CN102307087B - 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.Especially, relate to a kind of system and method for realizing the atomic time signal transmission of overlength baseline (distance) by 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 for the benchmark that the time is provided.The 2nd, the transmission system of temporal frequency has had good a reference source, also needs temporal frequency is 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, at present comparative maturity, for example GPS receiver and so on of the technology in this field.

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 at present in the world best atomic clock sky stability can reach 10 ^-16Magnitude.For the transmission system of temporal frequency, transmission and the synchronous method that adopts of overlength baseline atomic time signal mainly contain clock carrying method, satellite common vision method (CV), the two-way temporal frequency TRANSFER METHOD of satellite (TWSTFT) etc. 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 comparing.For example, if transmit best in the world atomic clock signal, then the stability of transmission system should be better than 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, A clock and C clock are compared, read respectively the reading τ of A, C clock _A0And τ _C0Then the C clock is along known path Be transported to the B station, compare with the B clock, read B, the reading τ of C clock _B1And τ _C1Like this, coordinate time t ₁Just can be by t ₀, τ _C0, τ _C1With

Derive, stand when former according to B again and the relation of coordinate time, come 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 different location height above sea level systematic error that the carrying small-sized atomic clock is introduced, thereby cause the precision of signal transmission lower.

(2) the clock carrying method must be carried to B more first after the clock on A ground and A ground is compared, and compares with the clock of B.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 medium as the atomic time signal with same clock carrying, so can't carry out temporal frequency transmission comparison simultaneously between, namely can't carry out simultaneously the Multipoint synchronous comparison.

Also there are the various transmission Comparison Methods that utilize 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 electromagnetic signals is via satellite measured the propagation delay of electromagnetic wave signal, perhaps receives simultaneously the clock signal from same satellite.By 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 existing satellite transmits Comparison Method and also has some shortcomings.For example, owing to be subjected to the impact of the 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, namely the precision of the 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 that satellite transmits 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 mentioned above, existing clock carrying method adopts a miniaturization high accuracy atomic clock to transmit medium as the atomic time signal, existing satellite transmits Comparison Method and utilizes artificial satellite as the transmission medium of atomic time signal, and all there are defective more or less in these transmission media and transmission method thereof.Therefore, be necessary to consider to adopt new transmission medium and corresponding transmission system and transmission method, to avoid or to solve above-mentioned problems of the 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 by 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 described 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 atomic time signal on the light signal by Optical Fiber Transmission between described 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, the 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 of being modulated at from optical fiber link in the relay, and the reproduction phase place is locked in the atomic time signal of reference clock; Atomic time signal waiting for transmission is modulated on the light signal again to pass through Optical Fiber Transmission; The phase noise of introducing when further the described atomic time signal of compensation transmits in optical fiber link in the relay.

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

The phase noise of preferably introducing when relay compensation atomic time signal transmits in optical fiber link is achieved in that the auxiliary compensating signal of the relaying that generates two phase places and be locked in reference clock; Produce the relaying feedback compensation signal that is used for the phase noise that the further described atomic time signal of compensation introduces when optical fiber link transmits based on the auxiliary compensating signal of described 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 optical fiber as the transmission medium of 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 realizes the compensation to the phase noise of fiber transmission link (especially extra long distance) by implementing phase noise detection and compensation technique.

Especially, 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 limit bandwidth and signal attenuation, greatly improved the transmitting accuracy of atomic time signal.

Description of drawings

Fig. 1 has shown the schematic diagram 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 schematic diagram 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 schematic diagram than facies unit of relaying auxiliary transmission section;

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 receiving system of the present invention;

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

Embodiment

For making the purpose, technical solutions and advantages of the present invention more cheer and bright, below in conjunction with embodiment and with reference to accompanying drawing, the present invention is described in more detail.

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 by 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 atomic time signal on the light signal by Optical Fiber Transmission between described emission compensation arrangement and a plurality of relaying compensation transmitting device.

As shown in Figure 2, the exemplary employing of a plurality of relaying compensation transmitting device of the present invention is connected in series mode, but is not restricted to this.In actual applications, 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 by transmission system of the present invention the atomic time signal being transmitted, received and the reproduction phase place is locked in the atomic time signal of reference clock by a terminal receiving system, and according to demand it is converted to corresponding frequencies, for the user.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 determines that by the design load Δ v=c/ (4 π nl) of system phase noise compensation loop bandwidth wherein c is the light velocity, and l is optical fiber link length between neighboring devices, and n is optical fibre refractivity.In a preferred embodiment, this spacing distance is set to about 100 kilometers.

