JP4444140B2 - Interference analysis method, interference analysis apparatus, interference analysis program, and recording medium recording the interference analysis program - Google Patents

Description

  The present invention relates to a method and apparatus for performing a process of analyzing mutual interference caused by electromagnetic induction between wirings formed on a circuit board and investigating the influence thereof, a program for causing a computer to execute the process, and a program thereof The present invention relates to a recorded recording medium.

  As a conventional method and apparatus for analyzing the mutual interference due to electromagnetic induction between wirings formed on a circuit board by a computer and examining the influence thereof, there is a noise check method and apparatus described in Patent Document 1, for example. It was.

  FIG. 9 is a flowchart showing a schematic procedure of conventional digital circuit design.

  At the beginning of this design, a basic specification is first designed (S911). In the design of basic specifications, the specific circuit configuration, element configuration, element layout, etc. are not touched, but the specifications required for the circuit to be the design specification and the basic matters for realizing the required specifications Selections and decisions are made.

  When the basic specifications are designed, next, based on the basic specifications, setting of component constants and designing of a specific circuit configuration are performed to specifically realize the basic specifications (S912).

  At this stage, past design assets and know-how accumulated in the design and development department are used (S921).

  These design assets and know-how are usually accumulated in the form of documented or undocumented tacit knowledge of past experiences and knowledge of organizations and individuals.

  When the setting of specific component constants based on the basic specifications and the design of the specific circuit configuration are completed, the component placement and the wiring design between the components are performed (S913).

  At this time, the organization or person in charge of the setting of the component constants or the design of the specific circuit configuration (S912) is different from the organization or person in charge of the specific part arrangement or wiring design between the parts (S913). There are many cases. Therefore, in order to share knowledge among these different organizations and people, and to ensure the accuracy and accuracy of design, matters to be observed and adhered to when performing specific component placement and wiring design between components In many cases, a design instruction sheet (S922) that describes the items to be used is used. The contents of this design instruction are mainly based on past design assets and know-how and information depending on the specific design object.

  When the component placement and the wiring design between components are completed, the verification is performed (S914).

  A lot of know-how (S923) is also used for this verification. This know-how (S923) is similar to the above-mentioned past design assets and know-how (S921), and the accumulation of past experiences and knowledge of organizations and individuals is either in a documented form or an undocumented tacit knowledge. It is accumulated in such a form.

  If a non-conforming part is found by this verification (S914) (in the case of NG in S914), a correction instruction is created (S931), setting of component constants and circuit design (S912), or component placement again. Wiring design between components (S913) is performed.

  The correction instruction (S931) is a document including a part determined to be non-conforming by the verification (S914), data as the reason, points to be noted for correction, and other various information. In other words, the correction instruction sheet (S931) includes many contents useful for more accurately and accurately performing component constant setting and circuit design (S912) and component placement and wiring design between components (S913). Contains. This correction instruction (S931) is often created based on the past design assets and know-how.

  Based on this correction instruction (S931), whether to design again by setting the component constant and circuit design (S912), or to design again by going back to the component layout and wiring design between components (S913) Is determined according to the content of the nonconformity discovered by the verification (S914).

  If a non-conforming part is not found by the verification (S914) (in the case of OK in S914), the creation of a prototype and the evaluation of the prototype are performed (S915).

  The verification (S914) is mainly performed by simulation using a computer, whereas after the creation and evaluation (S915) of the prototype, the verification is performed after actually creating a physical circuit. .

  Many design assets and know-how may be used in the creation and evaluation of this prototype.

  When the prototype and the general evaluation on the desk (S915) are finished, the prototype is then actually operated and verified (S916).

  A lot of know-how (S924) is also used for this verification. This know-how (S924) is similar to the above-mentioned know-how (S923), and the past experience and accumulation of knowledge of the organization and individuals are in a documented form or in a form of tacit knowledge that is not documented. It has been accumulated.

  When a non-conforming part is found by this verification (S916) (in the case of NG in S916), a correction instruction is created (S932), and again, setting of component constants and circuit design (S912), or component placement Wiring design between components (S913) is performed.

  The correction instruction sheet (S932) is the same as the correction instruction sheet (S931) determined to be non-conforming by the verification (S914), the portion determined to be non-conforming by the verification (S916), the data that is the reason, the correction This is a document that contains points to keep in mind and other various information. The correction instruction (S932) includes a lot of contents useful for setting the component constant and circuit design (S912) again and performing component placement and wiring design between components (S913) more accurately and accurately. . This correction instruction (S932) is also often created based on the past design assets and know-how.

  Based on the correction instruction (S932), whether to design again by setting the component constant and circuit design (S912), or to design again by going back to the component layout and wiring design between components (S913). Is determined according to the content of the nonconformity discovered by the verification (S916). This is the same as when it is determined as non-conforming by the verification (S914).

  If a non-conforming part is not found by the verification (S916) (in the case of OK in S916), the final mass production stage is entered (S917), and the digital circuit design process ends.

  When designing a high-frequency circuit according to the procedure shown in FIG. 9, a serious problem called interference between wirings due to electromagnetic induction occurs.

  When a high frequency current flows on one wiring, a magnetic field is generated around it. However, when the current fluctuates at a high frequency, the magnetic field also fluctuates, thereby generating an electromotive force on the adjacent wiring. That is, a signal flowing through one wiring affects as a noise a signal flowing on an adjacent wiring. This is a problem of interference between wirings.

  The influence of this interference is larger as the frequency of the current flowing on the wiring is higher, and is greater as the distance between the two wirings is shorter.

  On the other hand, electronic circuits are required to operate at high speed and to be miniaturized. Therefore, recent electronic circuits have a very high vibration frequency for high-speed operation, and are mounted with high density for miniaturization. In such an electronic circuit in which the frequency of the current flowing on the wiring is high and the distance between the wirings is short, the influence of the interference between the wirings is large and becomes a serious problem.

  FIG. 10 is a diagram schematically illustrating an example of a portion where interference may occur in the high-frequency electronic circuit.

  The high-frequency electronic circuit shown in FIG. 10 is, for example, a part of a mobile phone, and an LSI component 955, an LSI component 956, a camera module 959, and a high-frequency circuit module 954 are mounted on a substrate 950.

  The high frequency circuit module 954 includes, for example, an element 951 and an element 952.

  The LSI component 955 and the LSI component 956 are connected by a wiring 958. The antenna 953 is connected to the high frequency circuit module 954 by a wiring 957.

  The wiring 957 and the wiring 958 are disposed on the substrate 950 (or in the substrate 950) and close to each other.

  In such a high-frequency electronic circuit, for example, interference may occur between the wiring 957 and the wiring 958, between the element 951 and the element 952, or between the camera module 959 and the high-frequency circuit module 954. is there.

  Further, the same problem occurs not only between the wirings of the substrate 950 and between the components mounted thereon, but also between the wirings in one LSI chip and between the cells connected to the wirings.

  In particular, the arrangement of wirings and cells in the LSI component 955 is far higher in density than the wiring and component mounting on the printed wiring board 950, so that the degree of interference may be higher.

  Therefore, in the pre-manufacturing stage, for example, in the design procedure shown in FIG. 9, it is required to analyze and evaluate the influence of interference between wirings and the like at the stage of verification (S914) before trial manufacture.

  As a method of analyzing such mutual interference, conventionally, a method of performing interference calculation on a computer using a CAD (Computer Aided Design) tool for placement and routing and an electromagnetic field analysis tool, and obtaining an interference frequency characteristic as a result of the analysis was there.

  A method for obtaining the amount of interference between wirings by electromagnetic field analysis using a conventional electromagnetic field analysis tool will be described. FIG. 11A is a diagram illustrating an example of a wiring pattern to be analyzed. Since the wiring pattern 1000 shown in FIG. 11A is a complicated wiring pattern, the electromagnetic field analysis cannot be performed as it is. Therefore, the entire wiring pattern 1000 is divided into a plurality of cells in a mesh shape (“2000”) as shown in FIG. Each cell after the division is represented by a relatively simple analysis model. The analysis model in each cell after division is subjected to electromagnetic field analysis. Then, the electromagnetic field analysis of the entire wiring pattern 1000 is performed by calculating the interaction between the cells. The amount of interference between the wirings is obtained from the result of the entire electromagnetic field analysis.

  However, as shown in FIG. 11A, in the case of the wiring pattern 1000 having a complicated structure, the number of cells after the division increases as shown in FIG. 11B. Therefore, the calculation time becomes enormous. As a result, there are many cases where the electromagnetic field analysis does not end within a realistic work time. That is, in a wiring board having a complicated structure, as an actual problem, it is extremely difficult to obtain the amount of interference between wirings by electromagnetic field analysis.

On the other hand, a method for checking noise flowing on the wiring with a small amount of calculation has been proposed (for example, see Patent Document 1). However, even with the method described in Patent Document 1, it is difficult to analyze interference between wirings in a wiring board having a complicated structure.
Japanese Patent Laid-Open No. 2000-035984

  SUMMARY OF THE INVENTION An object of the present invention is to provide an interference analysis method, an interference analysis apparatus, an interference analysis program, and a recording medium on which the interference analysis program is recorded, which can analyze interference between wirings at high speed, low load, and in a short time. And

  An interference analysis apparatus according to the present invention is an interference analysis apparatus that analyzes, by computer simulation, interference caused by electromagnetic induction between wirings formed on a circuit board, wherein the shape of the wiring and the element or component connected to the wiring A design data input unit for inputting design data of the circuit board including data representing the properties of the circuit, and at least one of the wirings formed on the circuit board, virtual noise input to the terminal The noise characteristics data representing the electrical characteristics of the at least one wiring among the noise characteristics setting unit for setting based on the design data and the wiring formed on the circuit board are received by the terminals. A limit value setting unit for setting a noise tolerance limit value based on the design data; the noise characteristic data; and the tolerance limit Based on the value, a wiring set to be analyzed is selected from wirings formed on the circuit board and includes a terminal to which the virtual noise is input and a terminal to receive the noise. A selection unit; an interference analysis unit that calculates an interference amount representing a degree of interference from a terminal to which the virtual noise is input to a terminal that receives the noise in the set of wirings selected by the selection unit; and the interference A reception noise level calculation unit for calculating a noise level received by the terminal receiving the noise based on the amount and the noise characteristic data.

