Waveform measuring instrument and waveform measuring method

Abstract

To acquire desired waveform data at the same timing using a plurality of waveform measuring instruments.SOLUTION: A waveform measuring instrument 100 according to the present disclosure includes an AD converter 103, a trigger circuit 104, a waveform data memory 106, and a control unit 107. When the waveform measuring instrument 100 is operated as a main device, the control unit 107 transmits trigger information to another waveform measuring instrument 100 operating as a sub-device when the trigger circuit 104 generates a trigger. When the waveform measuring instrument 100 is operated as the sub-device, the control unit 107, upon acquiring the trigger information, causes the waveform data memory 106 to hold waveform data at a second pre-trigger time before a trigger acquisition time and waveform data at a second post-trigger time after the trigger acquisition time.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a waveform measuring device and a waveform measuring method.

Background Art

[0002] Conventionally, there is a waveform measuring device that captures an electrical signal and displays the waveform of the captured electrical signal.

[0003] For example, Patent Document 1 discloses a waveform measuring device capable of performing signal processing and waveform parameter measurement with high resolution and high accuracy.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When a waveform measuring device satisfies a predetermined trigger condition, it generates a trigger and holds waveform data before and after the trigger time in a memory. The waveform measuring device can display the held waveform data on a display unit.

[0006] There are various trigger conditions. For example, when generating a trigger based on an input signal, the trigger can be generated when the input signal passes from below to above a predetermined threshold value, or when passing from above to below.

[0007] When generating a trigger based on something other than the input signal, the waveform measuring device can generate a trigger, for example, at an arbitrarily specified time.

[0008] Conventionally, waveform measuring devices can operate with time synchronization among multiple waveform measuring devices. For example, when multiple waveform measuring devices that are time-synchronized generate a trigger by specifying the same time, waveform data at the same timing can be acquired by the multiple waveform measuring devices.

[0009] In this way, when a trigger is generated at the same time, waveform data at the same timing can be acquired by multiple waveform measuring devices located at distant locations.

[0010] However, when a trigger is generated by specifying a time, since the trigger is generated regardless of the input signal, there are cases where desired waveform data cannot be acquired.

[0011] FIG. 5 shows an example of the case where a trigger is generated by specifying a time in a conventional waveform measuring device. In the example shown in FIG. 5, it is assumed that the waveform measuring device generates a trigger by specifying a time and holds waveform data from time t11 to time t12.

[0012] In the case of the example shown in FIG. 5, the waveform data is constantly 0V from time t11 to time t12. This waveform data is meaningless data even if it is acquired. Therefore, even if the waveform data during such a period is acquired, it cannot be said that the waveform measuring device has acquired the desired waveform data.

[0013] In this way, when multiple waveform measuring devices generate a trigger by specifying the same time, there are cases where the waveform measuring devices cannot acquire the desired waveform data.

[0014] Therefore, an object of the present disclosure is to provide a waveform measuring device and a waveform measuring method capable of acquiring desired waveform data at the same timing with multiple waveform measuring devices.

Means for Solving the Problems

[0015] A waveform measuring device according to some embodiments is a waveform measuring device that can operate in time synchronization with other waveform measuring devices, and includes an AD converter that converts an input signal of an analog waveform into waveform data of digital values, a trigger circuit that generates a trigger when the waveform data satisfies a trigger condition, a waveform data memory that holds the waveform data, and a control unit that controls whether the waveform measuring device operates as a main device or a sub-device. When the waveform measuring device operates as the main device, the control unit causes the waveform data memory to hold the waveform data of a first pre-trigger time before the trigger time and the waveform data of a first post-trigger time after the trigger time when the trigger circuit generates the trigger, and transmits trigger information including information on the trigger time to the other waveform measuring device operating as the sub-device. When the waveform measuring device operates as the sub-device, the control unit causes the waveform data memory to hold the waveform data of a second pre-trigger time before a trigger acquisition time, which is the time when the trigger information is acquired, and the waveform data of a second post-trigger time after the trigger acquisition time when the trigger information is acquired from the other waveform measuring device operating as the main device. According to such a waveform measuring device, it is possible to acquire desired waveform data at the same timing with a plurality of waveform measuring devices.

