by port 2 outputs by the light of port one incident; 402: the one-to-two fiber coupler, divide incident optical power to two-way optical fiber in 1: 9 ratio; 403: semi-conductor optical amplifier (SOA), its working range should cover 1550nm, and gain 20-30dB is about saturated output 7dBm.Here also can use the identical erbium-doped fiber amplifier of index (EDFA) to replace SOA; 404: high speed photodetector, its operation wavelength covers 1550nm, and the 3dB responsive bandwidth is higher than 10GHz; 405: the low phase noise microwave power amplifier, its operating frequency range covers 9.1GHz, about gain 30dB, P _1dBAbout output 12dBm; 406: the microwave frequency frequency mixer, frequency mixer LO and RF end frequency cover 9.1GHz, and IF end frequency covers 100MHz; 407 with 413:100MHz constant temperature VCXO (VCXO); 408: External Reference phase locking dielectric oscillator (DRO), its input reference frequency 100MHz, output frequency of oscillation 9.1GHz; 409: one minute four microwave power divider of phase equilibrium; 410 and 415: proportional integral servo circuit (Servo), its responsive bandwidth should be greater than 1kHz; 411: the microwave frequency divider, division factor 91 removes the 9.1GHz signal frequency to 100MHz; 412: the rf frequency frequency mixer, frequency mixer LO and RF end frequency must cover 100MHz, and IF end frequency must be initial from DC; 414: phase equilibrium one-to-two microwave power divider.

The concrete working method of atomic time signal reproduction portion 400 is following.

The input port of port 3 and fiber coupler 402 that is coupled to the port 2,401 of fiber optical circulator 401 from the 1550nm light signal of optical fiber link is welded together.402 90% output port and 401 port one are welded together, and 90% light signal is returned along the former road of optical fiber link.402 10% output port and 403 optic fibre input end mouth are welded together, and amplify the back through 403 and import 404, and the 9.1GHz microwave signal demodulation that is modulated on the 1550nm laser is come out.9.1GHz microwave signal after 405 amplifications, inputs to 406 RF port.407 produce the 100MHz radiofrequency signal, are input to 408 external reference signal input port.408 through its inner phase lock circuitry, and output phase is locked in 407 9.1GHz microwave signal.409 are divided into the quarter that phase equilibrium, power equate with 408 output signal.Wherein one the tunnel with from 405 9.1GHz signal through 406 mixing, 406 IF port output signal carries out transporting to 407 voltage controling end after proportional integral amplifies through 410, FEEDBACK CONTROL 407 is exported the phase place of signals.So just make 408 output signals phase locking on the reference clock of transmitting terminal.Another road output signal of 409 through 411 with its frequency divided by 91, transport to 412 LO port then.The 100MHz signal of 413 outputs is divided into two equal portions that phase equilibrium, power equate through 414.One tunnel output supplies the user to use, another road export to 412 RF port with from 411 signal mixing.412 IF port output signal carries out exporting 413 voltage controling end to after proportional integral amplifies through 415, the phase place of FEEDBACK CONTROL 413 output signals.So just make the phase locking of 413 output signals on the reference clock of transmitting terminal, thereby at the reference clock (for example hydrogen clock) of relay end reproduction transmitting terminal.

Two, the auxiliary transport part of relaying

500 are the auxiliary transport part of relaying, are used for producing phase place and the 9GHz that is locked in reference clock and 9.2GHz microwave signal to assist compensating signal as relaying.

As shown in Figure 8, the auxiliary transport part of relaying 500 is exemplary comprises following assembly: 501 with 505:100MHz constant temperature VCXO (VCXO); 502: External Reference phase locking dielectric oscillator (DRO), its input reference frequency 100MHz, output frequency of oscillation 9.0GHz; 503 and 507: phase equilibrium one-to-two microwave power divider; 504 and 508: the microwave frequency frequency mixer, frequency mixer LO and RF end frequency must cover 9 to 9.2GHz, and IF end frequency must cover 100MHz; 506: External Reference phase locking dielectric oscillator (DRO), its input reference frequency 100MHz, output frequency of oscillation 9.2GHz; 509: the rf frequency frequency mixer, the LO of this frequency mixer and RF end frequency must cover 100MHz, and IF end frequency must be initial from DC; 510: proportional integral servo circuit (Servo), its responsive bandwidth should be greater than 1kHz.

