CN112688753B - High-precision transmission device for looped network double-channel time frequency - Google Patents
High-precision transmission device for looped network double-channel time frequency Download PDFInfo
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Abstract
The invention provides a looped network double-channel time frequency high-precision transmission device which comprises an optical fiber first interface and an optical fiber second interface, wherein a pulse per second signal and a frequency signal are transmitted between the optical fiber first interface and the optical fiber second interface through an optical fiber.
Description
Technical Field
The invention relates to a looped network dual-channel transmission device, in particular to a looped network dual-channel time frequency high-precision transmission device, and belongs to the technical field of time frequency.
Background
The present high-precision time frequency output device uses the atomic and molecular energy level difference of an atomic clock as a reference signal to calibrate a crystal oscillator so as to output a standard frequency signal. It utilizes the signal generated by atomic energy level transition, and utilizes the photoelectric conversion and signal processing to obtain negative feedback error-correcting signal for correcting crystal oscillator so as to make it output stable oscillation frequency for accurately calculating time.
Because the frequency stability and accuracy of different atomic clocks have small deviation, the deviation affects the precision of time frequency output, so that the time output by the time frequency output devices in various regions cannot be completely synchronous, and the time output by the time frequency output devices in various regions has certain difference.
At present, a scheme for time frequency local area network transmission has been proposed, but most of the schemes are one-way transmission or partial one-way transmission, for example, pulse signal two-way transmission and frequency signal one-way transmission, and as the precise position of the rising edge or the falling edge of the pulse signal per second is difficult to be accurately positioned, the time transmission precision is easy to be problematic.
In general, in time-frequency high-precision transmission, the transmission of the pulse per second signal and the transmission of the frequency signal are separately performed, and although two channels are occupied, the frequency signal is often used only for eliminating line delay, and only the pulse per second signal is used as a mark of a time signal, so that the accuracy of time transmission is difficult to improve.
In the prior art, a method for transmitting a pulse per second signal and a frequency signal by using a single channel exists, and although the time accuracy of single channel transmission is high, in practical application, the time accuracy of single channel transmission is often higher than the use requirement. In addition, the single channel transmission method has poor short-term stability of the transmitted frequency signal, so that the requirement on the crystal oscillator is high, and the system cost is higher
In addition, in time high-precision transmission, a frequency signal is an analog quantity, when a time signal is transmitted, line delay needs to be considered, the frequency signal is usually converted into a digital quantity by using an a/D module, and then a transmission frequency phase is controlled, so that the line delay is eliminated, but the adjustment speed is low, the stability of the frequency is insufficient, and the further improvement of the time transmission precision is restricted.
The prior art also discloses an intermediate node device, and the intermediate node device is arranged between the dual-channel time frequency transmission devices, so that the time frequency can be acquired at the intermediate node, and the effect of transmitting the time frequency to multiple places is realized.
Therefore, there is a need to develop a ring network dual-channel transmission device that is safe, reliable, low in noise, and more stable in frequency transmission.
Disclosure of Invention
The present inventors have conducted intensive studies in order to solve the above problems.
On one hand, the invention provides a looped network double-channel time frequency high-precision transmission device, which comprises an optical fiber first interface and an optical fiber second interface, wherein the optical fiber first interface and the optical fiber second interface are double-channel optical fiber interfaces, and a pulse per second signal and a frequency signal are transmitted between the optical fiber first interface and the optical fiber second interface through optical fibers;
the dual channel includes a first channel and a second channel, and the first channel and the second channel both transmit signals with pulse-per-second signals and frequency signals.
