JP2011082844A - Signal waveform-generating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology for dulling a digital signal waveform more easily than the prior arts. <P>SOLUTION: A signal waveform-generating method includes: a D/A conversion step of outputting an analog signal waveform using a D/A converter 140; a measurement step of measuring a strength of an electromagnetic wave generated based on output of the analog signal waveform; a waveform standard determination step of determining whether or not the outputted analog signal waveform satisfies a predetermined standard as a pulse signal; an electromagnetic wave standard determination step of determining the strength of the electromagnetic wave measured in the measurement step satisfies a predetermined standard; and a waveform data generation step of generating digital waveform data, wherein the digital waveform data are determined as satisfying the predetermined standard as a pulse signal in the waveform standard determination step and determined as satisfying the predetermined standard in the electromagnetic wave standard determination step, by correcting digital waveform data inputted to the D/A converter 140. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a signal waveform generation method.

  A digital signal transmitted through a signal line has a high-frequency component, and its level may cause a problem in an EMI (Electro Magnetic Interference) test.

  As a countermeasure, it is common practice to dull the digital signal waveform. For example, the digital signal waveform can be blunted by attaching various analog filters to the signal line (Patent Document 1).

JP 2002-142075

  However, if the digital signal waveform is dulled using the analog filter, the work of determining the setting value of the analog filter (designing the analog filter constant) becomes a heavy burden on the user.

  An object of the present invention is to provide a technique for dulling a digital signal waveform more easily than in the past.

  The present invention for solving the above problems is a signal waveform generation method, a storage step for storing digital waveform data for generating an analog signal waveform, and inputting the digital waveform data to a D / A converter. A D / A conversion step for generating and outputting an analog signal waveform by converting to an analog signal, and a measurement step for measuring the intensity of the electromagnetic wave generated based on the output of the analog signal waveform in the D / A conversion step; A waveform standard determining step for determining whether the analog signal waveform output in the D / A conversion step satisfies a predetermined standard as a pulse signal, and the intensity of the electromagnetic wave measured in the measuring step satisfies the predetermined standard Electromagnetic wave standard determination step to determine whether or not the digital waveform data input to the D / A converter is corrected Waveform data for generating digital waveform data that is determined to satisfy a predetermined standard as a pulse signal in the waveform standard determination step and that is determined to satisfy a predetermined standard in the electromagnetic wave standard determination step Generating step.

1 is a schematic configuration diagram of a waveform data generation system according to an embodiment of the present invention. It is explanatory drawing about the interpolation calculation method. It is a functional block diagram of a waveform data generation device. (A) It is a figure which shows the example of the output waveform data which satisfy | fills both EMI specification and a waveform specification. (B) It is a figure which shows the example of the output waveform data which does not satisfy | fill EMI specification. (C) It is a figure which shows the example of the output waveform data which do not satisfy | fill a waveform specification. It is a flowchart for demonstrating a waveform data generation process. It is explanatory drawing about the correction method of waveform data.

  Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of a waveform data generation system 50 to which an embodiment of the present invention is applied.

  The waveform data generation system 50 includes an electronic device such as a printing device and an EMI emulation system (dotted line frame).

  As illustrated, the electronic device includes a waveform data memory 110, a waveform data RAM 120, an interpolation operation device 130, a DAC (Digital-to-Analog Converter) 140, and a reception-side IC 150.

  The waveform data memory 110 is a storage medium such as a Flash ROM, and stores ideal digital waveform data used in an electronic device. Here, the ideal digital waveform data is [1: EMI standard] the intensity of electromagnetic waves generated during transmission satisfies a predetermined standard (for example, the intensity of electromagnetic waves is less than a predetermined value in all frequency bands), and [ 2: Waveform standard] Refers to original data (coordinate data) for generating analog waveform data that satisfies a predetermined standard (for example, the duration of high and low is a predetermined value or more) as a pulse signal.

  FIG. 2 shows an example of digital waveform data stored in the waveform data memory 110. The digital waveform data stored in the waveform data storage memory 110 is given by a predetermined number of discrete points. For example, the coordinate data (n of black circles (point A, point B, point C) shown in FIG. , Y0), (m, y0), (k, 0).

