CN110149562B - Optical fiber single-channel time frequency high-precision transmission intermediate node device - Google Patents
Optical fiber single-channel time frequency high-precision transmission intermediate node device Download PDFInfo
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Abstract
The invention provides an optical fiber single-channel time frequency high-precision transmission intermediate node device which is arranged at an intermediate node of an optical fiber single channel communicated between a local end and a remote end, and is used for coupling and detecting a second pulse signal and a frequency signal which are sent to the remote end by the local end of the single channel and a second pulse signal and a frequency signal which are sent to the local end by the remote end. The intermediate node device can accurately recover the time frequency signal of the intermediate node connecting the single channel of the local end and the remote end.
Description
Technical Field
The invention relates to the technical field of time frequency transmission synchronization, in particular to an optical fiber single-channel time frequency high-precision transmission intermediate node device.
Background
In general, in time-frequency high-precision transmission, a time signal is transmitted separately from a frequency signal. The pulse per second transmission synchronously occupies one channel; the frequency signal transmission occupies two channels, one channel is used for transmitting the frequency signal from the local end to the remote end, and the other channel is used for transmitting the frequency signal returned from the remote end to the local end, so as to eliminate the influence of the line delay variation.
Only the pulse-per-second signal is usually used as a marker for the time-of-day signal, so that the accuracy of the time transfer is difficult to improve, and it is often difficult to exceed 20 ps.
In order to save channel resources, there is a method in the prior art for simultaneously transmitting a pulse-per-second signal, a time code signal, and a 10MHz signal by using a wavelength channel, and implementing multi-site fiber time synchronization transmission by using time division multiple access and clean regeneration, specifically: the remote ends of all the sites have respective unique equipment addresses, the local end realizes the polling synchronization of all the remote ends in a time division multiple access mode, a pulse per second signal is used for time transmission synchronization, and a 10MHz signal is used for an internal time keeping module.
Compared with the method that the pulse per second transmission synchronously occupies one channel and the frequency signal transmission occupies two channels, the method has the advantages that the accuracy and the stability of the pulse per second transmission are basically consistent, but the performance of the frequency transmission is deteriorated by several orders of magnitude, and the short-term frequency stability of the obtained atomic clock signal is seriously damaged. Therefore, the frequency signal is usually used only as an internal auxiliary means of the time transmission system device and is not output to the user for use.
Disclosure of Invention
In view of the above problems, an object of the present invention is to provide an optical fiber single channel time frequency high-precision transmission intermediate node apparatus for accurately recovering time frequency signals of an intermediate node connecting local and remote single channels, which can output time synchronization signals with accuracy up to ps and jitter sub-ps, and can output frequency signals meeting user requirements without reducing source microwave atomic clock indexes.
In order to achieve the above object, the present invention provides an optical fiber single channel time frequency high precision transmission intermediate node device, which is disposed at an intermediate node of an optical fiber single channel for local and remote communication, the intermediate node device including:
the signal detection demodulation module is used for detecting the pulse per second signal and the frequency signal which are sent to a remote end from a local end of a single channel and sent to the local end from the optical fiber single channel coupling, and respectively outputting the pulse per second signal and the frequency signal which are demodulated from the carrier wave modulated by the optical fiber single channel to the pulse per second receiving processing module and the down-conversion module;
the plurality of down-conversion modules are used for down-converting the frequency signals from the local end to the remote end, the frequency signals from the remote end to the local end and the crystal oscillator frequency signals output by the crystal oscillator module, which are demodulated by the signal detection and demodulation module, and sending the down-converted frequency signals to the signal acquisition and processing control module;
the crystal oscillator module generates a crystal oscillator frequency signal and sends the crystal oscillator frequency signal to the down-conversion module; the crystal oscillator frequency signal processed by the signal acquisition processing control module is used as an output standard frequency signal and is sent to the pulse per second receiving and processing module;
the signal acquisition processing control module comprises a multi-channel A/D acquisition unit and a multi-channel D/A unit, wherein the A/D acquisition unit acquires frequency signals from a local end to a remote end after down-conversion, crystal oscillator frequency signals and frequency signals from the remote end to the local end to obtain relative phases among the signals, and the D/A unit is used for controlling the crystal oscillator frequency signals output by the crystal oscillator module to enable the phases of the crystal oscillator frequency signals to be consistent with the phases of the frequency signals output by the remote end;
a pulse-per-second receiving and processing module for receiving the pulse-per-second signals from the local end to the remote end and from the remote end to the local end demodulated by the identification signal detection and demodulation module, measuring the time interval between the rising edges of the two pulse-per-second signals, dividing the time interval by 2 after subtracting the receiving and sending delays of the remote end to obtain the one-way transmission delay value of the signals from the intermediate node of the optical fiber single channel to the remote end, subtracting the receiving delays of the intermediate node and the remote end from the received pulse-per-second signals from the local end to the remote end, and after a time delay value transmitted from the intermediate node to a far-end signal in a single way is added, a pulse per second signal of the intermediate node is obtained and used as a reference signal, a plurality of pulse per second signals generated by using the zero-crossing point of a crystal oscillator frequency signal controlled and output by the crystal oscillator module through the signal acquisition processing control module as a rising edge are selected, and the pulse per second signal closest to the reference signal is used as the output pulse per second signal.
