Measurement method for an automatic time synchronization stability measuring device

Abstract

To provide an automatic measurement device and method that can automatically measure, in a device connected to a PTP network, whether the device itself has stable time synchronization accuracy after starting up of the device to be measured and continuously achieve that trial.SOLUTION: An automatic time synchronization stability measurement device 10 includes: a control and monitoring terminal 1 that controls and monitors measurement; a USB contact converter 2 that converts a USB signal transmitted from the control and monitoring terminal 1 into a contact signal; a power supply controller 3 that is connected to the USB contact converter 2 and turns on / off power according to the contact signal; a measuring instrument 4 for measuring time synchronization stability; a device-to-be-measured 5 that is connected to a PTP network and has an oscillator and a PLL circuit inside; a reference device 6 that receives a time synchronization signal and generates a reference signal that matches the time synchronization signal required by the measuring instrument 4; and a PTP network 7 through which the time synchronization signal is transmitted.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an automatic measurement device and method that can automatically measure whether a device connected to a PTP network has stable time synchronization accuracy after the device to be measured is started, and continuously realize such trials.

Background Art

[0002] In a device connected to a PTP network, it is necessary to measure whether the device itself has stable time synchronization accuracy after the device to be measured is started. However, in the conventional method, the pass / fail is determined by human eyes, and the work itself is carried out manually.

[0003] As a signal measurement device and its clock synchronization method, as disclosed in Patent Document 1, there is a signal measurement device that measures the characteristics and states of received signals, and calculates the error in the clock frequency between the signal transmission source and the signal measurement device from the pattern of a predetermined signal included in the received signal. A signal measurement device including a frequency error calculation unit and a clock frequency change unit that changes the clock frequency of an internal clock based on the error in the clock frequency is disclosed. With this configuration, the error in the clock frequency between the signal transmission source and the signal measurement device is calculated from the pattern of a predetermined signal included in the received signal, and the clock frequency of the internal clock is changed based on this error in the clock frequency. Therefore, accurate measurement results can be obtained without causing an increase in cost or power consumption.

[0004] Furthermore, as a network tester for verifying each device connected to a PTP network, as described in Patent Document 2, a network tester has been disclosed that includes a flag field data holding unit that holds a unique value that can be changed according to user input, a field extraction unit that identifies the location of a predetermined flag field from the header of each generated PTP packet, a flag update unit that, when functioning as a master, replaces the content of the flag field of each PTP packet with the unique value held by the flag field data holding unit, and a PTP packet transmission unit that sends each PTP packet with the updated flag field content to the network. With this network tester, the user performing the test can verify the operation of each device connected to the PTP network under various conditions as needed. In addition, since there is no need to wait for the state of the entire network to change, the time required to verify various conditions can be shortened.

[0005] Furthermore, as described in Patent Document 3, there are methods for inspecting, evaluating, or diagnosing electronic devices formed by electronic circuits, which are characterized by repeatedly testing by sequentially changing the off-time interval from the power "off" to the restart "on" of the electronic device, for example, by the time limit of a timer, in order to automatically detect startup failures when the device is started up and use this for fault countermeasures. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2001-5781 [Patent Document 2] Japanese Patent Publication No. 2021-164056 [Patent Document 3] Patent No. 4778251 [Overview of the project] [Problems that the invention aims to solve]

[0007] These conventional measuring instruments and methods have the problem of requiring manual monitoring and power-on for some instruments, thus increasing working time as a person must constantly attend to the equipment. Furthermore, while power-on automation is easily automatable, it is not possible to retain the state in the event of a failure, which makes it impossible to analyze the cause of the failure. In addition, guaranteeing performance requires thousands or tens of thousands of trials, which has limitations when performed manually.

[0008] Furthermore, in devices that generate video signals based on a time-synchronized clock, the quality of the video signal is affected by the accuracy of the time synchronization. Also, since the clock is generated using an oscillator inside the device as a reference, the quality of the video signal depends on the performance of the oscillator. When the power is started up, fluctuations in the frequency output accuracy are clearly observed due to changes in the voltage and temperature of the oscillator, so a method for measuring the time synchronization accuracy is necessary.

[0009] This invention has been made in view of the above-mentioned problems, and the present invention is an automatic measurement method for evaluating the time synchronization stability of a device to be measured when it is powered on. The device to be measured is assumed to be an IP gateway used for broadcasting purposes, which receives PTP packets compliant with SMPTE ST2059-2 and achieves time synchronization using a physical oscillator located inside the device as a reference. The device to be measured outputs an SDI video signal to a receiver or video switch that is the destination of the signal, using the high-precision video clock obtained by this time synchronization as a reference.