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

＜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 auxiliary transmission section 1 and the first phase noise compensation section 2.The described auxiliary transmission auxiliary compensating signal of section's 1 generation also outputs to the first phase noise compensation section, and this auxiliary compensating signal is used for auxiliary the first phase noise compensation section and produces feedback compensation signal.Specifically, auxiliary transmission section 1 comprises first frequency oscillator F1 and second frequency oscillator F2, it generates respectively the first auxiliary compensating signal and the second auxiliary compensating signal, exports to the first phase noise compensation section 2 (wherein first than facies unit) and produces feedback compensation signal with auxiliary its.Wherein, the phase place of this first auxiliary compensating signal and the second auxiliary compensating signal is locked in reference clock.

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

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

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 hydrogen clock, caesium clock or rubidium clock etc. by the punctual clock of National primary standard clock (caesium fountain clock) calibration.

First frequency oscillator F1 produces the first auxiliary compensating signal that phase place is locked in reference clock

Ω ₁＝A ₁cos(aω ₀t+aφ _ref)

A wherein ₁The amplitude of expression the first auxiliary compensating signal, a are that Arbitrary Digit (satisfies Be the Arbitrary Digit of a certain certain number, this certain number is obtained divided by the reference clock signal frequency by the atomic time signal frequency that will transmit), can produce the optional frequency microwave signal that phase place is locked in the reference clock signal by phase-locked loop and frequency synthesizer.

Second frequency oscillator F2 produces the second auxiliary compensating signal that phase place is locked in reference clock

Ω ₂＝A ₂cos(bω ₀t+bφ _ref)

Wherein A2 represents the amplitude of the second auxiliary compensating signal, and b is that Arbitrary Digit (satisfies

Be the Arbitrary Digit of a certain certain number, this certain number is obtained divided by the reference clock signal frequency by the atomic time signal frequency that will transmit).

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

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

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

Wherein, A ₃The amplitude that represents the 3rd microwave signal, the frequency of this microwave signal is

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

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

As shown in Figure 3, the light signal of the first laser output is input to an optical fiber circulator, and it is used for utilizing emitted light and back light are separated.Optical fiber circulator makes modulated light signal enter into optical fiber link by 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 the first detector.In addition, receive this light signal at the relaying of far-end compensation transmitting device, and the detector by wherein (in vide infra shown in Figure 5 the 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 section of transmitting device in vide infra):

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

Wherein, A ₄The amplitude that represents the 4th microwave signal, φ _pBe the phase noise that optical fiber link is introduced, this phase noise is subject to 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 such as vibration, etc.).

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 section 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 the first detector, its by opto-electronic conversion will be modulated on the light signal the microwave signal demodulation out and export to first and compare facies unit.Thus, this light signal that returns obtains the 5th microwave signal after the first detector demodulates

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

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, by the first output phase than facies unit FEEDBACK CONTROL the 3rd frequency oscillator F3.Specifically, the first described first, second auxiliary compensating signal and the 3rd, the 5th microwave signal that will receive than facies unit carried out than processing 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 place be locked 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 adopts is constant temperature VCXO and External Reference phase place locking dielectric oscillator or frequency multiplier.

Fig. 4 has shown the of the present invention first operation principle schematic diagram than facies unit.

Among Fig. 4 Represent frequency mixer, it is so that two input signals are done multiplying, thereby so that the frequency of two signals and phase place are done signed magnitude arithmetic(al).

Of the present invention first is used for the above-mentioned signal Ω that provides than facies unit ₁, Ω ₂, Ω ₃And Ω ₅Carry out than processing mutually, to obtain the feedback compensation signal Ω for the output phase of FEEDBACK CONTROL the 3rd frequency oscillator F3 ₈Ratio among the present invention is processed mutually and is referred to by 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 after mixing and the low-pass filtering

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

With microwave signal Ω ₁With Ω ₃Obtain signal after mixing and the low-pass filtering

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

Then, with signal Ω ₆With Ω ₇Obtain feedback compensation signal after mixing and the low-pass filtering

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

It should be noted that above-mentioned method of work than facies unit only is exemplary, be not construed as limiting the invention, 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 mixing and low-pass filtering 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:

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

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

By following formula as seen, 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 thus the phase noise φ that optical fiber link is introduced _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, namely the relative datum clock is stable.

