Timing system control unit in measurement and control system

Abstract

The invention discloses a timing system control unit in a measurement and control system. The timing system control unit comprises a first time-frequency source, a second time-frequency source, a phase testing unit, an internal processing unit and an OCXO (Oven Controlled Crystal Oscillator), the phase testing unit collects time-frequency signals input by the first time-frequency source, the second time-frequency source and the OCXO respectively, compares the input signals of the first time-frequency source with the input signals of the OCXO and compares the input signals of the second time-frequency source with the input signals of the OCXO respectively. Obtaining a first phase correction value and a second phase correction value; the internal processor obtains a phase difference between the first time-frequency source and the second time-frequency source based on the first phase correction value and the second phase correction value, and the phase difference is recorded as a time-frequency source correction value; and when time-frequency source switching is carried out, the internal processor completes phase fine tuning of the switched time-frequency source based on the time-frequency source correction value, so that phase synchronization of the first time-frequency source and the second time-frequency source is ensured.

Description

Technical Field

[0001] The present application belongs to the technical field of time-frequency control, and in particular, relates to a time-frequency control unit in a measurement and control system. Background Art

[0002] In order to build a highly secure and reliable measurement and control system, the stability and reliability of the time and frequency equipment are particularly important for the measurement and control system. Generally, the time control unit is configured with two or more frequency standards to form a backup working clock group. If effective technical measures are not taken, when the working time and frequency equipment fails and needs to be switched to another time and frequency equipment, it will cause a large change in the phase of the frequency source inside the equipment (us level), causing the time frequency to jump and then cause the measurement and control system to work abnormally. Therefore, the problem of lossless switching of the phase of the frequency signal must be solved in the design of the time control unit. Summary of the invention

[0003] The purpose of this application is to overcome the problems of the prior art and disclose a time control unit in a measurement and control system. The structural design of the time control unit of this application realizes the continuity of the phases of different time frequency sources when different frequency sources are switched arbitrarily, thereby ensuring the stability and reliability of the measurement and control communication system and having broad application prospects.

[0004] The purpose of this application is achieved through the following technical solutions:

[0005] A time control unit in a measurement and control system, the time control unit comprising: a first time-frequency source, a second time-frequency source, a phase test unit, an internal processing unit, and a constant temperature crystal oscillator (OCXO);

[0006] The phase test unit collects the time-frequency signals input by the first time-frequency source, the second time-frequency source, and the oven-controlled crystal oscillator OCXO, and respectively compares the first time-frequency source input signal with the oven-controlled crystal oscillator OCXO input signal, and compares the second time-frequency source input signal with the oven-controlled crystal oscillator OCXO input signal, to obtain a first phase correction value and a second phase correction value;

[0007] The internal processor obtains a phase difference between the first time-frequency source and the second time-frequency source based on the first phase correction value and the second phase correction value, and records it as a time-frequency source correction value;

[0008] During the measurement and control operation of the measurement and control system, when the first time-frequency source or the second time-frequency source fails and the time-frequency source is switched, the internal processor completes the phase fine-tuning of the time-frequency source after switching based on the time-frequency source correction value, thereby ensuring the phase synchronization of the first time-frequency source and the second time-frequency source.

[0009] According to a preferred implementation, the oven-controlled crystal oscillator OCXO uses a 48-bit direct digital frequency synthesizer DDS to output a 10 MHz signal, and the input of the direct digital frequency synthesizer DDS is a 40 MHz clock signal.

[0010] According to a preferred embodiment, the frequency correction word of the direct digital frequency synthesizer DDS is 48 bits, and the frequency adjustment accuracy of the oven controlled crystal oscillator OCXO is:

[0011]

[0012] According to a preferred embodiment, the phase correction word of the direct digital frequency synthesizer DDS is 14 bits, and the phase adjustment resolution of the oven controlled crystal oscillator OCXO is:

[0013]

[0014] According to a preferred embodiment, the first time-frequency source and the second time-frequency source are atomic clocks.

[0015] According to a preferred embodiment, the first time-frequency source and the second time-frequency source are rubidium atomic clocks.

[0016] The aforementioned main scheme of the present application and its further options can be freely combined to form multiple schemes, all of which are schemes that can be adopted and claimed for protection in the present application. After understanding the scheme of the present application, those skilled in the art can understand that there are multiple combinations based on the prior art and common knowledge, all of which are technical schemes to be protected by the present application, and they are not exhaustively listed here.

[0017] Beneficial effects of this application:

[0018] In view of the shortcomings of the existing system, the present invention proposes a solution to the phase change caused by switching between any two or more different 10MHz frequency standard sources, effectively solving the shutdown of the measurement and control system caused by frequency source failure, and ensuring that the measurement and control system works uninterruptedly for 24 hours. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of an implementation of the time control unit in the measurement and control system of the present application;

[0020] Figure 2 This is a schematic diagram of phase lossless switching. DETAILED DESCRIPTION

[0021] The following describes the embodiments of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. The present application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0022] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0023] In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0024] In addition, the present application would like to point out that, in the present application, unless the specific structure, connection relationship, positional relationship, power source relationship, etc. are specifically written out, the structure, connection relationship, positional relationship, power source relationship, etc. involved in the present application are all known by those skilled in the art on the basis of the prior art without creative work.

