Display device and display method

Abstract

The present invention suppresses delay of drawing or operation even if a demagnification ratio becomes small when a graph is reduced and displayed for a time-series signal.　This display device that displays digital signals in time series comprises: a signal history acquisition unit that acquires a signal history of the digital signals; a demagnification ratio reception unit that receives input of a demagnification ratio related to time-series display of the signal history of the digital signals; a display width / compression ratio determination unit that determines a display width ratio and a data compression ratio on the basis of the received demagnification ratio and a threshold of the demagnification ratio; and a data compression unit that compresses the signal history of the acquired digital signals at the determined data compression ratio. The display device performs the time-series display of the compressed signal history on the basis of the display width ratio.

Description

Display device and display method ,

[0006] ,

[0005] ,

[0001] The present disclosure relates to a display device and a display method, and particularly to a display device and a display method for displaying a digital signal in a time series.

[0002] When displaying a signal in a time series, a display device and a display method capable of compressing and displaying a signal waveform are described in Patent Document 1 and Patent Document 2. Patent Document 1 describes a compressed waveform image display device that executes display compression optimized to maintain the luminance information of a rasterized waveform image in real time. Specifically, Patent Document 1 describes that the compressed waveform image display device includes a demultiplexer, a compression circuit, and a graphic chip. The demultiplexer demultiplexes the data representing the waveform image from the raster memory into a number of groups determined by the maximum desired integer compression ratio in a cyclic format. The compression circuit combines one or more groups according to the desired compression ratio based on priority and generates a compressed waveform image so as to hold the luminance information of the waveform image. The graphic chip displays the compressed waveform image on a display.

[0003] Patent Document 2 describes a waveform display method for an electrical measuring instrument that always displays the entire waveform on a display even during long-time measurement. Specifically, Patent Document 2 describes that when continuously displaying a signal waveform on a display as time elapses, when the signal waveform reaches the full-scale value of the time axis currently being displayed, the time axis range is changed to a new full-scale value time axis range compressed at a predetermined magnification, and after compressing and displaying the signal waveform on the display with the new time axis range at the same magnification, the signal waveform is continuously displayed. A waveform display method for an electrical measuring instrument is described.

[0004] Japanese Patent Application Laid-Open No. 2007-155716, Japanese Patent Application Laid-Open No. 8-043443

[0005] When reducing and displaying a graph for a time-series signal with a large display size, as the reduction magnification decreases, the number of display points increases, and drawing or operation becomes slow.

[0006] Therefore, when displaying a time-series signal as a scaled-down graph, a display device and display method are desired that can suppress slowdowns in drawing or operation even when the scaling factor is small.

[0007] A typical first aspect of this disclosure is a display device for displaying a digital signal in a time series, comprising: a signal history acquisition unit for acquiring the signal history of the digital signal; a reduction ratio receiving unit for receiving input of a reduction ratio for displaying the signal history of the digital signal in a time series; a display width / compression ratio determination unit for determining a display width ratio and a data compression ratio based on the received reduction ratio and a threshold for the reduction ratio; and a data compression unit for compressing the acquired signal history of the digital signal with the determined data compression ratio, wherein the compressed signal history is displayed in a time series based on the display width ratio.

[0008] A typical second aspect of this disclosure is a display method in which a computer performs the following steps: acquiring a signal history of a digital signal; receiving input for a reduction ratio related to the time-series display of the signal history of the digital signal; determining a display width ratio and a data compression ratio based on the received reduction ratio and a threshold for the reduction ratio; compressing the acquired signal history of the digital signal with the determined data compression ratio; and displaying the compressed signal history in the time series based on the display width ratio.

[0009] This is a block diagram illustrating an example configuration of a display device according to the first embodiment of this disclosure. This diagram illustrates the operation of the display width / compression ratio determination unit in an example of operation of the display device according to the first embodiment. This diagram shows a digital signal for one pulse displayed on the display unit without data compression and display width reduction. This diagram shows a digital signal for one pulse displayed on the display unit with display width reduction. This diagram shows a digital signal for one pulse displayed on the display unit with data compression and display width reduction. This diagram shows an example of a graph displayed on the display screen of the display unit when the reduction ratio is 1 / 1. This diagram shows an example of a graph displayed on the display screen of the display unit when the reduction ratio is 1 / 2. This flowchart shows an example of a display method. This is an explanatory diagram showing an example where, when compressing data for four periods of the time series of the signal history to data for two periods, the data for all four periods is not all 0 or 1. This is a block diagram illustrating an example configuration of a display device according to the second embodiment of this disclosure. This diagram shows an example of operation of the screen resolution acquisition unit and threshold setting unit in the display device according to the second embodiment. This diagram shows an example of operation of the display width / compression ratio determination unit in the display device according to the second embodiment. This is a block diagram illustrating an example configuration of a display device according to the third embodiment of this disclosure. This diagram shows an example of operation of the CPU load acquisition unit and threshold setting unit in the display device according to the third embodiment. This figure shows an example of the operation of the display width / compression ratio determination unit in the display device of the third embodiment. This is a block diagram showing an example of the configuration of the display device of the fourth embodiment of this disclosure. This figure shows an example of the operation of the display width / compression ratio determination unit in the display device of the fourth embodiment when the reduction ratio threshold is 1 / 8. This figure shows an example of the operation of the display width / compression ratio determination unit in the display device of the fourth embodiment when the reduction ratio threshold is 1 / 32. This is a block diagram showing an example of the configuration of the display device of the fifth embodiment of this disclosure. This figure shows an example of a graph displayed on the display screen of the display unit when the reduction ratio threshold is 1 / 8 in the display device of the fifth embodiment. This figure shows an example of the operation of the display width / compression ratio determination unit 103 when the reduction ratio threshold is 1 / 8 in the display device of the fifth embodiment. This figure shows an example of a graph displayed on the display screen of the display unit when the reduction ratio threshold is 1 / 32 in the display device of the fifth embodiment.This figure shows an example of the operation of the display width / compression ratio determination unit in the display device of the fifth embodiment when the reduction ratio threshold is 1 / 32.

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. (First Embodiment) Figure 1 is a block diagram showing an example configuration of a display device according to the first embodiment of the present disclosure. As shown in Figure 1, the display device 10 includes a signal history acquisition unit 101, a reduction ratio receiving unit 102, a display width / compression ratio determination unit 103, a data compression unit 104, and a display unit 105. The display unit 105 is not included in the display device 10 and may be provided outside the display device 10. The display unit 105 is, for example, a liquid crystal display device.