For example, by 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,, be not strict with its phase place and be equal to the transmitting terminal phase place with respect to the locking of transmitting terminal reference clock 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 fixing phase difference item

The atomic time signal (the 4th microwave signal) that transfers to like this far-end (relaying compensation transmitting device or terminal receiving system) is

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

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

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

As mentioned above, in a preferred embodiment of the invention, the emission compensation arrangement adopts two phase places to be locked in first frequency oscillator F1 and the auxiliary feedback compensation signal that produces of second frequency oscillator F2 of reference clock, realization is to the phase compensation of the atomic time signal that will transmit, so that transfer to the phase place that the phase place of the atomic time signal of far-end (relaying compensation transmitting device and terminal receiving system) is locked in reference clock.

The phase place of the above-mentioned first auxiliary compensating signal and the second auxiliary compensating signal and 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 (namely having a constant term on above-mentioned equation the right) of a fixed value is perhaps arranged on the basis that is directly proportional.That is to say, as long as so that the phase place of two auxiliary compensating signals and linear with the phase place of transmitting terminal reference clock, just can guarantee the phase place of two auxiliary compensating signals and be locked in 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 the atomic time signal frequency of transmitting Any multiple, phase place and be locked in the phase place of reference clock.Namely as long as so that the frequency of two auxiliary compensating signals and with the proportional relation of frequency of the atomic time signal that transmits, the phase place of two auxiliary compensating signals and the phase place that is locked in the transmitting terminal reference clock get final product.

For example, take the frequency of two auxiliary compensating signals with as ξ (a+b) ω ₀, phase place is 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 the ξ/2 times of the atomic time signal frequency transmitted, phase place is locked 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 low-pass filtering 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

For convenient statement, here equally with the fixed skew item Omit.

As mentioned above, transmission system of the present invention is come the phase noise in the compensated fiber transmission link by 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 namely 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 further compensating the phase noise of introducing when the atomic time signal transmits in optical fiber link (n relaying compensation transmitting device to the n+1 relaying compensation transmitting device).Optionally, relaying compensation transmitting device also has following effects: (1) receives the microwave signal on the light signal of being modulated at from optical fiber link, and reappear the atomic time signal that phase place is locked in reference clock, for the relay, and play the effect that compensates atomic time signal transmission attenuation; (2) solve because the problem of the compensation loop locking limit bandwidth that the time delay of atomic time signal long-distance transmission causes.

As shown in Figure 5, relaying compensation transmitting device of the present invention comprises the atomic time signal reproduction A of section, the relaying auxiliary transmission B of section and the second C of phase noise compensation section, is respectively applied to realize reappearing atomic time signal, relay transmission, this three functions of phase noise compensation that phase place is locked in reference clock.

The atomic time signal reproduction A of section comprises the second detector and the 4th frequency oscillator, and it receives the microwave signal on the light signal of being modulated at from optical fiber link, and the reproduction phase place is locked in the atomic time signal of reference clock.As shown in Figure 5, the light signal from optical fiber link (adds on it and carries aforesaid the 4th microwave signal Ω ₄) enter fiber optical circulator by port 2, from port 3 outputs, be divided into two parts by one-to-two fiber coupler FC again.Wherein, a part is from port one input optical fibre circulator, and again enters optical fiber link from port 2, returns along the former road of optical fiber link, and another part is inputted the second detector.

The second detector will be modulated at the 4th microwave signal Ω on the light signal by opto-electronic conversion ₄Demodulation out obtains the 4th microwave signal of phase stabilization

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

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

${\mathrm{\&Omega;}}_{T1}=A_{T1}\cos [\frac{a+\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="HDA0000073738340000021.png"\; state="\{\{state\}\}">b</figure-callout>}}{2}{\mathrm{\&omega;}}_{0}t+\frac{a+\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="HDA0000073738340000021.png"\; state="\{\{state\}\}">b</figure-callout>}}{2}{\mathrm{\&phi;}}_{\mathrm{ref}}]$

In the following formula, a, b are that Arbitrary Digit (satisfies

Be the Arbitrary Digit of a certain certain number, this certain number is obtained divided by the reference clock signal frequency by the atomic time signal frequency that will transmit), φ _RefBe reference clock signal phase, ω ₀Be the frequency of reference clock, A _T1The amplitude that represents this signal.For convenient statement, here equally with the fixed skew item

Omit.Like this, just reappear the atomic time signal that phase place is locked in reference clock in the relay, thereby played the effect of compensation atomic time signal transmission attenuation.

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

In addition, between the second detector and the 4th frequency oscillator T1 The expression frequency mixer, it is used for making two input signals do multiplying, even the frequency of two signals and phase place do add, subtraction.