[0025] In order to build a highly secure and reliable time and frequency device, the measurement and control system is equipped with multiple time and frequency devices, each of which has a built-in rubidium atomic clock to form a working clock group that backs up each other. When the time and frequency devices are switched, if effective technical measures are not taken, it will cause a large change in phase (us level) and a jump in time and frequency, which will cause abnormal operation of the measurement and control system. Therefore, the phase jump problem of the frequency signal when multiple time and frequency devices are switched must be solved in the system design.

[0026] refer to Figure 1 and Figure 2 As shown, the present application discloses a time control unit in a measurement and control system, wherein the time control unit includes: a first time-frequency source, a second time-frequency source, a phase test unit, an internal processing unit, and a constant temperature crystal oscillator (OCXO).

[0027] The phase test unit collects the time-frequency signals input by the first time-frequency source, the second time-frequency source, and the oven-controlled crystal oscillator OCXO, and respectively compares the first time-frequency source input signal with the oven-controlled crystal oscillator OCXO input signal, and compares the second time-frequency source input signal with the oven-controlled crystal oscillator OCXO input signal, to obtain a first phase correction value and a second phase correction value;

[0028] The internal processor obtains a phase difference between the first time-frequency source and the second time-frequency source based on the first phase correction value and the second phase correction value, and records it as a time-frequency source correction value;

[0029] During the measurement and control operation of the measurement and control system, when the first time-frequency source or the second time-frequency source fails and the time-frequency source is switched, the internal processor completes the phase fine-tuning of the time-frequency source after switching based on the time-frequency source correction value, thereby ensuring the phase synchronization of the first time-frequency source and the second time-frequency source.

[0030] Preferably, the oven-controlled crystal oscillator OCXO uses a 48-bit direct digital frequency synthesizer DDS to output a 10 MHz signal, and the input of the direct digital frequency synthesizer DDS is a 40 MHz clock signal.

[0031] Furthermore, the frequency correction word of the direct digital frequency synthesizer DDS is 48 bits, and the frequency adjustment accuracy of the oven controlled crystal oscillator OCXO is:

[0032] This can meet the system frequency correction accuracy requirement of ≤1E-13.

[0033] Furthermore, the phase correction word of the direct digital frequency synthesizer DDS is 14 bits, and the phase adjustment resolution of the oven controlled crystal oscillator OCXO is:

[0034] The resolution of phase adjustment is less than 10ps, which meets the 100ps requirement of the 10MHz output clock phase jump before and after switching, and improves the reliability of the measurement and control system in the mission.

[0035] The first time-frequency source and the second time-frequency source are atomic clocks.

[0036] That is, in view of the shortcomings of the existing system, the present invention proposes a solution to the phase change caused by the switching of any two or more different 10MHz frequency standard sources. The seamless switching of the frequency standard source phase can effectively solve the shutdown of the measurement and control system caused by frequency source failure, ensuring that the measurement and control system works uninterruptedly for 24 hours.

[0037] Specifically, as a time-frequency device that provides time-frequency signals to the measurement and control system, the corresponding time-frequency device consists of three parts: two independent 10MHz frequency sources (the first time-frequency source and the second time-frequency source) and a switching device. The two 10MHz frequency sources and the switching device are independently designed in physical structure. The 10MHz signals output by the two 10MHz frequency sources are sent to the switching device. The switching device has the function of automatically switching the input signal according to the presence or absence of the signal, and can compensate for the phase difference introduced by the switching of the two signals based on the time-frequency source correction value input by the internal processor, thereby realizing seamless switching of the phases of two different 10MHz frequency standard sources, thereby improving the reliability of the measurement and control communication system in the mission.

[0038] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A time control unit in a measurement and control system, characterized in that: The timing control unit includes: a first time-frequency source, a second time-frequency source, a phase test unit, an internal processing unit, and an oven-controlled crystal oscillator (OCXO); The phase test unit collects the time-frequency signals input by the first time-frequency source, the second time-frequency source, and the oven-controlled crystal oscillator OCXO, and respectively compares the first time-frequency source input signal with the oven-controlled crystal oscillator OCXO input signal, and compares the second time-frequency source input signal with the oven-controlled crystal oscillator OCXO input signal, to obtain a first phase correction value and a second phase correction value; The internal processor obtains a phase difference between the first time-frequency source and the second time-frequency source based on the first phase correction value and the second phase correction value, and records it as a time-frequency source correction value; During the measurement and control operation of the measurement and control system, when the first time-frequency source or the second time-frequency source fails and the time-frequency source is switched, the internal processor completes the phase fine-tuning of the time-frequency source after switching based on the time-frequency source correction value, thereby ensuring the phase synchronization of the first time-frequency source and the second time-frequency source.

2. The time control unit according to claim 1, characterized in that: The oven controlled crystal oscillator OCXO uses a 48-bit direct digital frequency synthesizer DDS to output a 10 MHz signal, and the input of the direct digital frequency synthesizer DDS is a 40 MHz clock signal.

3. The time control unit according to claim 2, characterized in that: The frequency correction word of the direct digital frequency synthesizer DDS is 48 bits, so the frequency adjustment accuracy of the oven-controlled crystal oscillator OCXO is:

4. The time control unit according to claim 2, characterized in that: The phase correction word of the direct digital frequency synthesizer DDS is 14 bits, and the phase adjustment resolution of the oven controlled crystal oscillator OCXO is:

5. The time control unit according to claim 1, characterized in that: The first time-frequency source and the second time-frequency source are atomic clocks.

6. The time control unit according to claim 5, characterized in that: The first time-frequency source and the second time-frequency source are rubidium atomic clocks.

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