JPH06309420A - Method for simulating radiation noise - Google Patents

Abstract

PURPOSE:To reduce the number of wirings for executing simulation and to shorten time required for simulation and design time by providing this simulation method with a function for judging the existence of simulation execution in each wiring. CONSTITUTION:A parameter for judging the existence of simulation execution is inputted to a parameter input part 8 by an operator or read out from a data base 7. For example, clock frequency, the waveform, amplitude, rise time, fall time of each signal, duty, wiring length, the dielectric constant of a base, and the thickness of a dielectric substance are used as parameters. The function 10 for judging the existence of simulation execution judges the existence of simulation execution in each wiring by using these parameters. A radiation noise simulation executing part 11 applies radiation noise simulation to wiring whose simulation necessity is judged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of simulating radiation noise generated from an electronic device or the like.

[0002]

2. Description of the Related Art FIG. 12 shows, for example, Electronic
Packing Technology (vo
l. 7 No. 11 1991.11) is a conventional radiation noise simulation system. Figure 1
2 is a schematic diagram of a printed circuit board design CAD including a module for simulating radiation noise. Figure 1
In FIG. 2, 1 is a module for radiation noise simulation, 2 is CAD for physical design, and 3 is a database.

In FIG. 12, the radiation noise simulation is performed by the radiation noise simulation module 1 on the physical design CAD 2. First, the CAD 2 for physical design performs article layout and routing, and at the stage when they are finished, radiation noise simulation is performed for all wirings. Parameters necessary for simulation include waveform, clock frequency, signal parameters such as rise time, wiring length, layout / routing parameters such as GND grid size,
There are device parameters such as input / output resistance and input / output capacitance, which are given by the radiation noise simulation module 1, the physical design CAD 2, and the database 3, respectively, or determined by inputting individually. The simulation result shows that each wiring is classified into 6 levels of colors corresponding to the magnitude of the radiated noise.
D Displayed on the display. As a result of the simulation, when the radiation noise is large, each parameter is changed and the simulation is performed again, and the parameters are changed and the simulation is repeated until the radiation noise has a desired magnitude.

[0004]

In the conventional radiation noise simulation method, the simulation is performed on all wirings as described above, and the result cannot be obtained without the simulation. If the radiation noise is large, it is desired. It takes time because the parameters must be changed and the simulation must be repeated until the size becomes large.

The present invention has been made in order to solve the above problems, and it is intended to reduce the number of wirings for executing the simulation, and to repeat the number of simulations until the radiation noise has a desired magnitude. A radiation noise simulation method that can shorten the design time by reducing the noise.

[0006]

According to a first aspect of the present invention, there is provided a radiation noise simulation method, which has a function of simulating radiation noise, a function of inputting parameters required for simulation, and a function of outputting a result of simulation. In the noise simulation system, a function is provided for each wiring to determine whether or not to execute the simulation.

A radiation noise simulation method according to a second aspect of the present invention is the radiation noise simulation method according to the first aspect, wherein the wiring length is used to determine whether or not the simulation is performed.

A radiation noise simulation method according to a third aspect of the present invention is the radiation noise simulation method according to the first aspect, wherein the wiring length and frequency are used to determine whether or not the simulation is performed.

A radiation noise simulation method according to a fourth aspect of the present invention is the radiation noise simulation method according to the first aspect, wherein the wiring length, frequency and voltage are used to determine whether or not the simulation is performed.

According to a fifth aspect of the present invention, in the radiation noise simulation method according to the first aspect, the wiring length, the frequency, the voltage, and the rise of the signal are used to determine whether or not the simulation is performed.

According to a sixth aspect of the radiation noise simulation method, in the first aspect, the wiring length, frequency, voltage, signal rise time, and substrate dielectric thickness are used to determine whether or not the simulation is performed. It is a thing.

According to a seventh aspect of the present invention, there is provided a method of simulating radiated noise, comprising a function of simulating radiated noise, a function of inputting parameters required for simulation,
In a radiated noise simulation system having a function of outputting a simulation result, a wiring with a large radiated noise is checked before executing the radiated noise simulation, and the parameters can be corrected.

According to an eighth aspect of the present invention, in the radiation noise simulation method according to the first to sixth aspects, the wiring having a large radiation noise is checked before determining whether or not the simulation is executed and executing the radiation noise simulation.
It is possible to modify the parameters.

According to a ninth aspect of the present invention, there is provided a method for simulating radiated noise according to the eighth aspect, wherein the discriminants for determining the presence / absence of parameter change and the presence / absence of simulation are the same, and parameters for determining the presence / absence of simulation are set. It is about 2 to 5 times the parameter used to determine whether or not the parameter has been changed.

[0015]

According to the radiation noise simulation method of the present invention, the time required for the radiation noise simulation can be shortened by reducing the number of wirings for performing the radiation noise simulation. Therefore, the design time can be shortened. You can

According to the radiation noise simulation method of the second aspect, the wiring length is used as a parameter for judging whether or not the simulation is executed, so that the simulation can be performed very easily.
Moreover, since it is possible to judge whether or not the simulation is executed in a very short time, the design time can be shortened.

According to the radiation noise simulation method of the present invention, the product of the wiring length and the clock frequency is used as a parameter for determining whether or not the simulation is executed, so that the clock frequency of each electronic device can be determined relatively easily. Since it is possible to judge whether or not the simulation is executed more accurately, it is possible to shorten the design time.

According to a fourth aspect of the present invention, in the radiation noise simulation method, the product of the wiring length, the clock frequency and the amplitude of the signal voltage is used as a parameter for determining whether or not the simulation is executed, and the electronic noise of each electronic device can be easily and quickly obtained. Since it is possible to judge whether or not the simulation is executed more accurately according to the clock frequency and the amplitude of the signal voltage, it is possible to shorten the design time.