The relaying auxiliary transmission B of section is used for the relay transmission of atomic time signal, it generates the auxiliary compensating signal of relaying and outputs to the second C of phase noise compensation section in the relay, the auxiliary compensating signal of this relaying is used for auxiliary the second phase noise compensation section 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 relaying auxiliary transmission B of section comprises the 5th frequency oscillator T2, and the 6th frequency oscillator T3 and second compares facies unit.Wherein frequency oscillator T2, T3 produce respectively the auxiliary compensating signal of the first relaying and the auxiliary compensating signal of the second relaying, export to the second C of phase noise compensation section (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 the first relaying:

Ω _T2＝A _T2cos(ω _T2t+φ _T2)

Wherein, A _T2, ω _T2, φ _T2The amplitude, frequency and the phase place that represent respectively signal.

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

Ω _T3＝A _T3cos(ω _T3t+φ _T3)

Wherein, A _T3, ω _T3, φ _T3The amplitude, frequency and the phase place that represent respectively signal.

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

Another is higher than the atomic time signal frequency of transmission

But both frequencies and satisfy equation:

ω _T2+ω _T3＝(a+b)ω ₀

The frequency of the auxiliary compensating signal of above-mentioned the first relaying and the auxiliary compensating signal of the second relaying and be 2 times of frequency of 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, as long as so that the frequency of the auxiliary compensating signals of two relayings and with the proportional relation of frequency of the atomic time signal that transmits.

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

φ _T2+φ _T3＝(a+b)φ _ref

The phase place of the auxiliary compensating signal of above-mentioned the first relaying and the auxiliary compensating signal of the second relaying and 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 (namely having a constant term on above-mentioned equation the right) of a fixed value is perhaps arranged on the basis that is directly proportional.That is to say, as long as so that the phase place of the auxiliary compensating signals of two relayings and linear with the phase place of transmitting terminal reference clock, 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.

Fig. 6 has shown the second operation principle schematic diagram than facies unit of relaying auxiliary transmission section.

As shown in Figure 6, second of relaying auxiliary transmission section than the microwave signal Ω of facies unit with input _T1, relaying is assisted compensating signal Ω _T2And Ω _T3Carry out than processing mutually, to obtain the compensating signal Ω for the output phase of FEEDBACK CONTROL the 6th frequency oscillator T3 _T7Specifically, with microwave signal Ω _T1With signal Ω _T2Obtain signal after mixing and the low-pass filtering

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

With microwave signal Ω _T1With signal Ω _T3Obtain signal after mixing and the low-pass filtering

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

With signal Ω _T5With Ω _T6Can be compensated signal after mixing and the low-pass filtering

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 mixing and low-pass filtering 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 the 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.For convenient statement, here equally with the fixed skew item

Omit.

As seen, 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 (namely keeping synchronously with reference clock) of reference clock.

As mentioned above, the relaying auxiliary transmission B of section 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.

By the atomic time signal phase noise compensation principle of the aforementioned emission compensation arrangement that is in transmitting terminal as can be known, the frequency of two auxiliary compensating signals and with optical fiber link in the proportional relation of frequency of the atomic time signal that transmits, phase place and be locked in the phase place of reference clock.In like manner, for (relaying compensation transmitting device) continues to the atomic time signal of 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 of the atomic time signal that transmits, phase place and be locked in the phase place of reference clock.Therefore, the atomic time signal that transmits in the optical fiber link of relay is the same with transmitting terminal, all is the signal that phase place is locked in reference clock.

The principle of the second C of phase noise compensation section 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 by Optical Fiber Transmission, and produce the relaying feedback compensation signal that is used for the phase noise that the further described atomic time signal of compensation introduces when optical fiber link transmits based on the auxiliary compensating signal of relaying that the relaying auxiliary transmission B of section generates.As shown in Figure 5, the second C of phase noise compensation section 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

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

Second laser is with this microwave signal Ω _T4Be modulated on the light signal and export to optical fiber circulator to enter optical fiber link.Wherein, the mode of modulation second laser is internal modulation or external modulation method.This modulated laser signal is input to optical fiber link, becomes so that transfer to the signal (not shown) of far-end

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

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 refers to that the atomic time signal is transferred to get next relay or receiving terminal.φ wherein _P1The phase noise of introducing when transmitting in optical fiber link corresponding to this relay 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

