JPH0443821Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a terminal connection structure, and is particularly applicable to circuit testing equipment, which is capable of transmitting high frequency signals and where digital signals and analog signals coexist. The invention relates to a terminal connection structure that can eliminate interference between both signal systems when

[Prior art and its problems]

In circuit test equipment such as semiconductor test equipment,
When connecting a measuring device and an object to be measured, a composite probe that connects many terminals is required.

Conventionally, the one shown in FIG. 3 has been generally used. That is, the probe device 31 includes a housing 32 made of an insulator and a compact probe 33 held in the housing. However, in the probe device 31, when transmitting a digital signal such as a high frequency analog signal, a rectangular wave with a high repetition rate, or a pulse signal with a fast rise, the compact probe 31 acts as an inductance, and also causes interference with the input/output circuit. Reflected waves occur due to impedance mismatch, so
The drawback was that the waveform distortion was large. In addition, in the conventional example described above, signals are usually transmitted using a pair of contact probes, which has the drawbacks of high cost and a large housing due to the need for a correspondingly large number of contact probes. Ta.

A coaxial contact probe 41 as shown in FIG. 4 is known to meet the requirements for a coaxial structure of signal lines. That is, the coaxial contact probe 41
The pin 4 serves as a plunger that is housed in the outermost cylindrical body 42 so as to be able to move in and out and is biased in the projecting direction.
3 and a cylindrical body 44.
The pin 43 and the cylindrical bodies 42 and 44 are insulated from each other and serve as the center conductor and outer conductor of the coaxial line, respectively. However, the coaxial contact probe 41
had the disadvantage of high manufacturing costs due to its relatively complex structure.

In contrast to the above-mentioned prior art, as in the probe device disclosed in U.S. Pat. is made of metal, and contact probes 5 are inserted into a plurality of holes provided in the housing ring via a dielectric material 53.
4 and use the housing ring 52 as a common ground for the contact probe 54. The ground of the measuring device and the circuit to be measured and the housing ring 52 are connected by a metal elastic member or the like. According to this, since a coaxial structure is formed between the housing ring 52 and the contact probe 54, the characteristic impedance can be easily matched with the input/output impedance of the measuring instrument, and high frequency signals can be accurately transmitted. can do. Moreover, the number of contact probes used can be reduced, and the structure is simple, so it can be manufactured at extremely low cost.

However, a problem occurs when digital signals and analog signals coexist in the probe device 51. As is well known, analog signals require higher transmission accuracy than digital signals.

For example, when a digital signal is input to a circuit under test and an analog signal output from the circuit under test is measured, a common impedance is generated in the housing 52 when the probe device 51 is used. Since the housing 52 has a small resistance, the current flowing through the housing 52 creates an electrical potential, the effect of which is to cause signal interference.

Normally, problems do not occur if only digital signals are transmitted, but in the case of analog signal transmission, which requires particularly high-precision measurements, it may be impossible to perform measurements using the probe device 51. Become.

On the other hand, it is also possible to consider a method in which the conductive housing is divided into a plurality of parts insulated by insulators. However, the manufacturing cost of the conductive housing is high, and it is difficult to process it into multiple pieces, making it extremely difficult to actually implement it.

[Problem that the invention attempts to solve]

The present invention was made in order to solve the problems of the prior art described above, and its purpose is to provide a conductive housing with a plurality of cylindrical holes, and an insulating housing in the holes. By forming a coaxial line consisting of a central conductor held through a body and having a common ground, impedance matching is performed while simplifying the configuration and improving high frequency characteristics.

The main purpose of the present invention is to use the signal path as a digital signal transmission path, to make the cylindrical body held in the hole through an insulator a ground floating from the conductive housing, and to make the cylindrical body held in the hole through an insulator a ground floating from the conductive housing. By holding the center conductor through the cable to form a second coaxial line and using it as a transmission path for analog signals, it is possible to eliminate interference between both signal systems when both digital and analog signals coexist. be.

Another object is to selectively provide floating grounds from the conductive housing in a plurality of holes provided in the conductive housing, thereby making it possible to arbitrarily determine the position of the analog signal connection terminal. That's true.

[Means for solving problems]

In short, the present invention uses a coaxial line consisting of a conductive housing having a plurality of cylindrical holes and a center conductor held in the holes via a dielectric as the first signal path, and a dielectric in the holes. The second signal path is a coaxial line consisting of a cylindrical conductor held through the cylindrical conductor and a center conductor held by the cylindrical conductor through a dielectric.

[Example of the present invention]

Hereinafter, the present invention will be explained based on embodiments shown in the drawings. As shown in FIG. 1, a terminal connection structure 1 according to the present invention includes a metal ring 2, which is an example of a conductive housing, and has a plurality of cylindrical holes 11. A center conductor 3 is held in the hole 11 via a dielectric (insulator) 12, and a metal ring 2
A coaxial line consisting of the center conductor 3 and the center conductor 3 forms the first signal path 8.

Further, a cylindrical conductor 4 is held in some of the plurality of holes 11 via a dielectric (insulator) 13,
Furthermore, a center conductor 6 is held within the cylindrical conductor 4 with a dielectric (insulator) 15 interposed therebetween. With this configuration, the coaxial line made up of the center conductor 6 and the cylindrical conductor 4 forms the second signal path 9.