[0010] When outputting SDI video signals, it is necessary to satisfy the timing jitter value specified by SMPTE, which is an important indicator. Furthermore, if the SDI video output of the device is connected to a video switch used in broadcast systems, the fluctuation value of the output phase of the SDI video signal also becomes an important indicator. While various devices with different time synchronization circuits exist to satisfy these indicators, none of them universally guarantee the accuracy of time synchronization immediately after power-on or its stability time.

[0011] This measurement method provides a device and method for continuously measuring the timing jitter and output phase fluctuation values ​​of SDI video signals, using user-defined criteria as acceptable values, in order to ensure these performance characteristics. Furthermore, if an unacceptable value is obtained, the trial is stopped, the state at the time of occurrence is preserved, and necessary parameters are acquired from the device. This state preservation can also help identify the cause of device malfunction when an unacceptable value occurs. [Means for solving the problem]

[0013] To address the above-mentioned problems, the present invention employs the following technical means. A device for automatically measuring the time synchronization stability of a device to be measured after startup, connected to a PTP network on which a time synchronization signal is transmitted, comprising: a device to be measured connected to the PTP network and having an oscillator and a PLL circuit inside; a measuring instrument that automatically measures the jitter and output phase of the signal output from the device to be measured; a reference device that receives the time synchronization signal transmitted through the PTP network and generates a reference signal that matches the time synchronization signal required by the measuring instrument; a control monitoring terminal that controls and monitors the measurement; and a power controller that turns the device to be measured on and off, wherein the first step is to wait for a set specified time and then measure The measurement method for an automatic time synchronization stability measuring device comprises the steps of: automatically turning on the power to the device to be measured; waiting for a specified time required for the device to be measured to stabilize; resetting the monitoring data of the measuring instrument; waiting for a specified time required for the measuring instrument to stabilize; and checking during the set monitoring time whether there is any data that fails the measuring instrument or whether an error has occurred in the monitoring items of the device to be measured itself, maintaining the state of the device to be measured while retaining the data of the measuring instrument if there is a failure or an error occurs, and stopping the power to the device to be measured if there is no failure and no error has occurred. [Effects of the Invention]

[0014] The advantages of the automatic time synchronization stability measurement device of the present invention are, firstly, that it automates measurement without human intervention, thereby reducing work hours; secondly, that it can guarantee product performance by increasing the number of trials as a result; and thirdly, that it can retain the state of a device that fails the test, allowing for analysis of the cause. [Brief explanation of the drawing]

[0015] [Figure 1] This is a schematic diagram of the system configuration of the automatic time synchronization stability measurement device of the present invention. [Figure 2] This is a flowchart of the automatic time synchronization stability measurement device of the present invention. [Modes for carrying out the invention]

[0016] A first embodiment of the system configuration of the automatic time synchronization stability measuring device according to the present invention will be described with reference to Figure 1. The automatic time synchronization stability measuring device 10 consists of a control monitoring terminal 1 that controls and monitors the measurement, a USB contact converter 2 that converts a USB signal transmitted from the control monitoring terminal 1 into a contact signal, a power controller 3 connected to the USB contact converter 2 that turns the power on and off by the contact signal, a measuring instrument 4 for measuring time synchronization stability, a device to be measured 5 connected to a PTP network 7 and having an oscillator A and a PLL circuit B inside, a reference device 6 that receives time synchronization signals transmitted through the PTP network and generates a reference signal that matches the time synchronization signal required by the measuring instrument 4, and a PTP network 7 through which time synchronization signals are transmitted.

[0017] Furthermore, the device under measurement 5 has the function of generating a video signal based on a time-synchronized clock. The synchronization accuracy of the video signal is based on oscillator A inside the device under measurement 5, and when the power is started up, fluctuations in frequency output accuracy are also clearly visible due to changes in the operating voltage of oscillator A and ambient temperature. The system configuration is designed to enable the measurement of time synchronization accuracy even under these conditions.

[0018] The system functions of the automatic time synchronization stability measuring device 10 as follows: A signal controlled from the control monitoring terminal 1 is transmitted as a USB signal to the USB contact converter 2, where it is converted into a contact signal and transmitted to the power controller 3, thereby enabling the switching of commercial power.

[0019] The device under test 5 has an oscillator A and a PLL circuit B (phase-locked loop circuit) inside, and is powered on by the operation of the power controller 3, which supplies power to the oscillator A inside the device. Also, it receives a time synchronization signal via the PTP network 7 and outputs an SDI video signal with high-precision synchronization.

[0020] When powered on, the oscillator A is affected by voltage and temperature changes, generating minute frequency changes and noise. This phenomenon affects the quality of the clock signal output by the PLL circuit B. As a result, it affects the performance of the SDI video signal output of the device under test 5. In other words, constructing a PLL circuit B that is not affected by the minute frequency changes and noise of the oscillator A is important for device design.

