Comprehensive frequency calibration device

Abstract

The invention discloses a comprehensive frequency calibration device, belongs to the technical field of electronic information systems, and solves the problems that the conventional timing equipment needs to be disassembled when the internal frequency standard is calibrated, the inspection procedure is tedious, the period is long, and the use of a user is influenced. A comprehensive frequency calibration device comprises a receiving unit which is used for receiving a satellite signal, analyzing the satellite signal and transmitting the analyzed satellite signal to a rubidium clock unit; the rubidium clock unit is used for outputting an internal frequency standard signal calibrated by the analyzed satellite signal; the input unit is used for inputting a signal to be detected and an external reference signal; the input unit and the rubidium clock unit are connected with the control unit, and the input unit and the rubidium clock unit are used for receiving, processing and outputting the external reference signal, the signal to be detected and the internal frequency standard signal. The comprehensive frequency calibration device provided by the invention can read and calibrate the frequency of the internal frequency standard of the timing equipment on site.

Description

Technical Field

[0001] The invention belongs to the technical field of electronic information systems, and in particular relates to a comprehensive frequency calibration device. Background Art

[0002] Time synchronization equipment (hereinafter referred to as "time synchronization equipment") mainly receives standard time information (such as GPS, GLONASS, Beidou, B code, shortwave, etc.) and maintains high-precision synchronization with it. At the same time, it provides unified standard time to various time users in the form of multiple interfaces, thereby achieving time unification. Time synchronization equipment can maintain high-precision timekeeping for a long time without an external signal source. Its timekeeping accuracy depends on the timekeeping error of the internal frequency standard (mainly rubidium atomic clocks, and a few are constant temperature crystal oscillators). The main source of the timekeeping error is the frequency and drift rate of the internal frequency standard configuration. The timekeeping error is related to the timekeeping time of the equipment, and the error will accumulate over time. As one of the core components of the time synchronization equipment, the internal frequency standard determines the aging drift phenomenon under long-term continuous operation due to physical mechanisms, and the output indicators will be out of tolerance.

[0003] The time system equipment delivered in the early stage does not have the function of monitoring and calibrating the internal frequency standard, and cannot test whether the internal frequency standard needs to have deviation. If there is a deviation, calibration measurement is required to correct the frequency deviation caused by aging. The operation process is to remove the frequency standard from the time system equipment and send it to the calibration laboratory for calibration, and then reinstall it into the time system equipment after the calibration is completed. Removing the internal frequency standard will cause the time system equipment to not work properly, and the inspection procedure is cumbersome and has a long cycle, which affects user use. Summary of the invention

[0004] The purpose of the present invention is to provide a comprehensive frequency calibration device, which solves the problem that the internal frequency standard of the time system equipment needs to be disassembled during calibration and the inspection procedure is cumbersome and has a long cycle, which affects user use.

[0005] In order to achieve the above object, the technical solution of the present invention is implemented as follows: a comprehensive frequency calibration device, characterized in that it includes:

[0006] A receiving unit, used for receiving satellite signals and transmitting them to the rubidium clock unit after analyzing them;

[0007] A rubidium clock unit, used for outputting an internal frequency standard signal calibrated by the analyzed satellite signal;

[0008] An input unit, used for inputting a signal to be tested and an external reference signal;

[0009] The control unit, the input unit and the rubidium clock unit are connected to the control unit, and are used to receive the external reference signal, the signal to be measured and the internal frequency standard signal and process and output them.

[0010] In some embodiments, the comprehensive frequency calibration device further includes a display unit, which is connected to the control unit and is used to display data output by the control unit.

[0011] In some embodiments, the control unit includes an external reference signal conditioning module, a signal conditioning module to be tested, a reference selection module, an error multiplication module and a frequency measurement module, wherein the external reference signal conditioning module is sequentially connected to the reference selection module, the error multiplication module and the frequency measurement module, and the signal conditioning module to be tested is respectively connected to the error multiplication module and the frequency measurement module.