The system comprises a signal comprehensive modulation module, a signal detection demodulation module, a second pulse sending and receiving processing module, a crystal oscillator module and a signal acquisition processing control module, wherein the number of the signal comprehensive modulation module, the number of the signal detection demodulation module, the number of the second pulse sending and receiving processing module and the number of the crystal oscillator module are two, and the signal comprehensive modulation module, the signal detection demodulation module, the second pulse sending and receiving processing module and the crystal oscillator module are respectively a first signal comprehensive modulation module, a first signal detection demodulation module, a first second pulse sending and receiving processing module, a first crystal oscillator module and a second signal comprehensive modulation module, a second signal detection demodulation module, a second pulse sending and receiving processing module and a second crystal oscillator module;
the signal comprehensive modulation module is used for modulating and sending signals and modulating the pulse per second signal and the frequency signal in a carrier wave;
the signal detection demodulation module is used for demodulating a pulse per second signal and a frequency signal in a carrier wave;
the first signal comprehensive modulation module is connected with the first second pulse transmitting and receiving processing module and the first crystal oscillator module, and the second signal comprehensive modulation module is connected with the second pulse transmitting and receiving processing module and the second crystal oscillator module;
the first signal detection demodulation module is connected with the first second pulse transmitting and receiving processing module and the first signal acquisition processing control module, and the second signal detection demodulation module is connected with the second pulse transmitting and receiving processing module and the second crystal oscillator module;
the second pulse sending, receiving and processing module is used for generating a second pulse signal, the first second pulse sending, receiving and processing module can acquire a standard second pulse signal and generate the second pulse signal on the basis of the standard second pulse signal, and the second pulse sending, receiving and processing module receives the second pulse signal demodulated by the second signal detection and demodulation module, and the second pulse signal is used as a reference signal for generating the second pulse signal, generates a second pulse signal and is transmitted to the second signal comprehensive modulation module;
the crystal oscillator module is used for generating frequency signals, the frequency signals generated by the first crystal oscillator module can be transmitted to the local pulse per second sending and receiving processing module, the local signal comprehensive modulation module and the first signal acquisition and processing control module, and the frequency signals generated by the second crystal oscillator module can be transmitted to the second pulse per second sending and receiving processing module, the second signal comprehensive modulation module and the signal acquisition and processing module;
the signal acquisition processing control module compares the frequency signal output by the first crystal oscillator module, the standard frequency signal, the frequency signal output by the second crystal oscillator module and the frequency signal demodulated by the first signal detection demodulation module to obtain the relative phase among the signals, and realizes indirect control of the phase of the frequency signal output by the first crystal oscillator module through phase adjustment of the frequency signal output by the phase shifting module, so that the phase of the frequency signal output by the second crystal oscillator module is consistent with the phase of the standard frequency signal.
The signal acquisition processing control module comprises a multi-channel A/D acquisition unit, a calculation unit and a D/A unit, wherein the A/D acquisition unit acquires frequency signals, the calculation unit calculates relative phases among the frequency signals, and the D/A unit outputs phases for controlling sine wave signals.
And a down-conversion module is arranged among the signal acquisition and processing control module, the first signal detection and demodulation module, the first crystal oscillator module and the second crystal oscillator module and before the standard frequency signal is acquired.
A first frequency mixing phase locking module and a phase shifting module are arranged between the signal acquisition processing control module and the first crystal oscillator module, and a second frequency mixing phase locking module is arranged between the second signal detection demodulation module and the second crystal oscillator module;
the phase shift module receives the standard frequency signal, is connected with the signal acquisition processing control module, changes the phase of the standard frequency signal according to the voltage output by the signal acquisition processing control module D/A, generates a phase shift frequency signal as an input signal of the first frequency mixing phase locking module,
the frequency mixing phase locking module is used for adjusting the output frequency of the crystal oscillator module, controlling the frequency of the signal generated by the first crystal oscillator module through the first frequency mixing phase locking module, and controlling the frequency of the signal generated by the second crystal oscillator module through the second frequency mixing phase locking module.
The first frequency mixing phase locking module is connected with the first signal detection module and the phase shifting module, and controls the first crystal oscillator module according to the phase shifting frequency signal and the frequency signal demodulated by the signal detection module,
on the other hand, the invention also provides a high-precision transmission method of the ring network double-channel time frequency, which realizes the time frequency transmission by transmitting the pulse per second signal and the frequency signal between the first interface of the optical fiber and the second interface of the optical fiber through the double-channel optical fiber, any node on the double-channel optical fiber is provided with an optical fiber double-channel time frequency high-precision transmission intermediate node device to obtain the high-precision time frequency signal,
the phase delay drift of the device is obtained through digital measurement, and the phase shift module is controlled to correct the phase, so that the phase of the frequency signal received by the second signal detection demodulation module is consistent with the phase of the standard frequency signal.
The device and the method for transmitting the intermediate node in the looped network with the double-channel time frequency and the high precision have the following beneficial effects:
(1) The pulse per second signal and the frequency signal are both transmitted in two directions, and the time transmission precision is high;
(2) The frequency signal is adjusted in a mode of combining digital control and analog quantity control, the adjusting speed is high, and the noise is low;
(3) The structure of the double-channel time frequency transmission device is simplified, and the possibility of acquiring time frequency signals at any node position of the optical fiber with high precision is realized.