[0011] The signal history acquisition unit 101 acquires the signal history of digital signals, for example, from a storage unit provided outside the display device 10 or via a network, and outputs the signal history of digital signals to the data compression unit 104. The storage unit for storing the signal history of digital signals may be provided inside the display device 10. The digital signals are not particularly limited, but for example, they are digital signals for analyzing the operation of a PMC (Programmable Machine Controller) that relays control between a CNC that controls machine tools or robots, etc., and external devices such as sensors.

[0012] The reduction ratio receiving unit 102 receives input of a reduction ratio related to the time-series display of a digital signal and outputs it to the display width / compression ratio determination unit 103. The reduction ratio receiving unit 102 receives a reduction ratio entered by the user via an input device such as a keyboard or touch panel. The reduction ratio receiving unit 102 may also receive a reduction ratio transmitted via a network or stored in a storage unit provided inside or outside the display device 10.

[0013] The display width / compression ratio determination unit 103 determines the display width ratio and the data compression ratio based on the reduction ratio output from the reduction ratio reception unit 102 and the input reduction ratio threshold. If the reduction ratio is greater than or equal to the input threshold, the display width / compression ratio determination unit 103 sets the data compression ratio to a constant value and the display width ratio to correspond to the reduction ratio. If the reduction ratio is less than the input threshold, the display width ratio is set to a constant value and the data compression ratio to correspond to the reduction ratio.

[0014] The display width / compression ratio determination unit 103 receives a reduction ratio threshold input by the user via an input device such as a keyboard or touch panel. The display width / compression ratio determination unit 103 may also receive a threshold transmitted via a network or stored in a storage unit located inside or outside the display device 10.

[0015] The display width / compression ratio determination unit 103 outputs the determined data compression ratio to the data compression unit 104 and the determined display width ratio to the display unit 105. However, if the data compression ratio is 100% and the data compression unit 104 outputs the signal history of the digital signal output from the signal history acquisition unit 101 directly to the display unit 105, the display width / compression ratio determination unit 103 does not need to output the data compression ratio to the data compression unit 104.

[0016] The data compression unit 104 compresses the signal history of the digital signal output from the signal history acquisition unit 101 using the data compression ratio determined by the display width / compression ratio determination unit 103, and outputs it to the display unit 105. Data compression can be performed, for example, by deleting (decimating) bits from the data. Note that if the display width ratio is 100% and the display unit 105 displays the signal history of the digital signal output from the signal history acquisition unit 101 as is on the display screen of the display unit 105, the display width / compression ratio determination unit 103 does not need to output the display width ratio to the display unit 105.

[0017] The display unit 105 displays the signal history of the digital signal compressed by the data compression unit 104 on the display screen, setting the display width using the display width multiplier output from the display width / compression multiplier determination unit 103.

[0018] The operation examples of the display device 10 described above will be explained below. Figure 2 is a diagram illustrating the operation of the display width / compression ratio determination unit in the operation example of the display device 10.

[0019] The display width / compression ratio determination unit 103 obtains from the reduction ratio receiving unit 102, for example, as shown in Figure 2, one of the following reduction ratios: 1 / 1 (no reduction), 1 / 2, 1 / 4, 1 / 8, 1 / 16, ... The display width / compression ratio determination unit 103 obtains, for example, 1 / 4 as a threshold for the reduction ratio from a storage unit provided inside or outside the display device 10.

[0020] The display width / compression ratio determination unit 103 sets the data compression ratio to a constant value and the display width ratio to correspond to the reduction ratio if the input reduction ratio is greater than or equal to a threshold of 1 / 4. Figure 2 shows an example where, if the input reduction ratios are 1 / 1, 1 / 2, or 1 / 4, the display width / compression ratio determination unit 103 sets the data compression ratio to 100% and the display width ratio to 100%, 50%, or 25% in accordance with the reduction ratio.

[0021] The display width / compression ratio determination unit 103 keeps the display width ratio constant and sets the data compression ratio in accordance with the reduction ratio if the input reduction ratio is less than a threshold of 1 / 4. Figure 2 shows an example where, when the input reduction ratios are 1 / 8 and 1 / 16, the display width / compression ratio determination unit 103 fixes the display width ratio to 25% and sets the data compression ratio to 50% and 25% in accordance with the reduction ratio. The fixed display width ratio of 25% is the same value as the display width ratio when the input reduction ratio is 1 / 4.

[0022] The display width / compression ratio determination unit 103 outputs a data compression ratio of 100% to the data compression unit 104 and a display width ratio of 100% to the display unit 105 when the reduction ratio is 1 / 1 (no reduction). Since the data compression ratio is 100%, the data compression unit 104 outputs the signal history of the digital signal acquired from the signal history acquisition unit 101 to the display unit 105 as is, without performing data compression. Since the display width ratio is 100%, the display unit 105 outputs the signal history of the digital signal acquired from the data compression unit 104 to the display unit 105 as is, without reducing the display width. Figure 3A shows a digital signal for one pulse displayed on the display unit 105 without data compression or display width reduction. The pulse width of one pulse is 4 msec.

[0023] The display width / compression ratio determination unit 103 outputs a data compression ratio of 100% to the data compression unit 104 and a display width ratio of 25% to the display unit 105 when the reduction ratio is 1 / 4. Since the data compression ratio is 100%, the data compression unit 104 outputs the signal history of the digital signal acquired from the signal history acquisition unit 101 to the display unit 105 as is, without performing any data compression. Since the display width ratio is 25%, the display unit 105 reduces the display width of the signal history of the digital signal acquired from the data compression unit 104 to 25% and outputs it to the display unit 105. Figure 3B shows a digital signal for one pulse displayed on the display unit 105 after the display width reduction. The pulse width of one pulse is 4 msec, but the display width is compressed to 25% compared to the display width shown in Figure 3A.

[0024] The display width / compression ratio determination unit 103 outputs a data compression ratio of 50% to the data compression unit 104 and a display width ratio of 25% to the display unit 105 when the reduction ratio is 1 / 8. Since the data compression ratio is 50%, the data compression unit 104 compresses the signal history of the digital signal acquired from the signal history acquisition unit 101 to 50% and outputs it to the display unit 105. Since the display width ratio is 25%, the display unit 105 reduces the display width of the data-compressed digital signal history acquired from the data compression unit 104 to 25% and outputs it to the display unit 105. Figure 3C shows a digital signal for one pulse displayed on the display unit 105 after data compression and display width reduction. The pulse width of one pulse is 8 msec. The display width of the pulse with a pulse width of 8 msec shown in Figure 3C is the same as the display width of the pulse with a pulse width of 4 msec shown in Figure 3B, because the display width ratio is 25%.