[0016] In a waveform measuring device according to an embodiment, the waveform measuring device further includes a display unit. When the waveform measuring device operates as the sub-device, the control unit may cause the display unit to display the waveform data held in the waveform data memory such that the trigger time included in the trigger information acquired from the other waveform measuring device operating as the main device is at the position of the trigger position. Thereby, the time of the trigger position of the waveform measuring device operating as the sub-device and the time of the trigger position of the waveform measuring device operating as the main device can be made the same time.

[0017] In a waveform measuring device according to an embodiment, when the waveform measuring device operates as the sub-device, the control unit may cause the display unit to display the waveform data for the first pre-trigger time before the trigger time and the waveform data for the first post-trigger time after the trigger time. Thereby, the range of the waveform data displayed on the display unit of the waveform measuring device operating as the sub-device can be made the same as the range of the waveform data displayed on the display unit of the waveform measuring device operating as the main device.

[0018] In a waveform measuring device according to an embodiment, the second pre-trigger time may be a time that is the sum of the delay time, which is the time from the trigger time to the trigger acquisition time, and the first pre-trigger time or more. Thereby, the waveform measuring device operating as the sub-device can hold the waveform data for a period including the period during which the waveform measuring device operating as the main device holds the waveform data.

[0019] In a waveform measuring device according to an embodiment, when the waveform measuring device operates as the sub-device, the control unit may acquire in advance the delay time, which is the time from the trigger time to the trigger acquisition time, and set a time that is the sum of the delay time and the first pre-trigger time or more as the second pre-trigger time. Thereby, the second pre-trigger time can be automatically set.

[0020] In a waveform measuring device according to an embodiment, the waveform measuring device may further include a communication unit and a time synchronization circuit, and the time synchronization circuit may operate the waveform measuring device in time synchronization with another waveform measuring device based on a time synchronization signal received by the communication unit. Thereby, a plurality of waveform measuring devices can be synchronized based on the time synchronization signal.

[0021] A waveform measurement method according to some embodiments is a waveform measurement method in a waveform measurement device that can operate in time synchronization with other waveform measurement devices. The waveform measurement device includes an AD converter that converts an analog waveform input signal into waveform data of digital values, a trigger circuit that generates a trigger when the waveform data satisfies a trigger condition, a waveform data memory that holds the waveform data, and a control unit that controls whether the waveform measurement device operates as a main device or a sub-device. When the waveform measurement device operates as the main device, the waveform measurement method includes, when the trigger circuit generates the trigger, causing the waveform data memory to hold the waveform data of a first pre-trigger time before the trigger time and the waveform data of a first post-trigger time after the trigger time, and transmitting trigger information including information on the trigger time to the other waveform measurement device operating as the sub-device. When the waveform measurement device operates as the sub-device, the waveform measurement method includes, when acquiring the trigger information from the other waveform measurement device operating as the main device, causing the waveform data memory to hold the waveform data of a second pre-trigger time before the trigger acquisition time, which is the time when the trigger information is acquired, and the waveform data of a second post-trigger time after the trigger acquisition time. According to such a waveform measurement method, it is possible to acquire desired waveform data at the same timing with a plurality of waveform measurement devices.

Effect of the Invention

[0022] According to the present disclosure, it is possible to provide a waveform measurement device and a waveform measurement method capable of acquiring desired waveform data at the same timing with a plurality of waveform measurement devices.

Brief Description of the Drawings

[0023]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Mode for Carrying Out the Invention

[0024] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings.

[0025] FIG. 1 is a diagram showing a schematic configuration of a waveform measuring device 100 according to an embodiment. The waveform measuring device 100 can operate in time synchronization with other waveform measuring devices 100.

[0026] When the waveform measuring device 100 operates in time synchronization with other waveform measuring devices 100, it can operate as either a main unit or a sub unit. In the present embodiment, the waveform measuring device 100 that transmits trigger information to other waveform measuring devices 100 will be referred to as the "main unit". Further, the waveform measuring device 100 that acquires trigger information from other waveform measuring devices 100 operating as the main unit will be referred to as the "sub unit".

[0027] Here, the "trigger information" is information including the information of the trigger time which is the time when a trigger occurs in the waveform measuring device 100 operating as the main unit. Details of the exchange of trigger information between the main unit and the sub unit will be described later.