The concrete working method of the auxiliary transport part 500 of relaying is following.

501 produce the 100MHz radiofrequency signal, are input to 502 external reference signal input port.502 through its inner phase lock circuitry, and output phase is locked in 501 9.0GHz microwave signal.503 are divided into two equal portions that phase equilibrium, power equate with 502 output signal.Wherein one the tunnel with from 409 9.1GHz signal through 504 mixing (microwave signal from 409 connects 504 LO port, and the signal from 503 connects 504 RF port).505 produce the 100MHz radiofrequency signal, are input to 506 external reference signal input port.506 through its inner phase lock circuitry, and output phase is locked in 505 9.2GHz microwave signal.507 are divided into two equal portions that phase equilibrium, power equate with 506 output signal.Wherein one the tunnel with from 409 9.1GHz signal through 508 mixing (microwave signal from 409 connects 508 LO port, and the signal from 507 connects 508 RF port).504 and 508 IF end output signal is through 509 mixing, and with its IF port output signal input 510, through transporting to 505 voltage controling end after the amplification of 510 proportional integrals, FEEDBACK CONTROL 505 is exported the phase place of signals.The innovative point of this programme is, need not prepare the auxiliary compensating signal of stable 9.0GHz of absolute frequency and 9.2GHz relaying in the relay, but both be 18.2GHz frequently, and two signal phases and be locked in transmitting terminal reference clock phase place.

Three, the second phase noise compensation portion

The structure of the second phase noise compensation portion 300 is identical with the first phase noise compensation portion 200 in the aforesaid emission compensation arrangement with working method, and the parameter index of used device is also identical, repeats no more here.

It should be noted, in practical implementation example shown in Figure 8, parts 407 and 408,501 and 502,505 and 506, and 301 and 302 form four frequency oscillators respectively.Here the implementation that adds DRO with VCXO is an example, but is not limited thereto method.Other phase places can may be used to this by the frequency oscillator of external voltage control.For example: VCXO adds frequency multiplier.

Parts 407 and 408, and the frequency of 301 and 302 frequency oscillators formed respectively is not only limited to 9.1GHz.Its frequency must be consistent with the frequency that is transmitted the atomic time signal.

Parts 501 and 502, and the frequency of 506 and 507 two frequency oscillators forming respectively is not only limited to 9.0GHz and 9.2GHz.According to principle of the present invention, the frequency sum of two frequency oscillators must be for being transmitted a times of atomic time signal frequency, and both frequencies are unequal.

Parts 305 are not only limited to wavelength 1550nm electro-absorption modulation semiconductor laser.The window wave band of the corresponding optical fiber communication of its wavelength for example is 840nm, 1310nm, 1550nm.Modulator approach is not only limited to electro-absorption modulation, and other can with internal modulation and external modulation method that transmission frequency is modulated on the laser.

Parts 306,308 and 403 are not only limited to SOA or EDFA.Also can be other laser amplifiers, operation wavelength be corresponding with selected transmission optical maser wavelength.

Parts 413 are not only limited to the VCXO of 100MHz, can select the voltage controlled oscillator of different frequency according to actual needs, with being converted to 10MHz under the atomic time frequency, conventional frequencies such as 50MHz.

The parameter of other devices of using in Fig. 8 example (as 401,402,404-406,409-412,414,415,503,504,507-510,303,304,307,309-314 etc.) all is the optimized choice of being done according to the 9.1GHz atomic time signal of this example transmissions.In transmission during other frequencies, the parameter of each device of optimized choice as the case may be.

Fig. 9 has shown an example of terminal of the present invention receiving system.