Preferably, the method further comprises the following steps:
and the data receiving and processing module is used for receiving the data signals from the local end to the remote end demodulated by the signal detection and demodulation module, receiving the data signals from the remote end to the local end and extracting the characteristic information of the data signals.
Preferably, the local and remote terminals perform time signal characterization using a frequency signal and a second pulse signal, the second pulse signal is used as a time coarse mark, the frequency signal phase is used as a time fine mark, the frequency signal phase and the second pulse signal maintain a fixed alignment relationship, the time coarse mark has a time signal mark accurate to tens of picoseconds, and the time fine mark has a time signal mark accurate to subpicosecond.
Further preferably, the local end includes:
the first time division module enables a local end to transmit and receive the pulse-per-second signal and the frequency signal in a time division mode in the optical fiber single channel;
the first signal comprehensive modulation module modulates the pulse-per-second signal and the frequency signal to be transmitted on the carrier wave of the single channel at different time according to the instruction of the first time division module in the local end transmission period and transmits the modulated signals to the remote end;
the first signal detection demodulation module demodulates a pulse per second signal and a frequency signal sent by a remote end from a carrier wave modulated by a single channel in a local end receiving period, and respectively outputs the pulse per second signal and the frequency signal to the pulse per second sending processing module and the first down-conversion module;
the second pulse sending and processing module is used for obtaining the time delay lead of the second pulse signal, wherein the initial second pulse signal is sent to a far-end through the first signal comprehensive modulation module, the second pulse signal which is sent back by the far-end and is demodulated by the first signal detection demodulation module is received, the time interval between the rising edges of the two second pulse signals is measured, the time interval is deducted by the sending and receiving time delays of a local end and the far-end and then is divided by 2, the time delay value of one-way transmission of the signal in a single channel is obtained, and the sending time delay of the local end and the receiving time delay of the far-end are added to be used as the next time delay lead sending second pulse signal;
the first crystal oscillator module generates a crystal oscillator frequency signal and sends the crystal oscillator frequency signal to the first down-conversion module; the crystal oscillator frequency signal processed by the first signal acquisition processing control module is used as a frequency signal to be transmitted in a local end transmission time period and is transmitted to the first signal comprehensive modulation module;
the plurality of first down-conversion modules carry out down-conversion on the input standard frequency signals and send the down-converted standard frequency signals to the first signal acquisition processing control module; carrying out down-conversion on a crystal oscillator frequency signal generated by the first crystal oscillator module, and sending the crystal oscillator frequency signal to the first signal acquisition processing control module; the frequency signal returned by the remote end and passing through the first signal detection demodulation module is subjected to down-conversion and sent to the first signal acquisition processing control module;
the first signal acquisition processing control module comprises a first A/D acquisition unit and a first D/A unit which are in multi-channel, the first A/D acquisition unit acquires crystal oscillator frequency signals and standard frequency signals which are subjected to down-conversion and receives frequency signals which are returned by a far-end and are subjected to down-conversion by the first signal detection demodulation module and the first down-conversion module to obtain relative phases among the signals, and the D/A unit controls the crystal oscillator frequency signals output by the first crystal oscillator module to enable the phase of the signals of the crystal oscillator frequency signals after single-channel one-way transmission to be consistent with the phase of the standard frequency signals.