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

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

${\mathrm{\&phi;}}_1+{\mathrm{\&phi;}}_{p1}=\frac{a+\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="HDA0000073738340000021.png"\; state="\{\{state\}\}">b</figure-callout>}}{2}{\mathrm{\&phi;}}_{\mathrm{ref}}$

As seen, transfer to the microwave signal Ω of far-end _T8Phase place be locked 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 low-pass filtering obtain signal

${\mathrm{\&Omega;}}_{\mathrm{<figure-callout\; id="10"\; label="T"\; filenames="HDA0000073738340000051.png,HDA0000073738340000061.png"\; state="\{\{state\}\}">T</figure-callout>}10}=A_{\mathrm{<figure-callout\; id="10"\; label="T"\; filenames="HDA0000073738340000051.png,HDA0000073738340000061.png"\; state="\{\{state\}\}">T</figure-callout>}10}\cos [({\mathrm{\&omega;}}_{T3}-\frac{a<figure-callout\; id="2"\; label="+\; b"\; filenames="HDA0000073738340000021.png"\; state="\{\{state\}\}">+</figure-callout>b}{2}{\mathrm{\&omega;}}_0)t+{\mathrm{\&phi;}}_{T3}-{\mathrm{\&phi;}}_1-2{\mathrm{\&phi;}}_{p1}]$

With microwave signal Ω _T2With Ω _T4Mixing and low-pass filtering obtain signal

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

With signal Ω _T10With Ω _T11Mixing and low-pass filtering obtain signal

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

Then, with Ω _T12After amplifying, ratio as the output phase of relaying feedback compensation signal FEEDBACK CONTROL the 7th frequency oscillator, makes its phase ₁Satisfy relational expression:

${\mathrm{\&phi;}}_1+{\mathrm{\&phi;}}_{p1}=\frac{{\mathrm{\&phi;}}_{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="HDA0000073738340000021.png"\; state="\{\{state\}\}">T</figure-callout>}2}+{\mathrm{\&phi;}}_{\mathrm{<figure-callout\; id="3"\; label="T"\; filenames="HDA0000073738340000051.png,HDA0000073738340000061.png"\; state="\{\{state\}\}">T</figure-callout>}3}}{2}=\frac{a+\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="HDA0000073738340000021.png"\; state="\{\{state\}\}">b</figure-callout>}}{2}{\mathrm{\&phi;}}_{\mathrm{ref}}$

Namely ${\mathrm{\&phi;}}_1=\frac{a+\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="HDA0000073738340000021.png"\; state="\{\{state\}\}">b</figure-callout>}}{2}{\mathrm{\&phi;}}_{\mathrm{ref}}-{\mathrm{\&phi;}}_{p1}$

By following formula as seen, 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 thus the phase noise φ that optical fiber link is introduced _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, namely the relative datum clock is stable.

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

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

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

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

As mentioned above, transmission system of the present invention compensates the phase noise in the transmission link by 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, be locked in reference clock so that transfer to the atomic time signal phase of far-end (follow-up relaying compensation transmitting device or terminal receiving system), namely the relative datum clock is stable.

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

In addition, at least one is constant temperature VCXO and External Reference phase place 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, low-pass filtering 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 〉

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

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

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

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

One, auxiliary transmission section

100 is auxiliary transmission section, is the auxiliary compensating signal that 9.0GHz and 9.2GHz and phase place are locked in reference clock for generation of frequency.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 transmission section 100 is exemplary comprises following assembly.101 and 107:100MHz constant temperature VCXO (VCXO); 102: External Reference phase place 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 coverage 100MHz, 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 place 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 coverage 9.0-9.2GHz, IF end frequency coverage 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 as follows: 101 produce the 100MHz radiofrequency signal, are input to 102 External Reference signal input part.102 by 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 the auxiliary compensating signal of 9.0GHz that a phase place is locked in hydrogen clock obtained.

The producing method of the auxiliary compensating signal of 9.2GHz is as follows in the present embodiment: 107 produce the 100MHz radiofrequency signal, are input to 108 External Reference signal input part.108 by 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 radiofrequency signals that obtain 100MHz.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 the auxiliary compensating signal of 9.2GHz that a phase place is locked in hydrogen clock obtained.