[0012] In some embodiments, the external reference signal conditioning module outputs an external frequency standard signal after conditioning the external reference signal, and feeds the output external frequency standard signal back to the reference selection module and the frequency measurement module;

[0013] The signal conditioning module outputs a standard signal to be tested after conditioning the signal to be tested, and feeds back the output standard signal to be tested to the error multiplication module and the frequency measurement module;

[0014] The reference selection module is connected to the rubidium clock unit, and the reference selection module selects the internal frequency standard signal output by the rubidium clock unit and the external frequency standard signal output by the external reference signal conditioning module, and transmits the selected signals to the error multiplication module and the frequency measurement module respectively;

[0015] The error multiplication module performs frequency difference signal identification on the signal output by the reference selection module and the standard signal to be measured and transmits the result to the frequency measurement module;

[0016] The frequency measurement module measures the external frequency standard signal, the internal frequency standard signal, the standard signal to be measured and the frequency difference signal.

[0017] In some embodiments, the control unit further includes a drive isolation module, which is connected to the reference selection module. The drive isolation module receives a signal output by the reference selection module and transmits it to an external device.

[0018] In some embodiments, the rubidium clock unit and the control unit are both connected to the terminal device to monitor the status of the rubidium clock unit and the external timing device.

[0019] In some embodiments, the external reference signal is 5 / 10 MHz.

[0020] In some embodiments, the comprehensive frequency calibration device further includes a power supply unit, which is connected to an external device under test and supplies power to the comprehensive frequency calibration device itself.

[0021] In some embodiments, the power supply unit includes a power filter and a DC / DC power supply connected to the power filter, the power filter converts AC 220V into DC 24V, and the DC / DC power supply outputs DC 24V into two paths, namely DC 12V and DC 24V.

[0022] In some embodiments, the signal to be tested is connected to a constant temperature crystal oscillator of an external timing device or a rubidium clock of an external timing device.

[0023] Compared with the prior art, the comprehensive frequency calibration device of the present invention can read and calibrate the frequency of the internal frequency standard of the time system equipment on site, which not only improves the frequency accuracy of the internal frequency standard of the time system, but also reduces the maintenance time without affecting the user's use. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A schematic diagram of a comprehensive frequency calibration device provided by an embodiment of the present invention;

[0025] Figure 2 A schematic diagram of a control unit in a comprehensive frequency calibration device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0027] In the description of the present invention, it should be clarified that the terms "vertical", "lateral", "longitudinal", "front", "rear", "left", "right", "up", "down", "horizontal" and the like indicating orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not mean that the device or element referred to must have a specific orientation or position, and therefore cannot be understood as a limitation on the present invention. In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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 an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] The comprehensive frequency calibration device provided by the embodiment of the present invention is as follows: Figure 1 As shown, including:

[0029] A receiving unit, used for receiving satellite signals and transmitting them to the rubidium clock unit after analyzing them;

[0030] The rubidium clock unit is used to output the internal frequency standard signal for calibrating the analyzed satellite signal;

[0031] An input unit, used for inputting a signal to be tested and an external reference signal;

[0032] The control unit, the input unit and the rubidium clock unit are connected to the control unit, and are used to receive the external reference signal, the signal to be measured and the internal frequency standard signal and process and output them.

[0033] After adopting the above scheme, the comprehensive frequency calibration device can read and calibrate the frequency of the internal frequency standard of the time system equipment on site, which not only improves the frequency accuracy of the internal frequency standard of the time system, but also reduces the maintenance time without affecting the user's use.

[0034] More specifically, the receiving unit is a receiver that receives satellite signals and analyzes them to obtain standard 1PPS signals. This embodiment uses WXJ-GB21 from Satellite Jie. The module integrates a dual-mode baseband chip and a radio frequency chip. It has the characteristics of small size and low power consumption. The module can realize BD2 or GPS positioning and timing alone, and can also realize BD2 / GPS dual-system hybrid positioning and timing. Its timing accuracy is better than 100ns, and its performance is stable.

[0035] The outdoor CPU of the control unit adopts ST's ARM chip STM32F207ZET6, which is only 20×20 in size, has rich internal resources, strong processing capability, and a maximum clock of 120MHz. The peripheral interface has a LOCAL BUS bus to realize receiver control and information analysis, rubidium clock training, parameter storage and external monitoring functions.

[0036] The interface model of the rubidium clock unit is SMA, which is connected to the control unit by means of a flat cable. The interface on the rubidium clock side is DB-9S.