  Returning to FIG. 1, the waveform data RAM 120 is a rewritable storage medium such as a RAM, and temporarily stores digital waveform data (coordinate data) to be input to the interpolation calculation device 130.

  The interpolation calculation device 130 interpolates (linearly interpolates) coordinate data between discrete points of the digital waveform data (coordinate data) stored in the waveform data RAM 120.

  Specifically, the interpolation calculation device 130 reads the digital waveform data from the waveform data RAM 120, supplements the coordinate data (white circles) in the rising portion (interval from O to A shown in FIG. 2), and the falling portion (FIG. 2). Coordinate data (white circles) are supplemented in the section from B to C shown in FIG. For example, as illustrated in the example of FIG. 2, the interpolation calculation device 130 interpolates coordinate data arranged at equal intervals on a straight line connecting the point O and the point A at the rising portion. In addition, coordinate data arranged at equal intervals on a straight line connecting points B and C is interpolated at the falling portion. Although not shown in FIG. 2, the interpolation calculation device 130 similarly supplements the coordinate data for the section from A to B. Further, the interpolation calculation of the present invention is not limited to this method.

  Then, the interpolation calculation device 130 inputs the digital waveform data obtained by interpolating the coordinate data by the interpolation calculation to the DAC 140.

  The DAC 140 converts the digital data (coordinate data) output from the interpolation calculation device 130 into analog data (analog signal) and outputs the analog data.

  An FFC (Flexible Flat Cable) 145 is a transmission cable having a predetermined length (for example, 1 m), and transmits analog waveform data output from the DAC 140 to the reception-side IC 150.

  Here, when analog waveform data is transmitted through the FFC 145, electromagnetic waves (radiated noise) are generated. It is known that the intensity of the electromagnetic wave generated from the FFC 145 increases as the rise time and fall time of the transmitted waveform data (pulse signal) are short (that is, a pulse signal close to a rectangle). Therefore, in order to keep the intensity of the electromagnetic wave generated from the FFC 145 low (meeting the “EMI standard”), the waveform data is close to a sine wave (in this embodiment, the rise time and the fall time are long, that is, the hypotenuse. (A pulse signal with a gentle trapezoidal shape) may be transmitted.

  The receiving side IC 150 receives the analog waveform data supplied via the FFC 145. However, if the high and low durations of the received analog waveform data are short, the receiving IC 150 cannot specify the analog waveform data as a pulse signal. For this reason, the analog waveform data received by the receiving-side IC 150 needs to have a high and low duration not less than a predetermined value (satisfying the above “waveform standard”).

  The electronic device to which the present embodiment is applied has the above-described configuration. However, the configuration of the electronic device is not limited to this. For example, the electronic device may be a printing device further including a print engine, a scanner device further including a scanner engine, and the like.

  In addition, each of the above-described components is classified according to main processing contents in order to facilitate understanding of the configuration of the electronic device. The present invention is not limited by the way of classification and names of the constituent elements. The configuration of the electronic device can be classified into more components depending on the processing content. Moreover, it can also classify | categorize so that one component may perform more processes. Further, the processing of each component may be executed by one hardware or may be executed by a plurality of hardware.

  Incidentally, the digital waveform data stored in the waveform data memory 110 is generated by the EMI emulation system. As shown in FIG. 1, an EMI emulation system that generates digital waveform data is connected to an electronic device at the time of manufacture. The EMI emulation system measures the intensity of electromagnetic waves generated from the FFC 145 of the electronic device, and generates ideal digital waveform data in the connected electronic device. Therefore, the EMI emulation system can store ideal digital waveform data in the waveform data memory 110 for each electronic device.

  As shown in the figure, the EMI emulation system includes a waveform data generation device (PC) 100 and an EMI measurement device 160.

  The EMI measuring device 160 measures the electric field strength of electromagnetic waves generated from the FFC 145 of the electronic device. Specifically, the EMI measuring device 160 receives an electromagnetic wave with an antenna corresponding to each frequency band of the electromagnetic wave, and measures the electric field strength of the received electromagnetic wave. Then, the EMI measuring device 160 outputs the measured electric field strength (analog signal) to the waveform data generating device 100.

