JP3237513B2 - Connector transmission characteristics analysis method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for analyzing transmission characteristics of a transmission circuit including a connector used for connection between signal transmission circuits.

[0002]

2. Description of the Related Art A transmission characteristic analysis of a transmission circuit including a connector is necessary at a design stage when an apparatus requiring high-speed signal transmission and high-density mounting is realized. In the evaluation of the transmission characteristics of a conventional connector, it has mainly been to prepare a measurement and evaluation board, obtain the amount of reflected noise and the amount of induced noise for each connector by actual measurement, and extrapolate and interpolate the results. In some cases, transmission characteristics are evaluated by analysis. In such a case, the characteristic analysis and evaluation circuit of the connector uses a signal terminal connected to one or several parallel lines having uniform characteristic impedance.

[0003]

In the conventional transmission characteristic analysis of a connector, the positions of the ground terminal and the signal terminal of the connector are fixed in advance, and the positions of the terminals cannot be arbitrarily selected thereafter. In addition, the analysis method ignores the impedance of the ground terminal and assumes zero ohm. Further, the method of analyzing the number of terminals of the connector is several.

The present invention has been made in view of the above circumstances, and does not consider the positions of the ground terminal and the signal terminal of the connector, and obtains all the line constants of each terminal according to the required number of terminals. It is an object of the present invention to provide a connector transmission characteristic analysis method for performing transmission characteristic analysis and the like of a transmission circuit including the above.

[0005]

In order to achieve the above object, a connector transmission characteristic analysis method according to the present invention is a method for analyzing transmission characteristics including a connector used for connection between signal transmission circuits. Extracting the connector, dividing the connector in a section perpendicular to the signal transmission direction, and creating connector structure input information, and extracting electromagnetic information for each section based on the created sectional structure information of the connector input information. By performing field analysis and deriving the line constant or actual measurement and deriving the line constant, the distance between connector terminals of the connector structure input information is summarized as a variable, the result is interpolated, extrapolated, and the correlation is calculated. Step 3 of creating a relational expression or table for determining line constants, and inputting the distance information between connector terminals of the connector structure input information into the above-described relational expression, and Step 4 of creating transmission circuits for each section based on the determined line constants, information on the number of terminals, and information on the length between sections, and using connection information on the divided transmission circuits. , A step 5 of connecting transmission circuits for each section, and a step 6 of creating a simple circuit for analyzing the transmission characteristics of the connector.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a flowchart showing an embodiment of the present invention. That is, a method for analyzing transmission characteristics including a connector used for connection between signal transmission circuits, wherein a step 1 of extracting a structural dimension of the connector and a step 2 of dividing the connector by a cross section perpendicular to the signal transmission direction. In step 3 of creating the structure input information 10 and creating a relational expression or table for line constant analysis and line constant determination, the electromagnetic information for each section is obtained based on the sectional structure information 11 of the connector input information 10 created above. Field analysis is performed, and the derived line constants or actual measured and derived line constants are summarized using the connector terminal distance information 12 of the connector structure input information 10 as a variable, and the results are interpolated and extrapolated to obtain correlation. In this way, a relational expression or table for determining the line constant is created, and the connector terminal distance information 12 of the connector structure input information 10 is added to the relational expression created above. Step 4 of determining line constants for each section and creating a transmission circuit for each section, based on the determined line constants, terminal number information 13 and section length information 14, A transmission circuit is created, and further, by using the connection information 15 of the divided transmission circuits, a step 5 of connecting the transmission circuits of each division is performed, thereby connecting the transmission circuits of each division and analyzing the transmission characteristics of the connector. Step 6 of outputting a circuit
This is a connector transmission characteristic analysis method characterized by comprising:

That is, the connector structure input information 10 includes:
It is created in a step 1 for extracting the structural dimensions of the connector and a step 2 for dividing the connector in a section perpendicular to the signal transmission direction. The connector structure input information 10 includes cross-sectional structure information 11, connector terminal distance information 12, terminal number information 13,
Section length information 14, Connection information 1 of sectioned transmission circuit
5 The method of dividing the cross-sectional structure information 11 is characterized in that the section is divided by a portion having a uniform dielectric constant or a portion having a uniform structure.