[0037] In a specific implementation process of this embodiment, the comprehensive frequency calibration device further includes a display unit, which is connected to the control unit and is used to display data output by the control unit.

[0038] More specifically, the display unit may be a display keypad, which includes keys, LED lights and a liquid crystal screen. The brightness of the LED lights is adjusted by the display keys, and the liquid crystal screen displays the data output by the control unit.

[0039] In the specific implementation process of this embodiment, Figure 2As shown, the control unit includes an external reference signal conditioning module, a signal conditioning module to be measured, a reference selection module, an error multiplication module and a frequency measurement module. The external reference signal conditioning module is connected to the reference selection module, the error multiplication module and the frequency measurement module in sequence, and the signal conditioning module to be measured is connected to the error multiplication module and the frequency measurement module respectively.

[0040] In the specific implementation process of this embodiment, Figure 2 As shown, the external reference signal conditioning module outputs an external frequency standard signal after conditioning the external reference signal, and feeds the output external frequency standard signal back to the reference selection module and the frequency measurement module;

[0041] The signal conditioning module outputs a standard signal to be tested after conditioning the signal to be tested, and feeds back the output standard signal to be tested to the error multiplication module and the frequency measurement module;

[0042] The reference selection module is connected to the rubidium clock unit, and the reference selection module selects the internal frequency standard signal output by the rubidium clock unit and the external frequency standard signal output by the external reference signal conditioning module, and transmits the selected signals to the error multiplication module and the frequency measurement module respectively;

[0043] The error multiplication module discriminates the frequency difference signal between the signal output by the reference selection module and the standard signal to be measured and transmits the result to the frequency measurement module;

[0044] The frequency measurement module measures the external frequency standard signal, the internal frequency standard signal, the standard signal to be measured and the frequency difference signal.

[0045] More specifically, the external reference signal conditioning module conditions the external reference signal and outputs the external frequency standard signal to the reference selection module and the frequency measurement module;

[0046] The external reference signal conditioning module is composed of an external reference signal conditioning circuit, which includes a first emitter-follower circuit, a first frequency selector, a first bandpass filter, and a first time-frequency distributor; after the standard 5 / 10MHz signal is amplified by the current of the first emitter-follower circuit, it enters the first frequency selector and the first bandpass filter to select a 10M sinusoidal signal, and the standard 10M signal is multi-channel output through the first time-frequency distributor;

[0047] The signal conditioning module to be tested conditions the signal to be tested and outputs the standard signal to be tested to the error multiplication module and the frequency measurement module;

[0048] The signal conditioning module to be tested is composed of a signal conditioning circuit to be tested, and the signal conditioning circuit to be tested includes a second radio-follower circuit, a second frequency selector, a second band-pass filter, and a second time-frequency distributor; after the current amplification of the 5 / 10MHz signal to be tested by the second radio-follower circuit, it enters the second frequency selector and the second band-pass filter to select a 10M sinusoidal signal, and the 10M signal to be tested is multi-channel output by the second time-frequency distributor;

[0049] The reference selection module selects an external frequency standard or an internal frequency standard according to the user setting. When the external frequency standard is valid, the external frequency standard is automatically selected. When the external frequency standard is invalid, the internal frequency standard is automatically selected. The reference selection module selects a reference source according to whether there is a satellite signal. The comprehensive frequency calibration device receives the satellite signal and analyzes it to obtain a standard 1PPS signal. The rubidium clock inside the rubidium clock unit is calibrated with the standard 1PPS signal, and an internal frequency standard signal, i.e., a standard 5 / 10MHz signal, is output. If there is no satellite signal, the on-site standard 5 / 10MHz signal is used as a reference to the external frequency standard signal. The reference selection module is connected to the rubidium clock unit, and the internal frequency standard signal output by the rubidium clock unit and the external frequency standard signal output by the external reference signal conditioning module are selected, and the selected signals are transmitted to the error multiplication module and the frequency measurement module respectively.

[0050] The error multiplication module identifies the frequency difference signal between the signal output by the reference selection module and the standard signal to be measured and transmits the result to the frequency measurement module; the error multiplication module is a filter amplification and shaping circuit, and the filter amplification and shaping circuit realizes the filtering of the output 500Hz signal;

[0051] The frequency measurement module measures the external frequency standard signal, the internal frequency standard signal, the standard signal to be measured and the frequency difference signal.