Drawings
Fig. 1 shows a schematic diagram of a two-channel time-frequency high-precision transmission device of a ring network according to a preferred embodiment.
Detailed Description
The features and advantages of the present invention will become more apparent and appreciated from the following detailed description of the invention, as illustrated in the accompanying drawings.
The word "exemplary" is used exclusively herein to mean "serving as an example, embodiment, or illustration. Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. While the various aspects of the embodiments are presented in drawings, the drawings are not necessarily drawn to scale unless specifically indicated.
On one hand, the invention provides a looped network double-channel time frequency high-precision transmission device, which comprises two double optical fiber interfaces, namely an optical fiber first interface and an optical fiber second interface, wherein the optical fiber first interface and the optical fiber second interface are double-channel optical fiber interfaces and are connected through optical fibers.
According to the invention, an optical fiber dual-channel time frequency high-precision transmission intermediate node device can be arranged at any position in the middle of an optical fiber to acquire a time frequency signal.
The optical fiber dual-channel time frequency high-precision transmission intermediate node device is a device capable of recovering time frequency signals at the intermediate node of an optical fiber. The optical fiber double-channel time frequency high-precision transmission intermediate node device can obtain a high-precision time frequency signal by simultaneously connecting an optical fiber first interface and an optical fiber second interface through an optical fiber,
furthermore, a pulse per second signal and a frequency signal can be transmitted between the first optical fiber interface and the second optical fiber interface through the optical fiber, the marking time is represented by the phase of the frequency signal and the pulse per second signal, wherein the pulse per second signal is used as a rough time marker, and the phase of the frequency signal is used as a fine time marker, so that the precise transmission of time is realized.
The dual channel includes a first channel and a second channel, and the first channel and the second channel both transmit signals with pulse-per-second signals and frequency signals.
According to the invention, the looped network dual-channel time frequency high-precision transmission device comprises a signal comprehensive modulation module, a signal detection demodulation module, a pulse per second sending and receiving processing module, a crystal oscillator module and a signal acquisition processing control module, as shown in fig. 1, the number of the signal comprehensive modulation module, the number of the signal detection demodulation module, the number of the pulse per second sending and receiving processing module and the number of the crystal oscillator module are two, and the two modules are respectively marked as a first signal comprehensive modulation module, a first signal detection demodulation module, a first pulse per second sending and receiving processing module, a first crystal oscillator module, a second signal comprehensive modulation module, a second signal detection demodulation module, a second pulse sending and receiving processing module and a second crystal oscillator module.
Specifically, the signal synthesis modulation module is used for modulating and transmitting signals, and modulating the pulse per second signal and the frequency signal in a carrier wave, wherein,
the first signal comprehensive modulation module is connected with the first second pulse sending, receiving and processing module and the first crystal oscillator module, can receive second pulse signals transmitted by the first second pulse sending, receiving and processing module and frequency signals transmitted by the first crystal oscillator module, modulates the second pulse signals and the frequency signals onto a carrier, and sends the second pulse signals and the frequency signals out through a first channel of a first interface of the optical fiber;
the second signal comprehensive modulation module is connected with the second pulse-per-second sending and receiving processing module and the second crystal oscillation module, can receive the pulse-per-second signal transmitted by the second pulse sending and receiving processing module and the frequency signal transmitted by the second crystal oscillation module, modulates the pulse-per-second signal and the frequency signal onto a carrier, and sends the modulated signal out through a second channel of the second optical fiber interface.
In a preferred embodiment, the signal synthesis modulation module divides each second into two time periods, denoted T 1 、T 2 A time period. At T 1 Time period, sending pulse-per-second signal, at T 2 And a period for transmitting a frequency signal. Further, in one second, T 1 The time interval length is 100-800 ns, and the rest time is T 2 A time period.
The signal detection demodulation module is used for demodulating a pulse per second signal and a frequency signal in a carrier wave, wherein,
the first signal detection demodulation module is connected with the first second pulse sending, receiving and processing module and the first signal acquisition processing control module, can receive and demodulate a carrier signal transmitted by a second channel of the first interface of the optical fiber, transmits the demodulated second pulse signal to the first second pulse sending, receiving and processing module, and transmits the demodulated frequency signal to the first signal acquisition processing control module;
the second signal detection demodulation module is connected with the second pulse per second sending and receiving processing module and the second crystal oscillator module, can receive and demodulate a carrier signal transmitted by a first channel of the second interface of the optical fiber, transmits the demodulated pulse per second signal to the second pulse sending and receiving processing module, and transmits the demodulated frequency signal to the second crystal oscillator module.