In the step 3 of analyzing line constants for each section based on the cross-sectional structure information 11 of the connector structure input information 10 described above, an ideal zero potential point, which is a reference required for the analysis, is set to the ground terminal of the connector. Instead, the line constant is determined at the point at infinity, and the line constant between terminals and for each terminal is obtained. Further, since the line constant determination relational expression for each section created in the step 3 uses the connector terminal distance information 12 of the connector structure input information 10 as a variable, the line number determination relational expression The line constant is obtained by substituting the connector terminal distance information 12 described above.

Since the connector characteristic analysis and evaluation circuit is determined by the cross-sectional structure information 11 which is the connector structure input information 10 and the connector terminal distance information 12, the analysis can be performed relatively easily as compared with the three-dimensional analysis. .

Since the line constant determining relational expression for each section is used, the number and positions of the connectors required for the transmission characteristic analysis can be freely set, and the line constant can be obtained according to the scale of the number of terminals.

Further, in the simplified circuit for analyzing the transmission characteristics of the connector created by using the process 5 for connecting the transmission circuits for each section, the terminal accommodation of the connector is not determined at the stage of creation. Therefore, the terminal accommodation can be arbitrarily determined when incorporated into a transmission circuit system for analyzing transmission characteristics. Similarly,
Since the characteristic impedance of all the terminals necessary for the characteristic analysis of the connector is taken into account, the signal transmission characteristics received from the ground terminal can be analyzed.

FIGS. 2A and 2B are configuration diagrams showing an example of a transmission circuit measurement system for evaluating transmission characteristics including the connector according to the present invention. That is, the signal output from the pulse generator 30 passes through the 50Ω coaxial cable 26, propagates through the wiring (50Ω) 22 in the printed circuit board 21, and is input to the connector 20. Further, the signal is output from the connector 20, passes through the wiring (50Ω) 23,
And flows into the ground layer of the printed circuit board 21. Induction lines 25 adjacent to the signal lines 24 through which signals are transmitted include induction noise and ground noise induced in the connector 20 included in the transmission characteristics of the connector 20. The result can be observed by the oscilloscope 31 connected to the guide wire 25. An example of this result is the measured waveform at the measurement point in FIG. This result differs depending on the terminal accommodation of the connector 20, the waveform shape of the input signal, the number of signal line operations, and the like. 28 is an output resistance (50Ω), 29 is an input resistance (50Ω), and 32 is a measurement point.

4 and 5 show an example of the connector structure input information 10 created in FIG. 1. FIG. 4 shows an example of the connector structure in which the connector is shown in a cross section parallel to the signal transmission direction. FIG. This is an example represented by a cross section perpendicular to the transmission direction. Reference numeral 40 denotes a cable connector pin, which is shown in FIG.
Corresponding to Reference numeral 41 denotes a driving pin portion, which is shown in FIG.
Corresponding to Reference numeral 43 denotes a lead portion, which corresponds to FIG. Reference numeral 44 denotes a PTH of the soldering portion, which corresponds to FIG. Reference numeral 45 denotes a printed circuit board (backplane) package. 46 is a package of a printed circuit board. 47 is a mold. Reference numeral 48 denotes a connector mold portion, which corresponds to FIGS. 5C and 5D. Based on this,
Sectional structure information 11 which is the extracted vertical section structure size
And connector terminal distance information 12, which is the center-to-center distance of the connector terminals, terminal number information 13, inter-section length information 14, which is the distance between the divided vertical sections, and connection information 15 of the divided transmission circuits. .

FIG. 6 is an example of a relational expression or table for determining a line constant according to the present invention. That is, it is a relational expression for determining a line constant by performing an electromagnetic field analysis based on the connector structure input information 10, obtaining a line constant for each terminal, and obtaining a correlation between the derived line constant results for each terminal. . When a relational expression or a table is obtained by actual measurement, the pulse generator 30 in the measurement system shown in FIG. 2 is provided with a TDR measuring device for inputting an impulse waveform and measuring a reflection coefficient which is a ratio of the amplitude of the reflected wave to the amplitude of the transmitted wave. Then, the line constant of the terminal is obtained by actual measurement for each section, and the line constant of each terminal is correlated to create a relational expression. From this relational expression, resistance, inductance, capacitance, conductance and the like per unit length, which are line constants between the terminals, are obtained from the cross-sectional structure information 11 and the number-of-terminals information 13. In addition, when creating a transmission circuit for each section, in order to further improve the accuracy, a correlation function between the section length for each terminal and a line constant between each terminal and the terminal is obtained, and the constant is weighted. Determine the resistance, inductance, capacitance, and conductance of the transmission circuit for each category.