When inputting a digital signal to the circuit under test 21 and measuring an analog signal output by the circuit under test 21 in response to the input, connections are made as shown in FIG. That is, one ends 22a and 21a of the digital input terminals of the digital signal source 22 and the circuit under test 21 are connected via the center conductor 3, and the other ends 22b and 21b are both grounded to the metal ring 2. On the other hand, the analog side output terminal of the circuit under test 21 and the analog measuring instrument 23 have one end 21c, 23c connected to the other end 21c, 23c through the center conductor 6, respectively.
d and 23d are connected via the cylindrical conductor 4.

Note that contact probes are normally used for the center conductors 3 and 6. On the other hand, for grounding the conductive housing 2 and connecting to the cylindrical conductor 4,
A conductive elastic member such as a metal spring member commercially available as a shield gasket or a contact probe can be used.

Further, when using a contact probe for electrical connection to the cylindrical conductor 4, it may be attached to the cylindrical conductor 4 by embedding, fixing, etc.
It may be arranged so as to be in contact with the cylindrical conductor 4.

The present invention is constructed as described above, and its operation will be explained below.

The digital signal generated from the digital signal source 22 is transmitted to the terminal 2 of the circuit under test 21 via the center conductor 3.
1a and grounded to the metal ring 2. At this time, since the metal ring 2 naturally has some resistance, a potential is generated in the metal ring 2 by the current generated by the digital signal.

Therefore, the signal path 8 including the center conductor 3 and the metal ring 2 interferes with each other because the metal ring 2 has a common impedance. However, in the case of digital signals, they are relatively less susceptible to noise, so even if other digital signal paths experience this interference, the measurement is not affected much. However, if a similar signal path 8 is used to transmit an analog signal output from the circuit under test in response to a digital signal input, the influence of crosstalk will directly appear in the measurement results.

According to the present invention, the analog signal is transmitted through the metal ring 2.
Since the signal is transmitted through the second signal path 9, which has a coaxial structure and is insulated from the ground of the digital signal, interference of the digital signal with the analog signal is eliminated.

In the above measurement applications, the number of connection terminals for digital signals is often greater than the number of connection terminals for analog signals.
Therefore, it is only necessary to provide as many signal passages 9 in the hole 11 as the number of analog signal terminals required.

In the above embodiment, the first signal path 8 with the metal ring 2 as a common ground transmits a digital signal, and the second signal path floating from the metal ring 2 transmits a digital signal.
Although the signal path 9 has been described as transmitting an analog signal, it is not limited thereto.
In other words, there are signals that do not require transmission accuracy, i.e., signals for which mutual interference due to common impedance is not a problem, and signals that require high-precision transmission or are susceptible to interference due to such signals. This can be applied when signals coexist.

Furthermore, in the above embodiments, the cylindrical conductor 4 is held within the hole 11 by the insulator 13, and the center conductor 6 is held within the cylindrical conductor 4 by the insulator 15. However, the center conductor 6 does not necessarily need to be mechanically supported by the dielectric 15; for example, air may be used as the dielectric and other suitable support structures may be provided. Furthermore, it goes without saying that the cylindrical conductor can be formed in various ways within the scope of achieving the functions and effects described in this specification.

[Effects] Since the present invention is constructed and operates as described above, it includes a conductive housing provided with a plurality of cylindrical holes, a central conductor held in the holes via an insulator, Since a coaxial line with a common ground is formed, the configuration is simplified and costs can be reduced, impedance matching is performed, and high frequency characteristics are improved.

In addition, as a main effect of the present invention, the signal path with the conductive housing as a common ground is used as a digital signal transmission path, and the cylindrical body held in the hole with an insulator interposed is connected to the ground suspended from the conductive housing. A second coaxial line is formed by holding the center conductor through an insulator, and it is used as a transmission path for analog signals, so when digital and analog signals coexist, it is possible to The effect of eliminating interference can be obtained.

Furthermore, since the ground floating from the conductive housing is provided in the plurality of holes provided in the conductive housing, the position of the analog signal connection terminal can be arbitrarily selected.

[Brief explanation of the drawing]

Figures 1 and 2 relate to embodiments of the present invention; Figure 1 is a perspective view of the main parts of the invention, Figure 2 is a sectional view and electric circuit diagram of the main parts of the invention, and Figures 3 and 4 are The figures relate to conventional examples; FIG. 3 is a perspective view of a probe device, FIG. 4 is a side view of a coaxial contact probe, and FIG. 5 is a perspective view of essential parts of a probe device invented by the same applicant as the present application. . DESCRIPTION OF SYMBOLS 1... Terminal connection structure, 2... Metal ring which is an example of a conductive housing, 3, 4... Center conductor, 6
... Cylindrical conductor, 8 ... First signal path, 9 ... Second signal path, 11 ... Hole, 12, 13, 15...
...It is an insulator (dielectric).

Claims (1)

[Scope of utility model registration request] The first signal path is a coaxial line consisting of a conductive housing having a plurality of cylindrical holes and a center conductor held in the holes through a dielectric, and the center conductor is held in the holes through a dielectric. A terminal connection structure characterized in that a coaxial line consisting of a cylindrical conductor and a center conductor held within the cylindrical conductor via a dielectric is used as a second signal path.