Further, preferably, the distal end includes:
the second time division module enables the remote end to transmit and receive the pulse per second signal and the frequency signal in a time division mode in the optical fiber single channel;
the second signal detection demodulation module demodulates the pulse per second signal and the frequency signal from the carrier wave modulated by the single channel in the receiving period of the far end, and respectively outputs the pulse per second signal and the frequency signal to the second pulse per second receiving processing module and the second down-conversion module;
the second crystal oscillator module generates a crystal oscillator frequency signal and sends the crystal oscillator frequency signal to the second down-conversion module; the crystal oscillator frequency signal processed by the second signal acquisition processing control module is used as a frequency signal to be returned in a far-end sending time period and sent to the second signal comprehensive modulation module; outputting the crystal oscillator frequency signal processed by the second signal acquisition processing control module as a standard frequency signal of a time fine mark, and sending the standard frequency signal to a pulse per second receiving and processing module;
the plurality of second down-conversion modules are used for down-converting the frequency signals demodulated by the second signal detection and demodulation module and the crystal oscillator frequency signals output by the second crystal oscillator module and sending the frequency signals to the second signal acquisition processing control module;
the second signal acquisition processing control module comprises a second A/D acquisition unit and a second D/A unit which are provided with multiple channels, the second A/D acquisition unit acquires a crystal oscillator frequency signal subjected to down-conversion and a frequency signal demodulated by the second signal detection demodulation module to obtain a relative phase between the crystal oscillator frequency signal and the frequency signal, and the second D/A unit controls the crystal oscillator frequency signal output by the second crystal oscillator module to enable the phase of the output crystal oscillator frequency signal to be consistent with the phase of a standard frequency signal input to a local end;
a second pulse-per-second receiving and processing module which receives a pulse-per-second signal transmitted from a local terminal and demodulated by a second signal detection and demodulation module, generates a plurality of pulse-per-second signals by using the pulse-per-second signal as a reference signal for generating the pulse-per-second signal and outputting a zero-crossing point of a frequency signal from a second oscillation module as a rising edge of the pulse-per-second signal, and selects the pulse-per-second signal closest to the reference signal from the plurality of pulses to output as a pulse-per-second signal of a remote terminal;
and the second signal comprehensive modulation module modulates the pulse per second signal, the data coding pulse signal and the frequency signal to be transmitted on the single-channel carrier wave at different times according to the instruction of the second time division module in the sending time period of the remote end and sends the signals to the local end.
Preferably, the standard frequency signal is a sine wave signal, the zero crossing point of the sine wave signal is aligned with the rising edge of the pulse per second signal, and the frequency of the sine wave signal is an integer.
The optical fiber single-channel time frequency high-precision transmission intermediate node device is characterized in that on the basis that single-channel time frequency high-precision transmission is established in an optical fiber at a local end and a remote end, an optical signal of the channel is coupled out at an intermediate node of the optical fiber, a pulse per second and a frequency signal (sine wave signal) sent to the remote end device by the local end device and a pulse per second and a frequency signal (sine wave signal) sent to the local end device by the remote end device are obtained through detection and demodulation, and an accurate time frequency signal is recovered at the intermediate node through further processing, so that the accurate transmission synchronization of the pulse per second, the frequency and the phase is simultaneously completed in one channel of the local end and the intermediate node of the remote end of the single-channel time frequency high-precision transmission device, resources are saved, and the high-precision time frequency transmission synchronization is realized.
Drawings
FIG. 1 is a schematic diagram of a block diagram of a fiber single-channel time-frequency high-precision transmission intermediate node device according to the present invention;
FIG. 2 is a block diagram of the local side according to the present invention;
fig. 3 is a schematic diagram of the remote end configuration of the present invention.
Detailed Description
In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of one or more embodiments. It may be evident, however, that such embodiment(s) may be practiced without these specific details.
Fig. 1 is a schematic diagram of a block diagram of an optical fiber single-channel time frequency high-precision transmission intermediate node device 10 according to the present invention, and as shown in fig. 1, the optical fiber single-channel time frequency high-precision transmission intermediate node device 10 is provided at an optical fiber single-channel intermediate node that is in communication between a local end 20 and a remote end 30, and couples and detects a pulse per second signal and a frequency signal that are sent from the local end 20 to the remote end 30 of the single channel, and a pulse per second signal and a frequency signal that are sent from the remote end 30 to the local end 20.