[0028] The waveform measuring device 100 includes an attenuator 101, a preamplifier 102, an AD converter 103, a trigger circuit 104, a time synchronization circuit 105, a waveform data memory 106, a control unit 107, a memory 108, a display unit 109, an input unit 110, and a communication unit 111.

[0029] The attenuator 101 is a circuit that attenuates an input signal of an analog waveform input to the waveform measuring device 100. The attenuator 101 outputs the attenuated input signal to the preamplifier 102.

[0030] The preamplifier 102 is a circuit that amplifies the input signal supplied from the attenuator 101. The preamplifier 102 outputs the amplified input signal to the AD converter 103. Note that the preamplifier 102 may attenuate the input signal supplied from the attenuator 101.

[0031] By attenuating and amplifying the input signal by the attenuator 101 and the preamplifier 102, the magnitude of the input signal supplied to the AD converter 103 can be made suitable for the AD converter 103.

[0032] The AD converter 103 converts the input signal of the analog waveform supplied from the preamplifier 102 into waveform data of digital values. The AD converter 103 outputs the waveform data of digital values to the trigger circuit 104 and the control unit 107.

[0033] The trigger circuit 104 generates a trigger when the waveform data supplied from the AD converter 103 satisfies a predetermined trigger condition. The trigger condition can be set to various conditions by the user's operation on the input unit 110. The trigger circuit 104 can generate a trigger, for example, when the waveform data passes from below to above a predetermined threshold value, or when it passes from above to below.

[0034] The time synchronization circuit 105 operates the waveform measuring device 100 in time synchronization with other waveform measuring devices 100 based on the time synchronization signal received by the communication unit 111. The time synchronization circuit 105 may receive, for example, a time synchronization signal based on the IEEE1588 standard as the time synchronization signal. When receiving a time synchronization signal based on the IEEE1588 standard as the time synchronization signal, the time synchronization circuit 105 may receive the time synchronization signal transmitted by another waveform measuring device 100, or may receive the time synchronization signal transmitted by a dedicated time synchronization device. Also, the time synchronization circuit 105 can transmit a time synchronization signal to other waveform measuring devices 100 via the communication unit 111.

[0035] The time synchronization circuit 105 may receive, for example, a time synchronization signal based on GPS (Global Positioning System) as the time synchronization signal.

[0036] The waveform data memory 106 holds the waveform data converted into digital values by the AD converter 13. The waveform data memory 106 is, for example, a semiconductor memory, a magnetic memory, an optical memory, or the like, but is not limited thereto. The waveform data memory 106 may be configured as a ring buffer-shaped memory.

[0037] The control unit 107 controls the entire waveform measuring device 100 and each block of the waveform measuring device 100. The control unit 107 executes arithmetic processing and analysis processing on the waveform data supplied from the AD converter 103. The control unit 107 causes the waveform data memory 106 to hold predetermined data among the waveform data supplied from the AD converter 103. The control unit 107 generates display information to be displayed on the display unit 109 based on the waveform data held by the waveform data memory 106. The control unit 107 can control whether to operate the waveform measuring device 100 as a main device or as a sub-device based on the setting received by the input unit 110.

[0038] The control unit 107 includes at least one processor, at least one dedicated circuit, or a combination thereof. The processor is a general-purpose processor such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit), or a dedicated processor specialized for specific processing. The dedicated circuit is, for example, an FPGA (Field-Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit).

[0039] Details of the operation of the control unit 107 will be described later. In FIG. 1, one control unit 107 is shown, but the functions of the control unit 107 may be shared and executed by a plurality of control units.

[0040] The memory 108 may store any information used for the operation of the waveform measuring device 100. For example, the memory 108 may store a system program, an application program, various data, and the like.

[0041] The memory 108 is, for example, a semiconductor memory, a magnetic memory, an optical memory, or the like, but is not limited thereto.

[0042] The display unit 109 can display waveform data. The display unit 109 can also display various data such as analysis results in addition to the waveform data.

[0043] The display unit 109 may include, for example, an LCD (Liquid Crystal Display) or an organic EL (Electro Luminescent) display.

[0044] The input unit 110 includes an interface capable of receiving operations from the user. The input unit 110 may include, for example, buttons, rotary knobs, and the like.

[0045] The communication unit 111 includes at least one of a communication module corresponding to wired communication and a communication module corresponding to wireless communication. For example, the communication unit 111 may include a communication module corresponding to a LAN (Local Area Network). The waveform measuring device 100 can communicate with other waveform measuring devices 100 via the communication unit 111.