[0025] The following explains why the display width / compression ratio determination unit 103 keeps the display width ratio constant when the input reduction ratio is less than a threshold value. Figure 4 shows an example of a graph displayed on the display screen of the display unit when the reduction ratio is 1 / 1. Figure 5 shows an example of a graph displayed on the display screen of the display unit when the reduction ratio is 1 / 2. When the reduction ratio is 1 / 2, the data compression ratio is 100% and the display width ratio is 50%, so as shown in the graph of Figure 5, the display width is 1 / 2 compared to the graph of Figure 4. The number of display points in the graph shown in Figure 4 is 64, and the number of display points in the graph shown in Figure 5 is 128.

[0026] As the reduction ratio is sequentially decreased from 1 / 1, 1 / 2, 1 / 4, 1 / 8, and 1 / 16, and the display width ratio is reduced from 100%, 50%, 25%, 12.5%, and 6.25% while the data compression ratio remains at 100%, the number of displayed points increases sequentially from 64, 128, 256, 512, and 1024. On the other hand, as shown in Figure 2, if the display width / compression ratio determination unit 103 determines that the input reduction ratio is less than the threshold of 1 / 4, it sets the display width ratio to a constant 25% and sequentially decreases the data compression ratio from 100%, thereby limiting the number of displayed points determined by the display width ratio to 256 points, thus preventing further slowdowns in drawing or operation.

[0027] Figure 6 is a flowchart showing an example of a display method. In the following description, an example in which the display method of this disclosure is performed by the display device 10 will be described, but the display method of this disclosure can also be performed by configurations other than the display device 10.

[0028] In step S1, the reduction ratio receiving unit 102 receives the reduction ratio and outputs it to the display width / compression ratio determination unit 103. In step S2, the display width / compression ratio determination unit 103 receives the threshold value for the reduction ratio.

[0029] In step S3, the display width / compression ratio determination unit 103 determines the display width ratio and the data compression ratio based on the reduction ratio output from the reduction ratio reception unit 102 and the input threshold.

[0030] In step S4, the data compression unit 104 compresses the signal history of the digital signal based on the determined data compression ratio and outputs it to the display unit 105.

[0031] In step S5, the display unit 105 displays the signal history of the compressed digital signal, setting the display width using the display width multiplier output from the display width / compression multiplier determination unit 103.

[0032] In step S6, a decision is made as to whether or not to continue processing. If the decision is not to continue processing ("NO"), the process ends; if the decision is to continue processing ("YES"), the process returns to step S1.

[0033] In the display device and display method of this embodiment described above, the display width magnification is kept constant and the data compression magnification is reduced when the reduction magnification is below a threshold. Therefore, according to the display device and display method of this embodiment, even if the reduction magnification is reduced, the number of display points determined by the display width magnification is kept at the upper limit, and slowdowns in drawing or operation can be suppressed.

[0034] (Variation) As the reduction ratio decreases, the display width decreases, making it difficult to determine whether or not there is a signal change. To make it easier to determine whether or not there is a signal change, the data compression unit 104 can perform the following operations. The data compression unit 104 compresses 2n (where n is an integer of 2 or more) periods of data from the time series of the signal history into n periods of data. In this case, if all the data for the 2n periods before compression is 0, the data compression unit 104 sets all the data for the n periods after compression to 0, and if all the data for the 2n periods before compression is 1, the data for the n periods after compression sets all to 1. If the data for the 2n periods before compression is not all 0 or 1, the data compression unit 104 sets the data for the n periods after compression to data in which the first n period and the second n period of the data for the 2n periods before compression are different digital values.

[0035] Specifically, an example will be described in which the data compression unit 104 compresses four periods of data from the time series of the signal history into two periods of data. If the four periods of data before compression are all "0000" and all are "0", the data compression unit 104 sets the two periods of data after compression to "00", and if the four periods of data are all "1111" and all are "1", the data for the two periods of data sets to "11". If the four periods of data are any of the values ​​from "0001" to "1110" and not all are "0" or "1", the data compression unit 104 sets the two periods of data after compression to "10" or "01" so that the data for the second period of the first four periods of data before compression and the data for the second period of the second four periods of data have different digital values ​​in the two periods of data after compression.

[0036] Figure 7 is an explanatory diagram showing an example of a case where four periods of data from a time series of signal history are compressed into two periods of data, and the data for all four periods is not all 0 or 1. When the data compression ratio of the time series signal of the signal history is set to 50%, if the data for all four periods is "0101" and not all "0" or "1", the data for the two periods after compression is set to "10" so that the data for the first second period "01" and the data for the second second period "01" of the four periods of data before compression become different digital values ​​in the two periods after compression. When data compressed at a data compression ratio of 50% is further compressed to a data compression ratio of 25%, if the data compressed at a data compression ratio of 50% contains "0010", the data for the two periods after compression is set to "10". Specifically, the data compression unit 104 sets the data for the two compressed periods to "10" such that the data "00" of the first second period and the data "10" of the second second period of the four periods of data "0010" before compression become different digital values ​​from each other in the two compressed periods of data.

[0037] According to the modified display device and display method, in addition to the effects of the first embodiment, it becomes easier to determine whether or not there is a signal change.

[0038] (Second Embodiment) Figure 8 is a block diagram showing an example configuration of a display device according to the second embodiment of the present disclosure. As shown in Figure 8, the display device 10A is the same as the display device 10 shown in Figure 1, with the addition of a screen resolution acquisition unit 106 and a threshold setting unit 107. The configuration other than the screen resolution acquisition unit 106 and the threshold setting unit 107 is the same as that of the display device 10. The operation of the configuration other than the screen resolution acquisition unit 106, the threshold setting unit 107 and the display width / compression ratio determination unit 103 is the same as in the first embodiment, so in the following description only the operation of the screen resolution acquisition unit 106, the threshold setting unit 107 and the display width / compression ratio determination unit 103 will be described.

[0039] The screen resolution acquisition unit 106 acquires the screen resolution for displaying the time-series history of the digital signal, and the threshold setting unit 107 sets a threshold for the reduction ratio from the acquired screen resolution and outputs it to the display width / compression ratio determination unit 103. The display width / compression ratio determination unit 103 determines the display width ratio and the data compression ratio based on the reduction ratio output from the reduction ratio reception unit 102 and the threshold set by the threshold setting unit 107.