  An interference analysis method according to the present invention is an interference analysis method for analyzing interference caused by electromagnetic induction between wirings formed on a circuit board by a computer simulation, wherein the shape of the wiring and an element or component connected to the wiring A design data input step for inputting design data of the circuit board including data representing the properties of the circuit, and at least one of the wirings formed on the circuit board, the virtual noise input to the terminal The noise characteristics data representing the electrical characteristics of the at least one wiring among the noise characteristics setting step for setting based on the design data and the wiring formed on the circuit board are received by the terminals. A limit value setting step for setting an allowable limit value of noise based on the design data; the noise characteristic data; and Based on the limit value, from the wiring formed on the circuit board, a wiring set to be analyzed, the wiring set including a terminal to which the virtual noise is input and a terminal to receive the noise An interference analysis step for calculating an interference amount representing a degree of interference from a terminal to which the virtual noise is input to a terminal for receiving the noise in the selection step to be selected and the set of wirings selected in the selection step; A reception noise level calculating step of calculating a noise level received by the terminal receiving the noise based on the interference amount and the noise characteristic data.

  An interference analysis program according to the present invention is an interference analysis program that causes a computer to execute a process of analyzing interference caused by electromagnetic induction between wirings formed on a circuit board by simulation. The design data input process for inputting the design data of the circuit board including data representing the properties of the elements or components to be connected, and the terminals of at least one of the wirings formed on the circuit board Noise characteristic setting processing for setting noise characteristic data representing the electrical characteristics of virtual noise inputted to the circuit based on the design data, and at least one terminal of the wiring formed on the circuit board Limit value setting processing for setting an allowable limit value of noise received by the terminal based on the design data; Based on the noise characteristic data and the allowable limit value, a set of wirings to be analyzed from wirings formed on the circuit board, and a terminal for receiving the virtual noise and a terminal for receiving the noise In the selection process for selecting a set of wirings including and the wiring set selected in the selection process, an interference amount that represents the degree of interference from the terminal that receives the virtual noise to the terminal that receives the noise is calculated. Causing the computer to execute an interference analysis program for causing the computer to execute an interference analysis process for performing the received noise level calculation process for calculating a noise level received by the terminal receiving the noise based on the interference amount and the noise characteristic data .

  A recording medium according to the present invention is a computer-readable recording medium recorded with an interference analysis program that causes a computer to execute a process of analyzing interference caused by electromagnetic induction between wirings formed on a circuit board by simulation. At least one of design data input processing for inputting design data of the circuit board including data representing the shape of the wiring and the properties of elements or parts connected to the wiring, and wiring formed on the circuit board. A noise characteristic setting process for setting, based on the design data, noise characteristic data representing electrical characteristics of virtual noise input to the terminal of the wiring of the book, and wiring formed on the circuit board For at least one terminal of wiring, the allowable limit value of noise received by the terminal is determined by the design data. A set of wirings to be analyzed from the wirings formed on the circuit board based on the noise characteristic data and the allowable limit values, and the virtual noise is input. A selection process for selecting a set of wires including a terminal to be received and a terminal for receiving the noise, and a terminal for receiving the noise from a terminal to which the virtual noise is input in the set of wires selected in the selection process An interference analysis process for calculating an interference amount representing the degree of interference with the computer and a reception noise level calculation process for calculating a noise level received by the terminal receiving the noise based on the interference amount and the noise characteristic data Record the interference analysis program to be executed.

  According to the interference analysis method, the interference analysis apparatus, the interference analysis program, and the recording medium on which the interference analysis program is recorded according to the present invention, it is possible to analyze the interference between the wirings at a high speed and with a low load in a short time.

  An interference analysis apparatus according to the present invention is an interference analysis apparatus that analyzes, by computer simulation, interference caused by electromagnetic induction between wirings formed on a circuit board, wherein the shape of the wiring and the element or component connected to the wiring A design data input unit for inputting design data of the circuit board including data representing the properties of the circuit, and at least one of the wirings formed on the circuit board, virtual noise input to the terminal The noise characteristics data representing the electrical characteristics of the at least one wiring among the noise characteristics setting unit for setting based on the design data and the wiring formed on the circuit board are received by the terminals. A limit value setting unit for setting a noise tolerance limit value based on the design data; the noise characteristic data; and the tolerance limit Based on the value, a wiring set to be analyzed is selected from wirings formed on the circuit board and includes a terminal to which the virtual noise is input and a terminal to receive the noise. A selection unit; an interference analysis unit that calculates an interference amount representing a degree of interference from a terminal to which the virtual noise is input to a terminal that receives the noise in the set of wirings selected by the selection unit; and the interference A reception noise level calculation unit for calculating a noise level received by the terminal receiving the noise based on the amount and the noise characteristic data.

  In the interference analysis apparatus according to the present invention, the noise characteristic setting unit and the limit value setting unit may be configured such that, based on the design data of the circuit board, the noise characteristic data and a specific terminal of a wiring formed in the circuit, Set the noise tolerance. The selection unit selects a set of wirings that need to be analyzed based on the set noise characteristic data and the allowable limit value of the noise. The interference analysis unit and the reception noise level calculation unit perform calculation only for a selected set of wirings, that is, wirings that need to be analyzed. Therefore, the interference between wirings can be analyzed in a short time. That is, since the minimum necessary wiring is extracted and the interference amount is calculated, the interference amount calculation is greatly reduced. As a result, it is possible to analyze the interference between the wirings at a high speed, with a low load and in a short time. As a result, even in a circuit having a complicated wiring or structure, the amount of interference can be calculated in a short time.

  In the interference analysis apparatus according to the present invention, by comparing the noise level calculated by the noise level calculation unit and the allowable limit value, whether or not the interference in the wiring set selected by the selection unit becomes a problem. It is preferable to further include a determination unit that determines whether or not.

  Since the determination unit determines whether or not the interference in the wiring set selected by the selection unit is a problem, in the designed circuit, the wiring set in which the influence of the interference becomes a problem becomes clear. As a result, it is determined whether or not the influence of interference becomes a problem in the designed wiring. In other words, it is possible to determine whether the designed wiring malfunctions due to the influence of interference, or even if it is affected by the interference, it is within a range in which normal operation is guaranteed. . As a result, the design load of the high-frequency circuit is greatly reduced.

  In the interference analysis apparatus according to the present invention, the noise characteristic data is data representing the intensity of the virtual noise provided for a plurality of different frequencies, and the interference analysis unit calculates the amount of interference for the plurality of different frequencies. It is preferable to do.

  The noise characteristic data is represented by the intensity of the virtual noise provided for a plurality of different frequencies, thereby representing a change in the intensity of the virtual noise depending on the frequency. In addition, since the interference analysis unit calculates the interference amount for a plurality of different frequencies, a change of the interference amount depending on the frequency is calculated. Therefore, the reception noise level calculation unit can calculate the reception noise level for different frequencies based on the noise characteristic data and interference amount for different frequencies. As a result, a change in the received noise level depending on the frequency is required.

  In the interference analysis apparatus according to the present invention, it is preferable that the allowable limit value is provided for a plurality of different frequencies.

  Since the allowable limit value is provided for a plurality of different frequencies, an allowable limit value that varies depending on the frequency is provided.

  In the interference analysis apparatus according to the present invention, the interference analysis unit uses the data representing the property of a component arranged in the middle of at least one wiring among the wirings included in the set of wirings to be analyzed. It is preferable to calculate the amount of interference.

  In the calculation of the amount of interference, the interference analysis unit includes the influence of, for example, resonance due to the components arranged in the middle of the wiring by using data representing the properties of the components arranged in the middle of the wiring. A more realistic interference amount can be obtained.

  In the interference analysis apparatus according to the present invention, the data representing the property of the component arranged in the middle of at least one of the wirings included in the set of wirings to be analyzed is impedance provided for a plurality of different frequencies or The data is preferably data representing an S parameter.

  The property of the component is expressed by impedances for a plurality of different frequencies, whereby the frequency characteristic of the component is expressed. Therefore, the interference analysis unit calculates the amount of interference reflecting the frequency characteristics of the component.

  In the interference analysis apparatus according to the present invention, the interference analysis unit uses data representing a termination condition of an element or component connected to at least one of wiring terminals included in the analysis target wiring set. It is preferable to calculate the amount of interference.

  The interference analysis unit uses the data representing the termination condition of the component in the calculation of the interference amount, thereby including the influence of the termination condition of the component to which the terminal of the wiring is connected. Is obtained.

  In the interference analysis apparatus according to the present invention, it is preferable that the termination condition is expressed by impedance or S parameter for a plurality of different frequencies.

  The termination condition of the component is represented by impedances for a plurality of different frequencies, so that the frequency characteristic of the termination condition is represented. Therefore, the interference analysis unit calculates the amount of interference reflecting the frequency characteristics of the component termination conditions.

  In the interference analysis apparatus according to the present invention, when the set of wirings selected by the selection unit includes a plurality of terminals of the wiring that gives the interference, the interference analysis unit uses the wiring that gives the plurality of interferences. For each of the terminals, the amount of interference of the interference given to the terminal of the wiring receiving the interference is calculated, and the reception noise level calculation unit is configured so that the terminal of the wiring receiving the interference is each of the terminals of the wiring giving the plurality of interferences. Preferably, the received noise level is calculated by synthesizing the received noise level received from. In this way, the reception noise level calculation unit calculates a noise level obtained by combining the noise levels received from the terminals of the plurality of wirings.

  In the interference analysis apparatus according to the present invention, it is preferable that the reception noise level calculation unit synthesizes the plurality of reception noise levels in consideration of a noise phase.

  In this way, since the plurality of reception noise levels are combined in consideration of the phase of noise, a reception noise level closer to reality is calculated.

  In the interference analysis apparatus according to the present invention, the wiring to be subjected to the interference analysis may be a wiring of a printed circuit board or a wiring in an LSI (Large Scale Integration).

  An interference analysis method according to the present invention is an interference analysis method for analyzing interference caused by electromagnetic induction between wirings formed on a circuit board by a computer simulation, wherein the shape of the wiring and an element or component connected to the wiring A design data input step for inputting design data of the circuit board including data representing the properties of the circuit, and at least one of the wirings formed on the circuit board, the virtual noise input to the terminal The noise characteristics data representing the electrical characteristics of the at least one wiring among the noise characteristics setting step for setting based on the design data and the wiring formed on the circuit board are received by the terminals. A limit value setting step for setting an allowable limit value of noise based on the design data; the noise characteristic data; and Based on the limit value, from the wiring formed on the circuit board, a wiring set to be analyzed, the wiring set including a terminal to which the virtual noise is input and a terminal to receive the noise An interference analysis step for calculating an interference amount representing a degree of interference from a terminal to which the virtual noise is input to a terminal for receiving the noise in the selection step to be selected and the set of wirings selected in the selection step; A reception noise level calculating step of calculating a noise level received by the terminal receiving the noise based on the interference amount and the noise characteristic data.