Two, phase noise compensation section

200 is the first phase noise compensation section, and being used for 9.1GHz microwave signal waiting for transmission is modulated to wavelength is 1550nm laser, enters 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 section 200 comprises following assembly: 201:100MHz constant temperature VCXO (VCXO); 202: External Reference phase place 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 replace SOA with the identical erbium-doped fiber amplifier (EDFA) of index; 207: fiber optical circulator, can only by port 2 outputs, can only be exported by port 3 by the light of port 2 incidents 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 replace SOA with the identical erbium-doped fiber amplifier (EDFA) of index; 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: microwave frequency frequency mixer, frequency mixer LO and RF end frequency coverage 9.0-9.2GHz, IF end frequency coverage 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 specific works mode of the first phase noise compensation section 200 is as follows.201 produce the 100MHz radiofrequency signal, are input to 202 External Reference signal input part.202 by 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, then input to 205 electro-absorption modulation port, realize the Modulation and Amplitude Modulation of 205 output 1550nm laser is namely 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 by circulator 207.Light signal is passed to the user side of far-end by 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 (microwave signal from 109 connects 211 LO port by 211 mixing from 109 road 9.2GHz microwave signal, 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 by 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 by 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, thereby realize the compensation to whole optical fiber link transmitted noise, namely guarantee to obtain the 9.1GHz microwave signal that phase place is locked in hydrogen clock frequency reference source at far-end (receiving terminal).

It should be noted that the reference clock in the above-mentioned 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, such as: caesium clock, rubidium clock etc.

Parts 101 and 102,107 and 108, and 201 and 202 form respectively three frequency oscillators.Here the implementation that adds DRO take VCXO is as example, but is not limited to the 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 that form respectively is not only limited to 9.0GHz and 9.2GHz.According to transmission principle of the present invention, the frequency that any frequency oscillator that phase place can be locked in reference clock produces can.

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

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 internal modulation and external modulation methods that transmission frequency can be modulated on the laser can.

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 to select according to the optimization that the 9.1GHz atomic time signal of present embodiment transmission is done.When other frequencies of transmission, can optimize as the case may be the parameter of selecting each device.

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 section 400, relaying auxiliary transmission section 500 and the second phase noise compensation section 300, and the below introduces respectively structure and the working method of each part

One, atomic time signal reproduction section

400 is atomic time signal reproduction section, be used for to receive the microwave signal on the light signal of being modulated at from optical fiber link, and the reproduction phase place is locked in the atomic time signal of reference clock.Optionally, by transfer process under the frequency, obtain phase place and be locked in 100MHz (or 10MHz) microwave signal of reference clock for the user.

As shown in Figure 8, atomic time signal reproduction section 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 replace SOA with the identical erbium-doped fiber amplifier (EDFA) of index; 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: microwave frequency frequency mixer, frequency mixer LO and RF end frequency coverage 9.1GHz, IF end frequency coverage 100MHz; 407 and 413:100MHz constant temperature VCXO (VCXO); 408: External Reference phase place 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 specific works mode of atomic time signal reproduction section 400 is as follows.

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 input 404 after amplifying through 403, be modulated on the 1550nm laser the demodulation of 9.1GHz microwave signal out.9.1GHz microwave signal inputs to 406 RF port after 405 amplifications.407 produce the 100MHz radiofrequency signal, are input to 408 external reference signal input port.408 by 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, the phase place of FEEDBACK CONTROL 407 output signals after proportional integral amplifies through 410.So so that the phase place of 408 output signals be locked on the reference clock of transmitting terminal.Another road output signal of 409 through 411 with its frequency divided by 91, then transport to 412 LO port.The 100MHz signals of 413 outputs are divided into two equal portions that phase equilibrium, power equate through 414.One tunnel output is for the user, and another road exports 412 RF port to and from 411 signal mixing.412 IF port output signal carries out exporting 413 voltage controling end to, the phase place of FEEDBACK CONTROL 413 output signals after proportional integral amplifies through 415.So so that the phase place of 413 output signals be locked on the reference clock of transmitting terminal, thereby at the reference clock (for example hydrogen clock) of relay end reproduction transmitting terminal.

Two, relaying auxiliary transmission section

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

As shown in Figure 8, relaying auxiliary transmission section 500 is exemplary comprises following assembly: 501 and 505:100MHz constant temperature VCXO (VCXO); 502: External Reference phase place 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 place 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 specific works mode of relaying auxiliary transmission section 500 is as follows.

501 produce the 100MHz radiofrequency signal, are input to 502 external reference signal input port.502 by 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 by 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 holds output signal through 509 mixing, and with its IF port output signal input 510, through transporting to 505 voltage controling end, the phase place of FEEDBACK CONTROL 505 output signals after the amplification of 510 proportional integrals.The innovative point of this programme is, do not need to prepare the auxiliary compensating signal of the stable 9.0GHz of absolute frequency and 9.2GHz relaying in the relay, but both be 18.2GHz frequently, and two signal phases be locked in transmitting terminal reference clock phase place.