  The waveform data generation device 100 generates ideal digital waveform data in an electronic device connected to the EMI emulation system.

  FIG. 3 is a functional configuration diagram of the waveform data generation device 100. As shown in the figure, the waveform data generation device 100 includes a data acquisition unit 201 and a waveform data generation unit 202.

  The data acquisition unit 201 acquires the electric field strength (measurement data) measured by the EMI measurement device 160 and the analog waveform data (waveform data) transmitted through the FFC 145.

  The waveform data generation unit 202 generates ideal digital waveform data in an electronic device connected to the EMI emulation system based on the measurement data and waveform data acquired by the data acquisition unit 201.

  Specifically, the waveform data generation unit 202 sets (stores) initial data (for example, a rectangle) of digital waveform data in the waveform data RAM 120. The digital waveform data set in the waveform data RAM 120 is converted into analog waveform data via the interpolation calculation device 130 and the DAC 140 of the electronic device, and is output to the FFC 145. At this time, the waveform data generation unit 202 uses the measurement data and waveform data acquired by the data acquisition unit 201 to determine whether the analog waveform data output to the FFC 145 satisfies the “EMI standard” and the “waveform standard”. To determine.

  FIG. 4A shows an example of analog waveform data that satisfies both the EMI standard and the waveform standard. FIG. 4B is a diagram illustrating an example of analog waveform data that does not satisfy the EMI standard. FIG. 4C illustrates an example of analog waveform data that does not satisfy the waveform standard.

  The waveform data generation unit 202 corrects the initial data according to a predetermined rule when at least one of the standards is not satisfied (in the case of the waveform shown in FIGS. 4B and 4C), The digital waveform data after correction is set (stored) in the waveform data RAM 120 again. As in the case of the initial data, the waveform data generation unit 202 uses the measurement data acquired by the data acquisition unit 201 and the waveform data, and the analog waveform data output to the FFC 145 is “EMI standard”. And whether or not the “waveform standard” is satisfied.

  The waveform data generation unit 202 performs the above processing (digital waveform data) until the analog waveform data output to the FFC 145 satisfies the “EMI standard” and the “waveform standard” (for example, the waveform shown in FIG. 4A). And determination of whether or not both standards are satisfied) are repeatedly executed to generate ideal digital waveform data in an electronic device. Then, the waveform data generation unit 202 stores the generated ideal digital waveform data in the waveform data memory 110.

  Thus, the electronic device storing the ideal digital waveform data is disconnected from the EMI emulation system and shipped.

  The waveform data generation device 100 to which this embodiment is applied has the above-described configuration. However, the configuration of the waveform data generation device 100 is not limited to this.

  Each component of the waveform data generation device 100 includes a CPU that is a main control device, a ROM that stores a program, a RAM that temporarily stores data as a main memory, and an electronic device. An interface that controls output, an input device (such as a keyboard and a mouse) that receives instructions from the user, an output device (such as a display) that displays various screens, and a system bus that serves as a communication path between each component This can be achieved by a general computer equipped. In addition, you may be comprised by ASIC (Application Specific Integrated Circuit) designed so that each process may be performed exclusively.

  Further, the EMI emulation system to which the present embodiment is applied has the above-described configuration. However, the configuration of the EMI emulation system is not limited to this.

  Each component described above is classified according to main processing contents in order to facilitate understanding of the configuration of the EMI emulation system. The present invention is not limited by the way of classification and names of the constituent elements. The configuration of the EMI emulation system can be further classified into more components depending on the processing content. Moreover, it can also classify | categorize so that one component may perform more processes. Further, the processing of each component may be executed by one hardware or may be executed by a plurality of hardware.

  Next, a characteristic operation of the waveform data generation system 50 configured as described above will be described. FIG. 5 is a flowchart for explaining the waveform data generation processing executed by the waveform data generation system 50 of the present embodiment.

  The waveform data generation unit 202 of the waveform data generation device 100 starts this flow, for example, at the timing when an electronic device is connected to the EMI emulation system or when the software for generating digital waveform data is activated. .