[0040] The operation examples of the screen resolution acquisition unit 106, the threshold setting unit 107, and the display width / compression ratio determination unit 103 will be explained using Figures 9 and 10. Figure 9 is a diagram showing an example of the operation of the screen resolution acquisition unit 106 and the threshold setting unit 107. Figure 10 is a diagram showing an example of the operation of the display width / compression ratio determination unit 103.

[0041] As shown in Figure 9, the screen resolution acquisition unit 106 acquires the screen resolution of the display unit 105. The screen resolution acquisition unit 106 acquires the screen resolution entered by the user via an input device such as a keyboard or touch panel. The screen resolution acquisition unit 106 may also accept screen resolutions transmitted via a network or stored in a storage unit provided inside or outside the display device 10. The screen resolution acquisition unit 106 may also acquire the pixel resolution from the display unit 105.

[0042] Screen resolutions include, for example, SVGA (Super Video Graphics Array) with an 800x600 pixel arrangement, XGA (Extended Graphics Array) with a 1024x768 pixel arrangement, WXGA (Wide Extended Graphics Array) with a 1280x800 pixel arrangement, Full HD (Full High Definition) with a 1920x1080 pixel arrangement, and WUXGA (Wide Ultra Extended Graphics Array) with a 1920x1200 pixel arrangement.

[0043] In FIG. 9, an example is shown in which the screen resolution acquisition unit 106 acquires SXGA or full HD as the screen resolution and outputs SXGA or full HD to the threshold setting unit 107. When the threshold setting unit 107 acquires SXGA, it outputs a threshold of 1 / 4 for the reduction ratio to the display width / compression ratio determination unit 103. When the threshold setting unit 107 acquires full HD, it outputs a threshold of 1 / 16 for the reduction ratio to the display width / compression ratio determination unit 103.

[0044] As shown in FIG. 10, when the display width / compression ratio determination unit 103 acquires a threshold of 1 / 4 as the threshold for the reduction ratio, it executes process T1, and when it acquires a threshold of 1 / 16 as the threshold for the reduction ratio, it executes process T2.

[0045] In process T1, when the reduction ratio input to the display width / compression ratio determination unit 103 is a value equal to or greater than the threshold of 1 / 4, for example, the data compression ratio is fixed at 100%, and the display width ratio is set to 100%, 50%, and 25% corresponding to the input reduction ratios of 1 / 1, 1 / 2, and 1 / 4, respectively. When the reduction ratio input to the display width / compression ratio determination unit 103 is a value less than the threshold of 1 / 4, the display width ratio is fixed at 25%, and the data compression ratio is set to 50%, 25%, and 12.5% corresponding to the input reduction ratios of 1 / 8, 1 / 16, and 1 / 32, respectively.

[0046] In process T2, when the reduction ratio input to the display width / compression ratio determination unit 103 is a value equal to or greater than the threshold of 1 / 16, for example, the data compression ratio is fixed at 100%, and the display width ratio is set to 100%, 50%, 25%, 12.5%, and 6.25% corresponding to the input reduction ratios of 1 / 1, 1 / 2, 1 / 4, 1 / 8, and 1 / 16, respectively. When the reduction ratio input to the display width / compression ratio determination unit 103 is a value less than the threshold of 1 / 16, the display width ratio is fixed at 6.25%, and the data compression ratio is set to �0% corresponding to the input reduction ratio of 1 / 32.

[0047] According to the display device and the display method of the present embodiment, in addition to the effects of the first embodiment, since the threshold of the reduction ratio can be set according to the screen resolution, the upper limit value of the number of display dots determined by the display width ratio can be suppressed according to the screen resolution.

[0048] (Third Embodiment) FIG. 11 is a block diagram showing a configuration example of a display device according to the third embodiment of the present disclosure. As shown in FIG. 11, the display device 10B has a CPU load acquisition unit 108 and a threshold setting unit 107A added to the display device 10 shown in FIG. 1. The configurations other than the CPU load acquisition unit 108 and the threshold setting unit 107A are the same as those of the display device 10. Since the operations of the configurations other than the CPU load acquisition unit 108, the threshold setting unit 107A, and the display width / compression ratio determination unit 103 are the same as those in the first embodiment, in the following description, only the operations of the CPU load acquisition unit 108, the threshold setting unit 107A, and the display width / compression ratio determination unit 103 will be described.

[0049] The CPU load acquisition unit 108 acquires the CPU load by calculation for time-series display. When the acquired CPU load exceeds a predetermined value, the threshold setting unit 107A newly sets a threshold for the reduction ratio and outputs it to the display width / compression ratio determination unit 103.

[0050] The display width / compression ratio determination unit 103 determines the display width ratio and the data compression ratio based on the reduction ratio output from the reduction ratio reception unit 102 and the threshold set by the threshold setting unit 107A.

[0051] Operation examples of the CPU load acquisition unit 108, the threshold setting unit 107A, and the display width / compression ratio determination unit 103 will be described using FIGS. 12 and 13. FIG. 12 is a diagram showing an operation example of the CPU load acquisition unit 108 and the threshold setting unit 107A. FIG. 13 is a diagram showing an operation example of the display width / compression ratio determination unit 103.

[0052] The CPU load acquisition unit 108 acquires the CPU load of the CPU included in the display device 10B and outputs it to the threshold setting unit 107A. When the display device shown in FIG. 11 is configured by a computer and the PC operates with Windows, the CPU load is obtained by the CPU usage rate acquired by the API of Performance Data Helper. The CPU load varies depending on the type of CPU included in the display device 10B, but also varies depending on other processes when performing other processes other than display processing. As shown in FIG. 12, it is assumed that the CPU load acquisition unit 108 acquires a CPU load of 13% or a CPU load of 73%.

[0053] The threshold setting unit 107A is set to output a reduction ratio threshold of 1 / 16 to the display width / compression ratio determination unit 103. As shown in Figure 12, when the CPU load is less than 70%, for example, when the CPU load is 13%, the threshold setting unit 107A outputs a reduction ratio threshold of 1 / 16 to the display width / compression ratio determination unit 103. On the other hand, when the CPU load is 70% or more, for example, when the CPU load is 73%, the threshold setting unit 107A outputs a reduction ratio threshold of 1 / 8 to the display width / compression ratio determination unit 103.

