JP3284170B2 - Satellite receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a satellite broadcast receiver, and more particularly to a low noise block down converter for converting a 10 GHz band high frequency radio wave from an artificial satellite into an output of a 1 GHz band frequency after receiving it with an antenna. Regarding the structure of the converter.

[0002]

2. Description of the Related Art Conventional low noise block down
A satellite broadcast receiving system using a converter (hereinafter, referred to as LNB) will be described with reference to FIG.

As shown in FIG. 4, a weak radio wave (11.45 GHz to 12.2 GHz) from an artificial satellite is transmitted to an antenna 1.
After receiving the signal at 00, the signal is low-noise amplified by a Ku-BAND LNB (hereinafter referred to as LNB) 101 to an IF output frequency (950 MHz to 1450 MHz) in a low band.
Next, this output is input to the indoor receiver 103 through the coaxial cable 102, and becomes a signal of a sufficient level with low noise. The indoor receiver 103 includes a DBS tuner 10
4. FM demodulator 105, video and audio circuit 1
06, and an RF modulator 107. The output from the indoor receiver 103 is output to the TV 108
And so on.

Here, the LNB 101 is attached to the antenna 100 with a support rod 109 as shown in FIG. The output from the LNB 101 is input to an indoor receiver 103 (not shown) through a coaxial cable 102 provided inside a support rod 109.

Further, a more specific structure of the LNB 101 is, for example, as shown in FIG. FIG. 6 is a side view of an LNB 101 having a conventional structure. In FIG. 6, 11
0 is an entrance into which the radio wave reflected by the antenna 100 is incident, 111 is a screw portion for attaching to the support rod 109,
Reference numeral 112 denotes an F plug.

FIG. 7 is a view of the LNB 101 of FIG. 6 as viewed from the bottom (direction A), and FIG. 8 is a cross-sectional view of the LNB of FIG. FIG. 8 shows the F plug 112 of FIG.
Is directed downward.

As shown in FIGS. 7 and 8, the F plug 112
Is connected to the conductive bridge 114.
Is connected to the LNB circuit board 115 via the. Each part is connected by soldering. F tangent 11
The connecting portion between 3 and the F plug 112 is filled with a silicone sealant 116 for waterproofing. In the figure, reference numeral 117 denotes a raised portion for reinforcing the connection between the F plug 112 and the chassis 118. Since a relatively large stress is applied when the F connector 112 is connected to the outside, such a structure is adopted.

[0008]

With the recent increase in the number of satellite broadcasting channels, the IF frequency of the LNB has been increased from the conventional 950 MHz to 1450 MHz to 950 MHz.
Hz to 1700 MHz and extends to a high frequency band. It has been found that when the band is widened in this way, there is a problem in that the output return loss characteristics in the high band deteriorate. This will be specifically described.

FIG. 9 shows the result of determining the return loss characteristics of the conventional structure shown in FIGS. IF on the horizontal axis
The output frequency is shown, and the return loss is shown on the vertical axis.
The smaller the value of the return loss (downward in the figure), the better the characteristics as a converter. As shown in FIG. 9, at the conventional IF output frequency of 950 MHz to 1450 MHz (between arrow 1 and arrow 2), the return loss value is between −13 dB and −15 dB, but is now found. IF output frequency 950MHz to 1700MHz
Between (arrows 1 and 3), the return loss value of arrow 3 has increased to about −7 dB, and characteristic deterioration is observed.

That is, it is shown that the return loss deteriorates when the frequency band is widened to a high band.

An object of the present invention is to provide a highly reliable satellite broadcast receiving converter capable of preventing the return loss characteristic from being deteriorated even when the frequency band is widened.

[0012]

According to a first aspect of the present invention, there is provided a satellite broadcast receiving converter according to the present invention.
A circuit board disposed in a chassis of the converter, and an F connector protruding outward from the converter for transmitting an output signal from the circuit board to an indoor receiver; and The F plug is connected to the F plug and protrudes in the direction of the circuit board, and is electrically connected by a conductive bridge connecting the F tang and the circuit board. In the converter for use, a partition wall electrically connected to the chassis is provided around the bridge so that a grounded portion is close to the bridge, and at least one of the front and back sides of the bridge is electrically connected to the chassis. part was formed, and the connecting portion of the F plug connector and F tangent, Ri Na filled with adhesive dielectric material so as to cover more than half of the F tangent, the
Using silicone sealant as sticky dielectric material
And wherein such Rukoto.

