JPH0527009Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Purpose of the Invention] (Field of Industrial Application) The present invention relates to a filter measuring jig used for measuring filter characteristics of various filter circuits.

(Prior Art) Conventionally, a filter measuring jig shown in FIGS. 4a and 4b has been used to test the characteristics of each mass-produced filter circuit.

This is used in the factory by the inventors and is not commercially available.

The filter measuring jig shown in the figure has a metal fitting 1 which is an inverted L-shaped conductive casing, and a horizontal member 1a of this metal fitting 1. There are provided filter circuit connection terminals 2, 3, and 4, and measurement terminals 5 and 6 for connecting a measuring device for measuring the characteristics of the filter circuit connected to the filter circuit connection terminals. On one side of the lower surface of the member 1a is an insulating plate 9, and an impedance conversion circuit that outputs a signal input at high impedance via the insulating plate 9 at a low impedance, for example, an emitter follower circuit that extracts an output signal from the emitter terminal of a transistor. The formed printed circuit boards 10 are provided in a stacked manner.

The printed circuit board 10, the insulating plate 9, and the horizontal member 1a are fixed to each other by, for example, an adhesive, and the electrically conductive connecting members 7 and 8 shown in the drawing are electrically conductive.
It is designed to be fixed to the metal fitting 1 by.

The filter circuit connection terminals 2, 3, and 4 each consist of an output terminal 2, a ground terminal 3, and an input terminal 4, and a conductive plate material 11 is sandwiched at the lower end of each of these terminals in the figure. It is designed to be electrically connected to a predetermined position of a conductive layer (not shown) formed on the lower surface of the printed circuit board 10 in the drawing.

The ground terminal 3 is electrically connected to a ground pattern on the printed circuit board.

The measurement terminals 5 and 6 have core wires, and each core wire is guided through a through hole (not shown) provided in the housing 1, the insulating plate 9, and the printed circuit board 10, and is connected to a conductive wire formed on the surface of the printed circuit board. Connected to the pattern section. The conductive casing 1 and the ground terminal of the printed circuit board 10 are electrically connected to each other via conductive communication members 7 and 8 and a pair of conductive plates 12.

An equivalent circuit diagram of the filter measuring jig having the external configuration as described above is shown in FIG.

The circuits 16 and 18 in the figure are emitter follower circuits which are impedance conversion circuits, and 17
is an example of a connected filter circuit. Note that the provision of the circuit portion to be connected to both terminals separately on the upper and lower surfaces of the horizontal member 1a as described above is particularly useful when connecting and removing the filter circuit to the filter circuit connection terminal. This is to ensure safety in consideration of the occurrence of failures due to contact with circuit parts.

By the way, there is usually a distance between the filter circuit to be measured and the measuring device.
This is because in order to efficiently measure the characteristics of filter circuits that are mass-produced in large numbers, one measuring device is connected to other filter circuits one after another. For this reason, the length of the connection path from each measuring device to the filter circuit connected to it varies, and changes in distributed capacitance due to the length of the connection path, that is, the length of the cable, have a significant impact on the filter characteristics being measured. Therefore, in order to prevent this influence, it is necessary to use a jig incorporating the impedance conversion circuit described above.

Now, the filter measuring jig having the above configuration is prepared in accordance with the number of filter circuits to be mass-produced, and is connected to a measuring device for multiple filter circuits. is being measured. Therefore, the filter measuring jig must have uniform performance among the jigs and must be able to obtain the same measured value even when measuring the characteristics of the same filter circuit multiple times.

(Problem to be solved by the invention) However, when using the conventional filter measurement jig described above, there is a problem that the measured values obtained for each measurement differ, as shown by the solid line and dotted line in Fig. 6. be. Particularly in the 5.5MHz band and 8.5MHz band, there is a large variation as shown by the dotted line. Although the cause of this is not clear, it is believed that the grounding terminal 3 and the metal fitting 1 are indirectly electrically connected. This makes it impossible to set the quality of manufactured filter circuits to a predetermined value, and also makes it impossible to improve the manufacturing process, so an immediate solution has been desired.

Therefore, an object of the present invention is to provide a filter measuring jig that solves the above problems.

[Structure of the invention] (Means for solving the problems) The structure of the invention to solve the above problems is as follows:
A conductive casing with an approximately inverted L shape, a measurement terminal connected to an external measuring device on the top surface of the horizontal member of this casing, and a filter circuit connection consisting of an input terminal, an output terminal, and a ground terminal for connecting the filter circuit. and an impedance conversion circuit with both terminals connected to the lower surface of the horizontal member, wherein the ground terminal of the filter circuit connection terminal is constituted by a screw member; The present invention is characterized in that the screw member and the conductive casing are directly electrically connected by screwing them together.