[0046] As described above, the waveform measuring device 100 can operate in time synchronization with other waveform measuring devices 100. FIG. 2 shows an example of a state in which a plurality of waveform measuring devices 100 are operating in time synchronization.

[0047] In the example shown in FIG. 2, a plurality of waveform measuring devices 100-1 to 100-3 operate in time synchronization. In the example shown in FIG. 2, the waveform measuring device 100-1 operates as the main device. The waveform measuring devices 100-2 and 100-3 operate as sub-devices.

[0048] In the waveform measuring device 100-1 operating as the main device, when the waveform data satisfies the trigger condition, the trigger circuit 104 generates a trigger. Then, the control unit 107 transmits trigger information including information on the trigger time, which is the time when the trigger occurred, to the waveform measuring devices 100-2 and 100-3 operating as sub-devices via the communication unit 111.

[0049] The waveform measuring devices 100-2 and 100-3 operating as sub-devices acquire the trigger information from the waveform measuring device 100-1 operating as the main device. When the waveform measuring devices 100-2 and 100-3 operating as sub-devices acquire the trigger information, they cause the waveform data memory 106 to hold the waveform data for a predetermined period based on the acquired trigger information.

[0050] Referring to FIG. 3, the operations of the waveform measuring device 100-1 operating as the main device and the waveform measuring device 100-2 operating as the sub-device will be described. Since the operation of the waveform measuring device 100-3 operating as the sub-device is the same as that of the waveform measuring device 100-2 operating as the sub-device, the description thereof will be omitted.

[0051] In FIG. 3, the waveform data 201 is the waveform data of the input signal of the waveform measuring device 100-1 operating as the main device. The waveform data 202 is the waveform data of the input signal of the waveform measuring device 100-2 operating as the sub-device.

[0052] Hereinafter, the operations of the waveform measuring device 100-1 operating as the main device and the waveform measuring device 100-2 operating as the sub-device will be described respectively.

[0053] <Operation of the main device> First, the operation of the waveform measuring device 100-1 operating as the main device will be described.

[0054] The trigger circuit 104 of the waveform measuring device 100-1 generates a trigger when the waveform data satisfies the trigger condition. At this time, the trigger condition is a condition based on the waveform data. Thus, by setting the trigger condition as a condition based on the waveform data, the trigger circuit 104 can generate a trigger at the timing when the desired waveform data can be acquired.

[0055] In the example shown in FIG. 3, the trigger circuit 104 generates a trigger at time t1. That is, time t1 is the trigger time.

[0056] When the trigger circuit 104 generates a trigger, the control unit 107 causes the waveform data memory 106 to hold the waveform data of the first pre-trigger time before the trigger time and the waveform data of the first post-trigger time after the trigger time. In the example shown in FIG. 3, the time from time t3 to time t1 is the first pre-trigger time. Also, the time from time t1 to time t4 is the first post-trigger time.

[0057] The first pre-trigger time and the first post-trigger time can be set by a user operation on the input unit 110.

[0058] When the waveform data memory 106 is a ring-shaped buffer memory, the control unit 107 may enable the trigger circuit 104 to generate a trigger after the waveform data memory 106 has captured the waveform data for the first pre-trigger time.

[0059] When the trigger circuit 104 generates a trigger, the control unit 107 generates trigger information including the trigger time information, which is the time when the trigger was generated. The trigger information may include information indicating that the trigger was generated in the waveform measuring device 100-1, in addition to the trigger time information. Also, the trigger information may include the information of the first pre-trigger time and the information of the first post-trigger time, in addition to the trigger time information.

[0060] When the control unit 107 generates trigger information, it operates as a sub-unit and transmits the generated trigger information to the waveform measuring devices 100-2 and 100-3, which are operating as sub-units, via the communication unit 111.

[0061] The control unit 107 causes the display unit 109 to display the waveform data of the first pre-trigger time and the waveform data of the second pre-trigger time held in the waveform data memory 106. At this time, the control unit 107 causes the display unit 109 to display the waveform data held in the waveform data memory 106 so that the time t1, which is the trigger time, is at the position of the trigger position.