[0054] As shown in Figure 13, the display width / compression ratio determination unit 103 obtains a threshold of 1 / 16 as the threshold for the reduction ratio, and then executes process T3.

[0055] In processing T3, the display width / compression ratio determination unit 103, if the input reduction ratio is greater than or equal to a threshold of 1 / 16, sets the data compression ratio to a constant value (100%) and sets the display width ratio to 100%, 50%, 25%, 12.5%, and 6.25%, corresponding to the input reduction ratios of 1 / 1, 1 / 2, 1 / 4, 1 / 8, and 1 / 16. If the input reduction ratio is less than a threshold of 1 / 16, the display width ratio determination unit 103 sets the display width ratio to a constant value (6.25%) and sets the data compression ratio to 50%, corresponding to the input reduction ratio of 1 / 32.

[0056] If the display width / compression ratio determination unit 103 is performing process T3, and the CPU load output by the CPU load acquisition unit 108 is less than 70%, then process T3 is maintained. However, if the CPU load output from the CPU load acquisition unit 108 increases from 13% to 73%, and the CPU load exceeds 70%, the threshold setting unit 107A sets the reduction ratio threshold to 1 / 8 in order to reduce the CPU load, and outputs this to the display width / compression ratio determination unit 103.

[0057] As shown in Figure 13, when the display width / compression ratio determination unit 103 obtains a threshold of 1 / 8 as the threshold for the reduction ratio, it executes process T4. In process T4, if the input reduction ratio is greater than or equal to the threshold of 1 / 8, the display width / compression ratio determination unit 103 sets the data compression ratio to a constant value (100%) and the display width ratio to 100%, 50%, 25%, and 12.5%, corresponding to the input reduction ratios of 1 / 1, 1 / 2, 1 / 4, and 1 / 8. If the input reduction ratio is less than the threshold of 1 / 8, the display width ratio determination unit 103 sets the display width ratio to a constant value (12.5%) and the data compression ratio to 50% and 25%, corresponding to the input reduction ratios of 1 / 16 and 1 / 32.

[0058] If the CPU load does not fall below 70% even when the threshold for the reduction ratio is set to 1 / 8, the threshold for the reduction ratio is set to a value greater than 1 / 8, for example, 1 / 4.

[0059] According to the display device and display method of this embodiment, in addition to the effects of the first embodiment, a threshold for the reduction ratio can be set based on the CPU load, so the display width ratio can be determined so that the CPU load does not exceed a predetermined value.

[0060] (Fourth Embodiment) Figure 14 is a block diagram showing an example configuration of a display device according to the fourth embodiment of the present disclosure. As shown in Figure 14, the display device 10C is the same as the display device 10 shown in Figure 1, with the addition of a minimum display width acquisition unit 109 and a threshold setting unit 107B. The configuration other than the minimum display width acquisition unit 109 and the threshold setting unit 107B is the same as that of the display device 10. The operation of the configuration other than the minimum display width acquisition unit 109, the threshold setting unit 107B and the display width / compression ratio determination unit 103 is the same as in the first embodiment, so in the following description, only the operation of the minimum display width acquisition unit 109, the threshold setting unit 107B and the display width / compression ratio determination unit 103 will be described.

[0061] The minimum display width acquisition unit 109 acquires the minimum display width for one cycle of the digital signal history and outputs it to the threshold setting unit 107B. The minimum display width acquisition unit 109 acquires the minimum display width for one cycle input by the user via an input device such as a keyboard or touch panel. The minimum display width acquisition unit 109 may also accept the minimum display width for one cycle transmitted via a network or stored in a storage unit provided inside or outside the display device 10. The minimum display width acquisition unit 109 may also acquire the minimum display width for one cycle from the display unit 105. The minimum display width for one cycle is determined by the screen size (length of the diagonal of the screen), screen resolution, etc. of the display unit 105.

[0062] The threshold setting unit 107B lowers the threshold of the reduction ratio output to the display width / compression ratio determination unit 103 until the display width acquired from the display unit 105 reaches the minimum display width acquired for one cycle. As the threshold of the reduction ratio is lowered, the lower limit of the display width ratio for the input reduction ratio decreases, and therefore the display width acquired from the display unit 105 also decreases.

[0063] When the display width acquired from the display unit 105 reaches the acquired minimum display width for one cycle, the threshold setting unit 107B stops decreasing the threshold for the reduction ratio and sets the threshold for the reduction ratio to a constant value. The display width / compression ratio determination unit 103 sets the display width ratio to a constant value when it is below a certain threshold and sets the data compression ratio to correspond to the input reduction ratio. In this way, the display width is reduced until it reaches the minimum display width for one cycle, and after reaching the minimum display width for one cycle, the data can be compressed and displayed.

[0064] Examples of operation of the minimum display width acquisition unit 109, the threshold setting unit 107B, and the display width / compression ratio determination unit 103 will be explained using Figures 14, 15, and 16. Figure 15 shows an example of operation of the display width / compression ratio determination unit 103 when the reduction ratio threshold is 1 / 4. Figure 16 shows an example of operation of the display width / compression ratio determination unit 103 when the reduction ratio threshold is 1 / 16.

[0065] As shown in Figure 14, the minimum display width acquisition unit 109 acquires the minimum display width for one cycle of the digital signal history and outputs it to the threshold setting unit 107B. The minimum display width for one cycle is, for example, 4 mm or 1 mm.

[0066] The threshold setting unit 107B operates as follows when the minimum display width for one cycle obtained from the minimum display width acquisition unit 109 is 4 mm. The threshold setting unit 107B obtains the display width from the display unit 105, and if that display width is greater than the minimum display width for one cycle of 4 mm obtained from the minimum display width acquisition unit 109, it lowers the threshold for the reduction ratio and outputs it to the display width / compression ratio determination unit 103. For example, if the threshold setting unit 107B had output a reduction ratio threshold of 1 / 2 to the display width / compression ratio determination unit 103, the threshold setting unit 107B lowers the reduction ratio threshold from 1 / 2 to 1 / 4. The display width / compression ratio determination unit 103, which had set the display width ratio for input reduction ratios less than 1 / 2 to 50%, changes it to 25% for input reduction ratios less than 1 / 4, as shown in Figure 15. As a result, the lower limit of the display width magnification decreases, and the display width obtained from the display unit 105 also decreases.