  In the interference analysis method according to the present invention, by comparing the noise level calculated in the noise level calculation step with the permissible limit value, whether or not interference in the wiring set selected by the selection unit becomes a problem. It is preferable to further include a determination step for determining whether or not.

The interference analysis program according to the present invention is an interference analysis program for causing a computer to execute a process of analyzing, by simulation, interference caused by electromagnetic induction between wirings formed on a circuit board,
A design data input process for inputting design data of the circuit board including data representing the shape of the wiring and the properties of elements or components connected to the wiring;
Noise characteristic setting that sets, based on the design data, noise characteristic data representing electrical characteristics of virtual noise input to a terminal of at least one of the wirings formed on the circuit board A limit value setting process for setting an allowable limit value of noise received by the terminal based on the design data for a terminal of at least one of the wirings formed on the circuit board; Based on noise characteristic data and the allowable limit value, a wiring set to be analyzed from wirings formed on the circuit board, and a terminal to which the virtual noise is input and a terminal to receive the noise A selection process for selecting a set of wirings to be included, and an end for receiving the noise from a terminal to which the virtual noise is input in the set of wirings selected in the selection process An interference analysis process for calculating an interference amount representing the degree of interference with the computer and a reception noise level calculation process for calculating a noise level received by the terminal receiving the noise based on the interference amount and the noise characteristic data Let the computer run.

  In the interference analysis program according to the present invention, by comparing the noise level calculated in the noise level calculation process with the allowable limit value, whether or not interference in the wiring set selected by the selection unit becomes a problem is determined. It is preferable to cause the computer to further execute a determination process for determining whether or not.

  A recording medium according to the present invention is a computer-readable recording medium recorded with an interference analysis program that causes a computer to execute a process of analyzing interference caused by electromagnetic induction between wirings formed on a circuit board by simulation. At least one of design data input processing for inputting design data of the circuit board including data representing the shape of the wiring and the properties of elements or parts connected to the wiring, and wiring formed on the circuit board. A noise characteristic setting process for setting, based on the design data, noise characteristic data representing electrical characteristics of virtual noise input to the terminal of the wiring of the book, and wiring formed on the circuit board For at least one terminal of wiring, the allowable limit value of noise received by the terminal is determined by the design data. A set of wirings to be analyzed from the wirings formed on the circuit board based on the noise characteristic data and the allowable limit values, and the virtual noise is input. A selection process for selecting a set of wires including a terminal to be received and a terminal for receiving the noise, and a terminal for receiving the noise from a terminal to which the virtual noise is input in the set of wires selected in the selection process An interference analysis process for calculating an interference amount representing the degree of interference with the computer and a reception noise level calculation process for calculating a noise level received by the terminal receiving the noise based on the interference amount and the noise characteristic data Record the interference analysis program to be executed.

  The interference analysis program recorded on the recording medium according to the present invention compares the noise level calculated in the noise level calculation process with the allowable limit value, thereby interfering with the set of wirings selected by the selection unit. It is preferable to cause the computer to further execute a determination process for determining whether or not the problem occurs.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, this invention is not limited to the following embodiment.

(Embodiment 1)
In the first embodiment, an interference analysis method and an interference analysis device for greatly reducing the design load of a high-frequency circuit, a program for causing a computer to execute processing for realizing the interference analysis method and the interference analysis device, and recording this program The recording medium.

  FIG. 1 is a flowchart showing a schematic procedure of high-frequency circuit design performed using the interference analysis method according to the present embodiment.

  The general procedure shown in FIG. 1 is similar to the general procedure of the conventional digital circuit design shown in FIG. 9 in many respects. Therefore, this similar part will be described briefly, and different parts will be described in detail. To do.

  At the beginning of this design, a basic specification is first designed (S111). In the design of basic specifications, the specific circuit configuration, element configuration, element layout, etc. are not touched, but the specifications required for the circuit to be the design specification and the basic matters for realizing the required specifications Selections and decisions are made. This is the same as the schematic procedure of digital circuit design shown in FIG.

  Subsequent to the basic specification design (S111), setting of component constants and a specific circuit configuration are specifically designed to realize the basic specification (S112).

  At this stage, past design assets and know-how accumulated in the design and development department are used (S121). This is also the same as the schematic procedure of the digital circuit design shown in FIG.

  Following the setting of specific component constants based on the basic specifications and the design of a specific circuit configuration (S112), component placement and wiring design between components are performed (S113).

  At this time, there are many cases where a design instruction (S122) in which matters to be noted and items to be observed are used when performing specific component placement and wiring design between components is used.

  The reason why the design instruction (S122) is used is that different organizations and people share knowledge with each other and ensure the accuracy and accuracy of the design. This is also the same as the schematic procedure of the digital circuit design shown in FIG.

  When the component placement and the wiring design between components (S113) are finished, the verification is performed next (S114).

  A lot of know-how (S123) is also used for this verification. This is also the same as the schematic procedure of the digital circuit design shown in FIG.

  However, in the outline procedure of the high-frequency circuit design in the present embodiment, this verification (S114) is the most different from the process in the outline procedure of the conventional digital circuit design shown in FIG.

  In this verification (S114), an interference analysis between wirings in the designed circuit is performed. The interference analysis apparatus according to the present embodiment is used for this interference analysis.

  Since this verification (S114) will be described in detail again, only the above simple description will be given here.

  If a non-conforming part is found by this verification (S114) (NG in S114), a correction instruction is created (S131), setting of component constants and circuit design (S112), or between component arrangement and components. Wiring design (S113) is performed.

  The correction instruction (S131) is a document including a part determined to be non-conforming by the verification (S114), data as the reason, points to be noted in correction, and other various information. The correction instruction includes many contents useful for setting the component constants again and circuit design (S112), as well as performing component placement and wiring design between components (S113) more accurately and accurately. Is the same as the general procedure of the conventional digital circuit design shown in FIG.

  Based on this correction instruction (S131), whether to design again by going back to setting of component constants and circuit design (S112), or to redesigning by going back to component layout and wiring design between components (S113) Is determined according to the content of the nonconformity discovered by the verification (S114). This is also the same as the general procedure of digital circuit design shown in FIG.

  If a non-conforming part is not found by the verification (S114) (OK in S114), creation of a prototype and evaluation of the prototype are performed (S115).

  The verification (S114) is mainly performed by simulation using a computer, whereas in the procedure after the creation and evaluation of the prototype (S115), a physical circuit is actually created and then the verification is performed. Done. This is also the same as the schematic circuit design procedure shown in FIG.

  When the prototype and the general evaluation on the desk (S115) are finished, the prototype is then actually operated and verified (S116). This is also the same as the schematic procedure of the digital circuit design shown in FIG.

  According to this embodiment, in this verification (S116), it is extremely rare that a non-conforming part occurs. (It is difficult to become NG in S116). That is, the second difference between the schematic procedure of the high-frequency circuit design in the present embodiment and the schematic procedure shown in FIG. 9 is that incompatible portions are unlikely to occur in this verification (S116).

  The reason is that in the verification (S114) after the component placement and the wiring design between the components (S113), detailed verification is performed according to the procedure described later, and therefore in the verification (S116) after the prototype and evaluation (S115). This is because new non-conformities are unlikely to occur.

  This will be described in more detail later.

  For this reason, almost no non-conformity is found in the verification (S116) (almost OK in S116). Therefore, after prototyping and evaluation are completed, there is almost no return to component constant setting and circuit design (S112), component placement and wiring design between components (S113).

  As a result, the trial production and evaluation (S115) can be performed once and the final mass production stage (S117) can be entered. Thus, the design process of the high frequency circuit in the present embodiment is completed.

  Next, an interference analysis apparatus that performs verification (S114) after component placement and wiring design between components (S113) will be described. FIG. 2 is a functional block diagram illustrating an example of the configuration of the interference analysis apparatus according to the present embodiment.

  The interference analysis apparatus 400 according to the present embodiment mainly includes a user interface unit 401, a control unit 402, a storage unit 403, and a calculation engine unit 410.

  The user interface unit 401 is a part where a user of the interference analysis apparatus 400 performs an operation for using the interference analysis apparatus 400, inputs various commands and data, and outputs a processing result. For example, the user interface unit 401 outputs a result of processing performed by the calculation engine unit 410.

  The control unit 402 is a part that controls the entire interference analysis apparatus 400, and controls all of the various processes described below. Data and programs necessary for the control are recorded in the storage unit 403.

  The interference analysis apparatus 400 can be configured by a computer such as a personal computer or a workstation, for example. The functions of the control unit 402 and the calculation engine unit 410 can be realized by the CPU of the computer executing a predetermined program.

  The computer includes, for example, a microcomputer, a general-purpose computer such as a personal computer, a workstation, a mainframe, a supercomputer, a minicomputer, etc., for example, various gate arrays (GA), a programmable GA, and a microcomputer core thereof. And those composed of wired logic.

  For the storage unit 403, for example, a recording medium that records information by a magnetic or optical method such as various semiconductor memories, various RAMs, various ROMs, HD (hard disk), DVD, or the like is used. The storage unit 403 may be configured by a single device, or may be configured by combining a plurality of devices. In the storage unit 403, for example, data used in all the various processes performed by the interference analysis apparatus 400, data of the processing results or intermediate results, programs for controlling the various processes in general, and the like are recorded.

  The calculation engine unit 410 mainly includes a design data input unit 411, a condition data setting unit 412, an analysis net selection unit 415, an interference analysis unit 416, an interference result determination unit 419, and an interference result output unit 422. The condition data setting unit 412 includes a noise characteristic setting unit 413 and a limit value setting unit 414. The interference analysis unit 416 includes a wiring division unit 417 and an S parameter calculation unit 418. The interference result determination unit 419 includes a noise level calculation unit 420 and a determination unit 421.

  The design data input unit 411 inputs circuit board design data 431. Here, the input of the design data means that the calculation engine unit 410 can access the design data 431. For example, the design data input unit 411 reads circuit board design data 431 created by the CAD 501 or the like from the CAD 501 and stores it in the storage unit 403.