Terminal of the present invention receiving system 600 is used for the reception atomic time signal at long baseline terminal, and obtains the microwave output of a phase locking in the transmitting terminal reference clock.

As shown in Figure 9, terminal receiving system 600 is exemplary comprises following assembly: 601: fiber optical circulator, the light of its port 2 incidents can only be by port 3 outputs, can only be by port 2 outputs by the light of port one incident; 602: the one-to-two fiber coupler, divide incident optical power to two-way optical fiber in 1: 9 ratio; 603: semi-conductor optical amplifier (SOA), its working range should cover 1550nm, and gain 20-30dB is about saturated output 7dBm.Here also can use the identical erbium-doped fiber amplifier of index (EDFA) to replace SOA; 604: high speed photodetector, its operation wavelength should cover 1550nm, and the 3dB responsive bandwidth should be higher than 10GHz; 605: the low phase noise microwave power amplifier, its operating frequency range should cover 9.1GHz, about gain 30dB, P _1dBAbout output 12dBm; 606: the microwave frequency frequency mixer, frequency mixer LO and RF end frequency cover 9.1GHz, and IF end frequency covers 100MHz; 607 with 613:100MHz constant temperature VCXO (VCXO); 608: External Reference phase locking dielectric oscillator (DRO), input reference frequency 100MHz, output frequency of oscillation 9.1GHz; 609: phase equilibrium one-to-two microwave power divider; 610 and 615: the proportional integral servo circuit, its responsive bandwidth should be greater than 1kHz; 611: the microwave frequency divider, comprise division factor 91, the 9.1GHz signal frequency is removed to 100MHz; 612: the rf frequency frequency mixer, frequency mixer LO and RF end frequency must cover 100MHz, and IF end frequency must be initial from DC; 614: phase equilibrium one-to-two microwave power divider.

The concrete working method of terminal receiving system 600 is following.

The input port of port 3 and fiber coupler 602 that is coupled to the port 2,601 of fiber optical circulator 601 from the 1550nm light signal of optical fiber link is welded together.602 90% output port and 601 port one are welded together, and 90% light signal is returned along the former road of optical fiber link.602 10% output port and 603 optic fibre input end mouth are welded together, and amplify the back through 603 and import 604, and the 9.1GHz microwave signal demodulation that is modulated on the 1550nm laser is come out.9.1GHz microwave signal after 605 amplifications, inputs to 606 RF port.607 produce the 100MHz radiofrequency signal, are input to 608 external reference signal input port.608 through its inner phase lock circuitry, and output phase is locked in 607 9.1GHz microwave signal.609 are divided into two equal portions that phase equilibrium, power equate with 608 output signal.Wherein one the tunnel with from 605 9.1GHz signal through 606 mixing, 606 IF port output signal carries out transporting to 607 voltage controling end after proportional integral amplifies through 610, FEEDBACK CONTROL 607 is exported the phase place of signals.So just make 608 output signals phase locking on the reference clock of transmitting terminal.Another road output signal of 609 through 611 with its frequency divided by 91, transport to 612 LO port then.The 100MHz signal of 613 outputs is divided into two equal portions that phase equilibrium, power equate through 614.One tunnel output supplies the user to use, another road transport to 612 RF port with from 611 signal mixing.612 IF port output signal carries out transporting to 613 voltage controling end after proportional integral amplifies through 615, the phase place of FEEDBACK CONTROL 613 output signals.So just make the phase locking of 613 output signals on the reference clock of transmitting terminal, thereby at the reference clock (hydrogen clock) of relay end reproduction transmitting terminal.

It should be noted that in practical implementation example shown in Figure 9, parts 607 and 608 are formed a frequency oscillator.Here the implementation that adds DRO with VCXO is an example, but is not limited thereto method.Other phase places can may be used to this by the frequency oscillator of external voltage control.For example: VCXO adds frequency multiplier.The frequency of this frequency oscillator is not only limited to 9.1GHz, and its frequency is consistent with the frequency that is transmitted the atomic time signal.