  When this flow is started, the waveform data generation unit 202 sets initial data (for example, a rectangle) of digital waveform data in the waveform data RAM 120 (step S101). Specifically, the waveform data generation unit 202 reads initial data stored in advance in a ROM or the like of the waveform data generation device 100 and stores it in the waveform data RAM 120 of the electronic device.

  Note that when the processing has shifted from step S111 described later, the waveform data generation unit 202 sets the digital waveform data corrected in step S109 or step S110 in the waveform data RAM 120.

  Next, the interpolation calculation device 130 performs an interpolation calculation on the digital waveform data set in the waveform data RAM 120 (step S102). Specifically, the interpolation calculation device 130 reads out digital waveform data (coordinate data indicated by black circles in FIG. 2) stored in the waveform data RAM 120 based on an instruction from the waveform data generation unit 202. Then, the interpolation calculation device 130 supplements the coordinate data (white circle) to the rising portion (the interval from O to A shown in FIG. 2) of the read digital waveform data and the falling portion (the interval from B to C shown in FIG. 2). ) Is supplemented with coordinate data (white circles). Thereafter, the interpolation calculation device 130 inputs the digital waveform data (black circle and white circle coordinate data) subjected to the interpolation calculation to the DAC 140 in ascending order (or descending order) of the X coordinate.

  The DAC 140 converts the digital waveform data input from the interpolation calculation device 130 into analog waveform data (analog signal) and outputs the analog waveform data (step S103). Specifically, for each input coordinate data, the DAC 140 generates an analog signal having a voltage value corresponding to (proportional to) the Y coordinate of the coordinate data, and continuously outputs the analog signal to the FFC 145. By doing so, the DAC 140 can output analog waveform data in which the shape (for example, rectangle) of the input digital waveform data is held to the FFC 145.

  Then, the data acquisition unit 201 drives the EMI measurement device 160 to measure the electric field strength of the electromagnetic wave generated from the FFC 145.

  Then, the data acquisition unit 201 acquires the electric field strength (measurement data) measured by the EMI measurement device 160 and the analog waveform data (waveform data) transmitted through the FFC 145 (step S104). Specifically, the data acquisition unit 201 performs A / D conversion on the electric field strength (analog signal) output from the EMI measurement device 160 to generate measurement data (digital data). Similarly, the data acquisition unit 201 A / D converts analog waveform data (analog signal) transmitted through the FFC 145 to generate waveform data (digital data). However, the measurement data may be generated in the EMI measurement device 160.

  Thereafter, the data acquisition unit 201 stores the acquired measurement data and waveform data (step S105). Specifically, the data acquisition unit 201 associates the acquired measurement data with the waveform data and stores them in a memory such as a RAM.

  Next, the waveform data generation unit 202 determines whether or not the analog waveform data transmitted to the FFC 145 satisfies the “waveform standard” (step S106). Specifically, the waveform data generation unit 202 reads the waveform data acquired from the FFC 145 in step S104 from the memory. Then, the waveform data generation unit 202, for the read waveform data, the duration of the high state “H” (for example, the distance between AB shown in FIG. 2) and the duration of the low state “L” (for example, The distance from the point C shown in FIG. 2 to the point O ′ (not shown) of the subsequent waveform data is specified. Here, the waveform data generation unit 202 determines that the analog waveform data is “when the duration of the specified high state“ H ”and the duration of the specified low state“ L ”are both greater than or equal to a predetermined value. It is determined that the “waveform standard” is satisfied. On the other hand, when at least one of the specified duration of the high state “H” and the specified duration of the low state “L” is less than a predetermined value, the waveform data generation unit 202 outputs the analog waveform data. Is determined not to meet the “waveform standard”.

  If the waveform data generation unit 202 determines in step S106 that the analog waveform data transmitted to the FFC 145 satisfies the “waveform standard” (step S106; Yes), the process proceeds to step S107.