[0052] In the specific implementation process of this embodiment, Figure 2 As shown, the control unit also includes a drive isolation module, which is connected to the reference selection module. The drive isolation module receives a signal output by the reference selection module and transmits it to an external device.

[0053] More specifically, the signal output by the reference selection module in the control unit of the comprehensive frequency comparison device can also provide a reference for external equipment.

[0054] In the specific implementation process of this embodiment, the rubidium clock unit and the control unit are both connected to the terminal device to monitor the status of the rubidium clock unit and the external timing device.

[0055] More specifically, the rubidium clock unit realizes the taming function of the built-in rubidium clock and the external rubidium clock. The rubidium clock unit and the control unit are both connected to the terminal device, and can monitor the rubidium clock unit and the control unit through the serial port and adjust their frequencies. The serial port adopts the RS232 interface, and the terminal device can record and analyze the data.

[0056] In the specific implementation process of this embodiment, the external reference signal is 5 / 10 MHz.

[0057] More specifically, the waveform of the signal to be tested is a sine wave or a square wave, and the external reference signal is a standard 5 / 10MHz, and the waveform is a sine wave. The comprehensive frequency calibration device can provide a universal reference signal for a variety of external devices on the market.

[0058] In the specific implementation process of this embodiment, Figure 1 As shown, the comprehensive frequency calibration device also includes a power supply unit, which is connected to an external device to be tested and supplies power to the comprehensive frequency calibration device itself.

[0059] In the specific implementation process of this embodiment, the power supply unit includes a power filter and a DC / DC power supply connected to the power filter. The power filter converts AC 220V into DC 24V, and the DC / DC power supply outputs DC 24V into two paths, namely DC 12V and DC 24V.

[0060] More specifically, since the rubidium clock and the external serial port level are in RS232 standard, and the CPU interface standard is LVTTL, a level conversion circuit is required to achieve the conversion of the level standard. The power supply unit can convert 220V AC into stable 24V and 12V DC. In addition to powering itself, it can also power external devices under test. The rubidium clock unit is also connected to the power supply unit by means of a flat cable, and the interface on the rubidium clock side is DB-9S.

[0061] The CPU power supply inside the control unit is 3.3V. The method of directly converting +12V to 3.3V through a low-voltage difference linear regulator (i.e., LDO) is too inefficient, and the direct DC / DC conversion method often has too large ripples. Therefore, a combination of DC / DC and LDO is adopted to convert +12V to +5V through DC / DC, and then convert +5V to +3.3V through LDO. In this embodiment, the DC / DC adopts a mature module circuit, and the LDO adopts a dedicated LDO chip, and only simple external capacitors are needed to filter the input and output.

[0062] LDO uniformly adopts AMS1117-3.3, which has the characteristics of small voltage drop, high precision, small size and large output current, and can meet the 3.3V power supply requirements of each module in the comprehensive frequency calibration device.

[0063] In the specific implementation process of this embodiment, the signal to be measured is connected to the constant temperature crystal oscillator of the external timing device or the rubidium clock of the external timing device.

[0064] More specifically, when the signal to be tested is connected to the constant temperature crystal oscillator of the external timing equipment, the integrated frequency calibration device is installed and connected and enters the power-on interface. The integrated frequency calibration device receives the satellite signal and the rubidium clock inside the rubidium clock unit is calibrated. The working mode selects the measurement mode. At this time, the integrated frequency calibration device is used as a frequency test device to measure the frequency accuracy of the constant temperature crystal oscillator 5 / 10MHz signal. The user can manually rotate the mechanical terminal of the crystal oscillator according to the measurement result of the integrated frequency calibration device to adjust the output frequency until the frequency accuracy meets the requirements.