The radiation noise simulation method according to the fifth aspect of the present invention can be simplified by using a value obtained by dividing the product of the wiring length, the clock frequency, and the amplitude of the signal voltage by the rise time of the signal as a parameter for determining whether or not to execute the simulation. In addition, it is possible to determine whether or not a more accurate simulation is performed in accordance with the clock frequency of each electronic device, the amplitude of the signal voltage, and the rise time of the signal in a short time, so that the design time can be shortened.

According to a sixth aspect of the radiation noise simulation method, a value obtained by dividing a product of a wiring length, a clock frequency, an amplitude of a signal voltage and a dielectric thickness by a signal rise time is used as a parameter for determining whether or not the simulation is executed. By doing so, it is possible to easily determine in a short time whether or not a more accurate simulation is performed, which matches the clock frequency of each electronic device, the amplitude of the signal voltage, the rise time of the signal, and the dielectric thickness of the substrate. Design time can be shortened.

According to the radiated noise simulation method of the present invention, the wiring having a large radiated noise is checked before executing the radiated noise simulation, and the parameters can be corrected. The number of times the end judgment is performed can be reduced, and the design time can be shortened.

According to the radiated noise simulation method of the present invention, the wiring having a large radiated noise is checked before executing the radiated noise simulation, and the parameters can be modified. In addition, the number of times the end judgment is performed can be extremely reduced, and the number of wirings to be simulated by judging whether or not the simulation of each wiring is executed is reduced, so that the time required for the radiation noise simulation can be shortened. . Therefore, the design time can be shortened.

According to a ninth aspect of the radiation noise simulation method, the equation for judging the presence / absence of parameter change is made the same as the equation for judging the presence / absence of simulation, and the parameter for judging the presence / absence of parameter change is judged as to the presence / absence of simulation execution. By setting the parameter to about 2 to 5 times, the value of each wiring calculated for determining whether the parameter is changed can be used as a value for determining whether the simulation is performed. In addition, the number of wires to be simulated does not increase or become too small due to a parameter setting error that determines whether or not parameters have been changed and whether or not simulation is to be executed. Parameter setting is easy, and simulation is performed. Since the number of wirings can be set to an appropriate value, design time can be shortened.

[0024]

【Example】

Example 1. First Embodiment FIG. 1 is a flow chart of a radiation noise simulation method according to a first embodiment of the present invention. In FIG. 1, 7 is a database, 8 is a parameter input section,
10 is a function for determining whether or not a simulation is executed, 1
Reference numeral 1 is a radiation noise simulation execution unit, 12 is a simulation result output unit, and 13 is a function for determining the end.

In FIG. 1, the parameter input unit 8 is
For example, parameters such as clock frequency, signal waveform, amplitude, rise time, fall time, duty and wiring length, board dielectric constant, dielectric thickness, input / output resistance of the device used, which are parameters necessary for simulation of radiation noise, It is for inputting input / output capacitances and parameters for determining the presence / absence of execution of simulation, and is input by an operator using, for example, CAD for physical design or read from the database 7. Using these parameters, it is determined in 10 whether or not the simulation of each wiring is executed, and for the wiring determined to require simulation, radiation noise is simulated in 11. The result is output at 12 to a display, a printer, a storage device, or the like. It outputs at 12 that the simulation was not performed for the wiring that does not require the simulation. If the results are output for all wirings, it is determined in 13 whether or not the radiation noise simulation is to be ended, and when the radiation noise is large and the simulation is performed again, or the parameters for determining whether or not the simulation is executed are changed. In this case, the parameter input section 8 is returned to and correction is performed. As described above, by reducing the number of wirings that perform the radiation noise simulation by 10, the time required for the radiation noise simulation 11 can be shortened, and thus the design time can be shortened.

Example 2. In the first embodiment, for example, the clock frequency of a digital circuit made of a multilayer substrate is 1
In the case of an electronic device having a relatively slow operation speed such as 0 MHz or less, by using the wiring length as a parameter for determining whether or not to execute the simulation, the radiation noise simulation can be performed very easily and in a very short time. It can be carried out. For example, in the parameter input unit 8, when the line length is set to 10 cm (C1 = 10 cm) as the parameter C1 for determining whether or not to execute the simulation, the parameter input unit 8 performs physical design at 10 to determine whether or not to execute the simulation. Length of each wiring L [cm] and C input by CAD
1 [cm] is compared by using the equation (1), and the radiation noise is simulated in the wiring 11 of 10 cm or more. L> C1 (1) As described above, by using the wiring length as a parameter for determining the presence / absence of simulation execution, the presence / absence of simulation execution can be determined very easily and in a very short time. , The design time can be shortened. However, the parameter C1 for determining whether or not to execute the simulation changes depending on other parameters.

Example 3. 2 is a flowchart of a radiation noise simulation method according to a third embodiment of the present invention.
FIG. 3 is a signal waveform, and FIG. 4 is an envelope of voltage at each frequency when the signal waveform is expanded by Fourier series. In FIG. 2, 7 is a database, 8 is a parameter input section,
Reference numeral 9 is a function for calculating an equation for determining whether or not a simulation is executed, 10 is a function for determining whether or not a simulation is executed, 11 is a simulation execution unit for radiating noise,
Reference numeral 2 is a simulation result output unit, and reference numeral 13 is a function of determining termination. In FIG. 3, 20 is the amplitude of the signal, 21
Is the pulse width of the signal, and 22 is the rise time. Figure 4
23 is a voltage envelope at each frequency when a trapezoidal wave with a pulse width τ1 is expanded by Fourier series, and 24 is a voltage envelope at each frequency when a trapezoidal wave with a pulse width τ2 (τ1> τ2) is expanded by Fourier series It is a line.