[0067] The threshold setting unit 107B lowers the reduction ratio threshold from 1 / 2 to 1 / 4. When the display width acquired from the display unit 105 reaches the acquired minimum display width for one cycle, the threshold setting unit 107B stops lowering the reduction ratio threshold and sets the reduction ratio threshold to 1 / 4. As shown in Figure 15, the display width / compression ratio determination unit 103 sets the display width ratio constant (25%) when it is less than the fixed threshold of 1 / 4, and sets the data compression ratio to 50%, 25%, and 12.5%, corresponding to the input reduction ratios of 1 / 8, 1 / 16, and 1 / 32. In this way, the display width is reduced until it reaches the minimum display width for one cycle, and after the display width reaches the minimum display width for one cycle, the data can be compressed and displayed.

[0068] The threshold setting unit 107B operates as follows when the minimum display width for one cycle obtained from the minimum display width acquisition unit 109 is 1 mm. The threshold setting unit 107B obtains the display width from the display unit 105, and if that display width is greater than the minimum display width for one cycle of 1 mm obtained from the minimum display width acquisition unit 109, it lowers the threshold for the reduction ratio and outputs it to the display width / compression ratio determination unit 103. For example, if the threshold setting unit 107B had output a reduction ratio threshold of 1 / 8 to the display width / compression ratio determination unit 103, the threshold setting unit 107B lowers the reduction ratio threshold from 1 / 8 to 1 / 16. The display width / compression ratio determination unit 103, which had set the display width ratio for input reduction ratios less than 1 / 8 to 12.5%, changes it to 6.5% for input reduction ratios less than 1 / 16, as shown in Figure 16. As a result, the lower limit of the display width magnification decreases, and the display width obtained from the display unit 105 also decreases.

[0069] The threshold setting unit 107B lowers the reduction ratio threshold from 1 / 8 to 1 / 16. When the display width acquired from the display unit 105 reaches the acquired minimum display width for one cycle, the threshold setting unit 107B stops lowering the reduction ratio threshold and sets the reduction ratio threshold to 1 / 16. As shown in Figure 16, the display width / compression ratio determination unit 103 sets the display width ratio constant (6.25%) when the threshold is less than 1 / 16, and sets the data compression ratio to 50%, corresponding to the input reduction ratio of 1 / 32. In this way, the display width is reduced until it reaches the minimum display width for one cycle, and after the display width reaches the minimum display width for one cycle, the data can be compressed and displayed.

[0070] According to the display device and display method of this embodiment, in addition to the effects of the first embodiment, the threshold for the reduction ratio can be set by the minimum display width of one cycle, so that the display width does not decrease after it reaches the minimum display width of one cycle.

[0071] In the above explanation, we described an example in which, when the display width acquired from the display unit 105 reaches the acquired minimum display width for one cycle, the threshold setting unit 107B stops decreasing the threshold for the reduction ratio and keeps the threshold for the reduction ratio constant. However, it is also possible to set a display width for one cycle that is larger than the minimum display width for one cycle, leaving a margin so that the display width acquired from the display unit 105 does not exceed the acquired minimum display width for one cycle, and then, when the display width acquired from the display unit 105 reaches the set display width for one cycle, the threshold setting unit 107B stops decreasing the threshold for the reduction ratio and keeps the threshold for the reduction ratio constant.

[0072] (Fifth Embodiment) Figure 17 is a block diagram showing an example configuration of a display device according to the fifth embodiment of the present disclosure. As shown in Figure 17, the display device 10D is the same as the display device 10 shown in Figure 1, with the addition of a maximum display point acquisition unit 110 and a threshold setting unit 107C. The configuration other than the maximum display point acquisition unit 110 and the threshold setting unit 107C is the same as that of the display device 10. The operation of the configuration other than the maximum display point acquisition unit 110, the threshold setting unit 107C and the display width / compression ratio determination unit 103 is the same as in the first embodiment, so in the following description only the operation of the maximum display point acquisition unit 110, the threshold setting unit 107C and the display width / compression ratio determination unit 103 will be described.

[0073] The maximum display points acquisition unit 110 acquires the maximum number of display points on one screen of the display unit 105 from the signal history of the digital signal and outputs it to the threshold setting unit 107C. The maximum display points acquisition unit 110 acquires the maximum number of display points on one screen that the user inputs via an input device such as a keyboard or touch panel. The maximum display points acquisition unit 110 may also accept the maximum number of display points on one screen that has been transmitted via a network or stored in a storage unit provided inside or outside the display device 10. The maximum display points acquisition unit 110 may also acquire the maximum number of display points on one screen from the display unit 105. The maximum number of display points on one screen is determined by the screen size (length of the diagonal of the screen), screen resolution, etc. of the display unit 105.

[0074] The threshold setting unit 107C lowers the threshold of the reduction ratio output to the display width / compression ratio determination unit 103 until the number of display points acquired from the display unit 105 reaches the maximum number of display points acquired for one screen. As the threshold of the reduction ratio is lowered, the lower limit of the display width ratio for the input reduction ratio decreases, and the number of display points acquired from the display unit 105 increases.

[0075] When the number of display points acquired from the display unit 105 reaches the maximum number of display points acquired for one screen, the threshold setting unit 107C stops the reduction of the reduction ratio threshold and sets the reduction ratio threshold to a constant value. The display width / compression ratio determination unit 103 sets the display width ratio to a constant value when it is below a certain threshold and sets the data compression ratio to correspond to the input reduction ratio. In this way, the number of display points is increased until the maximum number of display points for one screen is reached, and after the maximum number of display points for one screen is reached, the data can be compressed and displayed.

[0076] Examples of operation of the maximum display point acquisition unit 110, the threshold setting unit 107C, and the display width / compression ratio determination unit 103 will be explained using Figures 17, 18A, 18B, 19A, and 19B. Figure 18A is a diagram showing an example of a graph displayed on the display screen of the display unit when the reduction ratio threshold is 1 / 4. Figure 18B is a diagram showing an example of operation of the display width / compression ratio determination unit 103 when the reduction ratio threshold is 1 / 4. Figure 19A is a diagram showing an example of a graph displayed on the display screen of the display unit when the reduction ratio threshold is 1 / 16. Figure 19B is a diagram showing an example of operation of the display width / compression ratio determination unit 103 when the reduction ratio threshold is 1 / 16.

[0077] As shown in Figure 17, the maximum display point acquisition unit 110 acquires the maximum number of display points for one screen of the digital signal history and outputs it to the threshold setting unit 107C. The maximum number of display points for one screen is, for example, 64 points or 256 points.