  Note that the design data 431 is not necessarily stored in the storage unit 403. For example, the calculation engine unit 410 may be able to access a recording apparatus on a CAD system connected to the interference analysis apparatus 400 via a network.

  Based on the design data 431, the condition data setting unit 412 generates various parameters for setting virtual noise characteristics and allowable noise limit values, which will be described later, and records them as setting condition data 432 in the storage unit 403.

  The analysis net selection unit 415 selects a net to be analyzed based on the setting condition data 432 and the design data 431, and records information representing the selected net in the storage unit 403 as selection data 433.

  The wiring division unit 417 divides the analysis target wiring into a plurality of segments based on pre-recorded division parameters (not shown) and selection data 433 (details of processing will be described later). The divided data is recorded in the storage unit 403 as divided data 434. The above division parameters are various parameters for performing segment division.

The S parameter calculation unit 418 mainly performs S matrix calculation of interference analysis based on the design data 431, the setting condition data 432, the selection data 433, the divided data 434, and the like (details of the process will be described later).
The S matrix calculation result is recorded in the storage unit 403 as calculation result data 435.

  The noise level calculation unit 420 calculates the reception noise level based on the setting condition data 432 and the calculation result data 435. The determination unit 421 determines the influence of interference based on the reception noise level and the setting condition data 432. (Details of the process will be described later).

  The result of reception noise level calculation and determination is also recorded in the storage unit 403 as determination result data 436.

  The interference result output unit 422 processes the determination result data 436 recorded in the storage unit 403 so as to be easily understood by the user, and outputs the processed result data 436 via the user interface unit 401.

  Data output from the interference result output unit 422 is also recorded in the storage unit 403 as output data 437.

  Next, a procedure of processing performed by the interference analysis apparatus 400 in the verification (S114) (see FIG. 1) after the component placement and wiring design between components (S113) will be described with reference to FIGS. .

  FIG. 3 is a diagram showing an outline of the flow of interference analysis processing performed by the interference analysis apparatus 400.

  First, the design data input unit 411 inputs design data 431 (S500). For example, the design data input unit 411 reads design data created by the CAD 501 into the storage unit 403 so that the calculation engine unit 410 can access it. The design data 431 includes, for example, the arrangement of components and elements and their terminals, the shape of a wiring pattern that connects the components and elements, the shapes of the elements and components and their terminals, the properties or product numbers of the components and elements and their terminals, and the board. And data representing the material of the wiring.

  Next, the condition data setting unit 412 sets analysis condition data (S501). The condition data setting unit 412 specifies a part or all of the circuit board represented by the design data 431 as an area to be analyzed. When the circuit board is composed of a plurality of layers, all layers constituting the circuit board may be specified as the analysis target, or some layers may be the analysis target.

  FIG. 4 is a diagram schematically illustrating an example of a wiring pattern in a certain layer included in a region to be analyzed. The wiring pattern shown in FIG. 4 is represented by design data 431.

  The noise characteristic setting unit 413 performs virtual noise characteristic setting (S511) for the region to be analyzed, and the limit value setting unit 414 performs noise allowable limit value setting (S512).

  In the virtual noise characteristic setting (S511), the noise characteristic setting unit 413 is a virtual input that is input to a terminal of a wiring that may interfere with another wiring in the computer simulation of the interference analysis. Sets the electrical characteristics of noise.

  Noise is usually generated in an active component or the like connected to a wiring terminal and input to the wiring terminal. In this case, the electrical characteristics of noise generated from the terminal of the component that is the noise generation source are often included in the design data 431. That is, in many cases, the design data 431 includes the electrical characteristics of virtual noise expected to be generated from the terminals of the component or element as data representing the properties of the component or element. For example, the electrical characteristics of virtual noise are set in advance at the design stage for terminals of active components mounted on a substrate and terminals connected to an antenna or the like.

  The data representing the electrical characteristics of the virtual noise of the component includes, for example, information on a noise source model, a terminal that generates noise, and the like. The noise source model is data representing the intensity of noise or changes in intensity and phase with frequency. The information regarding the terminal that generates noise includes, for example, a flag indicating whether or not the terminal generates noise, the impedance of the terminal, and the like.

  FIG. 5A is a diagram illustrating an example of a noise source model. The noise source model is represented by noise intensity at a plurality of different frequencies, for example. Usually, the intensity of the noise changes depending on the frequency of the noise. Therefore, the frequency characteristic of noise intensity can be used as a noise source model.

  Here, the noise source model can be the frequency characteristics of the noise intensity and the phase of the noise, not the frequency characteristics of only the noise intensity. For example, when there are a plurality of terminals to which the noise source model is set, the analysis accuracy can be further improved by setting the phase difference between the respective noises.

  The noise source model shown in FIG. 5A is merely an example, and there may be various types of frequency, width, intensity level, and number of steps to be set.

  The noise characteristic setting unit 413 sets the electrical characteristics of the virtual noise input to the wiring connected to the terminal of the component based on the data representing the electrical characteristics of the virtual noise of the component included in the design data 431. To do.

  For example, in the wiring pattern shown in FIG. 4, the parts 211, 212, 213, 214, 215, the wirings 201, 202, 203, 204, 205, 206 connected to these parts and the ground patterns 207, 208, 209 are arranged. , 210 exists.

  When the component 211 is an active element, and in the design data 431, when data representing the electrical characteristics of virtual noise is set for the terminals 201a and 202a of the component 211, the noise characteristic setting unit 413 automatically By selecting the 201a and the terminal 202a, the virtual noise characteristic data set for these terminals can be set as data representing the virtual noise electrical characteristics input to the wirings 201 and 202.

  In addition, when the data representing the electrical characteristics of the virtual noise of the component 211 is not included in the design data 431, the designer inputs data representing the electrical characteristics of the virtual noise via the user interface unit 401. be able to.

  Further, when there is no input of data representing the noise source model from the designer, a preset constant value (default value) can be set as data representing the electrical characteristics of the virtual noise.

  Similar to the wiring 201, noise source models are set for the wirings 202, 203, and 204. The wiring for which the noise source model is set is a wiring that may interfere with other wiring. Wiring that may cause interference is, for example, wiring that is connected to a component that is a noise generation source, such as an active component.

  In the wiring 203, the characteristics of noise input to the respective terminals are set in two places, the terminal 203a connected to the component 212 and the terminal 203b connected to the component 213. Which terminal the noise characteristic is set to may be selected by the designer via the user interface unit 401, or the noise characteristic setting unit 413 is included in the design data 431 as described above. A terminal for which virtual noise is set in the component data may be automatically selected.

  As described above, the electrical characteristics of the virtual noise set at the terminals of the wiring may be different for each wiring. Further, the same electrical characteristics of virtual noise may be set for all wirings. The same electrical characteristics of virtual noise may be set for some of the wirings in the analysis region.

  Note that the terminals 205a and 206a of the wirings 205 and 206 are terminals that are not selected as terminals to be analyzed. In the present embodiment, the terminals of the ground patterns 207, 208, and 209 are not selected as terminals to be analyzed.

  Note that the electrical characteristics of virtual noise may be set at the terminals of the ground patterns 207, 208, and 209. Interference analysis with respect to common mode noise can be performed by treating the ground pattern and the power supply pattern in the same manner as the wiring.

  The noise characteristic setting unit 413 includes data representing the set electrical characteristics of the virtual noise in the setting condition data 432 and stores the data in the storage unit 403.

  Next, the limit value setting unit 414 sets an allowable limit value of noise received by the terminal of at least one of the wirings formed on the circuit board (S512).

  The allowable noise limit is a value that is set for the terminal of the wiring that is subject to interference in computer simulation of interference analysis, and is the allowable noise intensity value even if the terminal receives noise due to interference. is there. That is, when a terminal of a wiring receives noise that exceeds the allowable limit value set for the terminal, the circuit including the wiring cannot operate normally.

  The allowable noise limit value is usually included in the design data 431 as data representing the component characteristics. In general, in the design data 431, an allowable noise limit value is set in advance for a terminal of an active component mounted on a substrate and, in some cases, a terminal of a passive component.

  The limit value setting unit 414 automatically selects the wiring terminals connected to the parts for which the allowable noise limit values are set in the design data 431, and sets the allowable noise limit values to the terminals of the wirings. To do.

  For example, in the example shown in FIG. 4, when the noise tolerance limit value is set for the terminals 203b and 204b of the component 213 in the design data 431, the noise tolerance limit value for the wiring terminals 203b and 204b is set. Is set.

  Further, the designer may select a wiring terminal for setting an allowable noise limit value via the user interface unit. Furthermore, the designer may input an allowable limit value of noise.

  It should be noted that the allowable limit value can be set for the same wiring as the wiring for which the noise characteristic setting unit 413 has set the electrical characteristics of the virtual noise. For example, in one wiring, an electrical characteristic of virtual noise input to one terminal can be set, and an allowable noise limit value received by the other terminal can be set. By setting in this way, it is possible to analyze the influence of noise passing through one wiring.

  In addition, an allowable limit value can be set to the same terminal as the wiring terminal in which the electrical characteristics of the virtual noise are set. By setting in this way, it is possible to analyze the influence of noise when noise input to a terminal is reflected and returned to the same terminal.

  FIG. 5C is a diagram illustrating an example of the noise allowable limit value. In FIG. 5C, an alternate long and short dash line j indicates an allowable noise level, that is, a noise allowable limit value. The allowable noise limit value varies depending on the noise frequency. Therefore, the noise allowable limit value is provided for a plurality of different frequencies. Noise The allowable noise limit value shown in FIG. 5C is merely an example, and the number of frequencies to be set, the width, the intensity level, and the number of steps may vary. I do not care. In FIG. 5C, the allowable noise level is indicated by a continuous one-dot chain line j, but the set allowable noise limit value is divided into specific frequency sections and set as discontinuous values. You can also

  Further, the set allowable noise limit value may be different for each wiring. Moreover, all the wirings may be the same. The same noise allowable limit value may be set for some of the wirings in the analysis region.

  The limit value setting unit 414 includes the set noise allowable limit value in the setting condition data 432 and saves it in the storage unit 403.

  In the above description, it is stated that the electrical characteristics of the virtual noise and the noise allowable limit value are set for the terminals of the wiring. In the circuit board, both ends of the wiring are always connected to the component or element, so the terminal of the wiring is also the terminal of the component or element.