  When the process proceeds to step S107, the waveform data generation unit 202 determines whether the analog waveform data transmitted to the FFC 145 satisfies the “EMI standard” (step S107). Specifically, the waveform data generation unit 202 reads measurement data associated with the waveform data acquired from the FFC 145 in step S104 from the memory. And the waveform data generation part 202 specifies the electric field strength of the electromagnetic wave for every frequency band about the read measurement data. Here, the waveform data generation unit 202 determines that the analog waveform data satisfies the “EMI standard” when the specified electric field strength is less than a predetermined value in the entire frequency band. On the other hand, the waveform data generation unit 202 determines that the analog waveform data does not satisfy the “EMI standard” when the specified electric field strength is equal to or greater than a predetermined value in at least one of the frequency bands. Note that the predetermined value used as a criterion for determining whether or not the “EMI standard” is satisfied may be a different value for each frequency band.

  If the waveform data generation unit 202 determines in step S107 that the analog waveform data transmitted to the FFC 145 satisfies the “EMI standard” (step S107; Yes), the process proceeds to step S108.

  When the process proceeds to step S108, the analog waveform data generated from the digital waveform data set in the waveform data RAM 120 in step S101 satisfies both the “waveform standard” and the “EMI standard”. That is, the digital waveform data set in the waveform data RAM 120 in step S101 is determined to be ideal waveform data for the electronic device connected to the EMI emulation system.

  Therefore, the waveform data generation unit 202 stores the digital waveform data set in the waveform data RAM 120 in step S101 in the waveform data memory 110 (step S108). Specifically, the waveform data generation unit 202 reads the digital waveform data set in the waveform data RAM 120 in step S <b> 101 from a memory such as a RAM and stores it in the waveform data memory 110.

  After the ideal digital waveform data is stored in the waveform data memory 110 in step S108, the waveform data generation unit 202 ends this flow.

  By the way, when the waveform data generation unit 202 determines in step S106 that the analog waveform data transmitted to the FFC 145 does not satisfy the “waveform standard” (step S106; No), the process is performed in step S109. Migrate to

  When the process proceeds to step S109, the digital waveform data set in the waveform data RAM 120 in step S101 is determined as waveform data that is not ideal for an electronic device connected to the EMI emulation system.

  Therefore, the waveform data generation unit 202 corrects the digital waveform data set in the waveform data RAM 120 in step S101.

  Specifically, the waveform data generation unit 202 corrects the digital waveform data set in the waveform data RAM 120 in step S101 so that the digital waveform data approaches a rectangular shape (makes the waveform sharper with the hypotenuse) (step S109).

  FIG. 6 is an explanatory diagram of a method for correcting waveform data. Note that n, m, k, and h included in the figure represent finite integers.

  The correction in step S109 will be described with reference to the illustrated example. The waveform data generation unit 202 decrements the X coordinate n of the point A and the X coordinate k of the point C. That is, the coordinate n ′ of the point A included in the corrected digital waveform data is “n−1”, and the coordinate k ′ of the point C is “k−1”.

  Then, the waveform data generation unit 202 stores the corrected digital waveform data in a memory (for example, RAM) provided in the waveform data generation device 100.

  If the waveform data generation unit 202 determines in step S107 that the analog waveform data transmitted to the FFC 145 does not satisfy the “EMI standard” (step S107; No), the process is performed in step S110. Migrate to

  When the process proceeds to step S110, the digital waveform data set in the waveform data RAM 120 in step S101 is determined as waveform data that is not ideal for the electronic device connected to the EMI emulation system.

  Therefore, the waveform data generation unit 202 corrects the digital waveform data set in the waveform data RAM 120 in step S101.

  Specifically, the waveform data generation unit 202 corrects the digital waveform data set in the waveform data RAM 120 in step S101 so as to approach a sine wave (including a trapezoid) (make the hypotenuse gentle and lay down the waveform). (Step S110).

  The correction in step S110 will be described with reference to the example shown in FIG. 6. The waveform data generation unit 202 increments the X coordinate n of the point A and the X coordinate k of the point C. That is, the X coordinate n ′ of the point A included in the corrected digital waveform data is “n + 1”, and the X coordinate k ′ of the point C is “k + 1”.