In FIG. 2, the parameter input unit 8 is
For example, parameters such as clock frequency, signal waveform, amplitude, rise time, fall time, duty and wiring length, board dielectric constant, dielectric thickness, input / output resistance of the device used, which are parameters necessary for simulation of radiation noise, The product C2 [cm · MHz] of the wiring length and the clock frequency is input as a parameter for determining the input / output capacitance and the presence / absence of the simulation execution. For example, it is input by an operator using CAD for physical design or a database. It is read from 7. Here, the signal flowing through the wiring of the digital circuit made of the multilayer board is
As shown in FIG. 3, the amplitude 20 is A [V] and the pulse width 21 is τ.
[Μsec], the rise time 22 is τr [μse
c] and the repetition of a trapezoidal wave with a duty of 50%, the envelope curve of the voltage at each frequency obtained by Fourier series expansion is as shown in FIG. That is, 1 / (μτ)
A [V], 1 / (πτ) to 1 up to the frequency determined by
Up to / (πτr), it decreases by -20 dB / dec and becomes 1 /
At frequencies above (πτr), it decreases at -40 dB / dec. Therefore, as shown in FIG. 4, the voltage at each frequency is inversely proportional to the pulse width 21. The radiated noise is proportional to the applied voltage, and since the pulse width is inversely proportional to the clock frequency, the radiated noise is proportional to the clock frequency. Therefore, the product of the wiring length and the clock frequency is C2 [cm · MH] as a parameter for determining whether or not the simulation is executed.
By using z], it is possible to determine whether or not a more accurate simulation matching the clock frequency of each electronic device is executed. For example, in the parameter input section 8, the product of the line length and the clock frequency is 100 cm
When the frequency is set to MHz, the left side of the equation (2) is calculated by using the length L [cm] of each wiring and the clock frequency f _c [MHz] input by the parameter input unit 8 in the physical design CAD or the like in 9. To calculate. This value is compared with C2 [cm · MHz] input in the parameter input unit 8 at the time of determining whether or not to execute the simulation by using the equation (2), and the radiation noise is simulated in only the wiring of 100 cm · MHz or more 11 To do. _{L · f c> C2 ... (} 2) the result is output at 12 a display, such as a printer or a storage device. It outputs at 12 that the simulation was not performed for the wiring that does not require the simulation. If the results are output for all wirings, it is determined in 13 whether or not the radiation noise simulation is to be ended, and when the radiation noise is large and the simulation is performed again, or the parameters for determining whether or not the simulation is executed are changed. In this case, the parameter input section 8 is returned to and correction is performed. As described above, by using the product of the wiring length and the clock frequency as a parameter for determining whether or not to execute the simulation, it is possible to perform a more accurate simulation that matches the clock frequency of each electronic device relatively easily and in a short time. Since the presence or absence can be determined, the design time can be shortened. However, the parameter C2 for determining whether or not to execute the simulation changes depending on other parameters.

Example 4. In the third embodiment, the wiring length, the clock frequency, and the amplitude of the signal voltage are used as the parameters for determining the presence or absence of the simulation, so that the clock frequency and the amplitude of the signal voltage of each electronic device can be matched easily and in a short time. It is possible to judge whether or not the simulation is accurately executed. The parameter input unit 8 includes, for example, a clock frequency, a waveform of a signal, an amplitude, which are parameters necessary for simulation of radiation noise.
Rise time, fall time, duty and wiring length, board permittivity, dielectric thickness, input / output resistance of device used, input / output capacitance, etc. Amplitude product of signal voltage C3 [cm · MHz ·
V] and is input by the operator using, for example, CAD for physical design, or the database 7
Read more. Here, the signal flowing through the wiring is shown in FIG.
Amplitude 20 is A [V] and pulse width 21 is τ [μs
ec], the rise time 22 is τr [μsec], and the repetition of trapezoidal waves with a duty of 50% is performed, and the Fourier series expansion is performed to obtain the voltage envelope at each frequency, as shown in FIG. That is, A [V] up to the frequency determined by 1 / (πτ), decreases by -20 dB / dec from 1 / (πτ) to 1 / (πτr), and −40 dB / dec at frequencies above 1 / (πτr). Dec decreases with dec. Therefore, as shown in FIG. 5, the voltage at each frequency is proportional to the amplitude 20. Since the radiated noise at each frequency is proportional to the applied voltage at each frequency, the radiated noise is proportional to the amplitude 20. Therefore, by using the product C3 [cm · MHz · V] of the wiring length, the clock frequency, and the amplitude of the signal voltage as a parameter for determining whether or not to execute the simulation, the clock frequency and the amplitude of the signal voltage used in each electronic device can be obtained. It is possible to judge whether or not a more accurate simulation is executed. For example, in the parameter input unit 8, when the product of the line length, the clock frequency and the amplitude of the signal voltage is set to 300 cm · MHz · V as the parameter C3 for determining whether or not to execute the simulation, the parameter input unit 8 at 9 The left side of the equation (3) is calculated by using the length L [cm] of each wiring, the clock frequency f _c [MHz], and the amplitude A [V] of the signal voltage input by the CAD for physical design or the like. This value is used to judge whether or not simulation is executed 1
0 C3 [cm ·
MHz · V] and the formula (3) are compared, and 300 cm ·
The radiation noise is simulated in only the wiring 11 of MHz · V or higher. _{L · f c · V> C3} ... (3) the result is output at 12 a display, such as a printer or a storage device. It outputs at 12 that the simulation was not performed for the wiring that does not require the simulation. If the results are output for all wirings, it is determined in 13 whether or not the radiation noise simulation is to be ended, and when the radiation noise is large and the simulation is performed again, or the parameters for determining whether or not the simulation is executed are changed. In this case, the parameter input section 8 is returned to and correction is performed. As described above, by using the product of the wiring length, the clock frequency, and the amplitude of the signal voltage as the parameter for determining whether or not to execute the simulation, it is possible to easily match the clock frequency and the amplitude of the signal voltage of each electronic device in a short time. In addition, since it is possible to judge whether or not the simulation is executed more accurately, the design time can be shortened. However, the parameter C3 for determining whether or not to execute the simulation changes depending on other parameters. FIG. 5 is an envelope of voltage at each frequency when the signal waveform is subjected to Fourier series expansion. In FIG. 5, 25 is the voltage envelope at each frequency when a trapezoidal wave of amplitude A1 is expanded by Fourier series, 2
Reference numeral 6 denotes an envelope of voltage at each frequency when a trapezoidal wave having an amplitude A2 (A2> A1) is expanded by Fourier series.