[0078] The threshold setting unit 107C operates as follows when the maximum number of display points for one screen obtained from the maximum number of display points acquisition unit 110 is 64 points. The threshold setting unit 107C obtains the number of display points from the display unit 105, and if the number of display points is less than the maximum number of display points for one screen obtained from the maximum number of display points acquisition unit 110, which is 64 points, it lowers the threshold for the reduction ratio and outputs it to the display width / compression ratio determination unit 103. For example, if the threshold setting unit 107C had output a reduction ratio threshold of 1 / 2 to the display width / compression ratio determination unit 103, the threshold setting unit 107C lowers the reduction ratio threshold from 1 / 2 to 1 / 4. The display width / compression ratio determination unit 103, which had set the display width ratio to 50% when the input reduction ratio was less than 1 / 2, changes it to 25% when the input reduction ratio was less than 1 / 4, as shown in Figure 18(B). As a result, the lower limit of the display width magnification decreases, and the number of display points acquired from the display unit 105 also increases.

[0079] The threshold setting unit 107C lowers the reduction ratio threshold from 1 / 2 to 1 / 4. When the number of display points acquired from the display unit 105 reaches the maximum number of display points acquired for one screen, the threshold setting unit 107C stops lowering the reduction ratio threshold and sets the reduction ratio threshold to 1 / 4. As shown in Figure 18B, the display width / compression ratio determination unit 103 sets the display width ratio to a constant (25%) when it is less than the fixed threshold of 1 / 4, and sets the data compression ratio to 50%, 25%, and 12.5%, corresponding to the input reduction ratios of 1 / 8, 1 / 16, and 1 / 32. In this way, the number of display points is increased until it reaches the maximum number of display points for one screen, and after the number of display points reaches the maximum number of display points for one screen, the data can be compressed and displayed.

[0080] The threshold setting unit 107C operates as follows when the maximum number of display points for one screen obtained from the maximum number of display points acquisition unit 110 is 256 points. The threshold setting unit 107C obtains the number of display points from the display unit 105, and if the number of display points is less than the maximum number of display points for one screen obtained from the maximum number of display points acquisition unit 110, which is 256 points, it lowers the threshold for the reduction ratio and outputs it to the display width / compression ratio determination unit 103. For example, if the threshold setting unit 107C had output a reduction ratio threshold of 1 / 8 to the display width / compression ratio determination unit 103, the threshold setting unit 107C lowers the reduction ratio threshold from 1 / 8 to 1 / 16. The display width / compression ratio determination unit 103, which had set the display width ratio for input reduction ratios less than 1 / 8 to 12.5%, changes it to 6.25% for input reduction ratios less than 1 / 16, as shown in Figure 19(B). As a result, the lower limit of the display width magnification decreases, and the number of display points acquired from the display unit 105 also increases.

[0081] The threshold setting unit 107C lowers the reduction ratio threshold from 1 / 8 to 1 / 16. When the number of display points acquired from the display unit 105 reaches the maximum number of display points acquired for one screen, the threshold setting unit 107C stops lowering the reduction ratio threshold and sets the reduction ratio threshold to 1 / 16. As shown in Figure 19B, the display width / compression ratio determination unit 103 sets the display width ratio to a constant (6.25%) when the threshold is less than 1 / 16, and sets the data compression ratio to 50%, corresponding to the input reduction ratio of 1 / 32. In this way, the number of display points is increased until the maximum number of display points for one screen is reached, and after the display width reaches the maximum number of display points for one screen, the data can be compressed and displayed.

[0082] According to the display device and display method of this embodiment, in addition to the effects of the first embodiment, the threshold for the reduction ratio can be set by the maximum number of display points on one screen, so that the number of display points does not increase after the number of display points reaches the maximum number of display points on one screen.

[0083] In the above explanation, we described an example in which, when the number of display points acquired from the display unit 105 reaches the maximum number of display points per screen, the threshold setting unit 107C stops decreasing the reduction ratio threshold and keeps the reduction ratio threshold constant. However, it is also possible to set a minimum number of display points per screen that is less than the maximum number of display points per screen, leaving a margin so that the number of display points acquired from the display unit 105 does not exceed the maximum number of display points per screen, and then, when the number of display points acquired from the display unit 105 reaches the set number of display points per screen, the threshold setting unit 107C stops decreasing the reduction ratio threshold and keeps the reduction ratio threshold constant.

[0084] In order to realize the functional blocks included in the display device in each embodiment described above, the display device can be implemented by hardware, software, or a combination thereof. Similarly, the access information output method can also be implemented by hardware, software, or a combination thereof. Here, implementation by software means that it is implemented by a computer reading and executing a program.

[0085] To realize the components included in a display device through software or a combination thereof, the display device is equipped with an arithmetic processing unit such as a CPU (Central Processing Unit). The arithmetic processing unit functions as an execution unit. The display device is also equipped with auxiliary storage devices such as an HDD (Hard Disk Drive) that store application software or various control programs such as an OS (Operating System), and main memory such as RAM (Random Access Memory) for storing data temporarily required for the arithmetic processing unit to execute programs.

[0086] The display device then uses a processing unit to read application software or an operating system from auxiliary storage, expand the read application software or OS into main memory, and perform calculations based on this application software or OS. Furthermore, it controls various hardware components of the display device based on these calculation results. This realizes the functional blocks of this embodiment. The display method can also be implemented with a configuration similar to that of the display device.

[0087] The components included in a display device can be realized by hardware, including electronic circuits. When a display device is configured with hardware, some or all of the functions of each component included in the display device can be implemented using integrated circuits (ICs) such as ASICs (Application Specific Integrated Circuits), gate arrays, FPGAs (Field Programmable Gate Arrays), and CPLDs (Complex Programmable Logic Devices).

[0088] Programs can be stored and supplied to a computer using various types of non-transitor computer-readable media. Non-transitor computer-readable media include various types of tangible storage media. Examples of non-transitor computer-readable media include magnetic recording media (e.g., hard disk drives), magneto-optical recording media (e.g., magneto-optical disks), CD-ROMs (Read Only Memory), CD-Rs, CD-R / Ws, and semiconductor memory (e.g., mask ROMs, PROMs (Programmable ROMs), EPROMs (Erasable PROMs), flash ROMs, and RAMs (random access memory)). Furthermore, the program may be supplied to the computer by various types of temporary computer-readable media.

[0089] According to the display device and display method of this disclosure, including the embodiments described above, when displaying a time-series signal as a reduced graph, it is possible to suppress slowdowns in drawing or operation even when the reduction ratio is small.