[0062] The trigger position may be, for example, the position at the center in the horizontal direction of the display unit 109. The trigger position can be set to an arbitrary position in the horizontal direction of the display unit 109 by a user operation on the input unit 110.

[0063] <Operation of Sub-unit>

[0064] Subsequently, the operation of the waveform measuring device 100-2, which is operating as a sub-unit, will be described.

[0065] The control unit 107 of the waveform measuring device 100-2 acquires the trigger information transmitted by the waveform measuring device 100-1, which is operating as the main unit, via the communication unit 111.

[0066] In the example shown in FIG. 3, the time when the control unit 107 acquires the trigger information is the time t2. Hereinafter, the time when the trigger information is acquired may be referred to as the "trigger acquisition time" for explanation.

[0067] Here, the delay time, which is the time from the trigger time to the trigger acquisition time, is caused by, for example, the following times. · The time it takes for the waveform measuring device 100-1, which is the main unit, to transmit the trigger information after generating the trigger. · The time it takes for communication from the waveform measuring device 100-1, which is the main unit, to the waveform measuring device 100-2, which is the sub-unit. · The time it takes for the waveform measuring device 100-2, which is a sub-device, to recognize that it has received the trigger information until it acquires the trigger information.

[0068] When the control unit 107 acquires the trigger information from the waveform measuring device 100-1 operating as the main device, it causes the waveform data memory 106 to hold the waveform data for the second pre-trigger time before the trigger acquisition time and the waveform data for the second post-trigger time after the trigger acquisition time.

[0069] In the example shown in FIG. 3, the time from time t5 to time t2 is the second pre-trigger time. Also, the time from time t2 to time t6 is the second post-trigger time.

[0070] The second pre-trigger time and the second post-trigger time can be set by the user's operation on the input unit 110.

[0071] At this time, the second pre-trigger time is set with a margin so that it is a time equal to or greater than the sum of the delay time and the first pre-trigger time. Then, since time t5 is a time before time t3, the control unit 107 can cause the waveform data memory 106 to hold the waveform data so as to include the period from time t3 to time t4, which is the period during which the waveform measuring device 100-1 operating as the main device holds the data in the waveform data memory 106.

[0072] The control unit 107 causes the display unit 109 to display the waveform data held in the waveform data memory 106 so that the trigger time included in the trigger information acquired from the waveform measuring device 100-1 operating as the main device is at the position of the trigger position.

[0073] At this time, the control unit 107 may cause the display unit 109 to display only the waveform data for the same period as that of the waveform measuring device 100-1 operating as the main device among the waveform data held in the waveform data memory 106. That is, the control unit 107 may cause the display unit 109 to display the waveform data for the first pre-trigger time before the trigger time included in the trigger information and the waveform data for the first post-trigger time after the trigger time included in the trigger information.

[0074] Alternatively, the control unit 107 may cause the display unit 109 to display all of the waveform data held in the waveform data memory 106. In this case, the control unit 107 causes the display unit 109 to display the waveform data for the third pre-trigger time before the trigger time included in the trigger information and the waveform data for the third post-trigger time after the trigger time included in the trigger information.

[0075] In the example shown in FIG. 3, the time from time t5 to time t1 is the third pre-trigger time. Also, the time from time t1 to time t6 is the second post-trigger time.

[0076] The third pre-trigger time and the third post-trigger time are calculated as follows, respectively. Third pre-trigger time = Second pre-trigger time - Delay time Third post-trigger time = Second post-trigger time + Delay time

[0077] With reference to the sequence diagram shown in FIG. 4, the operations of the waveform measuring device 100-1 operating as the main device and the waveform measuring device 100-2 operating as the sub-device will be described.

[0078] The trigger circuit 104 of the waveform measuring device 100-1 operating as the main device generates a trigger when the waveform data supplied from the AD converter 103 satisfies a predetermined trigger condition (step S101).

[0079] When the trigger circuit 104 generates a trigger, the control unit 107 of the waveform measuring device 100-1 operating as the main unit causes the waveform data memory 106 to hold the waveform data for the first pre-trigger time before the trigger time and the waveform data for the first post-trigger time after the trigger time (step S102).