Example 5. In the fourth embodiment, the wiring length, the clock frequency, the amplitude of the signal voltage, and the rise time of the signal are used as the parameters for determining whether or not the simulation is executed, and the clock frequency and the signal voltage of each electronic device can be easily and quickly obtained. It is possible to judge whether or not there is a very accurate simulation execution that matches the amplitude and rise time of. The parameter input unit 8 includes, for example, parameters required for simulation of radiation noise, such as clock frequency, signal waveform, amplitude, rise time, fall time, duty and wiring length,
The product of the dielectric constant of the board, the thickness of the dielectric, the input / output resistance of the device used, the input / output capacitance, etc., and the parameter of the wiring length, the clock frequency, and the amplitude of the signal voltage is used as the parameter to judge whether the simulation is to be performed. The divided value C4 [cm · MHz · V / μsec] is input, and is input by the operator using the CAD for physical design or read from the database 7. Here, the electric field e [V / m] radiated from the wiring having the length L [cm] connected to the signal source 28 having the amplitude A [V] as shown in FIG. 6 has the frequencies f [MHz] and K ₁ Can be expressed as in equation (4). e = K ₁ · L · f ₂ · A (4) Further, the signal flowing through the wiring has an amplitude of A as shown in FIG.
[V], pulse width 21 is τ [μsec], rising time 22 is τr [μsec], and a trapezoidal wave with a duty of 50% is repeated, and Fourier series expansion is performed to obtain the voltage envelope at each frequency. It becomes like 5. Therefore, f ₁ = 1 / (πτ) [MHz], f ₂ = 1 / (π
τr) [MHz], the envelope of the electric field E [dBV / m] is as shown in FIG. 7, and K ₂ is a proportional constant (4)
The maximum value emax of the equation is expressed by the equation (5), and when K ₃ is a constant of proportionality and f _c = ½τ, the equation (6) is obtained. emax = K ₂ · L · f ₁ · f ₂ · A (5) = K ₃ · L · f _c · A / τr (6) Therefore, the wiring length, clock frequency, and Value obtained by dividing the product of the amplitude of the signal voltage by the rise time of the signal C4 [cm · MHz
By using [V / μsec], it is possible to determine whether or not a very accurate simulation is performed that matches the clock frequency used in each electronic device, the amplitude of the signal voltage, and the rise time. For example, in the parameter input unit 8, the value obtained by dividing the product of the line length, the clock frequency, and the amplitude of the signal voltage by the signal rise time is 1 as the parameter C4 for determining whether or not to execute the simulation.
When it is set to 00 cm · MHz · V / μsec, the parameter input unit 8 in 9 sets the physical design CA.
The length of each wiring entered by D, such as L [cm], the clock frequency f _c [MHz], the amplitude A [V] of the signal voltage, the left side of using the signal rise time τr [μsec] (7) equation calculate. This value is compared with C4 [cm · MHz · V / μsec] input by the parameter input unit 8 at the time of determining whether or not to execute the simulation using the equation (7), and wiring of 100 cm · MHz · V / μsec or more is obtained. A simulation of radiation noise is performed only at 11. _{L · f c · A / τr} > C4 ... (7) the result is output at 12 a display, such as a printer or a storage device. It outputs at 12 that the simulation was not performed for the wiring that does not require the simulation. If the results are output for all wirings, it is determined in 13 whether or not the radiation noise simulation is to be ended, and when the radiation noise is large and the simulation is performed again, or the parameters for determining whether or not the simulation is executed are changed. In this case, the parameter input section 8 is returned to and correction is performed. As described above, by using the value obtained by dividing the product of the wiring length, the clock frequency, and the amplitude of the signal voltage by the rise time of the signal as a parameter for determining whether or not to execute the simulation, it is possible to easily and quickly Since it is possible to determine whether or not a more accurate simulation is performed, which matches the clock frequency, the amplitude of the signal voltage, and the rise time of the signal, it is possible to reduce the design time. However, the parameter C4 for determining whether or not to execute the simulation changes depending on other parameters. FIG. 6 is a model of a radiation noise source, and FIG. 7 is an envelope of a radiation electric field at each frequency. In FIG. 6, 27 is a signal source and 28 is a load.