[0090] While the embodiments described above are preferred embodiments of the present invention, the scope of the present invention is not limited to these embodiments, and various modifications can be made to implement the invention without departing from the spirit of the invention.

[0091] With respect to the above embodiment, the following additional information is disclosed. (Addendum 1) A display device (10, 10A, 10B, 10C, 10D) for displaying digital signals in a time series, comprising: a signal history acquisition unit (101) for acquiring the signal history of the digital signals; a reduction ratio acceptance unit (102) for receiving input of a reduction ratio related to the time series display of the signal history of the digital signals; a display width / compression ratio determination unit (103) for determining a display width ratio and a data compression ratio based on the received reduction ratio and a threshold of the reduction ratio; and a data compression unit (104) for compressing the acquired signal history of the digital signals with the determined data compression ratio, wherein the display device displays the compressed signal history in a time series based on the display width ratio.

[0092] (Note 2) The display device according to Note 1, wherein the display width / compression ratio determination unit (103) sets the data compression ratio to a constant value and the display width ratio to a constant value corresponding to the received reduction ratio if the received reduction ratio is greater than or equal to the threshold value, and sets the display width ratio to a constant value and the data compression ratio to a constant value corresponding to the received reduction ratio if the received reduction ratio is less than the threshold value.

[0093] (Note 3) The display device according to Note 1, wherein the data compression unit (104) compresses 2n (an integer n >= 2) periods of data from the time series of the signal history into n periods of data, if all of the data for the 2n periods before compression is 0, then all of the data for the n periods after compression is 0, if all of the data for the 2n periods before compression is 1, then all of the data for the n periods after compression is 1, and if all of the data for the 2n periods before compression is not 0 or 1, then the data for the n periods after compression is data in which the first n period and the second n period of the data for the 2n periods before compression are different digital values.

[0094] (Note 4) A display device according to any one of Notes 1 to 3, comprising: a screen resolution acquisition unit (106) that acquires the screen resolution for displaying the time series; and a threshold setting unit (107) that sets the threshold based on the acquired screen resolution.

[0095] (Note 5) A display device according to any one of Notes 1 to 3, comprising: a CPU load acquisition unit (108) that acquires the CPU load by calculation for performing the time series display; and a threshold setting unit (107A) that sets the threshold based on the acquired CPU load.

[0096] (Note 6) A display device according to any one of Notes 1 to 3, comprising: a minimum display width acquisition unit (109) that acquires the minimum display width of one period of the signal history of the digital signal; and a threshold setting unit (107B) that sets the threshold based on the acquired minimum display width and the display width of the signal history of the digital signal displayed in time series.

[0097] (Note 7) A display device according to any one of Notes 1 to 3, comprising: a maximum display point acquisition unit (110) that acquires the maximum number of display points on one screen of the signal history of the digital signal; and a threshold setting unit (107C) that sets the threshold based on the acquired maximum display point and the number of display points of the signal history of the digital signal displayed in time series.

[0098] (Note 8) A display method comprising the steps of: a computer acquiring a signal history of a digital signal; accepting input of a reduction ratio for the time-series display of the signal history of the digital signal; determining a display width ratio and a data compression ratio based on the accepted reduction ratio and a threshold for the reduction ratio; compressing the acquired signal history of the digital signal with the determined data compression ratio; and displaying the compressed signal history in time-series based on the display width ratio.

[0099] 10, 10A, 10B, 10C, 10D Display device 101 Signal history acquisition unit 102 Reduction ratio acceptance unit 103 Display width / compression ratio determination unit 104 Data compression unit 105 Display unit 106 Screen resolution acquisition unit 107, 107A, 107B, 107C Threshold setting unit 108 CPU load acquisition unit 109 Minimum display width acquisition unit 110 Maximum display point acquisition unit

Claims

1. A display device for displaying digital signals in chronological order, comprising: a signal history acquisition unit for acquiring the signal history of the digital signals; a reduction ratio acceptance unit for receiving input of a reduction ratio related to the chronological display of the signal history of the digital signals; a display width / compression ratio determination unit for determining a display width ratio and a data compression ratio based on the accepted reduction ratio and a threshold for the reduction ratio; and a data compression unit for compressing the acquired signal history of the digital signals with the determined data compression ratio, wherein the display device displays the compressed signal history in chronological order based on the display width ratio.

2. The display device according to claim 1, wherein the display width / compression ratio determination unit, when the received reduction ratio is greater than or equal to the threshold, sets the data compression ratio constant and sets the display width ratio in correspondence with the received reduction ratio, and when the received reduction ratio is less than the threshold, sets the display width ratio constant and sets the data compression ratio in correspondence with the received reduction ratio.

3. The display device according to claim 1, wherein the data compression unit compresses 2n (an integer n >= 2) periods of data from the time series of the signal history into n periods of data, if all of the data for the 2n periods before compression is 0, then all of the data for the n periods after compression is 0, if all of the data for the 2n periods before compression is 1, then all of the data for the n periods after compression is 1, and if all of the data for the 2n periods before compression is not 0 or 1, then the data for the n periods after compression is data in which the first n period and the second n period of the data for the 2n periods before compression are different digital values.

4. A display device according to any one of claims 1 to 3, comprising: a screen resolution acquisition unit that acquires the screen resolution for performing the time-series display; and a threshold setting unit that sets the threshold based on the acquired screen resolution.

5. A display device according to any one of claims 1 to 3, comprising: a CPU load acquisition unit for acquiring the CPU load by calculation for performing the time-series display; and a threshold setting unit for setting the threshold based on the acquired CPU load.

6. A display device according to any one of claims 1 to 3, comprising: a minimum display width acquisition unit that acquires the minimum display width of one period of the signal history of the digital signal; and a threshold setting unit that sets the threshold based on the acquired minimum display width and the display width of the signal history of the digital signal displayed in time series.

7. A display device according to any one of claims 1 to 3, comprising: a maximum display point acquisition unit that acquires the maximum number of display points on one screen of the signal history of the digital signal; and a threshold setting unit that sets the threshold based on the acquired maximum display point and the number of display points of the signal history of the digital signal displayed in time series.

8. A display method comprising the steps of: a computer acquiring a signal history of a digital signal; accepting input of a reduction ratio for the time-series display of the signal history of the digital signal; determining a display width ratio and a data compression ratio based on the accepted reduction ratio and a threshold for the reduction ratio; compressing the acquired signal history of the digital signal with the determined data compression ratio; and displaying the compressed signal history in time-series based on the display width ratio.

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