The pulse per second sending and receiving processing module is used for generating a pulse per second signal, the pulse per second signal is a high-low level signal, the start of each second is marked by the conversion of the high-low level of the pulse per second signal, and the rising edge is used as a signal for the start of the pulse per second. Further, the pulse per second sending and receiving processing module is connected with the crystal oscillator module, and can acquire the frequency signal output by the crystal oscillator module. The frequency signal is a sine wave signal, and at the beginning of each second, the rising edge of the pulse per second signal is aligned with the zero crossing point of the frequency signal, so that the phase of the frequency signal and the pulse per second signal can be kept in fixed alignment.
The first second pulse sending, receiving and processing module can obtain a standard second pulse signal and generate a second pulse signal on the basis of the standard second pulse signal.
Further, the first second pulse sending and receiving processing module can obtain the delay lead, generate a second pulse signal in advance according to the delay lead, and transmit the second pulse signal to the first signal comprehensive modulation module.
Specifically, when the first second pulse sending and receiving processing module obtains the delay advance, an initial second pulse signal is generated first, the initial second pulse signal is transmitted to the first signal comprehensive modulation module and is sent out through the first optical fiber interface, the initial second pulse signal is transmitted to the second optical fiber interface along the optical fiber, is demodulated by the second signal detection demodulation module and is transmitted to the second pulse sending and receiving processing module, the second pulse sending and receiving processing module generates a new second pulse signal according to the received signal, the second pulse signal is transmitted to the second signal comprehensive modulation module, is modulated by the second signal comprehensive modulation module and is sent out through the second channel of the second optical fiber interface, the signal is transmitted to the first optical fiber interface along the optical fiber, and is demodulated by the first signal detection demodulation module and then is transmitted to the first second pulse sending and receiving processing module. The first second pulse sending and receiving processing module obtains the time delay lead by measuring the time interval between the signals transmitted to the first signal comprehensive modulation module and the signals received and transmitted by the first signal detection demodulation module, dividing the time interval by 2 after subtracting the sending time delay and the receiving time delay, and adding the sending time delay of the first optical fiber interface and the receiving time delay of the second optical fiber interface.
The sending time delay, the receiving time delay, the sending time delay of the optical fiber first interface and the receiving time delay after the optical fiber second interface are related to the performance of a device module, and the device is obtained through related performance tests after being produced.
And the second pulse per second sending and receiving processing module is used for receiving the pulse per second signal demodulated by the second signal detection demodulation module, taking the pulse per second signal as a reference signal for generating the pulse per second signal, recovering the pulse per second signal by taking the zero-crossing position of the sine wave signal as the rising edge of the pulse, and transmitting the pulse per second signal to the second signal comprehensive modulation module.
Specifically, the second pulse-per-second transmitting/receiving processing module acquires the frequency signal output by the second oscillator module, generates a plurality of pulse signals by using a zero-crossing point of the frequency signal as a rising edge of the pulse-per-second, and selects a pulse signal closest to the reference signal from the plurality of pulse signals as the recovered pulse-per-second signal.
The crystal oscillator module is used for generating a frequency signal.
The frequency signal generated by the first crystal oscillator module can be transmitted to the local second pulse sending and receiving processing module, the local signal comprehensive modulation module and the first signal acquisition processing control module;
the frequency signal generated by the second crystal oscillator module can be transmitted to the second pulse sending, receiving and processing module, the second signal comprehensive modulation module and the signal acquisition and processing module.
The signal acquisition processing control module is used for comparing the frequency signal output by the first crystal oscillator module, the standard frequency signal, the frequency signal output by the second crystal oscillator module and the frequency signal demodulated by the first signal detection demodulation module to obtain the relative phase between the signals, and realizes indirect control of the phase of the frequency signal output by the first crystal oscillator module by adjusting the phase of the frequency signal output by the phase shifting module, so that the phase of the frequency signal output by the second crystal oscillator module is consistent with the phase of the standard frequency signal.
Specifically, the first signal acquisition processing control module comprises a multi-channel A/D acquisition unit, a calculation unit and a D/A unit, wherein the A/D acquisition unit acquires frequency signals, the calculation unit calculates relative phases among the frequency signals, and the D/A unit outputs phases of control sine wave signals.
In a preferred embodiment, a down-conversion module is further provided between the first signal acquisition processing control module and the first signal detection and demodulation module, the first crystal oscillator module, the second crystal oscillator module, and before the standard frequency signal is acquired, and each frequency signal is down-converted through the down-conversion module to reduce the frequency of the frequency signal, so as to reduce the performance requirement on the first signal acquisition processing control module, and facilitate the a/D acquisition unit to acquire the phase more accurately.