Three, the second phase noise compensation section

The structure of the second phase noise compensation section 300 is identical with the first phase noise compensation section 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 implementation example shown in Figure 8, parts 407 and 408,501 and 502,505 and 506, and 301 and 302 form respectively four frequency oscillators.Here the implementation that adds DRO take VCXO is as example, but is not limited to the 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 that form 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 that form 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 internal modulation and external modulation methods that transmission frequency can be modulated on the laser can.

Parts 306,308, and 403 be 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 according to actual needs the voltage controlled oscillator of different frequency, will be converted to 10MHz under the atomic time frequency, the conventional frequencies such as 50MHz.

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

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

Terminal receiving system 600 of the present invention is used for receiving the atomic time signal in long baseline terminal, and obtains the microwave output that a phase place is locked 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 replace SOA with the identical erbium-doped fiber amplifier (EDFA) of index; 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: microwave frequency frequency mixer, frequency mixer LO and RF end frequency coverage 9.1GHz, IF end frequency coverage 100MHz; 607 and 613:100MHz constant temperature VCXO (VCXO); 608: External Reference phase place 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 specific works mode of terminal receiving system 600 is as follows.

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 input 604 after amplifying through 603, be modulated on the 1550nm laser the demodulation of 9.1GHz microwave signal out.9.1GHz microwave signal inputs to 606 RF port after 605 amplifications.607 produce the 100MHz radiofrequency signal, are input to 608 external reference signal input port.608 by 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, the phase place of FEEDBACK CONTROL 607 output signals after proportional integral amplifies through 610.So so that the phase place of 608 output signals be locked on the reference clock of transmitting terminal.Another road output signal of 609 through 611 with its frequency divided by 91, then transport to 612 LO port.The 100MHz signals of 613 outputs are divided into two equal portions that phase equilibrium, power equate through 614.One tunnel output is for the user, and 612 RF port is transported to and from 611 signal mixing in another road.612 IF port output signal carries out transporting to 613 voltage controling end, the phase place of FEEDBACK CONTROL 613 output signals after proportional integral amplifies through 615.So so that the phase place of 613 output signals be locked 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 implementation example shown in Figure 9, parts 607 and 608 form a frequency oscillator.Here the implementation that adds DRO take VCXO is as example, but is not limited to the 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 according to actual needs the voltage controlled oscillator of different frequency, will be converted to 10MHz under the atomic time frequency, the 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 (such as 601,602,604-606,609-612,614,615 etc.) parameter all is to select according to the optimization that the 9.1GHz atomic time signal of this example transmissions is done.When other frequencies of transmission, can optimize as the case may be the parameter of selecting each device.

＜atomic time method for transmitting signals 〉

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

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

As 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; Compensate the phase noise that the atomic time signal is introduced at transmitting terminal in optical fiber link, so that transfer to the phase place that the phase place of the atomic time signal of far-end is locked in reference clock; Receive the microwave signal on the light signal of being modulated at from optical fiber link in the relay, and the reproduction phase place is locked in the atomic time signal of reference clock; Atomic time signal waiting for transmission is modulated on the light signal again to pass through Optical Fiber Transmission; The phase noise of introducing when further the described atomic time signal of compensation transmits in optical fiber link in the relay is so that transfer to the phase place that the phase place of the atomic time signal of far-end is locked in reference clock.

Wherein, the step of the described phase noise of introducing when transmitting terminal compensation atomic time signal transmits in optical fiber link 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 described atomic time signal introduces when optical fiber link transmits based on described auxiliary compensating signal, and this feedback compensation signal is loaded in the atomic time signal waiting for transmission.

Wherein, the step of the described phase noise of introducing when relay compensation atomic time signal transmits 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 the phase noise that the further described atomic time signal of compensation introduces when optical fiber link transmits based on the auxiliary compensating signal of described 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.

By the atomic time signal is modulated on the wavelength 1550nm laser, and carry out that optical fiber transmission is passed and noise compensation, can realize high-precision atomic time signal transmission.At present successfully demonstration in 86 kilometers commercial optical fiber, stability was better than 2 * 10 in attainable second ^-14, a day stability is better than 4 * 10 ^-18

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

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

(3) between many ground the atomic time of real-time continuous transmission with compare.