Preferably, as shown in fig. 1, the intermediate node apparatus 10 includes:
the signal detection demodulation module 11 is used for detecting the pulse-per-second signal and the frequency signal which are sent to a remote end from a local end of a single channel and sent to the local end from the optical fiber single channel coupling, and respectively outputting the pulse-per-second signal and the frequency signal which are demodulated from the carrier wave modulated by the optical fiber single channel to the pulse-per-second receiving processing module and the down-conversion module;
a plurality of down-conversion modules 12, which down-convert the frequency signals from the local end 20 to the remote end 30, the frequency signals from the remote end 30 to the local end 20 and the crystal oscillator frequency signals output by the crystal oscillator module, which are demodulated by the signal detection and demodulation module 11, and send the down-converted frequency signals to the signal acquisition and processing control module 14;
the crystal oscillator module 13 generates a crystal oscillator frequency signal and sends the crystal oscillator frequency signal to the down-conversion module 12; the crystal oscillator frequency signal processed by the signal acquisition processing control module 14 is used as an output standard frequency signal and is sent to the pulse per second receiving and processing module 15;
the signal acquisition processing control module 14 comprises a multi-channel A/D acquisition unit and a multi-channel D/A unit, wherein the A/D acquisition unit acquires frequency signals from the local end 20 to the remote end 30 after down-conversion, crystal oscillator frequency signals and frequency signals from the remote end 30 to the local end 20 to obtain relative phases among the signals, and the D/A unit controls the crystal oscillator frequency signals output by the crystal oscillator module to enable the phases of the crystal oscillator frequency signals to be consistent with the phases of the frequency signals output by the remote end 30;
a pulse-per-second receiving and processing module 15, which receives the pulse signals from the local end 20 to the remote end 30 seconds and the pulse signals from the remote end 30 to the local end 20 seconds demodulated by the identification signal detecting and demodulating module 11, measures the time interval between the rising edges of the two pulse signals, divides the time interval by 2 after subtracting the receiving and sending time delay of the remote end to obtain the time delay value of one-way transmission of the signal from the middle node to the remote end 30 of the optical fiber single channel, obtains the pulse-per-second signal of the middle node as a reference signal after subtracting the receiving time delay of the middle node and the remote end from the pulse signals from the local end 20 to the remote end 30 seconds and adding the time delay value of one-way transmission of the signal from the middle node to the remote end 30, selects the pulse-per-second signal closest to the reference signal (with the smallest error) as the pulse-per-second signal generated by the rising edge from the zero crossing point of the crystal frequency signal controlled and output by the crystal oscillator module through the signal collecting and processing control module, and selects the pulse-per-second signal closest to (with the smallest error) to the reference signal as the second pulse signal output by the middle node The signal is pulsed.
The intermediate node device can measure the time delay value of the signal at the intermediate node to the far-end and then to the intermediate node, thereby obtaining the one-way time delay value of the signal at the intermediate node to the far-end, and further delaying the received signal by one-way time delay amount, namely the signal position at the far-end.
Further, preferably, the method further comprises the following steps:
the data receiving and processing module 16 receives the data signals from the local end 20 to the remote end 30 demodulated by the signal detecting and demodulating module 11, receives the data signals from the remote end 30 to the local end 20, and extracts characteristic information of the data signals, for example, valuable information such as source atomic clock characteristics and line asymmetric delay correction is extracted.
Preferably, the local end 20 and the remote end 30 perform time signal characterization using a frequency signal and a second pulse signal, the second pulse signal is used as a time coarse mark, the frequency signal phase is used as a time fine mark, the frequency signal phase and the second pulse signal maintain a fixed alignment relationship, the time coarse mark has a time signal mark accurate to tens of picoseconds, and the time fine mark has a time signal mark accurate to subpicosecond.