In a preferred embodiment, a first mixing phase-locking module and a phase-shifting module are disposed between the signal acquisition processing control module and the first crystal oscillator module, and further, a second mixing phase-locking module is disposed between the second signal detection demodulation module and the second crystal oscillator module.
The phase shifting module receives the standard frequency signal, is connected with the signal acquisition processing control module, changes the phase of the standard frequency signal according to the voltage value output by the signal acquisition processing control module, and generates a phase shifting frequency signal as an input signal of the first frequency mixing phase locking module.
The frequency mixing phase locking module is used for adjusting the output frequency of the crystal oscillator module, controlling the frequency of the signal generated by the first crystal oscillator module through the first frequency mixing phase locking module, and controlling the frequency of the signal generated by the second crystal oscillator module through the second frequency mixing phase locking module.
Furthermore, the first frequency-mixing phase-locking module is connected with the first signal detection module and the phase-shifting module, and controls the first crystal oscillator module according to the phase-shifting frequency and the frequency signal demodulated by the signal detection module, so that the frequency phase of the frequency output by the first crystal oscillator module after being transmitted to the second signal detection demodulation module through the optical fiber is the same as the standard frequency phase.
According to the invention, the second mixing phase-locking module locks the output frequency of the second crystal oscillator module according to the received frequency signal output by the first crystal oscillator module, and further, the effect that the phase of the output frequency of the second crystal oscillator module is consistent with that of the standard frequency signal can be realized by adjusting the output frequency of the first crystal oscillator module.
In a preferred embodiment, the first mixing phase-locking module adjusts the output frequency of the first crystal oscillator module, the first mixing phase-locking module receives the frequency signal output by the second crystal oscillator module and the standard frequency signal transmitted by the phase shifting module, mixes the two signals and controls the first crystal oscillator module, so as to change the output frequency of the first crystal oscillator module, so that the frequency signal received by the second mixing phase-locking module is changed, and further, the second mixing phase-locking module changes the output frequency of the second crystal oscillator module, so that the phase of the output frequency of the second crystal oscillator module is consistent with the phase of the standard frequency signal.
Because the frequency mixing phase locking module adjusts the output frequency of the crystal oscillator into analog quantity control adjustment, the invention has the advantages of high frequency phase adjustment speed, high frequency stability and the like.
The inventor finds that each component in the device brings about a phase drift phenomenon in the transmission process of the frequency signal, and the phase drift of the frequency signal can be accumulated along with the long-term operation of the device, so as to cause an accumulated error.
Specifically, an output frequency signal of the first crystal oscillator module is transmitted to the second frequency mixing phase locking module sequentially through the first signal comprehensive modulation module, the first channel and the second signal detection demodulation module;
the output frequency signal of the second crystal oscillator module is transmitted to the signal acquisition processing control module and the first frequency mixing phase locking module sequentially through the second signal comprehensive modulation module, the second channel and the first signal detection demodulation module;
the signal acquisition processing control module acquires a standard frequency signal and an output signal of the first crystal oscillator module, controls the phase shifting module to shift the phase of the standard frequency signal, and transmits the phase-shifted frequency signal to the first frequency mixing phase locking module; the first frequency mixing phase locking module corrects the output frequency of the first crystal oscillator module, so that the frequency phase of the output frequency signal of the second crystal oscillator module locked by the second frequency mixing phase locking module is consistent with the frequency phase of the standard frequency signal.
The phase shift of the standard frequency is controlled by the signal acquisition processing control module and the phase shift module, and the phase drift problem caused by analog quantity control adjustment is solved by controlling the phase by a digital quantity.
In a preferred embodiment, the second crystal oscillator module is connected to the signal acquisition processing control module, so that the signal acquisition processing control module can directly obtain the signal output by the second crystal oscillator module to more accurately measure the phase drift of the device, perform phase correction through the phase shifting module, transmit the phase-corrected signal to the first mixing phase-locked module, control the output frequency signal of the first crystal oscillator module through the first mixing phase-locked module, and further make the phase of the frequency signal received by the second signal detection demodulation module consistent with the phase of the standard frequency signal.
