JPH021971Y2 - - Google Patents

Description

[Detailed explanation of the invention] <Industrial application field> This invention is based on the following:
The present invention relates to a power supply inserter for superimposing an operating current to an electrical device that sends or receives the above signal.

<Prior Art> Conventionally, as the above-mentioned power supply inserter, there has been one as shown in FIG. 3, for example. This is terminal 2, 4
Coaxial cables (not shown) are connected to these terminals 2 and 4, respectively. These terminals 2,
A capacitor 6 is connected between the terminals 4 and 4. Therefore, the signal supplied to the terminal 2 by the coaxial cable is supplied to the coaxial cable connected to the terminal 4 via the capacitor 6.

Further, the terminal 2 is connected to the secondary winding 12 of the power transformer 12 via the high frequency blocking coil 8 and the fuse 10.
connected to one end of a. The terminal 4 is connected to the contact 1 of the changeover switch 16 via the high frequency blocking coil 14.
6a, contact 1 of this changeover switch 16
6b is connected to the connection point between the high frequency blocking coil 8 and the fuse 10, and is connected to the contact point 16c of the changeover switch 16.
is grounded. The other end of the secondary winding 12a of the power transformer 12 is grounded, and the primary winding 12b of the power transformer 12 is connected to a commercial AC power source via a fuse 18. Therefore, when the contact 16a of the changeover switch 16 is switched to the contact 16b side, the alternating current induced in the secondary winding 12a is
It is supplied to the coaxial cable connected to the terminal 2 via the fuse 10 and the high frequency blocking coil 8, and also to the coaxial cable connected to the terminal 4 via the fuse 10, the changeover switch 16 and the high frequency blocking coil 14. . In addition, the changeover switch 16
When the contact 16a is switched to the contact 16c side, 2
The alternating current induced in the next winding 12a is supplied only to the coaxial cable connected to the terminal 2 via the fuse 10 and the high frequency blocking coil 8.

In addition, 20 and 22 are feed-through capacitors for bypass, 24 is a rectifier diode, 25 is a current limiting resistor,
26 is a light emitting diode, 28 is a bypass capacitor, rectifier diode 24 and light emitting diode 2
6 is for displaying that this power supply inserter is operating.

<Problems to be solved by the invention> However, in the above power supply inserter, the capacitor 6 is required to supply the signal supplied to the terminal 2 to the terminal 4.
is used. Therefore, when the signal transmitted by a coaxial cable is a UHF signal or a VHF signal, the voltage standing wave ratio and insertion loss must be set to be sufficient for practical use, as shown by the dotted lines in Figures 4 and 5, respectively. However, when transmitting a converted signal obtained by converting a 12 GHz band satellite broadcasting signal to a 1 GHz band signal using a coaxial cable, a voltage standing wave is generated as shown in Figures 4 and 5. The problem was that the ratio and insertion loss were large, making it impractical. This problem arises because the transmitted signal has a high frequency and is affected by stray inductance caused by the capacitor leads.

<Means for solving the problem> The means for solving the above problem is to provide two terminals spaced apart on a double-sided printed circuit board, and to install both terminals on one side of the double-sided printed circuit board. microstrip lines extending from each other so that their tips are spaced apart from each other; stubs provided at the tips of these lines; a capacitor connected between these stubs; and high frequency blocking coils each having one end connected to the loop line.
The stub is formed in a shape that cancels out inductance caused by the capacitor lead in the SHF band.

<Operation> According to the above means, since a capacitor is provided between the microstrip lines, a high frequency signal can be transmitted from one terminal to the other. If it's expensive,
The voltage standing wave ratio and insertion loss are affected by the stray inductance caused by the capacitor leads.
Although this is an improvement over simply connecting a capacitor between the terminals, it is still insufficient for practical use. Therefore, a stub is provided to offset the stray inductance.

<Embodiment> In this embodiment, terminals 2 and 4 are connected as shown in FIG.
The structure is the same as the conventional one shown in FIG. 3, except for the difference in the structure for electrically connecting the two. Equivalent parts are given the same reference numerals and their explanations will be omitted.