Parts 613 are not only limited to the VCXO of 100MHz, can select the voltage controlled oscillator of different frequency according to actual needs, with being converted to 10MHz under the atomic time frequency, conventional frequencies such as 50MHz.

Parts 603 are not only limited to SOA or EDFA, can be other laser amplifiers yet, and operation wavelength is corresponding with selected transmission optical maser wavelength.

In addition, other devices of using in Fig. 9 example (as 601,602,604-606,609-612,614,615 etc.) parameter all is the optimized choice of being done according to the 9.1GHz atomic time signal of this example transmissions.In transmission during other frequencies, the parameter of each device of optimized choice as the case may be.

< atomic time method for transmitting signals >

Introduce the atomic time method for transmitting signals that atomic time signal transmission system according to the present invention is implemented below.

Figure 10 has shown the flow chart of atomic time method for transmitting signals of the present invention.

Shown in figure 10, atomic time method for transmitting signals of the present invention comprises the steps: to receive the atomic time signal as the reference signal that reference clock produces; Atomic time signal waiting for transmission is modulated on the light signal to pass through Optical Fiber Transmission; At the phase noise that transmitting terminal compensation atomic time signal is introduced in optical fiber link, make the phase locking of the atomic time signal that transfers to far-end in the phase place of reference clock; Receive the microwave signal on the light signal that is modulated in the relay, and reproduction phase locking is in the atomic time of reference clock signal from optical fiber link; Atomic time signal waiting for transmission is modulated on the light signal to pass through Optical Fiber Transmission once more; The phase noise of introducing when further the said atomic time signal of compensation transmit in optical fiber link in the relay, the phase locking of the feasible atomic time signal that transfers to far-end is in the phase place of reference clock.

Wherein, the step of the said phase noise of when transmitting terminal compensation atomic time signal transmits in optical fiber link, introducing comprises: generate two phase places and the auxiliary compensating signal that is locked in reference clock; Produce the feedback compensation signal that is used for compensating the phase noise that said atomic time signal introduces when optical fiber link transmits based on said auxiliary compensating signal, and this feedback compensation signal is loaded in the atomic time signal waiting for transmission.

Wherein, the said step that compensates the phase noise of introducing when the atomic time signal transmits in the relay in optical fiber link comprises: generate two phase places and the auxiliary compensating signal of the relaying that is locked in reference clock; Produce the relaying feedback compensation signal that is used for further compensating the phase noise that said atomic time signal introduces when optical fiber link transmits based on the auxiliary compensating signal of said relaying, and this relaying feedback compensation signal is loaded in the atomic time signal waiting for transmission.

In sum, the present invention is intended to protect a kind of atomic time signal transmission system and transmission method, and technical scheme of the present invention compares and has following significant technique effect in prior art:

(1) transmitting accuracy of raising atomic time signal.

Through the atomic time signal is modulated on the wavelength 1550nm laser, and carry out optical fiber transmission and noise compensation, can realize high-precision atomic time signal transmission.Successfully demonstration in 86 kilometers commercial optical fiber at present, stability was superior to 2 * 10 in attainable second ^-14, a day stability is superior to 4 * 10 ^-18

The atomic time of (2) realizing the overlength baseline transmits.

Through the phase noise relaying compensation method that the present invention proposes, can realize that the high accuracy atomic time of overlength baseline transmits.With the transmission of 3000 kilometers overlength baselines is example, needs 30 phase noise relaying compensation arrangements.Can realize that a second stability is superior to 1 * 10 ^-13, a day stability is superior to 6 * 10 ^-17This index is far superior to the prior art scheme, and (a day stability is about 1 * 10 to be superior to the long-term stability of reference clock (hydrogen clock) ^-15Or 2 * 10 ^-15).

(3) transmission of the atomic time of real-time continuous and comparison between many ground.

How technical scheme of the present invention can be utilized the transmission medium of existing Networks of Fiber Communications as the atomic time signal, carry out the transmission and the comparison of atomic time signal between simultaneously, and all devices can the long-time continuous operation.