[0021] The measuring instrument 4 is a device that evaluates the performance of the SDI video signal output from the device under test 5. The measuring instrument 4 receives an important reference signal for performance evaluation from the reference device 6 and uses it as an evaluation criterion for the SDI video signal output from the device under test 5. Note that the reference device 6 receives a time synchronization signal via the PTP network 7, similar to the device under test 5, and generates a reference signal with high precision.

[0022] The measuring instrument 4 has measuring functions for jitter measurement and output phase measurement by the waveform monitor C, measures the timing jitter and video output phase, which are important performance evaluation indicators of the SDI video signal, and transmits the results to the control and monitoring terminal 1. Note that the measuring instrument 4 transmits data to the control and monitoring terminal 1 using Ethernet or contact signals (the contact signals are via the USB contact converter 2).

[0023] The control and monitoring terminal 1 determines pass or fail based on the measurement results transmitted from the measuring instrument 4 and the unique information of the device under test 5, and decides whether to continue the measurement. In the case of a test failure, it holds the state without turning on or off the power by the power controller 3. This has the advantage that the state can be maintained even if a non-conforming device occurs, allowing the cause to be analyzed.

[0024] The flow of the measurement method is as shown in Figure 2. The first step is to wait for the set specified time T1 and then automatically turn on the power to the device 5 to be measured. The second step is to wait for the specified time T2 required for the measurement target device 5 to stabilize. The third step is to reset the monitoring data of measuring instrument 4. The fourth step is to wait for the specified time T3 required for the set measuring instrument 4 to stabilize. The fifth step involves checking whether there is any data that would result in failure at the measuring instrument 4 during the set monitoring time T4, or whether there are any errors in the monitoring items of the device under measurement 5 itself. If there are failures or errors, the state of the device under measurement 5 is maintained while retaining the data from the measuring instrument 4. If there are no failures and no errors, the power to the device under measurement 5 is shut off, and depending on the settings, the necessary parameters are also obtained from the device under measurement 5.

[0025] The parameters used for measurement are shown in Table 1. The parameters that determine whether the device under measurement 5 passes or fails are managed by the control monitoring terminal 1. These parameters are important indicators for measuring the performance of the device. [Table 1]

[0026] By using this pass / fail criterion as a standard value and changing the pass / fail judgment criterion value for each of the 5 devices being measured, it becomes possible to perform measurements with greater flexibility. Furthermore, as mentioned above, if this pass / fail criterion is met, repeatedly turning the power of the device being measured 5 on and off will improve the reliability of the device's pass / fail criteria.

[0027] On the other hand, if a trial of the measurement target device 5 fails to meet the pass / fail criteria, the trial is stopped and the current operation is maintained, making it easy to investigate the cause. At that time, parameters like those shown in Table 2, output from the measurement target device 5, are imported into the control monitoring terminal 1 to further facilitate analysis. [Table 2]

[0028] The measurement method according to the present invention offers several advantages: firstly, it automates the measurement process without human intervention, reducing labor costs; secondly, it ensures product performance by increasing the number of trials; and thirdly, it allows for the retention of data and analysis of the cause of any defective devices. [Industrial applicability]

[0029] This invention is particularly suitable for the automatic measurement of the time synchronization stability of devices that are being measured for video signals, and by setting various measurement parameters, it enables measurement of various devices. [Explanation of Symbols]

[0030] A Oscillator B PLL circuit C Waveform Monitor 10. Automatic Time Synchronization Stability Measurement Device 1. Control and monitoring terminal 2 USB contact converters 3 Power Controller 4 Measuring instrument 5. Device to be measured 6. Reference device 7 PTP Network

Claims

[Claim 1] A device for automatically measuring the time synchronization stability of a device to be measured after it has been started up, which is connected to a PTP network on which a time synchronization signal is transmitted. A device to be measured, connected to the aforementioned PTP network and having an oscillator and a PLL circuit inside, A measuring instrument that automatically measures the jitter and output phase of the signal output from the device to be measured, A reference device that receives the time synchronization signal transmitted through the PTP network and generates a reference signal that matches the time synchronization signal required by the measuring instrument, A control and monitoring terminal that performs control and monitoring during measurement, A power controller that turns the device under measurement on and off, A method for measuring the time synchronization stability of an automatic measuring device, characterized in that a feature is provided, The first step is to wait for a set specified time and then automatically turn on the power to the device to be measured. The second step is to wait for a specified time necessary for the measurement target device to stabilize, The third step is to reset the monitoring data of the measuring instrument, The fourth step is to wait for a specified time necessary for the setting of the measuring instrument to stabilize, The fifth step involves checking whether there is any data that would result in failure in the measuring instrument during the set monitoring time, or whether there are any errors in the monitoring items of the device being measured itself, and if there are failures or errors, maintaining the state of the device being measured while retaining the data from the measuring instrument, and if there are no failures and no errors, shutting off the power to the device being measured. A method for measuring the time synchronization stability of an automatic measuring device having the following characteristics.

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