[0065] When the signal to be measured is connected to the rubidium clock of the external timing equipment, the integrated frequency calibration device is installed and connected to enter the power-on interface. The integrated frequency calibration device receives the satellite signal, and the rubidium clock inside the rubidium clock unit is calibrated; the working mode selects the calibration mode (you can also select the measurement mode first to check whether the current measured frequency source meets the requirements); select the rubidium clock type, and select the frequency threshold for setting the rubidium clock calibration, such as 5×10 -11 After the setting is completed, the frequency calibration work can be started automatically; after the display unit reads the frequency accuracy of the rubidium clock of the current external time system equipment, it is compared with the set threshold. If there is a deviation, the frequency of the rubidium clock to be measured is adjusted through the serial port, and then compared again after adjustment, and then adjusted again until the output frequency reaches the threshold requirement.

[0066] The types of rubidium clocks are XHTF1021, WR1011, and LPFRS01, but are not limited to these three types of rubidium clocks.

[0067] The working process provided by the embodiment of the present invention is as follows: when the signal to be measured is connected to the constant temperature crystal oscillator of the external timing equipment, the comprehensive frequency calibration device is installed and connected to enter the power-on interface, the reference selection module selects the reference source according to whether there is a satellite signal, the comprehensive frequency calibration device receives the satellite signal and analyzes it to obtain a standard 1PPS signal, uses the standard 1PPS signal to calibrate the rubidium clock inside the rubidium clock unit, and outputs an internal frequency standard signal, that is, a standard 5 / 10MHz signal; if there is no satellite signal, the on-site standard 5 / 10MHz signal is used as an external frequency standard signal for reference; the reference selection module is connected to the rubidium clock unit, selects the internal frequency standard signal output by the rubidium clock unit and the external frequency standard signal output by the external reference signal conditioning module, and transmits the selected signals to the error multiplication module and the frequency measurement module respectively; the error multiplication module identifies the frequency difference signal of the signal output by the reference selection module and the standard signal to be measured and transmits the result to the frequency measurement module; the frequency measurement module measures the external frequency standard signal, the internal frequency standard signal, the standard signal to be measured and the frequency difference signal until the frequency accuracy meets the requirements. Select the measurement mode as the working mode. At this time, the comprehensive frequency calibration device is used as a frequency test device to measure the frequency accuracy of the constant temperature crystal oscillator 5 / 10MHz signal. The user can manually rotate the mechanical terminals of the crystal oscillator to adjust the output frequency according to the measurement results of the comprehensive frequency calibration device; the signal conditioning module to be tested will condition the constant temperature crystal oscillator and output the standard signal to be tested to the error multiplication module and the frequency measurement module.

[0068] When the signal to be measured is connected to the rubidium clock of the external timing equipment, enter the power-on interface after the integrated frequency calibration device is installed and connected, select the calibration mode for the working mode (you can also select the measurement mode first to check whether the current measured frequency source meets the requirements); select the rubidium clock type, and select the frequency threshold for setting the rubidium clock calibration, such as 5×10 -11, after the setting is completed, the frequency calibration work can be started automatically; the reference selection module selects the reference source according to whether there is a satellite signal, the comprehensive frequency calibration device receives the satellite signal and analyzes it to obtain the standard 1PPS signal, uses the standard 1PPS signal to calibrate the rubidium clock inside the rubidium clock unit, and outputs the internal frequency standard signal, that is, the standard 5 / 10MHz signal; if there is no satellite signal, the on-site standard 5 / 10MHz signal is used as the external frequency standard signal for reference; the comprehensive frequency calibration device receives the satellite signal, and the rubidium clock inside the rubidium clock unit is calibrated; the reference selection module is connected to the rubidium clock unit, and the internal frequency standard signal output by the rubidium clock unit and the external frequency standard signal output by the external reference signal conditioning module are selected and the selected signals are transmitted to the error multiplication module and the frequency measurement module respectively; the error multiplication module identifies the frequency difference signal of the signal output by the reference selection module and the standard signal to be measured and transmits the result to the frequency measurement module; the frequency measurement module measures the external frequency standard signal, the internal frequency standard signal, the standard signal to be measured and the frequency difference signal until the frequency accuracy meets the requirements. After the display unit reads the frequency accuracy of the rubidium clock of the current external time system equipment, it is compared with the set threshold. If there is a deviation, the frequency of the rubidium clock to be measured is adjusted through the serial port, and then compared again after adjustment, and then adjusted again until the output frequency reaches the threshold requirement. The working mode selects the measurement mode. At this time, the comprehensive frequency calibration device is used as a frequency test device to measure the frequency accuracy of the rubidium clock 5 / 10MHz signal of the external time system equipment.