7 to 9 show an example of a simplified circuit for analyzing the transmission characteristics of the connector according to the present invention. FIG. 7 shows an example of the structure of the connector, FIG. 8 shows a simplified circuit of the connector, and FIG. 9 shows a transmission circuit for analysis. Here is an example. In the figure, the same parts as those in FIGS. 4 and 5 are denoted by the same reference numerals, and description thereof will be omitted. That is, based on the determined line constants, a transmission circuit 56 for each section is created, and each transmission circuit is connected based on the section transmission circuit connection information 15 to output a simple connector circuit example (FIG. 8).
It is. The simple connector circuit of FIG. 8 is an example of a divided transmission circuit, and includes a cable connector pin portion 40, a driving pin portion 41, a connector mold portion 48, a lead portion 43,
It was divided by the PTH44 of the soldering part. The number of input / output terminals of the divided transmission circuit 56 is equal to the determined number of terminals. In order to improve the analysis accuracy, some further divisions are made even within the divided transmission circuit. One of the divided transmission circuits 56 can be represented by a ladder circuit using line constants R, L, and C, as shown in the transmission circuit example for analysis in FIG. Also, R, L, G, C per terminal position and section length
Can also be represented by a matrix. In addition, there is a method of expressing by a scattering matrix.

FIG. 10 shows an example in which a transmission circuit evaluation system necessary for evaluating the characteristics of the transmission system is created using a simple circuit for analyzing the transmission characteristics of the connector shown in FIG. That is, the ground terminal 64 of the connector 60 is connected to an earth board model 72 representing the characteristics of the earth layer of the printed board of the backplane 61 and the package 62, and is connected to an ideal ground. The signal terminals 63 are connected to transmission lines 65 and 66, which are wirings on both printed circuit boards, respectively.
The other ends of the terminals 66 and 66 are connected to terminating resistors 67 and 69, a signal source, and the like, and are connected to the ground board model 72. The open end of the terminal connects a high resistance 70, a capacitor, and the like. 68 is an output resistance (50Ω), and 71 is a measurement point.

FIGS. 11 and 12 are diagrams comparing the results of evaluating the connector transmission characteristics. That is, the comparative example of the analysis result of the induced noise waveform in FIG. 11 is a comparison between the noise waveform of the induction wire obtained by the conventional analysis method of (a) and the analysis waveform obtained by the present invention of (b). is there. Compared with the result obtained by the conventional analysis method of (a), the result obtained by the present invention of (b) can show unstable characteristics of the waveform under the influence of the impedance of the ground terminal. Further, as can be seen from the tendency of the comparative example of the measurement result and the analysis result of the induced noise amount in FIG.
The tendency of No. 4 is consistent with the tendency of the analysis result 85 obtained by the present invention.

As is apparent from the above results, by using a simplified circuit for analyzing the transmission characteristics of the connector obtained by the present invention, the high-precision characteristics of the transmission circuit including the connector can be improved as compared with the conventional method. The effect of being able to analyze is obtained.

In this embodiment, a pin-type connector is used as the terminal structure. However, the same effect can be obtained with connectors having any structure such as an edge type and a knife type. Further, the same applies to the optical connector.

As described above, the transmission characteristics are analyzed and evaluated using the simple circuit for analyzing the transmission characteristics of the connector obtained by the present invention. Without considering the impedance of all terminals and using a relational expression or table for determining line constants, the number of terminals can be set arbitrarily. The transmission characteristics can be analyzed up to parallel transmission. Therefore, there is an effect that the noise margin condition of the transmission circuit required at the stage of designing the device can be accurately determined.

[0021]

As described above, according to the present invention, all the line constants of each terminal are determined according to the required number of terminals without considering the positions of the ground terminal and the signal terminal of the connector. It is possible to provide a connector transmission characteristic analysis method for performing transmission characteristic analysis of a transmission circuit including the same.

[Brief description of the drawings]

FIG. 1 is a flowchart illustrating an embodiment of the present invention.

FIG. 2 is a configuration diagram showing an example of a transmission circuit measurement system for evaluating transmission characteristics including the connector according to the present invention.