Furthermore, because the signal frequency mixing phase locking module is insensitive to the pulse per second signal with the length of only 100-800 ns, the signal demodulated by the signal detection demodulation module can be mixed with the pulse per second signal, but the signal frequency mixing phase locking module does not influence the control of the signal frequency mixing phase locking module on the crystal oscillator module, the pulse per second transmission can be realized without additional channels, lasers, modulators and the like, and the resources are greatly saved.
On the other hand, the invention also provides a high-precision transmission method of the ring network dual-channel time frequency, which realizes the time frequency transmission by transmitting the pulse per second signal and the frequency signal between the first interface of the optical fiber and the second interface of the optical fiber through the dual-channel optical fiber, and sets the intermediate node device of the optical fiber dual-channel time frequency high-precision transmission at any position on the dual-channel optical fiber, thus obtaining the high-precision time frequency signal.
Furthermore, the frequency signal output by the first crystal oscillator is adjusted through the frequency mixing phase-locking module, so that the phase of the frequency signal output by the second crystal oscillator is consistent with that of the standard frequency signal, and the standard frequency signal received by the frequency mixing phase-locking loop is adjusted through the phase shifting module, so that the phase drift phenomenon caused by devices is eliminated.
Specifically, the method comprises the following steps:
s1, a signal acquisition processing module acquires a standard frequency signal and generates an initial frequency signal; the first second pulse sending, receiving and processing module acquires a second pulse signal and generates an initial second pulse signal; the initial frequency signal and the initial pulse per second signal are sent out through a first interface of the optical fiber;
s2, after the optical fiber second interface receives the initial frequency signal and the initial pulse per second signal, the second crystal oscillator module and the second pulse sending and receiving processing module respectively generate a new frequency signal and a new pulse per second signal, and the new frequency signal and the new pulse per second signal are sent out through the optical fiber second interface;
and S3, adjusting the frequency signal output by the first crystal oscillator through the frequency mixing phase-locking module to enable the phase of the frequency signal output by the second crystal oscillator to be consistent with the phase of the standard frequency signal, adjusting the standard frequency signal received by the frequency mixing phase-locking module through the phase shifting module, further changing the frequency signal output by the first crystal oscillator, and eliminating the phase drift phenomenon generated by the device.
In the invention, the frequency signal and the pulse-per-second signal are modulated in a carrier wave, in particular each second is divided into two time periods, denoted T 1 、T 2 Time period at T 1 Time interval, sending pulse-per-second signal, at T 2 And a period for transmitting the frequency signal. Further, in one second, T 1 The time interval length is 50-500 ns, and the rest time is T 2 A time period.
In step S1, the output frequency signal of the first crystal oscillator module is sequentially transmitted to the second mixing phase-locking module through the local-end signal comprehensive modulation module, the first channel, and the second signal detection demodulation module, and the second mixing phase-locking module controls the output frequency of the second crystal oscillator module according to the received frequency signal.
In step S2, the output frequency signal of the second crystal oscillator module is transmitted to the signal acquisition processing control module and the first mixing phase-locking module sequentially through the second signal comprehensive modulation module, the second channel and the first signal detection demodulation module;
further, the generation of the new pulse per second comprises the following processes:
s21, acquiring the time delay lead, transmitting the second pulse signal from the first second pulse transmitting and receiving processing module to the second pulse transmitting and receiving processing module through measuring the second pulse signal, and transmitting the time interval, the transmitting time delay and the receiving time delay of the first second pulse transmitting and receiving processing module back to the second pulse transmitting and receiving processing module to acquire;
s22, the first second pulse sending and receiving processing module generates a second pulse signal in advance according to the time delay advance and sends the second pulse signal to the second pulse sending and receiving processing module, and the second pulse sending and receiving processing module takes the received second pulse signal as a reference signal;
and S23, generating a plurality of pulse signals by taking the zero-crossing point of the frequency signal output by the second crystal oscillator module as the rising edge of the second pulse, and selecting the pulse signal closest to the reference signal from the plurality of pulse signals as the second pulse signal.
In step S3, the signal acquisition processing control module acquires a standard frequency signal, an output signal of the first crystal oscillator module, an output signal of the second crystal oscillator module, and a signal transmitted by the first signal detection demodulation module, and after digital measurement, controls the phase shift module to shift the phase of the standard frequency signal, and transmits the phase-shifted frequency signal to the first mixing phase-locking module; the first frequency mixing phase locking module corrects the output frequency of the first crystal oscillator module, so that the output frequency of the second crystal oscillator module locked by the second frequency mixing phase locking module is consistent with the frequency phase of the standard frequency signal.