(4) can be at the reference clock of receiving terminal and relaying compensation end reproduction transmitting terminal.

Because the long-term stability of Optical Fiber Transmission channel used in the present invention is much better than the long-term stability of reference clock; Therefore can be at receiving terminal and relaying compensation end; Crystal oscillator phase locking through having fine weak point steady (second steady) with one reappears reference clock on the atomic time signal that is transmitted.

(5) transmitting terminal atomic time and the receiving terminal relative stability difference between the reproduction atomic time can improve the precision of satellite monitoring and astronomical observation greatly much smaller than the difference between the hydrogen clock.

Should be understood that above-mentioned embodiment of the present invention only is used for exemplary illustration or explains principle of the present invention, and is not construed as limiting the invention.Therefore, any modification of under situation without departing from the spirit and scope of the present invention, being made, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.In addition, accompanying claims of the present invention be intended to contain fall into accompanying claims scope and border, or the equivalents on this scope and border in whole variations and modification.

Claims (14)

1. atomic time signal transmission system, this system comprises:

The emission compensation arrangement is used for atomic time signal waiting for transmission is modulated on the light signal with through Optical Fiber Transmission, and the phase noise of compensation atomic time signal introducing when in optical fiber link, transmit; With

A plurality of relaying compensation transmitting devices, each said relaying compensation transmitting device is used for further compensating the phase noise that the atomic time signal is introduced when optical fiber link transmits;

Wherein, be modulated at the atomic time signal on the light signal through Optical Fiber Transmission between said emission compensation arrangement and a plurality of relaying compensation transmitting device.

2. transmission system according to claim 1, wherein, said emission compensation arrangement also comprises:

Auxiliary transport part, it generates auxiliary compensating signal and outputs to the first phase noise compensation portion;

The first phase noise compensation portion; It is modulated on the light signal atomic time signal waiting for transmission with through Optical Fiber Transmission, and produces the feedback compensation signal that is used for compensating the phase noise that said atomic time signal introduces when optical fiber link transmits based on said auxiliary compensating signal.

3. transmission system according to claim 2, wherein, said auxiliary transport part comprises:

The first frequency oscillator, it produces the first auxiliary compensating signal of phase locking in reference clock;

The second frequency oscillator, it produces the second auxiliary compensating signal of phase locking in reference clock; With

The said first auxiliary compensating signal and the second auxiliary compensating signal, the first phase noise compensation portion that outputs to produce feedback compensation signal with auxiliary its.

4. transmission system according to claim 2, wherein, the said first phase noise compensation portion comprises:

The 3rd frequency oscillator, it produces the 3rd microwave signal and exports to first than the facies unit and first laser;

First than facies unit, and it produces the compensation of the phase noise of introducing when feedback compensation signal transmits for the 3rd frequency oscillator in the optical fiber link in said the 3rd microwave signal, to be introduced in;

First laser, it is modulated to said the 3rd microwave signal on the light signal and exports to optical fiber circulator to get into optical fiber link;

Optical fiber circulator, it will be launched light and separate with back light, make modulated light signal enter into optical fiber link transferring to far-end, and make the light signal that is returned along optical fiber link by far-end export to first detector;

First detector will be modulated to microwave signal demodulation on the light signal through opto-electronic conversion and come out obtaining the 5th microwave signal, and export to first and compare facies unit.

5. transmission system according to claim 4, wherein, first carries out than handles mutually to produce said feedback compensation signal to said first, second auxiliary compensating signal and the 3rd, the 5th microwave signal than facies unit.

6. transmission system according to claim 1, said relaying compensation transmitting device comprises:

Atomic time signal reproduction portion, it receives the microwave signal on the light signal that is modulated at from optical fiber link, and reappears phase locking in the atomic time of reference clock signal;

Relaying is assisted the transport part, and it generates the auxiliary compensating signal of relaying and outputs to the second phase noise compensation portion;

The second phase noise compensation portion; It is modulated on the light signal atomic time signal waiting for transmission with through Optical Fiber Transmission once more, and produces the relaying feedback compensation signal that is used for further compensating the phase noise that said atomic time signal introduces when optical fiber link transmits based on the auxiliary compensating signal of this relaying.