  Then, the waveform data generation unit 202 stores the corrected digital waveform data in a memory (for example, RAM) provided in the waveform data generation device 100.

  When the process of step S109 or step S110 is completed, the waveform data generation unit 202 moves the process to step S111.

  Here, the waveform data generation unit 202 determines whether the digital waveform data corrected in step S109 or step S110 is data that can be generated in the present system (step S111). Specifically, the waveform data generation unit 202 holds that (X coordinate n ′ of the corrected point A) <(X coordinate m of the point B) <(X coordinate k ′ of the corrected point C), If the digital waveform data is within the range (that is, the X coordinate n ′> 0 of the corrected point A and the X coordinate n ′ of the corrected point A <the upper limit X coordinate h), It is determined that the data can be generated in this system. On the other hand, when at least one of n ′ <m <k ′, n ′> 0, and k ′ <h is not satisfied, the waveform data generation unit 202 determines that data that cannot be generated in this system. judge.

  In step S111, when the waveform data generation unit 202 determines that the modified digital waveform data is data that cannot be generated in the present system (step S111; No), the process proceeds to step S112.

  When the process proceeds to step S112, the waveform data generation unit 202 makes the adjustment impossible for the digital waveform data set in the waveform data RAM 120 in step S101, and issues an error notification (step S112). Specifically, the waveform data generation unit 202 displays a message for error notification on an output device (for example, a display).

  Thereafter, the waveform data generation unit 202 ends this flow.

  On the other hand, when the waveform data generation unit 202 determines in step S111 that the corrected digital waveform data is data that can be generated in the present system (step S111; Yes), the process returns to step S101.

  The waveform data generation system 50 then performs steps S101 to S106, S109, and S111 or steps S101 to S107, S110, and S111 until the analog waveform data output to the FFC 145 satisfies the “EMI standard” and the “waveform standard”. The series of processes is repeatedly executed. Thereby, finally, the waveform data generation unit 202 can store digital waveform data ideal for an electronic device connected to the EMI emulation system in the waveform data memory 110.

  By performing the above waveform data generation processing with the waveform data generation system 50, the digital waveform data can be blunted more easily than in the past. Moreover, since the method of blunting digital waveform data can be freely changed by a program, the degree of freedom of the digital waveform data generated by this system is higher than in the past. Furthermore, it is not necessary to change the design of each circuit constituting the waveform data generation system 50 in accordance with the type of electronic equipment to which the system is applied and the usage method, and the system can be manufactured at low cost.

  Each processing unit of the above-described flow is divided according to main processing contents in order to make the waveform data generation system 50 easy to understand. The invention of the present application is not limited by the method of classification of the processing steps and the names thereof. The processing performed by the waveform data generation system 50 can be divided into more processing steps. One processing step may execute more processes.

  Further, the present invention is not limited to the above-described embodiment, and various modifications and applications are possible.

  For example, in the above embodiment, the waveform data generation unit 202 determines that the analog waveform data is “waveform” when the duration of the high state “H” and the duration of the low state “L” are both greater than or equal to a predetermined value. It is determined that the “standard” is satisfied. However, the present invention is not limited to this. For example, the waveform data generation unit 202 may determine whether the analog waveform data satisfies the “waveform standard” using the rise time and the fall time. Specifically, the waveform data generation unit 202 determines that the analog waveform data satisfies the “waveform standard” when the rise time (or the rise time and the fall time) is equal to or greater than a predetermined value.

  Further, the waveform data generation unit 202 uses the time displacement (dV / dT) of the voltage at the rising time and the time displacement (dV / dT) of the voltage at the falling time so that the analog waveform data satisfies the “waveform standard”. It may be determined whether or not. Specifically, the waveform data generation unit 202 generates an analog waveform when the time displacement of the voltage at the rise (or the time displacement of the voltage at the rise and the time displacement of the voltage at the fall) is equal to or greater than a predetermined value. It is determined that the data satisfies the “waveform standard”.