Example 6. In the fifth embodiment, the wiring length, the clock frequency, the amplitude of the signal voltage, the rising time of the signal, and the dielectric thickness of the substrate are used as the parameters for determining whether or not to execute the simulation, so that each electronic device can be easily and quickly processed. It is possible to judge whether or not a very accurate simulation is performed according to the clock frequency, the amplitude of the signal voltage, the rise time and the dielectric thickness of the substrate. The parameter input unit 8 includes, for example, parameters necessary for simulation of radiation noise, such as clock frequency, signal waveform, amplitude, rise time, fall time, duty and wiring length, board permittivity, dielectric thickness and use. The value of the product of the wiring length, clock frequency, signal voltage amplitude, and dielectric thickness divided by the signal rise time C5 [ cm ² · MHz · V / μsec] is input by an operator using the CAD for physical design or the like or read from the database 7. Here, the wiring 6 and the ground 2 as shown in FIG.
9. The electric field radiated from the microstrip line constituted by the dielectric 30 has a value proportional to the thickness d [cm] of the dielectric due to the influence of the ground 29. Therefore K
_{When 4} is a proportional constant, equation (6) can be transformed into equation (8). _{emax = K 4 · L · f} c · A · d / τr (8) Therefore simulation wiring length whether to execute as a parameter for determining the clock frequency, the amplitude of the signal voltage at the rising time of the signal the product of the dielectric thickness Value divided by C5 [c
m ² · MHz · V / μsec], the clock frequency used in each electronic device, the amplitude of the signal voltage,
It is possible to judge whether or not a very accurate simulation is executed, which matches the rise time and the dielectric thickness of the substrate. For example, in the parameter input unit 8, the value obtained by dividing the product of the line length, the clock frequency, the amplitude of the signal voltage, and the dielectric thickness by the signal rise time is 5 cm ² MH as the parameter C5 for determining whether or not to execute the simulation.
If z · V / μsec is set, the length L [cm] of each wiring and the clock frequency f _c [M input by the CAD for physical design in the parameter input unit 8 in 9 are set.
Hz], the amplitude A [V] of the signal voltage, the signal rise time τr [μsec], and the dielectric thickness d [cm], the left side of the equation (9) is calculated. The parameter input unit 8 is used to determine whether or not the simulation is executed based on this value.
C5 [cm ² · MHz · V / μsec] input in step 5 is compared with the formula (9) to obtain 5 cm ² · MHz · V / μse
The radiation noise is simulated in the wiring 11 of only the wiring of c or more. _{L · f c · A · d} / τr> C4 ... (9) The result is output at 12 a display, such as a printer or a storage device. It outputs at 12 that the simulation was not performed for the wiring that does not require the simulation. If the results are output for all wirings, it is determined in 13 whether or not the radiation noise simulation is to be ended, and when the radiation noise is large and the simulation is performed again, or the parameters for determining whether or not the simulation is executed are changed. In this case, the parameter input section 8 is returned to and correction is performed. As described above, by using the value obtained by dividing the product of the wiring length, the clock frequency, the amplitude of the signal voltage, and the dielectric thickness by the signal rise time as a parameter for determining whether or not to execute the simulation, it can be performed easily and in a short time. Since it is possible to determine whether or not a more accurate simulation is performed according to the clock frequency of each electronic device, the amplitude of the signal voltage, the rising time of the signal, and the dielectric thickness of the substrate, the design time can be shortened. However, the parameter C5 for determining whether or not to execute the simulation changes depending on other parameters. FIG. 8 is a sectional view of the microstrip line. In FIG. 8, 6 is a wiring, 9 is a ground, and 30 is a dielectric.

Example 7. Embodiment 7 FIG. 9 is a flow chart of a radiation noise simulation method showing Embodiment 7 of the present invention. In FIG. 9, 7 is a database, 8 is a parameter input unit, 9 is a function for calculating an expression for determining whether or not a parameter has been changed, 11 is a radiated noise simulation execution unit, 12 is a simulation result output unit, and 13 is the end. Is a function of determining whether there is a parameter change, and 14 is an output unit that outputs the result of determining whether there is a parameter change, and 15 is a function of determining whether a parameter is changed.

In FIG. 9, the parameter input section 8 is
For example, parameters such as clock frequency, signal waveform, amplitude, rise time, fall time, duty and wiring length, board dielectric constant, dielectric thickness, input / output resistance of the device used, which are parameters necessary for simulation of radiation noise, The input / output capacitance and parameters for determining whether or not the parameters are changed are input, and are input by an operator using a CAD for physical design or read from the database 7. For example, in the parameter input unit 8, a value obtained by dividing the product of the line length, the clock frequency, the amplitude of the signal voltage and the dielectric thickness by the signal rise time is 10 cm ² · MHz · V / When μsec is set, the length L [cm] of each wiring input by the parameter design unit 8 by CAD for physical design or the like in 9,
Clock frequency f _c [MHz], amplitude of signal voltage A
The left side of the equation (9) is calculated using [V], the signal rise time τr [μsec], and the dielectric thickness d [cm]. This value is used to judge whether or not the parameter has been changed. In C15 [cm ² · MHz · V] input in the parameter input unit 8
/ Μsec] and equation (9) are used to compare 5 cm ² · MH
For wirings of z · V / μsec or more, the result is output to the determination result output unit 14, and the parameter input unit 8 determines a parameter necessary for simulation of radiation noise and, if necessary, a parameter for determining whether or not the parameter is changed. To change. The above operation is repeated, and when there is no wiring that requires the parameter change, or when the parameter is not changed any more, the radiation noise simulation is performed in 11. The result is output at 12 to a display, a printer, a storage device, or the like. When the results are output for all the wirings, it is determined in 13 whether or not the simulation of the radiation noise is ended, and when the radiation noise is large and the simulation is performed again, or the parameter for determining whether or not the parameter is changed is changed. In this case, the parameter input section 8 is returned to and correction is performed. As mentioned above, in 15,
The radiation noise simulation is checked before executing the radiation noise simulation, and the parameters can be modified.
It is possible to reduce the number of times the simulation result output 12 and the end determination 13 are performed (the number of times No in 13), and the design time can be shortened.