[0080] When the trigger circuit 104 of the waveform measuring device 100-1 operating as the main unit generates a trigger, the control unit 107 generates trigger information including the information of the trigger time which is the time when the trigger is generated. When the control unit 107 generates the trigger information, it transmits the generated trigger information to the waveform measuring device 100-2 operating as the sub-unit via the communication unit 111 (step S103). The operation of step S103 may be executed before step S102. Also, the operation of step S103 may be executed simultaneously with step S102.

[0081] Thereafter, the control unit 107 of the waveform measuring device 100-1 operating as the main unit may cause the display unit 109 to display the waveform data for the first pre-trigger time and the waveform data for the second pre-trigger time held in the waveform data memory 106.

[0082] The control unit 107 of the waveform measuring device 100-2 operating as the sub-unit acquires the trigger information transmitted by the waveform measuring device 100-1 operating as the main unit via the communication unit 111 (step S104).

[0083] When the control unit 107 of the waveform measuring device 100-2 operating as the sub-unit acquires the trigger information from the waveform measuring device 100-1 operating as the main unit, it causes the waveform data memory 106 to hold the waveform data for the second pre-trigger time before the trigger acquisition time and the waveform data for the second post-trigger time after the trigger acquisition time (step S105).

[0084] After that, the control unit 107 of the waveform measuring device 100-2 operating as a sub-unit may cause the waveform data stored in the waveform data memory 106 to be displayed on the display unit 109 such that the trigger time included in the trigger information acquired from the waveform measuring device 100-1 operating as a main unit is at the position of the trigger position.

[0085] <Automatic Setting of Second Pre-Trigger Time> In the above description, an example of setting the second pre-trigger time by the user's operation on the input unit 110 has been described. However, the second pre-trigger time may be automatically set. Hereinafter, the process of automatically setting the second pre-trigger time will be described.

[0086] Before starting the measurement, the waveform measuring device 100-1 operating as a main unit transmits trigger information to the waveform measuring device 100-2 operating as a sub-unit.

[0087] The control unit 107 of the waveform measuring device 100-2 operating as a sub-unit calculates a delay time based on the difference between the trigger time included in the acquired trigger information and the trigger acquisition time. Thereby, the control unit 107 can acquire the delay time in advance before starting the measurement.

[0088] The control unit 107 of the waveform measuring device 100-2 operating as a sub-unit automatically sets the second pre-trigger time such that the time obtained by adding the first pre-trigger time of the waveform measuring device 100-1 operating as a main unit and the previously acquired delay time is the second pre-trigger time.

[0089] At this time, the control unit 107 may set the second pre-trigger time such that the time obtained by adding the first pre-trigger time and the delay time is the second pre-trigger time. By doing so, the control unit 107 of the waveform measuring device 100-2 operating as a sub-unit can cause the waveform data memory 106 to hold the minimum necessary waveform data.

[0090] Alternatively, the control unit 107 may set the second pre-trigger time so that the second pre-trigger time is longer than the time obtained by adding the first pre-trigger time and the delay time. By doing so, even if the delay time varies, the control unit 107 of the waveform measuring device 100-2 operating as a sub-unit can stably cause the waveform data memory 106 to hold the waveform data so as to include the period from time t3 to time t4, which is the period during which the waveform measuring device 100-1 operating as the main unit holds the waveform data in the waveform data memory 106. How much longer the time obtained by adding the first pre-trigger time and the delay time is than the second pre-trigger time may be set as an initial value or may be set by a user operation on the input unit 110.

[0091] <Usage example of waveform measuring device> A usage example in the case of using a combination of a waveform measuring device 100-1 operating as a main unit and a waveform measuring device 100-2 operating as a sub-unit will be described.

[0092] (First usage example) The same input signal can be measured by a plurality of waveform measuring devices 100 having different characteristics, and the characteristics of the input signal can be effectively measured.

[0093] For example, let the waveform measuring device 100-1 operating as the main unit and the waveform measuring device 100-2 operating as the sub-unit be devices having the following advantages and disadvantages. · Waveform measuring device 100-1 operating as the main unit Advantage: The sample rate of the AD converter 103 is high. Disadvantage: The number of bits of the AD converter 103 is small and the resolution is low. · Waveform measuring device 100-2 operating as the sub-unit Advantage: The number of bits of the AD converter 103 is large and the resolution is high. Disadvantage: The sample rate of the AD converter 103 is low.

[0094] In this case, since the sampling rate of the ADC 103 in the waveform measuring device 100-1 operating as the main device is high, it can generate a trigger without missing a sudden and high-speed error signal.