FIG. 3 is an actually measured waveform at a measurement point in FIG. 2;

FIG. 4 is a configuration diagram showing an example of a connector structure in which a connector according to the present invention is represented by a cross section parallel to a signal transmission direction.

FIG. 5 is a sectional view of an example in which the connector according to the present invention is represented by a section perpendicular to the signal transmission direction.

FIG. 6 is a characteristic diagram showing an example of a relational expression or table for determining a line constant according to the present invention.

FIG. 7 is a configuration diagram showing a structural example of a connector according to the present invention.

FIG. 8 is a configuration diagram showing an example of a simplified connector circuit according to the present invention.

FIG. 9 is a configuration diagram showing an example of a transmission circuit for analysis according to the present invention.

FIG. 10 is a configuration diagram showing an example of a connector transmission characteristic analysis evaluation system according to the present invention.

FIG. 11 is a characteristic diagram showing a comparative example of an analysis result of an induced noise waveform according to the present invention.

FIG. 12 is a characteristic diagram showing a comparative example of an actual measurement result and an analysis result of an induced noise amount according to the present invention.

[Explanation of symbols]

 1: Connector structural dimension extraction process 2: Connector vertical cross section classification process 3: Line constant analysis and line constant determination relational expression and table creation process 4: Transmission circuit creation process 5: Transmission circuit connection process 6: Connector transmission characteristic analysis circuit Output process 10: Connector structure input information 11: Cross-sectional structure information 12: Connector terminal distance information 13: Terminal number information 14: Section length information 15: Section transmission circuit connection information 20: Connector 21: Printed circuit board 22: Wiring ( 23: Wiring (50Ω) 24: Signal line 25: Induction wire 26: Coaxial cable (50Ω) 27: Terminator (50Ω) 28: Output resistance (50Ω) 29: Input resistance (50Ω) 30: Pulse generator 31: Oscilloscope 32: Measurement point 40: Cable connector pin part 41: Driving pin part 43: Lead part 44: P of soldering part TH 45: Printed circuit board (back plane) 46: Printed circuit board (package) 48: Connector mold section 56: Transmission circuit 60: Connector 61: Back plane 62: Package 63: Signal terminal 64: Ground terminal 65: Transmission line 66: Transmission Line 67: Terminating resistance (50Ω) 68: Output resistance (50Ω) 69: Terminating resistance (50Ω) 70: High resistance equivalent to open state 71: Measurement point 72: Model of earth substrate 84: Measurement result 85: Analysis result

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-6-243193 (JP, A) Hironori Oka, Tetsuro Mikazuki "Study of electrical characteristics analysis model for high-speed and high-density connectors", IEICE Technology Research report (EMD93-21), p. 13-18, 1993 Heike Wolter et al. "Field-Based Analysis of a High Pin Board Board Connector", IEEE TRANSACTIONS ON COMPONENTS, PACKAGING, AND MA NUFACTURING TECHNOLOGY TECHNOLOGY TECH. 19, NO. 1, Feb 1996 (58) Field surveyed (Int. Cl. ⁷ , DB name) H04B 3/46

Claims (1)

(57) [Claims] 1. A method for analyzing transmission characteristics include a connector used for connection between the signal transmission circuit, a step 1 for extracting a feature size of the connector, divided in a cross section perpendicular to the connector in the signal transmission direction, the dielectric rate
Sectional structure information divided by uniform parts of the structure and uniform parts of the structure
And connector terminal distance information, terminal number information,
A step 2 of creating connector structure input information including length information and connection information of the divided transmission circuits; and an electromagnetic field for each section based on the sectional structure information of the created connector structure input information. Analyze and derive the derived line constants or the measured and derived line constants and summarize the connector-to-terminal distance information of the connector structure input information as a variable,
Step 3 of creating a relational expression or table for determining line constants by interpolating and extrapolating the results and calculating the correlation.
And the distance information between the connector terminals of the connector structure input information is input to the created relational expression, the line constant for each section is determined, and the determined line constant and the number of terminals of the connector structure input information and the length between sections are determined. Step 4 of creating a transmission circuit for each section based on the transmission information, and Step 5 of connecting the transmission circuits for each section using the connection information of the transmission circuit that has been classified in the connector structure input information.
And a step 6 of creating a simple circuit for analyzing the transmission characteristics of the connector.