  For example, by setting the electrical characteristics of virtual noise to the terminal of a component such as a signal input / output terminal or a power supply terminal of an active element such as an IC or an amplifier, a noise source specific to the component is set. In particular, the electrical characteristics of virtual noise are often set at the output terminal of a power amplifier, the output driver terminal of an IC, or the like.

  In addition, the electrical characteristics of virtual noise can be set for filters, switches, connectors, and the like. By setting the electrical characteristics of the virtual noise to the connector that connects the boards, it is possible to perform an interference analysis that takes into account the influence of noise that travels between boards.

  The allowable noise limit value is also set to the wiring terminal, that is, the component terminal, in the same manner as the electrical characteristics of the virtual noise. Therefore, a value unique to the component is set. In a board on which a plurality of components of the same type are mounted, the same value can be set for the corresponding terminals of the components of the same type, so that versatility is enhanced.

  The allowable noise limit value is often set, for example, at an antenna terminal of an antenna switch, an input terminal of a low noise amplifier, an IC receiver terminal, or the like.

  Next, the analysis net selection unit 415 selects a set of analysis target nets (S502). In selecting a set of analysis target nets, the analysis net selection unit 415 selects a set of wirings to be analyzed when performing interference analysis by computer simulation. The set of wirings selected here may be called a wiring pair or a net pair.

  The set of wirings selected includes a wiring that causes interference and a wiring that receives interference. The wiring that gives interference has a terminal to which virtual noise is input, and the wiring that receives the interference has a terminal that receives noise. The terminal to which virtual noise is input is one of the terminals of the wiring to which the virtual noise electrical characteristics are set in the virtual noise characteristic setting (S511). The terminal that receives noise is one of the terminals for which the allowable noise limit value is set in the setting of the allowable noise limit value (S512).

  Here, the concept of wiring will be described. In the selected wiring set, a line that electrically connects from a terminal of a component or element to a terminal of another component or element is regarded as one wiring. This concept of wiring is a concept called “net” in the field related to CAD, and a group of nets connected in an electrical circuit via components is simply called a net. One net may include passive components such as resistors, inductances, capacitors, and switches, for example.

  FIG. 8A is a diagram illustrating an example of wiring including components. A part 216 and a part 217 are arranged between the terminal 215a and the terminal 215b. The component 216 is connected to the ground pattern 218. The component 217 is electrically connected in series between the terminal 215a and the terminal 215b.

  In the wiring 215, as a line, the terminal 215 a and the terminal 215 b are separated by a component 217. However, in the interference analysis, for example, a two-terminal component such as a resistor, an inductor, or a capacitor provided on the line is connected to an end of the two lines via an element having an impedance as an electric circuit. Since they are equivalent, a line including parts is treated as a series of wirings.

  The component 216 is also equivalent to a state where an element having the impedance of the component 216 is connected between the wiring and the ground. Therefore, the component 216 may be handled as a part of the wiring 215 when performing interference analysis related to the terminal 215a.

  For parts with 3 or more terminals, the information on which terminals and which terminals are electrically connected in the parts can be included in the information of the parts so that analysis between arbitrary terminals can be performed at the time of interference analysis. it can.

  For example, information that should be held by a component 219 having six terminals 219a, 219b, 219c, 219d, 219e, and 219f as shown in FIG. 8B will be described. Information is given to the component that the terminals 219a and 219d, the terminals 219b and 219d, and the terminals 219c and 219e are electrically connected, and the terminal 219f is not connected to any other terminal. be able to. The electrical characteristics between the terminals 219a and 219d, between the terminals 219b and 219d, and between the terminals 219c and 219e should be included in the component information as information such as impedance or S parameter that varies depending on the frequency. Can do.

  Thus, by including the connection relationship between terminals and the electrical characteristics in the component information, for example, the terminals 220a to 220b can be handled as one wiring.

  Information on such components and information on which terminals are used as one wiring are often set at the stage of designing a circuit using CAD or the like. Further, in the above-described analysis condition setting data setting (S501) step, information regarding these parts may be set by input from a designer or the like.

  By defining components and wiring as described above, it is possible to calculate interference characteristics that take into account the characteristics of the components. In addition, since the influence of the wiring through the components can be analyzed simultaneously, the reception noise level can be calculated more accurately. Furthermore, since the number of terminals for setting the characteristics of virtual noise and the noise allowable limit value is reduced, the model to be analyzed is simplified. Moreover, since the number of sets of wirings to be analyzed can be reduced, the determination result output after the interference analysis result determination can be easily confirmed.

  In the selection of the analysis target net group (S502), the analysis net selection unit 415 determines whether or not the frequency characteristic calculation of the interference amount is necessary (S521), and then extracts the wiring group for calculating the interference (S522). .

  In the determination of necessity of calculation (S521), the analysis net selection unit 415 determines the strength of the virtual noise and the noise for the set of the terminal for which the electrical characteristics of the virtual noise are set and the terminal for which the allowable noise limit is set. Are compared to determine whether the noise intensity exceeds the allowable noise limit.

  For example, in the wiring pattern shown in FIG. 4, the noise source model of the component 211 is set as the electrical characteristic of the virtual noise at the terminal 201 a of the wiring 201. The noise intensity at a certain frequency in the noise source model is compared with the noise allowable limit value at the frequency set in the terminal 204a of the wiring 204. For example, if the allowable noise limit value at the terminal 204a is 90% or less of the strength of the virtual noise input to the terminal 201a, it is determined that it is necessary to calculate the amount of interference between the terminal 201a and the terminal 204a. . The value of 90% is an example, and it is preferable to adopt an appropriate value depending on the situation. Similarly, the determination of the necessity of calculating the interference amount is made between the other terminals.

  In the wiring set extraction (S522), the terminal set for which it is determined that the amount of interference needs to be calculated in the calculation necessity determination (S521) is extracted. Further, all the wirings electrically connected to the extracted terminals are extracted. When passive components such as resistors, inductors, capacitors, filters, connectors, and switches are connected to the ends of the extracted wires, up to the terminals connected in a circuit may be extracted as one wire. .

  For example, in FIG. 4, the wiring 201 and the wiring 204 that are electrically connected to the terminal 201a in which the noise source model is set and the terminal 204a in which the noise allowable limit value is set are extracted as a set of wirings. In this wiring set, the wiring 201 is a wiring that causes interference, and the wiring 204 is a wiring that receives interference.

  If it is determined that it is also necessary to calculate the amount of interference between the terminal 203a and the terminal 204a, the wiring 203 is a wiring that causes interference, and the wiring 204 is a wiring that receives interference. Are extracted as a wiring set.

  The amount of interference, which will be described later, is calculated for each set of wires consisting of two wires extracted in this way, that is, for each wire pair. Since the calculation is performed for each wiring pair, the calculation amount and time required for the analysis are reduced as compared to the conventional analysis method in which the calculation is performed by dividing the entire substrate into meshes.

  Further, the wiring set does not necessarily need to be composed of two wirings, and may be a wiring group composed of two or more wirings.

  In a computer simulation of one interference analysis, in principle, there is one wiring that receives interference, and one or a plurality of wirings interfere with the wiring that receives this interference. Interference analysis calculations are performed.

  Further, as described above, instead of selecting the wiring set for calculating the interference amount by the calculation of the analysis net selection unit 415, the designer selects the wiring set for which the interference amount should be calculated via the user interface unit 401. You can also choose.

  For example, the designer can select the wirings 201, 202, and 203 arranged adjacent to the wiring 204 as wiring that may cause interference with respect to the wiring 204 that receives interference. A noise source model is set for each of the terminals 201a, 202a, and 203a.

  The noise source model set for each of the terminal 201a, the terminal 202a, and the terminal 203a is a noise source model set as an electrical characteristic of the virtual noise in the virtual noise characteristic setting (S511). The noise source model of the terminal 201a, the noise source model of the terminal 202a, and the noise source model 3 of the terminal 203a may be the same or different.

  The wiring 204 that receives this interference, the wiring 201 that gives interference, the wiring 202 that gives interference, and the wiring 203 that gives interference are merely examples. There may be a plurality of wirings that cause interference with respect to one wiring that receives interference.

  Interference analysis may be performed on all the wiring groups selected by the designer, but in order to reduce the calculation load, wiring groups that actually need to be subjected to interference analysis may be extracted. Whether or not it is necessary to perform interference analysis is determined based on the electrical characteristics of the virtual noise set for the wiring that causes interference in the set of wirings and the allowable noise limit value set for the wiring that receives the interference. be able to. Thus, the calculation load is reduced by performing the actual interference analysis only on the extracted wiring set.

  As described above, in the analysis target net set selection (S502) step, a plurality of wiring sets, that is, net sets are usually selected. The subsequent interference analysis (S503) and interference analysis result determination (S504) are performed for each set of wirings.

  For example, in FIG. 4, it is assumed that a set of wires composed of the wires 204 and 201 and a set of wires composed of the wires 204 and 203 are selected. In this case, first, the amount of interference between the terminal 204b of the wiring 204 and the terminal 201a of the wiring 201 and between the terminal 204a and the terminal 204b is calculated (S503), and the noise level received by the terminal 204b of the wiring 204 is calculated. Is done. Similarly, the amount of interference is calculated for the set of wirings 204 and 203, and the noise level received by the terminal 204b from the wiring 203 is calculated. Thereafter, the noise level received by the terminal 204b from the wiring 203 and the noise level received by the terminal 204b from the wiring 201 are combined.

  In addition to the method described above, for example, the wiring on the display screen, the wiring pattern, the terminal, or the component can be designed as a method for identifying the wiring set that needs to perform the interference analysis from the plurality of wirings. There is also a method of designating a wiring that needs to be subjected to interference analysis by direct selection by a person.

  In FIG. 4, wirings 205 and 206 and ground patterns 207, 208, 209, and 210 that are not subject to interference analysis are shown. These are selected as a set of wirings to be analyzed in this embodiment. It will never be.

  Using various methods as described above, a set of wirings for finally calculating the amount of interference is extracted and determined (S522).

  Next, the interference analysis unit 416 performs interference analysis on the wiring selected in S502 (S503). The interference analysis unit 416 calculates the frequency characteristic of the interference amount obtained from the wiring pattern, that is, the interference characteristic.