Further, preferably, as shown in fig. 2, the local end 20 includes:
a first time division module 21, which enables the local end 20 to transmit and receive the pulse-per-second signal and the frequency signal in a time-division manner in the optical fiber single channel;
the first signal comprehensive modulation module 22 modulates the pulse-per-second signal and the frequency signal to be transmitted on the carrier wave of the single channel at different times according to the instruction of the first time division module in the transmission time period of the local end 20 and transmits the modulated signals to the remote end 30;
the first signal detection demodulation module 23 demodulates the pulse per second signal and the frequency signal from the carrier wave modulated by the single channel in the receiving period of the local end 20, and respectively outputs the pulse per second signal and the frequency signal to the pulse per second sending and processing module and the first down-conversion module;
the pulse per second sending and processing module 24 obtains the delay advance of the pulse per second signal, wherein, the initial pulse per second signal is sent to the far-end 30 through the first signal comprehensive modulation module, the pulse per second signal demodulated by the first signal detection demodulation module 23 and sent back from the far-end 30 is received, the time interval between the rising edges of the two pulse per second signals is measured, the time interval is divided by 2 after the sending and receiving delays of the local end and the far-end are deducted, the delay value of the signal single-pass transmission in the single channel is obtained, and the sending delay of the local end 20 and the receiving delay of the far-end 30 are added as the next delay advance sending pulse per second signal;
the first crystal oscillator module 25 generates a crystal oscillator frequency signal and sends the crystal oscillator frequency signal to the first down-conversion module; the crystal oscillator frequency signal processed by the first signal acquisition processing control module is used as a frequency signal to be transmitted in the local end 20 transmission time period and is transmitted to the first signal comprehensive modulation module;
the plurality of first down-conversion modules 26 down-convert the input standard frequency signals and send the signals to the first signal acquisition processing control module; carrying out down-conversion on a crystal oscillator frequency signal generated by the first crystal oscillator module, and sending the crystal oscillator frequency signal to the first signal acquisition processing control module; the frequency signal returned by the remote end 30 and passing through the first signal detection demodulation module 23 is down-converted and sent to the first signal acquisition processing control module;
the first signal acquisition processing control module 27 includes a first a/D acquisition unit and a first D/a unit with multiple channels, the first a/D acquisition unit acquires the crystal oscillator frequency signal and the standard frequency signal after down-conversion and receives the frequency signal returned by the remote end 30 and demodulated by the first signal detection demodulation module 23 and down-converted by the first down-conversion module, so as to obtain the relative phase between the above signals, and the D/a unit controls the crystal oscillator frequency signal output by the first crystal oscillator module, so that the phase of the signal after single-channel single-pass transmission of the crystal oscillator frequency signal is consistent with the phase of the standard frequency signal.
Preferably, the standard frequency signal is a sine wave signal, the zero crossing point of the sine wave signal is aligned with the rising edge of the pulse per second signal, and the frequency of the sine wave signal is an integer.
Further, preferably, as shown in fig. 3, the distal end 30 includes:
a second time division module 31, which enables the remote end 30 to transmit and receive the pulse-per-second signal and the frequency signal in a time-sharing manner in the single optical fiber channel;
the second signal detection demodulation module 32 demodulates the pulse-per-second signal and the frequency signal from the carrier modulated by the single channel in the receiving period of the remote end 30, and respectively outputs the pulse-per-second signal and the frequency signal to the second pulse-per-second receiving processing module and the second down-conversion module;
the second crystal oscillator module 33 generates a crystal oscillator frequency signal and sends the crystal oscillator frequency signal to the second down-conversion module; the crystal oscillator frequency signal processed by the second signal acquisition processing control module 37 is used as a frequency signal to be returned in the sending time period of the remote end 30 and sent to the second signal comprehensive modulation module; the crystal oscillator frequency signal processed by the second signal acquisition processing control module 37 is output as a standard frequency signal of a time fine mark and is sent to the second pulse-per-second receiving and processing module 36;
the plurality of second down-conversion modules 34 down-convert the frequency signal demodulated by the second signal detection demodulation module 32 and the crystal oscillator frequency signal output by the second crystal oscillator module, and send the frequency signal and the crystal oscillator frequency signal to the second signal acquisition processing control module;
the second signal acquisition processing control module 37 includes a second a/D acquisition unit and a second D/a unit with multiple channels, the second a/D acquisition unit acquires the crystal oscillator frequency signal after down-conversion and the frequency signal demodulated by the second signal detection demodulation module 32 to obtain the relative phase between the crystal oscillator frequency signal and the frequency signal, and the second D/a unit controls the crystal oscillator frequency signal output by the second crystal oscillator module to make the phase of the output crystal oscillator frequency signal consistent with the phase of the received frequency signal sent by the local end 20 device demodulated by the second signal detection demodulation module 32;
a second pulse-per-second receiving and processing module 36 for receiving the pulse-per-second signal transmitted from the local terminal 20 and demodulated by the second signal detecting and demodulating module 32, generating a plurality of pulse-per-second signals by using the pulse-per-second signal as a reference signal for generating the pulse-per-second signal and outputting a zero-crossing point of the frequency signal from the second crystal oscillating module as a rising edge of the pulse-per-second signal, and selecting the pulse-per-second signal closest to the reference signal from the plurality of pulses to output as the pulse-per-second signal of the remote terminal 30;
the second signal comprehensive modulation module 35 modulates the pulse-per-second signal, the data coding pulse signal and the frequency signal to be transmitted at the transmission time interval of the remote end 30 at different times according to the instruction of the second time division module, and transmits the modulated signals to the local end 20 on the single-channel carrier.