In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", "front", "rear", and the like indicate orientations or positional relationships based on operational states of the present invention, and are only used for convenience of description and simplification of description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," "first," and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
The invention has been described in detail with reference to specific embodiments and illustrative examples, but the description is not intended to be construed in a limiting sense. Those skilled in the art will appreciate that various equivalent substitutions, modifications or improvements may be made to the embodiments and implementations of the invention without departing from the spirit and scope of the invention, and are within the scope of the invention. The scope of the invention is defined by the appended claims.
Claims (6)
1. A high-precision transmission device of double-channel time frequency of a ring network is characterized by comprising a first optical fiber interface and a second optical fiber interface, wherein the first optical fiber interface and the second optical fiber interface are double-channel optical fiber interfaces, and a pulse per second signal and a frequency signal are transmitted between the first optical fiber interface and the second optical fiber interface through optical fibers;
the dual channels comprise a first channel and a second channel, and the signals transmitted by the first channel and the second channel both have pulse per second signals and frequency signals;
the system also comprises a signal comprehensive modulation module, a signal detection demodulation module, a second pulse sending and receiving processing module, a crystal oscillator module and a signal acquisition processing control module, wherein the number of the signal comprehensive modulation module, the number of the signal detection demodulation module, the number of the second pulse sending and receiving processing module and the number of the crystal oscillator module are two, and the signal comprehensive modulation module, the signal detection demodulation module, the second pulse sending and receiving processing module and the crystal oscillator module are respectively a first signal comprehensive modulation module, a first signal detection demodulation module, a first second pulse sending and receiving processing module, a first crystal oscillator module and a second signal comprehensive modulation module, a second signal detection demodulation module, a second pulse sending and receiving processing module and a second crystal oscillator module;
the signal comprehensive modulation module is used for modulating and sending signals and modulating the pulse per second signal and the frequency signal in a carrier wave;
the signal detection demodulation module is used for demodulating a pulse per second signal and a frequency signal in a carrier;
the first signal comprehensive modulation module is connected with the first second pulse transmitting and receiving processing module and the first crystal oscillator module, and the second signal comprehensive modulation module is connected with the second pulse transmitting and receiving processing module and the second crystal oscillator module;
the first signal detection demodulation module is connected with the first second pulse sending, receiving and processing module and the signal acquisition processing control module, receives and demodulates a carrier signal transmitted by a second channel of the first interface of the optical fiber, transmits the demodulated second pulse signal to the first second pulse sending, receiving and processing module, transmits the demodulated frequency signal to the signal acquisition processing control module, is connected with the second pulse sending, receiving and processing module and the second crystal oscillator module, receives and demodulates the carrier signal transmitted by the first channel of the second interface of the optical fiber, transmits the demodulated second pulse signal to the second pulse sending, receiving and processing module, and transmits the demodulated frequency signal to the second crystal oscillator module;
the second pulse sending, receiving and processing module is used for generating a second pulse signal, the first second pulse sending, receiving and processing module can acquire a standard second pulse signal and generate the second pulse signal on the basis of the standard second pulse signal, and the second pulse sending, receiving and processing module receives the second pulse signal demodulated by the second signal detection and demodulation module, and the second pulse signal is used as a reference signal for generating the second pulse signal, generates a second pulse signal and is transmitted to the second signal comprehensive modulation module;
the crystal oscillator module is used for generating frequency signals, the frequency signals generated by the first crystal oscillator module can be transmitted to the first second pulse sending and receiving processing module, the first signal comprehensive modulation module and the signal acquisition processing control module, and the output frequency signals of the first crystal oscillator module are transmitted to the second frequency mixing phase locking module through the first signal comprehensive modulation module, the first channel and the second signal detection demodulation module in sequence; the frequency signal generated by the second crystal oscillator module can be transmitted to the second pulse per second sending and receiving processing module, the second signal comprehensive modulation module and the signal acquisition processing control module, and the output frequency signal of the second crystal oscillator module is transmitted to the signal acquisition processing control module and the first frequency mixing phase locking module through the second signal comprehensive modulation module, the second channel and the first signal detection demodulation module in sequence; the signal acquisition processing control module acquires a standard frequency signal and an output signal of the first crystal oscillator module, controls the phase shifting module to shift the phase of the standard frequency signal, and transmits the phase-shifted frequency signal to the first frequency mixing phase locking module; correcting the output frequency of the first crystal oscillator module through the first frequency mixing phase locking module, so that the frequency phase of an output frequency signal of the second crystal oscillator module locked by the second frequency mixing phase locking module is consistent with the frequency phase of a standard frequency signal;