  The amount of interference is an amount representing the degree of interference. For example, it can be represented by a ratio between the intensity of noise input to a certain terminal and the intensity of the received noise when the noise is received by another terminal. The interference characteristic represents the amount of interference for a plurality of different frequencies.

  FIG. 5B is a diagram showing an example of interference characteristics obtained from this wiring pattern.

  The interference characteristic shown in FIG. 5B shows, for example, a change in the absolute value of the interference amount between the terminal 201a of the wiring 201 and the terminal 204b of the wiring 204 depending on the frequency in the wiring pattern shown in FIG.

  That is, the interference characteristic shown in FIG. 5B is the ratio of the noise intensity at the frequency with noise applied to the wiring 201 to the noise intensity at the frequency with noise at which the wiring 204 receives interference. It represents a plurality of different frequencies.

  For example, the following can be understood from the example of the interference characteristics shown in FIG. In the lowest frequency band, the amount of interference is relatively large, but the amount of interference decreases as the noise frequency increases. Further, as the noise frequency increases, the amount of interference gradually increases and takes a maximum value at a certain frequency. After the interference amount reaches the maximum value, the interference amount decreases as the noise frequency increases.

  The interference characteristic obtained from the wiring pattern shown in FIG. 5B is merely an example, and the change pattern of the interference amount is not limited to this.

  This interference characteristic is calculated from the geometric feature of the wiring pattern. The concrete and detailed procedure for calculating the interference characteristics is as follows. The entire procedure of the interference analysis (S503) is 4 of GND search (S531), segmentation (S532), connection condition derivation (S533), and S matrix calculation (S534). It can be roughly divided into two procedures.

  In these four procedures, the interference analysis unit 416 first extracts the ground pattern in the wiring pattern by GND search (S531), then divides the set of wirings to be analyzed into segments, and obtains circuit characteristics for each segment ( S532). On the other hand, connection conditions between the divided segments are derived (S533). The S matrix calculation (S534) is performed based on the circuit characteristics for each segment and the connection conditions, whereby the amount of interference in the set of wirings to be analyzed is obtained. Details of these procedures will be described below.

  The interference analysis unit 416 performs a GND search based on the design data 431 (S531). In the GND search (S531), the GND wiring existing in the vicinity of the wiring whose interference characteristics are to be calculated, that is, the pattern of the ground or ground area is extracted.

  For example, in the example shown in FIG. 4, if the wiring set to be analyzed is a wiring 201 and a wiring 204, ground patterns 207, 208, and 209 in the same layer as these wirings are extracted. In addition to these, the ground patterns in all layers above and below the layer having the wiring pattern shown in FIG. 4 are extracted. It is preferable that a ground pattern with a short distance from the wiring 204 is extracted with priority.

  The wiring division unit 417 performs segment division based on the design data 431 and the result of the GND search (S532). Segment division (S532) is to divide a region including a set of wirings to be analyzed into smaller segments. A segment is a unit in which circuit characteristics such as S parameters and impedance are set in interference analysis.

  For example, the example shown in FIG. 4 is a procedure for dividing an area including wirings 201 and 204, which are a set of wirings to be analyzed, and GND wiring existing in the vicinity thereof into small segment areas.

  FIG. 6 is a diagram illustrating an example of segment division. FIG. 6A is a diagram illustrating a region 500 including a set of wirings to be analyzed, that is, a wiring 202 that gives noise and a wiring 204 that receives noise. The wiring dividing unit 417 divides the wirings 201, 202, 203, and 204 in the region 500 shown in FIG. 6A into a plurality of segments as shown in FIG. 6B. For example, the wiring 204 is divided into eight segments including the segments 30a and 30b.

  A portion where the segments are arranged close to each other is a coupled line. A coupled line is a pair of lines in which electromagnetic field coupling exists between the lines to an extent that cannot be ignored. For example, in FIG. 6B, the segment 30 a and the segment 30 e that are arranged in parallel are the coupled line 35. Further, not only between lines provided in the same wiring layer but also between lines provided between different wiring layers are treated as coupled lines.

  When the wiring set is divided into segments, for example, a portion where the angle of the wiring changes, such as the boundary 31a, can be used as the boundary. In addition, there is a boundary that is divided into a portion 30c in which the two wirings 204 and 203 are arranged in parallel and a non-parallel portion 30d, as in the boundary 31b. Further, for a portion where the two wires are not parallel, for example, a portion that intersects with wires in different layers or a portion where the angle of the coupled line in the wiring set changes can be used as the segment boundary.

  In segment division, for example, as shown in FIG. 6B, it is preferable to divide as many wiring segment pairs as possible. This is because if the segments are divided so that the number of parallel wiring segments increases, it becomes easier to shorten the processing time while maintaining high accuracy.

  In the segment division, the ground pattern extracted by the GND search (S531) is also taken into consideration. For example, on the wiring, a portion where the ground pattern exists in any layer above or below the wiring and a portion where the ground pattern does not exist can be divided into different segments. Also, in the wiring, portions where the upper and lower grant patterns are different can be divided into different segments.

  Further, when the component 217 is arranged in the middle of the wiring as in the wiring 215 shown in FIG. 8A, the component 217 is made one segment in the segment division.

  The segment division method may be recorded in advance in the storage unit 403 as data representing the division method. The data representing the division method can include data representing the above-described division method and fineness when segmenting.

  The wiring division unit 417 obtains a circuit matrix for each segment obtained by the segment division. The circuit matrix is, for example, an S matrix.

  The S matrix (scattering matrix) defines the characteristics of a circuit by the magnitude and phase of a wave related to the power that enters and exits each terminal pair (port) of the circuit. Each element of the S matrix is called an S parameter.

  As an example, a 4-terminal S matrix is obtained for the coupled line 35 composed of the segment 30a and the segment 30e in FIG.

  The value of the S matrix of the coupled line 35 is obtained, for example, by referring to an S matrix database (not shown) recorded in the storage unit 403 in advance. In the S matrix database, there are various 4 types depending on the wiring information such as the wiring interval, wiring width, wiring length, wiring arrangement of the layers in the multilayer substrate, material constant (for example, dielectric constant, etc.) of the substrate. The value of the S matrix of the terminal is stored. The wiring division unit 417 refers to the value of the 4-terminal S matrix corresponding to the wiring information of the coupled line 35. That is, an S matrix for wiring information representing the same structure as the wiring information of the coupled line 35 to be analyzed is found from the database by pattern matching or the like. The wiring information of the coupled line 35 is included in the design data 431. In this way, a circuit element having four terminals of the coupled line 35 is obtained.

  If the S matrix value corresponding to the wiring width in the wiring information of the coupled line 35, the thickness of the dielectric between the wiring and the ground, and the distance between the coupled lines does not exist in the S matrix database, the coupled line 35 The data can be interpolated using data corresponding to the wiring width, the thickness of the dielectric between the wiring and the ground, and the wiring information close to the interval between the coupled lines.

  Similarly to the coupled line, the single line that is not the coupled line refers to the value of the 2-terminal S matrix stored in the database in advance, and obtains the 2-terminal circuit element corresponding to the wiring information of the line. In this way, each divided segment acquires an S matrix from the database.

  Note that the method of obtaining the circuit matrix of each segment is not limited to the method of acquiring values from the above database. For example, a circuit matrix such as an S matrix can be calculated by performing an electromagnetic field analysis based on the wiring information of the segments. It is also possible to prepare a function that returns a circuit matrix using the wiring information of the segment as an argument, and obtain the circuit matrix using this function.

  In this way, the wiring is segmented and the analysis is performed based on the segment, so that the analysis can be performed at high speed, with a low load, and in a short time. That is, if the entire region including the wiring is divided into a mesh shape as shown in FIG. 11B and electromagnetic field analysis is performed based on a large number of divided pieces, a huge amount of processing time is required. On the other hand, as shown in FIG. 6B, the wiring to be analyzed is divided into segments, the coupling line 35 between the segments is replaced with an equivalent model, and interference is determined based on the equivalent model. As a result, the processing time can be greatly shortened.

  Here, as the circuit matrix, for example, a Z matrix, a Y matrix, an F matrix, and a T matrix can be used in addition to the S matrix often used in the industry. Z, Y, F, and T parameters (that is, parameters that configure the Z matrix, Y matrix, F matrix, and T matrix) and S parameters (that is, parameters that configure the S matrix) can be converted into each other. Although it is convenient to use the T parameter for the synthesis of the circuit for the continuous connection, there are circuits that cannot be defined by the T parameter, so the S parameter is more versatile.

  After the segment division process (S532), the interference analysis unit 416 derives a connection condition (S532).

  The connection condition derivation (S533) includes, for example, processing for calculating the connection relationship between the divided segments and processing for calculating the characteristics of the components connected to the wiring.

  For example, in the example shown in FIG. 4, the segment when dividing the wiring pattern of the wiring 201 for setting the noise source model, the wiring 204 to be subjected to interference analysis, and the GND wiring in the vicinity thereof into small segment areas. The connection relationship between them is calculated.

  In addition, the characteristics of the components connected to each wiring are calculated. The characteristic of the component is expressed by, for example, an impedance that changes with frequency. For example, the frequency characteristic of the component 217 shown in FIG. 8A, that is, how the impedance or S parameter of the component 217 changes depending on the frequency is obtained.

  When there are a plurality of components 216 and 217 as shown in FIG. 8A, the amount of interference varies extremely at a specific frequency due to resonance due to the characteristics between the components by calculating the characteristics of the components by impedance. Even in this case, the amount of interference can be calculated accurately.

  Also, the characteristics of the termination conditions of the parts 211, 212, and 213 are calculated. The term “termination condition” refers to electrical characteristics of a component at that terminal when the terminal at the end of the wiring is a component terminal. The characteristic of the termination condition of a component is represented by an impedance that varies with frequency. For example, how the impedance of the terminals of the components 211, 212, and 213 changes depending on the frequency is obtained.

  Here, an example of component impedance will be described.

  Normally, the input / output impedance of the component terminal is equal to the normalized impedance. The standardized impedance is usually 50Ω. For example, the S matrix of the wiring connected to the component is calculated assuming that the input / output impedance of the component terminal is 50Ω. On the other hand, when the input / output impedance of the component terminal is different from 50Ω, the interference characteristic closer to the actual can be calculated by using the input / output impedance of the component terminal as the standardized impedance of each terminal.

  As the input / output impedance Zin of the component, for example, the one defined as the following Equation 1 can be used.