The phase of the frequency signal output by the remote end is consistent with that of the local end reference standard frequency signal (the most accurate atomic clock signal), so that the intermediate node also realizes the phase consistency of the local end reference standard frequency signal.
The local end, the remote end and the device adopt the rising edge of the pulse-per-second signal as a rough mark of the moment, the phase of the sine wave as a fine mark of the moment, and the digital measurement and control technology is used for measuring and processing the phase of the sine wave, thereby greatly reducing the links of analog devices with larger temperature coefficients and greatly improving the performance of time transfer synchronization.
In one embodiment of the invention, optical signals of channels for time-frequency transmission are coupled out by optical fiber splitters and wave dividers at intermediate nodes of a local end and a remote end of the fiber single-channel time-frequency high-precision transmission. The intermediate node device uses the photoelectric detector to detect the pulse per second signal, data information and frequency signal (phase) sent by the local end to the remote end and the pulse per second signal, data information and frequency signal (phase) sent by the remote end to the local end. And a time interval measuring device in the intermediate node device measures the time interval between the reception of the pulse-per-second signal sent by the local end and the reception of the pulse-per-second signal returned by the remote end, deducts the receiving and sending time delay of the pulse-per-second at the remote end and the receiving time delay in the intermediate node device, and then calculates the line time delay from the intermediate node device to the remote end. Because the accuracy of the rising edge moment of the pulse per second at the far end is better than 1ns, the intermediate node can process the pulse per second with the accuracy of nearly 1 ns. The intermediate node device measures the phase difference between the received frequency signal (sine wave signal) sent by the local end and the frequency signal output by the crystal oscillator module in the intermediate node device, and the phase difference between the received frequency signal returned by the remote end and the frequency signal output by the crystal oscillator module in the intermediate node device. After deducting the receiving and transmitting time delay of the frequency signal of the far-ground end and the receiving time delay in the intermediate node device, the line phase delay from the intermediate node device to the far-ground end can be calculated. Because the phase of the frequency signal at the far end is strictly synchronous with the phase of the standard frequency signal at the local end, the crystal oscillator module at the middle node can be controlled to realize accurate frequency signal phase output. The pulse per second receiving and processing module 15 converts a zero crossing point of a frequency signal (sine wave signal) with an accurate phase output by the crystal oscillator module into a rising edge of a pulse per second, the pulse per second with accuracy reaching nearly 1ns obtained by receiving and processing is used as a new accurate pulse per second selection switch, and a pulse closest to the pulse per second with accuracy nearly 1ns is selected from a large number of pulses with the rising edge at the zero crossing point and is used as a pulse per second, so that an accurate pulse per second signal is restored.
While the foregoing disclosure shows illustrative embodiments of the invention, it should be noted that various changes and modifications could be made herein without departing from the scope of the invention as defined by the appended claims. Furthermore, although elements of the invention may be described or claimed in the singular, the plural is contemplated unless limitation to the singular is explicitly stated.