7. transmission system according to claim 6, said atomic time signal reproduction portion comprises:

Second detector, it will be modulated at microwave signal demodulation on the light signal through opto-electronic conversion and come out obtaining four microwave signal of phase locking in reference clock, and offer the 4th frequency oscillator;

The 4th frequency oscillator, its based on said the 4th microwave signal generated frequency and phase locking in the microwave signal of the 4th microwave signal.

8. transmission system according to claim 7, said atomic time signal reproduction portion also comprises the divider that is connected to the 4th frequency oscillator output, its microwave signal with the output of the 4th frequency oscillator is removed to corresponding frequencies, supplies the user of relay to use.

9. transmission system according to claim 6, the auxiliary transport part of said relaying comprises:

The 5th frequency oscillator, it generates the auxiliary compensating signal of first relaying;

The 6th frequency oscillator, it generates the auxiliary compensating signal of second relaying;

Second than facies unit, and it produces compensating signal and gives the 6th frequency oscillator, makes said first, second relaying assist the phase place and the phase place that is locked in reference clock of compensating signal.

10. transmission system according to claim 6, the said second phase noise compensation portion comprises:

The 7th frequency oscillator, it produces microwave signal and exports to the 3rd than the facies unit and second laser;

The 3rd than facies unit, and it produces the relaying feedback compensation signal and gives the 7th frequency oscillator, the compensation of the phase noise of introducing when transmitting in the optical fiber link in the microwave signal of its generation, to be introduced in;

Second laser, its microwave signal that said the 7th frequency oscillator is produced are modulated on the light signal and export to optical fiber circulator to get into optical fiber link;

The 3rd detector will be modulated to microwave signal demodulation on the light signal through opto-electronic conversion and come out and export to the 3rd and compare facies unit;

Optical fiber circulator, it will be launched light and separate with back light, make modulated light signal enter into optical fiber link transferring to far-end, and make the light signal that is returned along the former road of optical fiber link by far-end export to the 3rd detector.

11. transmission system according to claim 10; Wherein, the 3rd microwave signal that the auxiliary compensating signal of said first, second relaying, said the 7th frequency oscillator produced than facies unit and the microwave signal of said the 3rd detector output carry out than handle mutually to produce said relaying feedback compensation signal.

12. an atomic time method for transmitting signals, this method comprises:

Receive the atomic time signal that reference clock produces as the reference signal;

Atomic time signal waiting for transmission is modulated on the light signal to pass through Optical Fiber Transmission;

Compensate the phase noise that the atomic time signal is introduced at transmitting terminal in optical fiber link;

Receive the microwave signal on the light signal that is modulated in the relay, and reproduction phase locking is in the atomic time of reference clock signal from optical fiber link;

Atomic time signal waiting for transmission is modulated on the light signal to pass through Optical Fiber Transmission once more;

The phase noise of introducing when further the said atomic time signal of compensation transmits in optical fiber link in the relay.

13. method according to claim 12, the step of the said phase noise of when transmitting terminal compensation atomic time signal transmits in optical fiber link, introducing comprises:

Generate two phase places and the auxiliary compensating signal that is locked in reference clock;

Produce the feedback compensation signal that is used for compensating the phase noise that said atomic time signal introduces when optical fiber link transmits based on said auxiliary compensating signal, and this feedback compensation signal is loaded in the atomic time signal waiting for transmission.

14. method according to claim 12, the said step that compensates the phase noise of introducing when the atomic time signal transmits in the relay in optical fiber link comprises:

Generate two phase places and the auxiliary compensating signal of the relaying that is locked in reference clock;

Produce the relaying feedback compensation signal that is used for further compensating the phase noise that said atomic time signal introduces when optical fiber link transmits based on the auxiliary compensating signal of said relaying, and this relaying feedback compensation signal is loaded in the atomic time signal waiting for transmission.

Images