In this embodiment, as shown in FIG.
4 is formed on one surface 26 of the double-sided printed circuit board 24. The microstrip line 2 is located almost on the same straight line from these terminals 2 and 4.
8 and 30 extend, and the tips of these lines 28 and 30 are located at a predetermined distance apart. In addition,
The length and width dimensions of both lines 28, 30 are selected to provide a predetermined impedance, for example 75Ω.

A stub 3 is provided at the tip of these lines 28, 30.
2 and 34 are formed. And stub 3
A capacitor, for example a ceramic capacitor 36, is connected between 2 and 34. Stub 32,3
The length and width dimensions of 4 are ceramic capacitor 3.
The stray inductance of the shape and lead length of 6.
It is chosen to function as a capacitive inductance element for cancellation in the SHF band. Note that the microstrip lines 28, 30 and stubs 32, 34 shown in FIG. 1 are shown at twice the size of those actually manufactured. In the figure, the hatched area is the area from which the metal foil has been removed, and the double-sided printed circuit board 24 has a dielectric constant of 4.0.

The voltage standing wave ratio of the power supply inserter constructed in this manner is shown in FIG. 4, and the insertion loss thereof is shown in solid lines in FIG. 5, respectively. As can be seen from the above, in this power supply inserter, the voltage standing wave ratio is close to 1 and the insertion loss is close to 0 dB at frequencies in the VHF and UHF bands as well as in the SHF band. Therefore, this power supply inserter can be fully put to practical use. Further, the voltage standing wave ratio and insertion loss when the stub is removed from this example are shown by dashed lines in FIGS. 4 and 5.
As you can see, if you don't provide a stub,
Both the voltage standing wave ratio and insertion loss worsen in the SHF band. This is because stray inductance caused by capacitor leads etc. cannot be canceled out.

In the above embodiment, a changeover switch 16 is provided so that alternating current is supplied to both terminals 2 and 4, and alternating current is supplied only to terminal 2.
may be removed, and the high-frequency blocking coil 14 is directly connected to the connection point between the fuse 10 and the high-frequency blocking coil 8, so that current is always supplied to both terminals 2 and 4. Although alternating current was supplied to both terminals 2 and 4, for example, the changeover switch 16 was removed and one end of the DC power supply was connected to the end of the high frequency blocking coil 14 to which the contact 16a of the changeover switch 16 was connected. However, the other end of the DC power source may be grounded to supply DC current to the terminal 4.

<Effects> As mentioned above, according to this invention, each microstrip line connected with a capacitor is provided with a stub shaped to cancel the inductance caused by the capacitor lead etc. in the SHF band at the tip. In the , VHF, UHF and SHF bands, both the voltage standing wave ratio and the insertion loss can be set to values that are sufficiently useful for practical use.

[Brief explanation of the drawing]

Fig. 1 is a partly omitted plan view of the main parts of an embodiment of the power supply inserter according to this invention, Fig. 2 is a circuit diagram of the same embodiment, Fig. 3 is a circuit diagram of a conventional power supply inserter, and Fig. 4. Figure 5 shows the voltage standing wave ratio characteristics of the same example, the same example with the stub removed, and a conventional power supply inserter, and Figure 5 shows the same example, the same example with the stub removed, and a conventional power supply. It is an insertion loss characteristic diagram of an inserter. 2, 4...terminal, 12...power transformer, 2
8,30...Microstrip line, 32,3
4...Stub, 36...Capacitor.

Claims (1)

[Scope of utility model registration request] two terminals provided at a distance on a double-sided printed circuit board; and a microstrip provided on one surface of the double-sided printed circuit board extending from both terminals and having their tips spaced apart from each other. A line, a stub provided at each end of each line, and a capacitor connected between these stubs,
A power supply inserter comprising a high frequency blocking coil having one end connected to each of the microstrip lines, the stub having a shape that cancels out inductance caused by the lead of the capacitor in the SHF band.