  In the above embodiment, if both the “EMI standard” and the “waveform standard” are satisfied, the electric field intensity value of the electromagnetic wave generated from the FFC 145 is stored in the waveform data memory 110 of the electronic device. Yes. However, the present invention is not limited to this. For example, the waveform data generation unit 202 may generate digital waveform data that minimizes the electric field strength of the electromagnetic wave generated from the FFC 145 after satisfying both the “EMI standard” and the “waveform standard”. . In this case, even when the “EMI standard” is satisfied in step S107 described above (step S107; Yes), the waveform data generation unit 202 proceeds to step S110. Then, steps S101 to S107, S110, and S111 are repeatedly executed until the “waveform standard” is not satisfied in step S106. Alternatively, steps S101 to S106, S109, and S111 are repeatedly executed until the “EMI standard” is not satisfied in step S107. By doing so, finally, digital waveform data that satisfies both the “EMI standard” and the “waveform standard” and that minimizes the electric field strength of the electromagnetic wave generated from the FFC 145 can be generated.

  In the above embodiment, the interpolation calculation device 130 performs linear interpolation on the input digital waveform data (coordinate data). However, the present invention is not limited to this. For example, the interpolation operation device 130 may further include an analog element (filter), and perform the interpolation processing so that the analog waveform data generated by the DAC 140 approaches a sine wave.

  Further, the present invention does not limit the digital waveform data generated by the waveform data generation device 100 to the coordinate data (black circles) of four points (O, A, B, C). For example, more coordinate data may be inserted between OA, AB, and BC. In this case, the corrections in steps S109 and S110 are also performed for each inserted point (X coordinate and Y coordinate).

  DESCRIPTION OF SYMBOLS 50 ... Waveform data generation system, 100 ... Waveform data generation apparatus, 110 ... Waveform data memory, 120 ... Waveform data RAM, 130 ... Interpolation operation apparatus, 140 ... DAC, 145 .. FFC, 150... Receiving side IC, 160... EMI measuring device, 201... Data acquisition unit, 202.

Claims (5)

A signal waveform generation method comprising:
A storage step for storing digital waveform data for generating an analog signal waveform;
A D / A conversion step of converting the digital waveform data into an analog signal by inputting the digital waveform data into a D / A converter to generate and output an analog signal waveform;
A measurement step of measuring the intensity of electromagnetic waves generated based on the output of the analog signal waveform in the D / A conversion step;
A waveform standard determination step for determining whether or not the analog signal waveform output in the D / A conversion step satisfies a predetermined standard as a pulse signal;
An electromagnetic wave standard determination step for determining whether the intensity of the electromagnetic wave measured in the measurement step satisfies a predetermined standard;
By correcting the digital waveform data input to the D / A converter, it is determined that the predetermined standard as the pulse signal is satisfied in the waveform standard determining step, and the predetermined standard is determined in the electromagnetic wave standard determining step. A waveform data generation step for generating digital waveform data determined to satisfy,
A signal waveform generation method characterized by: The signal waveform generation method according to claim 1,
In the waveform data generation step,
Digital waveform data that is determined to satisfy a predetermined standard as a pulse signal in the waveform standard determination step, is determined to satisfy a predetermined standard in the electromagnetic wave standard determination step, and has a minimum intensity of the generated electromagnetic wave Generate
A signal waveform generation method characterized by the above. The signal waveform generation method according to claim 1 or 2,
The digital waveform data generated in the waveform data generation step is input to the D / A converter, converted to an analog signal to generate an analog signal waveform, and the step of outputting is further performed.
A signal waveform generation method characterized by the above. The signal waveform generation method according to any one of claims 1 to 3,
In the waveform data generation step,
When it is determined in the waveform standard determination step that the predetermined standard as a pulse signal is not satisfied, the digital waveform data input to the D / A converter is brought close to a rectangular waveform,
When it is determined that the predetermined standard is not satisfied in the electromagnetic wave standard determination step, the digital waveform data input to the D / A converter is brought close to a sine wave waveform.
A signal waveform generation method characterized by the above. The signal waveform generation method according to any one of claims 1 to 4,
In the waveform data generation step,
Modifying the digital waveform data input to the D / A converter by changing the coordinate data constituting the digital waveform data;
A signal waveform generation method characterized by the above.

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