Claims (6)
1. An optical fiber single channel time frequency high precision transmission intermediate node device, characterized in that, an optical fiber single channel intermediate node arranged at local end and remote end communication, the intermediate node device comprises:
the signal detection demodulation module is used for detecting the pulse per second signal and the frequency signal which are sent to a remote end from a local end of a single channel and sent to the local end from the optical fiber single channel coupling, and respectively outputting the pulse per second signal and the frequency signal which are demodulated from the carrier wave modulated by the optical fiber single channel to the pulse per second receiving processing module and the down-conversion module;
the plurality of down-conversion modules are used for down-converting the frequency signals from the local end to the remote end, the frequency signals from the remote end to the local end and the crystal oscillator frequency signals output by the crystal oscillator module, which are demodulated by the signal detection and demodulation module, and sending the down-converted frequency signals to the signal acquisition and processing control module;
the crystal oscillator module generates a crystal oscillator frequency signal and sends the crystal oscillator frequency signal to the down-conversion module; the crystal oscillator frequency signal processed by the signal acquisition processing control module is used as an output standard frequency signal and is sent to the pulse per second receiving and processing module;
the signal acquisition processing control module comprises a multi-channel A/D acquisition unit and a multi-channel D/A unit, wherein the A/D acquisition unit acquires frequency signals from a local end to a remote end after down-conversion, crystal oscillator frequency signals and frequency signals from the remote end to the local end to obtain relative phases among the signals, and the D/A unit is used for controlling the crystal oscillator frequency signals output by the crystal oscillator module to enable the phases of the crystal oscillator frequency signals to be consistent with the phases of the frequency signals output by the remote end;
a pulse-per-second receiving and processing module for receiving the pulse-per-second signals from the local end to the remote end and from the remote end to the local end demodulated by the identification signal detection and demodulation module, measuring the time interval between the rising edges of the two pulse-per-second signals, dividing the time interval by 2 after subtracting the receiving and sending delays of the remote end to obtain the one-way transmission delay value of the signals from the intermediate node of the optical fiber single channel to the remote end, subtracting the receiving delays of the intermediate node and the remote end from the received pulse-per-second signals from the local end to the remote end, and after a time delay value transmitted from the intermediate node to a far-end signal in a single way is added, a pulse per second signal of the intermediate node is obtained and used as a reference signal, a plurality of pulse per second signals generated by using the zero-crossing point of a crystal oscillator frequency signal controlled and output by the crystal oscillator module through the signal acquisition processing control module as a rising edge are selected, and the pulse per second signal closest to the time of the reference signal is used as the output pulse per second signal.
2. The fiber single-channel time-frequency high-precision delivery intermediate node apparatus according to claim 1, further comprising:
and the data receiving and processing module is used for receiving the data signals from the local end to the remote end demodulated by the signal detection and demodulation module, receiving the data signals from the remote end to the local end and extracting the characteristic information of the data signals.
3. The apparatus of claim 1, wherein the local end and the remote end use frequency signals and pulse-per-second signals for time signal characterization, the pulse-per-second signals are used as time coarse marks, the frequency signal phases are used as time fine marks, the frequency signal phases and the pulse-per-second signals are maintained in a fixed alignment relationship, the time coarse marks have time signal marks accurate to tens of picoseconds, and the time fine marks have time signal marks accurate to subpicosecond.
4. The apparatus of claim 3, wherein the local end comprises:
the first time division module enables a local end to transmit and receive the pulse-per-second signal and the frequency signal in a time division mode in the optical fiber single channel;
the first signal comprehensive modulation module modulates the pulse-per-second signal and the frequency signal to be transmitted on the carrier wave of the single channel at different time according to the instruction of the first time division module in the local end transmission period and transmits the modulated signals to the remote end;
the first signal detection demodulation module demodulates a pulse per second signal and a frequency signal sent by a remote end from a carrier wave modulated by a single channel in a local end receiving period, and respectively outputs the pulse per second signal and the frequency signal to the pulse per second sending processing module and the first down-conversion module;
the second pulse sending and processing module is used for obtaining the time delay lead of the second pulse signal, wherein the initial second pulse signal is sent to a far-end through the first signal comprehensive modulation module, the second pulse signal which is sent back by the far-end and is demodulated by the first signal detection demodulation module is received, the time interval between the rising edges of the two second pulse signals is measured, the time interval is deducted by the sending and receiving time delays of a local end and the far-end and then is divided by 2, the time delay value of one-way transmission of the signal in a single channel is obtained, and the sending time delay of the local end and the receiving time delay of the far-end are added to be used as the next time delay lead sending second pulse signal;
the first crystal oscillator module generates a crystal oscillator frequency signal and sends the crystal oscillator frequency signal to the first down-conversion module; the crystal oscillator frequency signal processed by the first signal acquisition processing control module is used as a frequency signal to be transmitted in a local end transmission time period and is transmitted to the first signal comprehensive modulation module;
the plurality of first down-conversion modules carry out down-conversion on the input standard frequency signals and send the down-converted standard frequency signals to the first signal acquisition processing control module; carrying out down-conversion on a crystal oscillator frequency signal generated by the first crystal oscillator module, and sending the crystal oscillator frequency signal to the first signal acquisition processing control module; the frequency signal returned by the remote end and passing through the first signal detection demodulation module is subjected to down-conversion and sent to the first signal acquisition processing control module;
the first signal acquisition processing control module comprises a first A/D acquisition unit and a first D/A unit which are in multi-channel, the first A/D acquisition unit acquires crystal oscillator frequency signals and standard frequency signals which are subjected to down-conversion and receives frequency signals which are returned by a far-end and are subjected to down-conversion by the first signal detection demodulation module and the first down-conversion module to obtain relative phases among the signals, and the D/A unit controls the crystal oscillator frequency signals output by the first crystal oscillator module to enable the phase of the signals of the crystal oscillator frequency signals after single-channel one-way transmission to be consistent with the phase of the standard frequency signals.