Example 8. In the seventh embodiment, for example, when the parameter input 8 is performed using the layout module of the CAD for physical design, the formula calculation 9 for determining the presence or absence of the parameter change in real time in association with this, the presence or absence of the parameter change 9 By performing the output 14 of the results of the judgments 15 and 9 and 10, the work efficiency can be improved and the design time can be shortened.

Example 9. Embodiment 9 FIG. 10 is a flow chart of a radiation noise simulation method showing Embodiment 9 of the present invention. In FIG. 10, 7 is a database, 8 is a parameter input section, 9a is a function for calculating an expression for determining whether or not a parameter is changed, 10 is a function for determining whether or not a simulation is performed, and 9b is for determining whether or not a simulation is performed. A function for calculating an expression, 11 is a simulation execution unit for radiation noise, 12 is an output unit for a simulation result, 13 is a function for determining the end, 14 is an output unit for determining whether or not a parameter is changed, and 15 is a parameter change It is a function to determine the presence or absence.

In FIG. 10, the parameter input unit 8 is
For example, parameters such as clock frequency, signal waveform, amplitude, rise time, fall time, duty and wiring length, board dielectric constant, dielectric thickness, input / output resistance of the device used, which are parameters necessary for simulation of radiation noise, Input parameters such as input / output capacitance and parameters for determining whether or not parameters are changed and parameters for determining whether or not simulation is to be performed. For example, the parameters are input by an operator using a CAD for physical design or read from the database 7. Be done. For example, a value obtained by dividing the product of the line length, the clock frequency, the amplitude of the signal voltage, and the dielectric thickness by the signal rise time is 10 cm ² · MHz · V / μsec as the parameter C5 for determining whether or not the parameter is changed in the parameter input unit 8. If it is set that the parameter input unit 8
The length L of each wiring input by CAD for physical design, etc.
[Cm], clock frequency f _c [MHz], signal voltage amplitude A [V], signal rise time τr [μse]
c] and the dielectric thickness d [cm] are used to calculate the left side of the equation (9). This value is used to determine whether the parameter has been changed 15
In C5 [cm ² ·
MHz · V / μsec] and equation (9) is used to compare 5c
For wirings of m ² · MHz · V / μsec or more, the result is output to the determination result output unit 14, and the parameter input unit 8 displays the parameters necessary for the simulation of the radiation noise and, if necessary, the parameter change. Change the discriminating parameter. The above operation is repeated, and when there is no wiring that requires the parameter change, or when the parameter is not changed any more, the process proceeds to the next step, that is, the presence / absence of simulation execution. In the parameter input unit 8,
Parameter C2 for determining whether or not simulation is executed
The product of line length and clock frequency is 100 cm · MH
When z is set, the left side of the equation (2) is calculated using the length L [cm] of each wiring and the clock frequency f _c [MHz] input by the physical design CAD or the like in the parameter input unit 8 in 9b. To calculate. This value is compared with C2 [cm · MHz] input in the parameter input unit 8 at the time of determining whether or not to execute the simulation by using the equation (2), and the radiation noise is simulated in only the wiring of 100 cm · MHz or more 11 To do. The result is output at 12 to a display, a printer, a storage device, or the like. For wiring that does not require simulation, it was noted that no simulation was performed.
Output at. When the results are output for all wirings, it is determined in 13 whether the radiation noise simulation is to be ended, and whether the radiation noise is large and the simulation is performed again, or whether the parameters are changed or whether the simulation is executed. When the parameter to be changed is changed, the correction is returned to the parameter input unit 8 to make a correction. As described above, in 15, the wiring having a large radiation noise is checked before the simulation of the radiation noise is performed, and the parameters can be corrected, whereby the radiation noise simulation 11, the simulation result output 12, and the end determination 13 are performed. Number of times (N at 13)
The number of times the number of times is 0) can be extremely reduced, and the number of wirings to be simulated by judging whether or not the simulation of each wiring is executed is reduced in 10 to shorten the time required for the radiation noise simulation 11. You can Therefore, the design time can be shortened.

Example 10. 11 is a tenth embodiment of the present invention.
3 is a flowchart of a radiation noise simulation method showing In FIG. 11, 7 is a database, 8 is a parameter input unit, 9 is a function for calculating an expression for determining whether or not a parameter is changed, 10 is a function for determining whether or not a simulation is performed, 11 is a simulation execution unit for radiated noise, 12 is a simulation result output unit, 1
Reference numeral 3 is a function of determining the end, 14 is an output unit of a result of determining whether or not the parameter is changed, and 15 is a function of determining whether or not the parameter is changed.