Technical scheme of the present invention can utilize existing Networks of Fiber Communications as the transmission medium of atomic time signal, the transmission of between how, carrying out simultaneously the atomic time signal with compare, 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, be locked on the atomic time signal that is transmitted by the crystal oscillator phase place that has fine weak point steady (second is steady) with, reappear reference clock.

(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 in situation without departing from the spirit and scope of the present invention, making, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.In addition, claims of the present invention are intended to contain whole variations and the modification in the equivalents that falls into claims scope and border or this scope and border.

Claims (10)

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 by Optical Fiber Transmission, and the phase noise of compensation atomic time signal introducing when transmit in optical fiber link; With

A plurality of relaying compensation transmitting devices, each described 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 atomic time signal on the light signal by Optical Fiber Transmission between described emission compensation arrangement and a plurality of relaying compensation transmitting device;

Wherein, described emission compensation arrangement comprises:

Auxiliary transmission section, it generates auxiliary compensating signal and outputs to the first phase noise compensation section;

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

Wherein, described the first phase noise compensation section comprises:

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

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

The first laser, it is modulated to described the 3rd microwave signal on the light signal and exports to optical fiber circulator to enter optical fiber link;

Optical fiber circulator, it separates utilizing emitted light and back light, makes modulated light signal enter into optical fiber link transferring to far-end, and makes the light signal that is returned along optical fiber link by far-end export to the first detector;

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

2. transmission system according to claim 1, wherein, described auxiliary transmission section comprises:

The first frequency oscillator, it produces the first auxiliary compensating signal that phase place is locked in reference clock;

The second frequency oscillator, it produces the second auxiliary compensating signal that phase place is locked in reference clock; With

The described first auxiliary compensating signal and the second auxiliary compensating signal output to the first phase noise compensation section and produce feedback compensation signal with auxiliary its.

3. transmission system according to claim 1, wherein, first carries out than processing mutually to produce described feedback compensation signal described first, second auxiliary compensating signal and the 3rd, the 5th microwave signal than facies unit.

4. transmission system according to claim 1, described relaying compensation transmitting device comprises:

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

Relaying auxiliary transmission section, it generates the auxiliary compensating signal of relaying and outputs to the second phase noise compensation section;

The second phase noise compensation section, it is modulated on the light signal atomic time signal waiting for transmission again with by Optical Fiber Transmission, and produces the relaying feedback compensation signal that is used for the phase noise that the further described atomic time signal of compensation introduces when optical fiber link transmits based on the auxiliary compensating signal of this relaying.

5. transmission system according to claim 4, described atomic time signal reproduction section comprises:

The second detector, it out is locked in the 4th microwave signal of reference clock by the microwave signal demodulation that opto-electronic conversion will be modulated on the light signal to obtain phase place, and offers the 4th frequency oscillator;

The 4th frequency oscillator, it is locked in the microwave signal of the 4th microwave signal based on described the 4th microwave signal generated frequency and phase place.

6. transmission system according to claim 5, described atomic time signal reproduction section also comprises the divider that is connected to the 4th frequency oscillator output, its with microwave signal of the 4th frequency oscillator output except to corresponding frequencies, for the user of relay.

7. transmission system according to claim 4, described relaying auxiliary transmission section comprises:

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

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

Second than facies unit, and it produces compensating signal to the 6th frequency oscillator, so that the phase place of the auxiliary compensating signal of described first, second relaying and the phase place that is locked in reference clock.

8. transmission system according to claim 4, described the second phase noise compensation section comprises:

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

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

Second laser, its microwave signal that described the 7th frequency oscillator is produced is modulated on the light signal and exports to optical fiber circulator to enter optical fiber link;

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

Optical fiber circulator, it separates utilizing emitted light and back light, makes modulated light signal enter into optical fiber link transferring to far-end, and makes the light signal that is returned along the former road of optical fiber link by far-end export to the 3rd detector.

9. transmission system according to claim 8, wherein, the 3rd microwave signal that the auxiliary compensating signal of described first, second relaying, described the 7th frequency oscillator is produced than facies unit and the microwave signal of described the 3rd detector output are carried out than processing mutually to produce described relaying feedback compensation signal.

10. atomic time method for transmitting signals, the 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;

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 of being modulated at from optical fiber link in the relay, and the reproduction phase place is locked in the atomic time signal of reference clock;

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

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

Wherein, the step of the described phase noise of introducing when transmitting terminal compensation atomic time signal transmits in optical fiber link 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 described atomic time signal introduces when optical fiber link transmits based on described auxiliary compensating signal, and this feedback compensation signal is loaded in the atomic time signal waiting for transmission;

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

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