the signal acquisition processing control module realizes indirect control of the phase of the frequency signal output by the crystal oscillator module by adjusting the phase of the frequency signal output by the phase shifting module;
the signal acquisition processing control module compares the frequency signal output by the first crystal oscillator module, the standard frequency signal, the frequency signal output by the second crystal oscillator module and the frequency signal demodulated by the first signal detection demodulation module to obtain the relative phase among the signals, and realizes indirect control on the phase of the frequency signal output by the first crystal oscillator module by adjusting the phase of the frequency signal output by the phase shifting module, so that the phase of the frequency signal output by the second crystal oscillator module is consistent with the phase of the standard frequency signal;
a first frequency mixing phase-locking module and a phase shifting module are arranged between the signal acquisition processing control module and the first crystal oscillator module, and a second frequency mixing phase-locking module is arranged between the second signal detection demodulation module and the second crystal oscillator module;
the phase shift module receives the standard frequency signal, is connected with the signal acquisition processing control module, changes the phase of the standard frequency signal according to the voltage value output by the signal acquisition processing control module, generates a phase shift frequency signal as an input signal of the first frequency mixing phase locking module,
the frequency mixing phase locking module is used for adjusting the output frequency of the crystal oscillator module, controlling the frequency of a signal generated by the first crystal oscillator module through the first frequency mixing phase locking module, and controlling the frequency of a signal generated by the second crystal oscillator module through the second frequency mixing phase locking module; the first frequency mixing phase locking module is connected with the first signal detection demodulation module and the phase shifting module, and controls the first crystal oscillator module according to the phase shifting frequency and the frequency signal demodulated by the first signal detection demodulation module, so that the frequency phase of the frequency output by the first crystal oscillator module after being transmitted to the second signal detection demodulation module through the optical fiber is the same as the standard frequency phase; the second frequency mixing phase locking module locks the output frequency of the second crystal oscillator module according to the received frequency signal output by the first crystal oscillator module, and the effect that the phase of the output frequency of the second crystal oscillator module is consistent with the phase of the standard frequency signal is achieved; the output frequency of the first crystal oscillator module is adjusted through the first frequency mixing phase locking module, the first frequency mixing phase locking module receives a frequency signal output by the second crystal oscillator module and a standard frequency signal transmitted by the phase shifting module, the two signals are mixed to control the first crystal oscillator module, the output frequency of the first crystal oscillator module is changed, the frequency signal received by the second frequency mixing phase locking module is changed, the output frequency of the second crystal oscillator module is changed through the second frequency mixing phase locking module, and therefore the phase of the output frequency of the second crystal oscillator module is consistent with the phase of the standard frequency signal.
2. The ring network dual-channel time-frequency high precision delivery apparatus of claim 1,
the signal acquisition processing control module comprises a multi-channel A/D acquisition unit, a calculation unit and a D/A unit, wherein the A/D acquisition unit acquires frequency signals, the calculation unit calculates relative phases among the frequency signals, and the D/A unit outputs phases for controlling sine wave signals.
3. The ring network dual-channel time-frequency high precision delivery apparatus of claim 1,
and a down-conversion module is arranged among the signal acquisition and processing control module, the first signal detection and demodulation module, the first crystal oscillator module and the second crystal oscillator module and before the standard frequency signal is acquired.
4. The ring network dual-channel time-frequency high precision delivery apparatus of claim 1,
the first frequency mixing phase locking module is connected with the first signal detection module and the phase shifting module, and controls the first crystal oscillator module according to the phase shifting frequency signal and the frequency signal demodulated by the first signal detection module.
5. A looped network double-channel time frequency high-precision transmission method, which realizes time frequency transmission by transmitting a pulse per second signal and a frequency signal through a double-channel optical fiber between an optical fiber first interface and an optical fiber second interface, wherein a high-precision time frequency signal can be obtained by arranging an optical fiber double-channel time frequency high-precision transmission intermediate node device at any node on the double-channel optical fiber, and the optical fiber double-channel time frequency high-precision transmission intermediate node device is the looped network double-channel time frequency high-precision transmission device as claimed in any one of claims 1 to 4.
6. The method for high precision transmission of time frequency of two channels in ring network according to claim 5,
the phase delay drift of the device is obtained through digital measurement, and the phase shift module is controlled to correct the phase, so that the phase of the frequency signal received by the second signal detection demodulation module is consistent with the phase of the standard frequency signal.
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