In the ninth embodiment, the equation for judging the presence or absence of the parameter change and the equation for judging the presence or absence of the simulation are made the same, and the parameters for judging the presence or absence of the parameter change are the parameters 2 to 2 for judging the presence or absence of the simulation. By making the number about 5 times, it is possible to reduce the number of times the discriminant is calculated, it is easy to set the parameters for determining whether or not the parameters are changed and whether or not the simulation is performed, and the number of wiring lines to be simulated can be set appropriately. Since the value can be set, the design time can be shortened. In FIG. 11, the parameter input unit 8
Is, for example, clock frequency, signal waveform, amplitude, rise time, fall time, duty and wiring length, board permittivity, dielectric thickness, device input / output used for simulation of radiation noise. Inputs parameters such as resistance and input / output capacitance and parameters for determining whether or not parameters are changed and parameters for determining whether or not simulation is executed. For example, a CAD for physical design is used to input by the operator or the database 7 Read more. For example, in the parameter input unit 8, the line length, clock frequency,
If the value obtained by dividing the product of the amplitude of the signal voltage and the dielectric thickness by the rise time of the signal is set to 10 cm ² · MHz · V / μsec, the parameter input section 8 inputs the value in 9 by the CAD for physical design or the like. Length of each wiring L
[Cm], clock frequency f _c [MHz], signal voltage amplitude A [V], signal rise time τr [μse]
c] and the dielectric thickness d [cm] are used to calculate the left side of the equation (9). This value is used to determine whether the parameter has been changed 15
In C5 [cm ² ·
MHz · V / μsec] and equation (9) is used to compare 5c
For wirings of m ² · MHz · V / μsec or more, the result is output to the determination result output unit 14, and the parameter input unit 8 displays the parameters necessary for the simulation of the radiation noise and, if necessary, the parameter change. Change the discriminating parameter. The above operation is repeated, and when there is no wiring that requires the parameter change, or when the parameter is not changed any more, the process proceeds to the next step, that is, the presence / absence of simulation execution. In the parameter input unit 8,
Parameter C5 for determining whether or not simulation is executed
The value obtained by dividing the product of the line length, the clock frequency, the amplitude of the signal voltage and the dielectric thickness by the signal rise time is 2 as C.
When 5 cm ² · MHz · V / μsec, which is half of 51, is set, the presence or absence of simulation execution can be determined in 10 by using the left side of the equation (9) calculated in 9 as it is. As described above, the formula for determining the presence / absence of parameter change is the same as the formula for determining the presence / absence of simulation, and the parameter for determining the presence / absence of parameter change is set to about 2 to 5 times the parameter for determining the presence / absence of simulation. By doing so, the value of each wiring calculated to determine whether or not the parameter is changed can be used as a value for determining whether or not to execute the simulation. In addition, the number of wires to be simulated does not increase or become too small due to a parameter setting error that determines whether or not parameters have been changed and whether or not simulation is to be executed. Parameter setting is easy, and simulation is performed. Since the number of wirings can be set to an appropriate value, design time can be shortened.

[0039]

According to the radiation noise simulation method of the present invention, a radiation noise simulation function is provided.
In the radiated noise simulation system that has the function of inputting parameters required for simulation and the function of outputting the result of simulation, the function to judge whether or not the simulation is executed is provided for each wiring. By reducing the number of wirings for executing the simulation, it is possible to shorten the time required for the radiation noise simulation, and thus it is possible to shorten the design time.

According to the radiation noise simulation method of the second aspect, in the first aspect, the wiring length is used to determine whether or not the simulation is performed. Therefore, the wiring is used as a parameter for determining whether or not the simulation is performed. It is very easy to use the length,
Moreover, since it is possible to judge whether or not the simulation is executed in a very short time, the design time can be shortened.

According to the radiation noise simulation method of claim 3, the wiring length and the frequency are used to determine whether or not the simulation is executed in the method of claim 1, so that the parameter for determining whether or not the simulation is executed is used. By using the product of the wiring length and the clock frequency as, it is possible to relatively easily determine the presence or absence of a more accurate simulation execution that matches the clock frequency of each electronic device in a short time, thus reducing the design time. it can.

According to the radiation noise simulation method of the fourth aspect, in the first aspect of the present invention, since the wiring length, frequency and voltage are used to determine whether or not the simulation is performed, it is determined whether or not the simulation is performed. By using the product of the wiring length and the clock frequency and the amplitude of the signal voltage as a parameter, it is possible to easily and in a short time determine whether or not a more accurate simulation is performed that matches the clock frequency and the amplitude of the signal voltage of each electronic device. Therefore, the design time can be shortened.

According to the radiation noise simulation method of claim 5, the wiring length, frequency, voltage, and rising edge of the signal are used to determine whether or not the simulation is executed. By using the product of the wiring length, the clock frequency, and the amplitude of the signal voltage divided by the rise time of the signal as a parameter to determine the presence or absence of the signal, the clock frequency of each electronic device and the amplitude of the signal voltage can be easily and quickly achieved. Further, it is possible to determine whether or not a more accurate simulation is executed according to the rise time of the signal, so that the design time can be shortened.

According to a sixth aspect of the radiation noise simulation method of the first aspect, the wiring length, frequency, voltage, signal rise time, and substrate dielectric thickness are used to determine whether or not the simulation is performed. Since the configuration is used, it is easy and short-time by using the value obtained by dividing the product of wiring length, clock frequency, signal voltage amplitude and dielectric thickness by the signal rise time as a parameter to judge whether or not simulation is executed. Since it is possible to determine whether or not a more accurate simulation is performed according to the clock frequency of each electronic device, the amplitude of the signal voltage, the rising time of the signal, and the dielectric thickness of the substrate, the design time can be shortened.

A radiation noise simulation method according to a seventh aspect of the present invention comprises a function of simulating radiation noise, a function of inputting parameters required for simulation,
In the radiated noise simulation system that has the function to output the result of simulation, the wiring that has a large radiated noise is checked before executing the radiated noise simulation, and the parameters can be modified. By checking wiring with a large radiated noise before executing, and making it possible to modify the parameters, it is possible to reduce the number of times radiation noise simulation, simulation result output, and end judgment are performed, and design time can be shortened. .