5. The fiber optic single channel time frequency high precision transfer intermediate node apparatus of claim 3, wherein the remote end comprises:
the second time division module enables the remote end to transmit and receive the pulse per second signal and the frequency signal in a time division mode in the optical fiber single channel;
the second signal detection demodulation module demodulates the pulse per second signal and the frequency signal from the carrier wave modulated by the single channel in the receiving period of the far end, and respectively outputs the pulse per second signal and the frequency signal to the second pulse per second receiving processing module and the second down-conversion module;
the second crystal oscillator module generates a crystal oscillator frequency signal and sends the crystal oscillator frequency signal to the second down-conversion module; the crystal oscillator frequency signal processed by the second signal acquisition processing control module is used as a frequency signal to be returned in a far-end sending time period and sent to the second signal comprehensive modulation module; outputting the crystal oscillator frequency signal processed by the second signal acquisition processing control module as a standard frequency signal of a time fine mark, and sending the standard frequency signal to a second pulse-per-second receiving and processing module;
the plurality of second down-conversion modules are used for down-converting the frequency signals demodulated by the second signal detection and demodulation module and the crystal oscillator frequency signals output by the second crystal oscillator module and sending the frequency signals to the second signal acquisition processing control module;
the second signal acquisition processing control module comprises a second A/D acquisition unit and a second D/A unit which are provided with multiple channels, the second A/D acquisition unit acquires a crystal oscillator frequency signal subjected to down-conversion and a frequency signal demodulated by the second signal detection demodulation module to obtain a relative phase between the crystal oscillator frequency signal and the frequency signal, and the second D/A unit controls the crystal oscillator frequency signal output by the second crystal oscillator module to enable the phase of the output crystal oscillator frequency signal to be consistent with the phase of a standard frequency signal input to a local end;
a second pulse-per-second receiving and processing module which receives a pulse-per-second signal transmitted from a local terminal and demodulated by a second signal detection and demodulation module, generates a plurality of pulse-per-second signals by using the pulse-per-second signal as a reference signal for generating the pulse-per-second signal and outputting a zero-crossing point of a frequency signal from a second oscillation module as a rising edge of the pulse-per-second signal, and selects the pulse-per-second signal closest to the reference signal from the plurality of pulses as a pulse-per-second signal of a remote terminal;
and the second signal comprehensive modulation module modulates the pulse per second signal and the frequency signal to be transmitted on the single-channel carrier wave at different times according to the instruction of the second time division module in the far-end transmitting period and transmits the pulse per second signal and the frequency signal to the local end.
6. The fiber single-channel time-frequency high-precision transmission intermediate node device according to claim 4, wherein the standard frequency signal is a sine wave signal, zero crossings of the sine wave signal are aligned with rising edges of the pulse-per-second signal, and the frequency of the sine wave signal is an integer.
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| CN110989327B (en) * | 2019-12-26 | 2021-03-30 | 中国计量科学研究院 | Distributed high-precision time frequency real-time integrated system |
| CN112671464B (en) * | 2020-12-10 | 2023-02-24 | 中国计量科学研究院 | Double-channel time frequency high-precision transmission intermediate node device |
| CN112713981B (en) * | 2020-12-10 | 2023-03-14 | 中国计量科学研究院 | Double-channel time frequency high-precision transmission device and method |
| CN112688734B (en) * | 2020-12-10 | 2022-03-15 | 中国计量科学研究院 | Looped network single-channel time frequency transmission device |
| CN112688753B (en) * | 2020-12-10 | 2023-02-24 | 中国计量科学研究院 | High-precision transmission device for looped network double-channel time frequency |
| CN114337891A (en) * | 2021-12-10 | 2022-04-12 | 中国人民解放军战略支援部队信息工程大学 | High-precision time frequency transfer coding method and system |
| CN118331021B (en) * | 2024-06-13 | 2024-08-09 | 中国人民解放军国防科技大学 | Time maintaining method and system for high-precision time-frequency transmission equipment |
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