(Function) The function of the present invention having the above-mentioned configuration is that among the terminals connecting the filter circuit, the ground terminal is directly electrically connected to the conductive casing to prevent variations in measured values.

(Embodiment) A filter measuring jig according to an embodiment of the present invention will be described below with reference to the drawings.

1A and 1B are a top view and a sectional view taken along the line AA in FIG. 1A, respectively, of a filter circuit measuring jig according to an embodiment of the present invention. The filter measuring jig shown in the same figure has substantially the same structure as that shown in FIGS. 4a and 4b, and therefore has the same function as the filter measuring jig shown in FIGS. 4a and 4b. Components are designated by the same reference numerals, and a description of the configuration will be omitted.

First, the difference between the filter measurement jig shown in Fig. 1 and the filter circuit measurement jig shown in Figs. 4a and b is that the filter circuit connection terminal 3 for connecting the filter circuit to be measured is approximately L. It is directly electrically connected to the electrically conductive casing 1 having a letter shape.

That is, the grounding terminal 3 among the filter circuit connection terminals shown in FIGS. I was letting it happen, but
In the present invention, the notch is not formed, and a female threaded portion 3a is bored at the location and the ground terminal 3 is screwed thereto, thereby electrically connecting the ground terminal 3 and the housing 1.

Further, an equivalent circuit diagram corresponding to the above configuration is shown in FIG.

Next, the functions and effects of the filter measuring jig having the above configuration will be explained.

As described above, in the present invention, by directly connecting the ground terminal 3 of the filter circuit connecting terminals to which the filter circuit is connected and the conductive casing 1, the high-frequency potential difference between the filter circuit and the casing 1 is reduced. It is thought that it is possible to eliminate this problem. Furthermore, Figure 3 shows the results of multiple measurements of the same filter circuit based on the above considerations.
As is clear from the figure, the variations in measured values that have conventionally occurred are not observed.

Therefore, according to the present invention, it is possible to eliminate variations in measured values from measurement to measurement, which conventionally occur when measuring the characteristics of the same filter circuit. Moreover, as a result of being able to improve the reliability of the filter measuring jig in this way, it is also possible to improve the quality of the filter circuit as a final product. Further, as in the above embodiment, by fixing the housing 1, the insulating plate 9, and the printed circuit board 10 by the screw connection of the screw member 3 serving as the ground terminal, the fixation of the three members described above can be made more secure. There are advantages.

Incidentally, although an emitter follower circuit is shown as an example of the impedance conversion circuit in the filter measuring jig, the impedance conversion circuit is not limited to this, and for example, a source follower circuit, a voltage follower circuit, etc. may be used.

It should be noted that the present invention is not limited to the illustrated embodiments described above, and various modifications can be made within the scope of the gist of the present invention.

For example, the conductive connection between the grounding terminal 3 and the housing 1 described above is not limited to screwing, but the grounding terminal and the housing may be connected by soldering or the like. The terminal 3 and the housing 1 may be directly electrically connected.

[Effects of the Invention] As detailed above, according to the present invention, it is possible to provide a filter measurement jig that does not cause measurement errors caused by the filter measurement jig.

[Brief explanation of drawings]

Figures 1a and 1b show the filter measuring jig of the present invention, where figure a is a top view, figure b is a sectional view taken along line A-A in figure a, and figure 2 is shown in figure 1. An equivalent circuit diagram of the filter measurement jig, Figure 3 is a characteristic diagram when using the filter measurement jig shown in Figure 1, and Figures 4a and b are top views of the conventional filter measurement jig. , a front view, FIG. 5 is an equivalent circuit diagram of the filter measuring jig shown in FIG. 4, and FIG. 6 is a characteristic diagram when the filter measuring jig shown in FIG. 4 is used. 1... Conductive housing, 1a... Horizontal member, 2,
3, 4... Filter circuit connection terminal, 5, 6...
Measurement terminals, 16, 18... impedance conversion circuit.

Claims (1)

[Claims for Utility Model Registration] (1) A conductive casing having a substantially inverted L shape, a measurement terminal connected to an external measuring device on the upper surface of a horizontal member of this casing, and an input terminal connected to a filter circuit. , a filter measurement jig comprising a filter circuit connection terminal consisting of an output terminal and a ground terminal, and an impedance conversion circuit in which both terminals are connected to the lower surface of the horizontal member, the ground terminal of the filter circuit connection terminal; 1. A filter measuring jig, characterized in that the screw member is constructed of a screw member, and the screw member and the conductive casing are screw-coupled to directly conductively connect them. (2) The filter measuring jig according to claim 1, wherein the impedance conversion circuit is an emitter follower circuit.