[0095] Then, the waveform measuring device 100-2 operating as the sub-device can hold waveform data including a sudden and high-speed error signal by acquiring trigger information from the waveform measuring device 100-1 operating as the main device. Also, since the resolution of the ADC 103 in the waveform measuring device 100-2 operating as the sub-device is high, it can obtain waveform data with high resolution for the error signal.

[0096] (Second usage example) A plurality of waveform measuring devices 100 are installed at distant locations, and different signals are measured by each waveform measuring device 100.

[0097] In this case, the waveform measuring device 100-1 operating as the main device generates a trigger and holds waveform data when the measured signal satisfies a predetermined condition.

[0098] Then, the waveform measuring device 100-2 operating as the sub-device can hold waveform data at the same timing as when the waveform measuring device 100-1 operating as the main device holds waveform data by acquiring trigger information from the waveform measuring device 100-1 operating as the main device. In this way, even if the waveform measuring device 100-1 operating as the main device and the waveform measuring device 100-2 operating as the sub-device are at distant locations, they can hold waveform data at the same timing.

[0099] According to the waveform measuring device 100 according to the above-described embodiment, it is possible to acquire desired waveform data at the same timing with a plurality of waveform measuring devices 100. More specifically, when the waveform measuring device 100 operates as the main device, when the trigger circuit 104 generates a trigger, the control unit 107 causes the waveform data memory 106 to hold the waveform data of the first pre-trigger time before the trigger time and the waveform data of the first post-trigger time after the trigger time, and transmits trigger information including the information of the trigger time to another waveform measuring device 100 operating as a sub-device. Further, when the waveform measuring device 100 operates as a sub-device, when the control unit 107 acquires trigger information from another waveform measuring device 100 operating as the main device, the waveform data of the second pre-trigger time before the trigger acquisition time, which is the time when the trigger information is acquired, and the waveform data of the second post-trigger time after the trigger acquisition time are caused to be held in the waveform data memory 106. Thereby, the waveform measuring device 100 operating as the main device can generate a trigger based on the input signal and acquire desired waveform data. Also, the waveform measuring device 100 operating as a sub-device can acquire waveform data at the same timing as the waveform measuring device 100 operating as the main device. Therefore, it is possible to acquire desired waveform data at the same timing with a plurality of waveform measuring devices 100, namely, the waveform measuring device 100 operating as the main device and the waveform measuring device 100 operating as the sub-device.

[0100] It is obvious to those skilled in the art that the present disclosure can be realized in other predetermined forms other than the above-described embodiments without departing from its spirit or its essential features. Therefore, the foregoing description is illustrative and not restrictive. The scope of the disclosure is defined by the appended claims rather than by the foregoing description. Some modifications within the scope of equivalents of any modification are included therein.

[0101] For example, the arrangement and number of each of the above-described components are not limited to the contents shown in the above description and the drawings. The arrangement and number of each component may be arbitrarily configured as long as its function can be realized.

[0102] For example, in the above-described embodiment, an example was shown in which the waveform measuring device 100-2 operating as a sub-device holds waveform data at the same timing as the waveform measuring device 100-1 operating as a main device. However, the waveform measuring device 100-2 operating as a sub-device may delay the timing from the waveform measuring device 100-1 operating as a main device and hold the waveform data during the delayed period.

Explanation of Reference Numerals

[0103] 100 Waveform measuring device 101 Attenuator 102 Preamplifier 103 AD converter 104 Trigger circuit 105 Time synchronization circuit 106 Waveform data memory 107 Control unit 108 Memory 109 Display unit 110 Input unit 111 Communication unit 201 Waveform data of the main device 202 Waveform data of the sub-device

Claims

1. A waveform measuring device capable of operating in time synchronization with another waveform measuring device, an AD converter that converts an input signal of an analog waveform into waveform data of digital values, a trigger circuit that generates a trigger when the waveform data satisfies a trigger condition, a waveform data memory that holds the waveform data, a control unit that controls whether the waveform measuring device operates as a main unit or a sub-unit, comprising: when the waveform measuring device operates as the main unit, when the trigger circuit generates the trigger, the control unit causes the waveform data memory to hold the waveform data of a first pre-trigger time before the trigger time and the waveform data of a first post-trigger time after the trigger time, and transmits trigger information including information on the trigger time to the other waveform measuring device operating as the sub-unit; when the waveform measuring device operates as the sub-unit, when the control unit acquires the trigger information from the other waveform measuring device operating as the main unit, the control unit causes the waveform data memory to hold the waveform data of a second pre-trigger time before the trigger acquisition time, which is the time when the trigger information is acquired, and the waveform data of a second post-trigger time after the trigger acquisition time, the waveform measuring device.