According to an eighth aspect of the present invention, in the radiation noise simulation method according to the first to sixth aspects, the wiring having a large radiation noise is checked before the presence or absence of the simulation is determined and the radiation noise simulation is performed.
Since the configuration is such that the parameters can be modified, the wiring with a large radiation noise is checked before executing the radiation noise simulation, and the parameters can be modified to simulate the radiation noise, output the simulation result, and end. The number of judgments can be extremely reduced, and the number of wirings to be simulated for judging whether or not the simulation of each wiring is executed is reduced, so that the time required for the radiation noise simulation can be shortened. Therefore, the design time can be shortened.

According to a ninth aspect of the radiation noise simulation method, in the eighth aspect, the discriminants for determining the presence / absence of parameter change and the presence / absence of simulation execution are the same, and the parameters for determining the presence / absence of simulation execution are set. Since the configuration is made to be about 2 to 5 times as large as the parameter used for determining whether or not the parameter has been changed, the equation for determining whether or not the parameter has been changed and the equation for determining whether or not the simulation has been executed are the same, and whether or not the parameter has been changed is determined. By making the parameter about 2 to 5 times the parameter that determines whether or not to execute the simulation,
The value of each wiring calculated to determine whether or not the parameter has been changed can be used as a value for determining whether or not to execute the simulation. In addition, the number of wires to be simulated does not increase or become too small due to a parameter setting error that determines whether or not parameters have been changed and whether or not simulation is to be executed. Parameter setting is easy, and simulation is performed. Since the number of wirings can be set to an appropriate value, design time can be shortened.

[Brief description of drawings]

FIG. 1 is a flowchart of a radiation noise simulation method according to a first embodiment of the present invention.

FIG. 2 is a flow chart diagram of a radiation noise simulation method according to a third embodiment of the present invention.

FIG. 3 is a signal waveform diagram for explaining a third embodiment of the present invention.

FIG. 4 is an envelope diagram of the voltage at each frequency when the signal waveform showing the third embodiment of the present invention is expanded by Fourier series.

FIG. 5 is an envelope diagram of a voltage at each frequency when a signal waveform showing a fourth embodiment of the present invention is subjected to Fourier series expansion.

FIG. 6 is a model diagram of a radiation noise generation source for explaining a fifth embodiment of the present invention.

FIG. 7 is an envelope diagram of a radiated electric field at each frequency according to a fifth embodiment of the present invention.

FIG. 8 is a sectional view of a microstrip line for explaining a sixth embodiment of the present invention.

FIG. 9 is a flowchart diagram of a radiation noise simulation method according to a seventh embodiment of the present invention.

FIG. 10 is a flowchart of a radiation noise simulation method according to a ninth embodiment of the present invention.

FIG. 11 is a flowchart of a radiation noise simulation method according to a tenth embodiment of the present invention.

FIG. 12 is a radiation noise simulation system diagram showing a conventional example of the present invention.

[Explanation of symbols]

1 Radiation Noise Simulation Module 2 Physical Design CAD 3 Database 4 Printed Circuit Board 5 IC 6 Wiring 7 Database 8 Parameter Input Section 9 Discriminant Calculation Function 10 Radiance Noise Simulation Execution Section 12 Output part of simulation result 13 Function to judge the end 14 Output part of result to judge the presence / absence of parameter change 15 Function to judge the presence / absence of parameter change 20 Signal voltage amplitude 21 Signal pulse width 22 Signal rising time 23 Pulse width Envelope of voltage at each frequency when the trapezoidal wave of τ ₁ is expanded by Fourier series 24 Envelope of voltage at each frequency when the trapezoidal wave of pulse width τ ₂ is expanded by Fourier series 25 Trapezoidal wave of amplitude A ₁ is Fourier Each when expanding the series Envelope 27 signal source 28 a load 29 ground 30 dielectric voltage at each frequency when the trapezoidal wave of the envelope 26 the amplitude A ₂ of the voltage at a wave number was expanded Fourier series

Claims (9)

[Claims] 1. A radiated noise simulation system having a function of simulating radiated noise, a function of inputting parameters required for simulation, and a function of outputting a result of simulation, and whether or not simulation is executed for each wiring. A radiation noise simulation method, which is provided with a determination function. 2. The radiation noise simulation method according to claim 1, wherein the wiring length is used to determine whether or not the simulation is executed. 3. The radiation noise simulation method according to claim 1, wherein the wiring length and frequency are used to determine whether or not the simulation is executed. 4. The radiation noise simulation method according to claim 1, wherein the wiring length, frequency, and voltage are used to determine whether or not the simulation is executed. 5. The radiation noise simulation method according to claim 1, wherein the wiring length, the frequency, the voltage, and the rise of the signal are used to determine whether or not the simulation is performed. 6. The wiring length, frequency, voltage, signal rise time, and substrate dielectric thickness are used to determine whether or not the simulation is executed.
Method of simulating radiated noise described. 7. A radiation noise simulation system having a function of simulating radiated noise, a function of inputting parameters required for simulation, and a function of outputting a result of simulation, before radiating noise is simulated. A radiation noise simulation method characterized in that wiring with large noise is checked and parameters can be modified. 8. The method according to claim 1, wherein the wiring having a large radiation noise is checked and the parameters can be corrected before the presence or absence of the simulation is judged and the simulation of the radiation noise is carried out. A method for simulating radiation noise according to claim 2. 9. A discriminant for determining whether or not a parameter has been changed and a determination for whether or not a simulation has been performed are the same, and a parameter for determining whether or not a simulation has been performed is 2 to 5 times the parameter used for determining whether or not a parameter has been changed. The radiation noise simulation method according to claim 8, wherein the radiation noise is simulated.