As another example, an S parameter defined as follows for each frequency can be used as the input impedance of a component. When the S parameters of the components at 100 MHz, 200 MHz, and 300 MHz are respectively expressed as Γ _100M , Γ _200M , and Γ _300M , each value is expressed by the following equations 2 to 4.

In the above formulas 2 to 4, Re _100M , Re _200M , and Re _300M are real parts of the S parameter of the component at 100 MHz, 200 MHz, and 300 MHz, respectively. Im _100M , Im _200M , and Im _300M are imaginary parts of the S parameter of the component at 100 MHz, 200 MHz, and 300 MHz, respectively.

  The S parameter of the component is converted into the impedance of the component by the following equation (5).

  Terminals for which virtual noise characteristics and allowable noise limit values are not set can be terminated by terminating the input / output impedances of the component terminals to reduce the number of terminals and simplify the calculation.

  When a component has a plurality of terminals, data representing the characteristics of the component is, for example, frequency characteristic data such as Z parameters, Y parameters, and S parameters having ports for the number of terminals, or equivalent circuits, etc. It is preferable that the design data 431 is prepared for each part in advance.

  In the case where the characteristic data of a part does not exist at the time of calculating the interference characteristic, the interference characteristic can be calculated by applying a preset default value as the characteristic data of the part.

  When the connection condition of each segment is derived, the S parameter calculation unit 418, the connection condition, the GND wiring pattern obtained by the GND search (S531), and the circuit matrix (S532) obtained by segment division (S532). The amount of interference is calculated based on (S matrix) (S534). Since the amount of interference varies depending on the frequency of noise, it is calculated for each frequency.

  Here, an example of the calculated interference amount will be described. FIG. 7 is a diagram illustrating an example of a set of wirings to be subjected to interference analysis. As shown in FIG. 7A, when the wiring 201 that causes interference and the wiring 204 that receives interference are wirings to be analyzed, the number of wiring terminals 201a, 201b, 204a, and 204b is four in total. The amount of interference between the four terminal wirings is represented by S parameter of 4 rows and 4 columns (for example, see the following formula 6).

  The S matrix shown in the above equation 6 is obtained, for example, by solving a circuit network in which circuit elements are connected based on electrical connection of wirings.

Further, as shown in FIG. 7B, when the wiring 201 to be analyzed has a branch, all the terminals 201a, 201b, 201 including the branched branch terminal 201c are included.
c, the amount of interference between 204a and 204b is calculated.

  When the amount of interference is expressed by the S parameter, the terminal termination condition usually represents a characteristic in a state where the terminal is terminated by the standardized impedance. However, in practice, components are electrically connected to the terminals that are the ends of the wiring and are often different from the standardized impedance. Therefore, in the calculation of the interference amount, it is preferable to consider the impedance of the component obtained in the derivation of connection conditions (S533).

  As described above, the amount of interference between the terminals of the wiring changes depending on the characteristics of the termination conditions of the components connected to the terminals of the respective wirings. Therefore, it is preferable that the interference is calculated in consideration of the termination conditions of the components. .

  When the interference amount is calculated by the interference analysis unit 416, the interference result determination unit 419 performs interference analysis result determination for determining the presence or absence of the influence of inter-wiring interference based on the values set or calculated so far ( S504).

  In the interference analysis result determination, reception noise level calculation (S541) and interference determination (S542) are performed.

  The noise level calculation unit 420 is a terminal for which an allowable noise limit value is set from the interference amount obtained in the S matrix calculation (S534) and the noise intensity set in the virtual noise characteristic setting (S511). Calculate the received noise intensity at.

  That is, in the reception noise level calculation (S541), the noise source model set in the virtual noise characteristic setting (S511) and the interference amount calculated in the interference analysis (S503) are selected as a set of analysis target nets ( By applying the set of wirings extracted in S502), the reception noise level in the wiring that receives interference is calculated.

Here, an example of the calculated reception noise level will be described. In the wiring pattern shown in FIG. 7 (a), when the amount of interference from the terminal 201a to 204a is given by S _31, the noise intensity P _f noise sources at frequency f, when the received noise level and below Equation 7, the receiving The noise level is calculated by the following equation (8).

  By the above equation 8, the reception noise level can be calculated for all frequencies where the noise source exists.

Here, S ₃₁ usually includes a complex number, and the received noise level is defined by the length of the vector. For example, the interference quantity S ₃₁ from the terminal 201a to the characteristics of the virtual noise is set to the terminal 204a of the noise allowable limit value is set, when the Re + jIm (j is an imaginary unit), the received noise level, the following equation 9 Become.

  When a plurality of virtual noise characteristics are set for one wiring, each virtual noise is treated as a synthesized value. For example, in the wiring 201 illustrated in FIG. 7A, the electrical characteristics of virtual noise are set in the terminal 201a and the terminal 201b, respectively. In this case, it is necessary to synthesize the noise level of the noise received by the terminal 204a from the terminal 201a and the noise level of the noise received by the terminal 204a from the terminal 201b. When synthesizing, the wiring and the coupled line are accurately calculated by performing effective synthesis in consideration of the phase instead of a simple sum of the intensities of the virtual noises. As a result, the amount of interference noise is not overestimated.

  When there are N noise sources and the received noise level from each is the following formula 10, assuming that the combined received noise level is the following formula 11, when combining simply, as shown in the following formula 12, The sum of the absolute values of the received noise levels is the combined received noise level. The combined received noise level expressed by the following equation 12 is a value when the combined noise level is maximized.

  On the other hand, when effective combining is performed in consideration of the phase, the combined received noise level is calculated by the following equation (13).

  That is, in Equation 13, the absolute value of the sum (vector sum) including the phases of individual reception noises is the combined reception noise level. By the above Equation 13, a combined reception noise level in which the phase difference of the reception noise level is considered is obtained. By doing in this way, the effect that the amount of interference noise is not overestimated can be obtained.

  Further, when a plurality of virtual noises are set in the above-described virtual noise characteristic setting (S511), the relative accuracy of the phase information in which each virtual noise is generated is set to further increase the accuracy when synthesizing the interference noise. Can be improved.

  The phase information set for the virtual noise is not a mere relative difference in time but has a different value for each frequency. Therefore, by setting the phase information in the characteristics of the virtual noise, it is possible to calculate in consideration of phase information (imaginary component) that differs depending on the frequency of the wiring or component when calculating the amount of interference. As a result, a reception noise level that faithfully reproduces the actual measurement can be synthesized.

  Even when there is a wiring that gives a plurality of interferences to a wiring that receives a single interference, the combined reception noise level can be obtained using the above-described combining method.

  As an example, a case will be described in which a wiring 204 that receives interference and wirings 201, 202, and 203 that give three interferences exist as shown in FIG. 4 in a set of wirings to be analyzed. A noise source model N1 is set for the wiring 201 as an electrical characteristic of virtual noise, a noise source model N2 is set for the wiring 202, and a noise source model N3 is set for the wiring 203. A reception noise level P1 is calculated from the amount of interference between the wiring 204 and the wiring 201 and the noise source model N1. A reception noise level P2 is calculated from the amount of interference between the wiring 204 and the wiring 202 and the noise source model N2. A reception noise level P3 is calculated from the amount of interference between the wiring 204 and the wiring 203 and the noise source model N3. These reception noise levels P1, P2, and P3 are superimposed, and a combined reception noise level in the wiring 204 that receives interference is calculated.

  FIG. 5C is a diagram illustrating an example of the reception noise level calculated by the noise level calculation unit 420. Five vertical lines g shown in FIG. 5C indicate the reception noise level, that is, the intensity of the reception noise in the analysis target wiring. In the example shown in FIG. 5C, reception noise levels are displayed for five different frequencies.

  When the reception noise level is calculated, the determination unit 421 performs interference determination (S542).

  In the interference determination (S542), it is determined whether or not the noise level in the wiring subject to the interference is acceptable, that is, whether or not the level is within a range in which normal operation is guaranteed.

  Specifically, the determination unit 421 compares the reception noise level at a certain terminal obtained in the reception noise level calculation (S541) with the allowable limit value of noise set at the terminal for a plurality of different frequencies, It is determined whether the received noise level exceeds a noise tolerance limit value.

  For example, the determination unit 421 compares the reception noise level expressed by the above formula 9 with the scalar amount of the noise allowable limit value. If the received noise level is higher as a result of the comparison, an error indicating that the allowable limit value is exceeded is output as determination result data 436. The determination result data 436 is recorded in the storage unit 403.

  The interference determination is performed for each wiring group selected as the analysis target in the selection of the analysis target net group (S502).

  Here, an example of interference determination will be described with reference to FIG.

  The five vertical lines g in FIG. 5C represent the reception noise level in the wiring that receives interference as described above. The dashed-dotted line j in FIG.5 (c) represents the noise allowable limit value set with respect to the wiring which receives interference in the setting of a noise allowable limit value (S512) as mentioned above.

  The received noise level g shown in FIG. 5C is compared with the noise allowable limit value j. For example, if there is a portion h that exceeds the allowable noise level, it is determined that the noise level in a certain wiring subject to interference is not allowable. That is, it is determined that the influence of interference is at a level that deviates from the range in which the normal operation of the circuit including the wiring is guaranteed.

  On the contrary, by comparing these, if there is no portion exceeding the allowable noise level (not shown), it is determined that the noise level in the wiring subjected to the interference is allowable. That is, the influence of interference is determined to be within a range in which normal operation of the circuit including the wiring can be guaranteed.

  The interference result output unit 422 outputs the determination result by the interference result determination unit 419 (S505).

  The interference result output unit 422 outputs the interference analysis result for each set of wirings determined in the interference analysis result determination (S504) to various output devices such as a display device and a recording device.

  For example, the interference result output unit 422 can highlight and display a portion determined by the interference determination that the received noise level exceeds an allowable level by a color scheme corresponding to the excess level. Further, as the interference determination log, for example, information such as a net name, a terminal name, a component name, an excess level amount, and a position of an interference area may be output.

  As a display method of the analysis result, in addition to the above-described highlight display, display by gradation with a difference depending on luminance and blinking display by changing the on / off time period can be performed. Further, it is possible to perform an enlarged display of an error location, a pointer instruction to the error location, a display of only the error location, an extraction display such as surrounding an abnormal location with a block, and the like. Furthermore, voice guidance may be performed in addition to or separately from these displays.