[0069] In summary, the comprehensive frequency calibration device of the present invention can read and calibrate the frequency of the internal frequency standard of the time system equipment on site, and can read the rubidium clock of the external time system equipment in real time, with a measurement resolution better than 1×10 -11 The integrated frequency calibration device needs to have a high-performance rubidium clock inside and can be self-calibrated through satellites. The accuracy after calibration is better than 5×10 -11 It can connect an external 5 / 10MHz signal as a reference signal for the frequency measurement of a universal rubidium atomic clock, provide a stable 24V and 12V DC power supply, monitor the status of external timing equipment through the serial port and adjust its frequency, and read and calibrate the frequency of the internal frequency standard of the timing equipment on site, which not only improves the frequency accuracy of the internal frequency standard of the timing equipment, but also reduces maintenance time without affecting user use.

[0070] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A comprehensive frequency calibration device, characterized in that: include: A receiving unit, used for receiving satellite signals and transmitting them to the rubidium clock unit after analyzing them; A rubidium clock unit, used for outputting an internal frequency standard signal calibrated by the analyzed satellite signal; An input unit, used for inputting a signal to be tested and an external reference signal; The control unit, the input unit and the rubidium clock unit are connected to the control unit, and are used to receive the external reference signal, the signal to be measured and the internal frequency standard signal and process and output them.

2. The comprehensive frequency calibration device according to claim 1, characterized in that: The comprehensive frequency calibration device also includes a display unit, which is connected to the control unit and is used to display data output by the control unit.

3. The comprehensive frequency calibration device according to claim 1 or 2, characterized in that: The control unit includes an external reference signal conditioning module, a signal conditioning module to be measured, a reference selection module, an error multiplication module and a frequency measurement module. The external reference signal conditioning module is connected to the reference selection module, the error multiplication module and the frequency measurement module in sequence, and the signal conditioning module to be measured is connected to the error multiplication module and the frequency measurement module respectively.

4. The comprehensive frequency calibration device according to claim 3, characterized in that: The external reference signal conditioning module outputs an external frequency standard signal after conditioning the external reference signal, and feeds the output external frequency standard signal back to the reference selection module and the frequency measurement module; The signal conditioning module outputs a standard signal to be tested after conditioning the signal to be tested, and feeds back the output standard signal to be tested to the error multiplication module and the frequency measurement module; The reference selection module is connected to the rubidium clock unit, and the reference selection module selects the internal frequency standard signal output by the rubidium clock unit and the external frequency standard signal output by the external reference signal conditioning module, and transmits the selected signals to the error multiplication module and the frequency measurement module respectively; The error multiplication module performs frequency difference signal identification on the signal output by the reference selection module and the standard signal to be measured and transmits the result to the frequency measurement module; The frequency measurement module measures the external frequency standard signal, the internal frequency standard signal, the standard signal to be measured and the frequency difference signal.

5. The comprehensive frequency calibration device according to claim 4, characterized in that: The control unit further includes a driving isolation module, which is connected to the reference selection module. The driving isolation module receives a signal output by the reference selection module and transmits the signal to an external device.

6. The comprehensive frequency calibration device according to claim 1 or 2, characterized in that: The rubidium clock unit and the control unit are both connected to the terminal device to monitor the status of the rubidium clock unit and the external timing device.

7. The comprehensive frequency calibration device according to claim 1, characterized in that: The external reference signal is 5 / 10 MHz.

8. The comprehensive frequency calibration device according to claim 1 or 2, characterized in that: The comprehensive frequency calibration device also includes a power supply unit, which is connected to an external device to be tested and supplies power to the comprehensive frequency calibration device itself.

9. The comprehensive frequency calibration device according to claim 8, characterized in that: The power supply unit includes a power filter and a DC / DC power supply connected to the power filter. The power filter converts AC 220V into DC 24V, and the DC / DC power supply outputs DC 24V into two paths, namely DC 12V and DC 24V.

10. The comprehensive frequency calibration device according to any one of claims 1, 2, 8 or 9, characterized in that: The signal to be tested is connected to a constant temperature crystal oscillator of an external timing device or a rubidium clock of an external timing device.

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