2. In the waveform measuring device according to Claim 1, further comprising a display unit, when the waveform measuring device operates as the sub-unit, the control unit causes the display unit to display the waveform data held in the waveform data memory such that the trigger time included in the trigger information acquired from the other waveform measuring device operating as the main unit is at the position of the trigger position, the waveform measuring device.

3. In the waveform measuring device according to Claim 2, when the waveform measuring device operates as the sub-unit, the control unit causes the display unit to display the waveform data of the first pre-trigger time before the trigger time and the waveform data of the first post-trigger time after the trigger time, the waveform measuring device.

4. In the waveform measuring device according to Claim 1, the second pre-trigger time is a time equal to or longer than the sum of the delay time, which is the time from the trigger time to the trigger acquisition time, and the first pre-trigger time, the waveform measuring device.

5. In the waveform measuring device according to Claim 1, when the waveform measuring device operates as the sub-unit, the control unit, Obtain in advance a delay time, which is the time from the trigger time to the trigger acquisition time, and set, as the second pre-trigger time, a time that is the sum of the delay time and the first pre-trigger time. A waveform measuring device. **Claim 6** In the waveform measuring device according to claim 1, further comprising a communication unit and a time synchronization circuit, wherein the time synchronization circuit operates the waveform measuring device in time synchronization with the other waveform measuring device based on a time synchronization signal received by the communication unit. A waveform measuring device. **Claim 7** A waveform measuring method in a waveform measuring device capable of operating in time synchronization with another waveform measuring device, wherein the waveform measuring device comprises an AD converter that converts an input signal of an analog waveform into waveform data of digital values, a trigger circuit that generates a trigger when the waveform data satisfies a trigger condition, a waveform data memory that holds the waveform data, and a control unit that controls whether the waveform measuring device operates as a main unit or a sub-unit, and the waveform measuring method when the waveform measuring device operates as the main unit, when the trigger circuit generates the trigger, causes the waveform data memory to hold the waveform data of the first pre-trigger time before the trigger time and the waveform data of the first post-trigger time after the trigger time, and transmits trigger information including information on the trigger time to the other waveform measuring device operating as the sub-unit, when the waveform measuring device operates as the sub-unit, when acquiring the trigger information from the other waveform measuring device operating as the main unit, causes the waveform data memory to hold the waveform data of the second pre-trigger time before the trigger acquisition time, which is the time when the trigger information is acquired, and the waveform data of the second post-trigger time after the trigger acquisition time. A waveform measuring method. **Claim 8** The waveform measuring method according to claim 7, wherein the waveform measuring device further comprises a display unit, and the waveform measuring method when the waveform measuring device operates as the sub-unit, further includes a step of causing the display unit to display the waveform data held in the waveform data memory such that the trigger time included in the trigger information acquired from the other waveform measuring device operating as the main unit is at the position of the trigger position. A waveform measuring method. **Claim 9** The waveform measuring method according to claim 8, when the waveform measuring device operates as the sub-unit, The step of causing the display unit to display includes causing the waveform data of the first pre-trigger time before the trigger time and the waveform data of the first post-trigger time after the trigger time to be displayed on the display unit, which is a waveform measurement method.

10. A waveform measurement method according to claim 7, wherein the second pre-trigger time is a time that is a sum of a delay time, which is a time from the trigger time to the trigger acquisition time, and the first pre-trigger time.

11. A waveform measurement method according to claim 7, when the waveform measuring device operates as the sub-device, a step of previously acquiring a delay time, which is a time from the trigger time to the trigger acquisition time; a step of setting, as the second pre-trigger time, a time that is greater than or equal to the sum of the delay time and the first pre-trigger time; and further includes a waveform measurement method.

12. A waveform measurement method according to claim 7, wherein the waveform measurement method operates in time synchronization with the other waveform measuring device based on a time synchronization signal.

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