  When there are a plurality of points to be emphasized in the output of the analysis result, a plurality of error points may be sequentially displayed in the screen display output. Also, a plurality of error locations can be divided and displayed on a plurality of screens, or error locations can be classified and displayed by adding labels to the plurality of error locations on the same screen.

  These display units may be net units, stroke units from specific wiring ends to pins or branch points, wiring units between pins, and the like.

  It is preferable that the user can directly check the interference analysis result output to the display device and know the result. Also, it is preferable that the interference analysis result output to the recording apparatus can be saved as data and later confirmed or used for other processing.

  The values and data in the present embodiment are recorded in various recording means such as various RAMs and ROMs which are semiconductor memories, for example. This recording means may be connected to a computer that performs processing in the present embodiment, or may be included in the computer. The processes and procedures in the present embodiment are executed by a computer according to the program recorded in the recording means. At that time, values and data recorded in the recording means are used. The results of the processes and procedures in this embodiment are output to various input / output devices connected to or included in the computer.

  Since general and general-purpose computers, recording means, and input / output devices used in the present embodiment can be used, their illustration and description are omitted.

  As described above, according to the interference analysis method, the interference analysis apparatus, the interference analysis program, and the recording medium on which the interference analysis program is recorded according to the present invention, the interference between the wirings can be analyzed at high speed, low load, and in a short time. Is possible. As a result, the technical effect of reducing the time and cost required for designing a circuit having wiring is obtained, so that the present invention has industrial applicability.

The flowchart which shows the schematic procedure of the high frequency circuit design in the 1st Embodiment of this invention Functional block diagram showing an example of the configuration of the interference analyzer The figure which shows the outline | summary of the flow of the interference analysis process which the interference analyzer 400 performs The figure which shows typically the example of the wiring pattern in one certain layer contained in the area | region to be analyzed Diagram showing examples of interference characteristics and noise intensity in interference analysis Diagram showing an example of segmentation Diagram showing an example of a set of wirings subject to interference analysis Diagram showing an example of wiring that includes parts Flow chart showing schematic procedure of conventional digital circuit design The figure which shows the example of the part where interference may occur in the high frequency electronic circuit Diagram showing an example of the wiring pattern to be analyzed

Explanation of symbols

201, 202, 203, 204 Wirings 205, 206 Wiring not subject to interference analysis 207, 208, 209, 210 Ground patterns 211, 212, 213, 214 Parts 400 Interference analysis device 401 User interface 402 Control unit 403 Storage unit 410 Calculation engine unit 411 Design data input unit 412 Condition data setting unit 413 Noise characteristic setting unit 414 Limit value setting unit 415 Analysis net selection unit 416 Interference analysis unit 417 Wiring division unit 418 S parameter calculation unit 419 Interference result Determination unit 420 Noise level calculation unit 421 Determination unit 422 Interference result output unit 431 Design data 432 Design condition data 433 Selection data 434 Divided data 435 Calculation result data 436 Determination result data 437 Output data 01 CAD
950 Substrate 951, 952 Element 953 Antenna 954 High-frequency circuit module 955, 956 LSI component 957, 958 Wiring 959 Camera module

Claims (16)

An interference analysis device that analyzes, by computer simulation, interference caused by electromagnetic induction between wirings formed on a circuit board,
A design data input unit for inputting design data of the circuit board including data representing the shape of the wiring and the properties of elements or components connected to the wiring;
Noise characteristic setting that sets, based on the design data, noise characteristic data representing electrical characteristics of virtual noise input to a terminal of at least one of the wirings formed on the circuit board And
A limit value setting unit that sets an allowable limit value of noise received by the terminal of at least one of the wirings formed on the circuit board based on the design data;
Based on the noise characteristic data and the allowable limit value, a set of wirings to be analyzed from wirings formed on the circuit board, and a terminal for receiving the virtual noise and a terminal for receiving the noise A selection unit for selecting a wiring set including
An interference analysis unit that calculates an interference amount representing a degree of interference from a terminal to which the virtual noise is input to a terminal that receives the noise in the set of wirings selected by the selection unit;
A reception noise level calculation unit that calculates a noise level received by the terminal receiving the noise based on the interference amount and the noise characteristic data ;
The noise characteristic data is data representing the intensity of the virtual noise provided for different frequencies,
The interference analysis unit, the interference analysis device you calculate the amount of interference for different frequencies.   The apparatus further includes a determination unit that determines whether interference in the wiring set selected by the selection unit causes a problem by comparing the noise level calculated by the noise level calculation unit and the allowable limit value. The interference analysis apparatus according to claim 1.   The interference analysis apparatus according to claim 1, wherein the allowable limit value is provided for a plurality of different frequencies.   The interference analysis unit calculates the amount of interference using data representing a property of a part arranged in the middle of at least one of the wirings included in the set of wirings to be analyzed. The interference analysis apparatus described.   The data representing the property of a part arranged in the middle of at least one of the wirings included in the set of wirings to be analyzed is data representing impedance or S parameters provided for a plurality of different frequencies. 5. The interference analysis apparatus according to 5.   The interference analysis unit calculates the amount of interference using data representing a termination condition of an element or a component connected to at least one of terminals of a wiring included in the set of wirings to be analyzed. The interference analysis apparatus according to 1. The interference analysis apparatus according to claim 6 , wherein the termination condition is represented by impedance or S parameter for a plurality of different frequencies. In the case where a plurality of wiring terminals giving the interference are included in the wiring set selected by the selection unit,
The interference analysis unit calculates, for each of the terminals of the wiring that gives the plurality of interferences, an interference amount of the interference given to the terminals of the wiring that receives the interference,
The reception noise level calculation unit calculates the reception noise level by combining the reception noise levels received by the terminals of the wiring that receives the interference from each of the terminals of the wiring that gives the plurality of interferences. Interference analysis equipment. The interference analysis apparatus according to claim 8 , wherein the reception noise level calculation unit combines the plurality of reception noise levels in consideration of a noise phase.   The interference analysis apparatus according to claim 1, wherein the wiring to be subjected to interference analysis is a wiring of a printed circuit board or a wiring in an LSI. An interference analysis method for analyzing interference caused by electromagnetic induction between wirings formed on a circuit board by computer simulation,
A design data input step for inputting design data of the circuit board including data representing the shape of the wiring and the properties of elements or components connected to the wiring;
Noise characteristic setting that sets, based on the design data, noise characteristic data representing electrical characteristics of virtual noise input to a terminal of at least one of the wirings formed on the circuit board Process,
A limit value setting step for setting an allowable limit value of noise received by the terminal of at least one of the wirings formed on the circuit board based on the design data;
Based on the noise characteristic data and the allowable limit value, a set of wirings to be analyzed from wirings formed on the circuit board, and a terminal for receiving the virtual noise and a terminal for receiving the noise A selection step of selecting a wiring set including
An interference analysis step of calculating an interference amount representing a degree of interference from a terminal to which the virtual noise is input to a terminal to receive the noise in the wiring set selected in the selection step;
A reception noise level calculation step of calculating a noise level received by the terminal receiving the noise based on the interference amount and the noise characteristic data ;
The noise characteristic data is data representing the intensity of the virtual noise provided for different frequencies,
Wherein in the interference analysis step, the interference analysis how to calculate the amount of interference for different frequencies. The method further includes a determination step of determining whether or not interference in the wiring set selected by the selection unit causes a problem by comparing the noise level calculated in the noise level calculation step with the allowable limit value. The interference analysis method according to claim 11 . The interference due to electromagnetic induction between formed on the circuit board wiring, the process of analyzing by simulation, a interference analysis program for causing a computer to execute,
A design data input process for inputting design data of the circuit board including data representing the shape of the wiring and the properties of elements or components connected to the wiring;
Noise characteristic setting that sets, based on the design data, noise characteristic data representing electrical characteristics of virtual noise input to a terminal of at least one of the wirings formed on the circuit board Processing,
A limit value setting process for setting an allowable limit value of noise received by at least one wiring terminal among the wiring lines formed on the circuit board based on the design data;
Based on the noise characteristic data and the allowable limit value, a set of wirings to be analyzed from wirings formed on the circuit board, and a terminal for receiving the virtual noise and a terminal for receiving the noise A selection process for selecting a pair of wires including
An interference analysis process for calculating an interference amount representing a degree of interference from a terminal to which the virtual noise is input to a terminal for receiving the noise in the wiring set selected in the selection process;
Based on the amount of interference and the noise characteristic data, the computer executes a reception noise level calculation process for calculating a noise level received by the terminal receiving the noise ,
The noise characteristic data is data representing the intensity of the virtual noise provided for different frequencies,
In the interference analysis process, an interference analysis program in which the interference amount is calculated for a plurality of different frequencies . The computer further includes a determination process for determining whether interference in the wiring set selected by the selection unit causes a problem by comparing the noise level calculated in the noise level calculation process with the allowable limit value. The interference analysis program according to claim 13 , wherein the interference analysis program is executed. A computer-readable recording medium recording an interference analysis program for causing a computer to execute a process of analyzing interference caused by electromagnetic induction between wirings formed on a circuit board by simulation,
A design data input process for inputting design data of the circuit board including data representing the shape of the wiring and the properties of elements or components connected to the wiring;
Noise characteristic setting that sets, based on the design data, noise characteristic data representing electrical characteristics of virtual noise input to a terminal of at least one of the wirings formed on the circuit board Processing,
A limit value setting process for setting an allowable limit value of noise received by at least one wiring terminal among the wiring lines formed on the circuit board based on the design data;
Based on the noise characteristic data and the allowable limit value, a set of wirings to be analyzed from wirings formed on the circuit board, and a terminal for receiving the virtual noise and a terminal for receiving the noise A selection process for selecting a pair of wires including
An interference analysis process for calculating an interference amount representing a degree of interference from a terminal to which the virtual noise is input to a terminal for receiving the noise in the wiring set selected in the selection process;
Based on the amount of interference and the noise characteristic data, the computer executes a reception noise level calculation process for calculating a noise level received by the terminal receiving the noise ,
The noise characteristic data is data representing the intensity of the virtual noise provided for different frequencies,
In the interference analysis process, a recording medium recording an interference analysis program in which the interference amount is calculated for a plurality of different frequencies . The computer further includes a determination process for determining whether interference in the wiring set selected by the selection unit causes a problem by comparing the noise level calculated in the noise level calculation process with the allowable limit value. A recording medium on which the interference analysis program according to claim 15 is recorded.

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