[0013]

Here, the invention of claim 2 is characterized in that the partition wall and the raised portion are formed integrally with the chassis.

According to a third aspect of the present invention, the adhesive dielectric material has a length not less than １ ／ of the line length of the F tangent and 3
/ 4 or less.

The operation of each claim will be described below.

According to the first aspect of the present invention, since the grounding portion is close to the bridge, the radio wave component radiated from the bridge to the outside can be efficiently transmitted through the F tangent line to the F portion.
Since it is transmitted to the connector, return loss can be improved even if the frequency band is wide. In addition, since the F tangent line is largely covered with the adhesive dielectric material as compared with the related art, this dielectric material has the same effect as the dielectric of the coaxial cable, and the loss of signal transmission can be reduced. That is, this point also contributes to the improvement of the return loss.

Here, the use of a silicone sealant as the adhesive dielectric material is useful because it can achieve waterproofness.

Further, if the partition wall and the raised portion for bringing the ground portion close to the conductive bridge are formed integrally with the chassis, the return can be made without increasing the number of parts only by changing the chassis shape. High loss characteristics are obtained.

As the dielectric material covers the F tangent, the return loss characteristics in the high frequency region become better, while the return loss in the lower frequency region slightly deteriorates. The region where the dielectric material covers the F tangent line is set to not less than の and not more than ／ of the line length of the F tangent line, so that there is practically no problem in the low frequency region and return loss in the high frequency region The characteristics can also be improved.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG.
This will be described with reference to FIG. FIGS. 1 and 2 are views corresponding to the conventional example shown in FIGS. 7 and 8, respectively, and are a view from the bottom of the LNB converter according to the present embodiment and a partial cross-sectional view of the LNB converter. The same symbols are given to the same functional parts as in the conventional example. Here, only the differences from the conventional example will be mainly described.

In this embodiment, first, as shown in FIG. 1, a structure is adopted in which a grounding portion (grounding portion) is arranged near the bridge 114. That is, the partition wall 1 that is integrated with the chassis (earth portion) 118 and stands upright on the bottom portion (inner wall portion) of the chassis 118 at a portion close to the bridge 114.
Is provided. Further, a raised portion 2 formed in a convex shape toward the direction of the bridge 114 is provided at a position located below the bridge 114. In the conventional example of FIG.
There is a raised portion 117 below the bridge 114, and the raised portion 117 is simply formed by the F plug 112 and the chassis 11.
This embodiment is intended to reinforce the reinforcing member 8 and is characterized in that the present embodiment has a structure in which this is positively brought close to the bridge.

Further, in this embodiment, as an adhesive dielectric material, a silicone sealant 3 is used and resin is filled so that up to about 3/4 of the F tangent line 113 is filled. Also in the conventional example shown in FIG.
In the conventional example, the length of the F-tangent 113 is up to about 1/4 of the length thereof. In this embodiment, the resin is filled so as to cover the F-tangent 113 greatly. There is a feature in doing. The silicone sealant 3 used in this example is liquid and has a viscosity of 45.
(P), the volume resistivity is 4 × 10 ¹⁴ (Ω-cm), and the dielectric constant is 2.8 (at 1 MHz).

As described above, in this embodiment, the bridge 11
By bringing the chassis surface close to either the periphery of the bridge 4 or one of the front and back sides of the bridge 114, the grounding portion is brought close to the bridge 114, whereby the conventional bridge 11
4 efficiently radiates radio waves to the outside from F
The transmission to the F-plug 114 via the tangent line 113 improves return loss over a wide frequency band.

Alternatively, a capacitance capacitor is formed spatially between the inner wall of the chassis 118 and the bridge 114, and L
It can be said that C is matched.

Moreover, since the F tangent line 113 is largely covered with the silicon sealant 3 as compared with the conventional case, the silicon sealant 3 has the same effect as the dielectric of the coaxial cable, and reduces the signal transmission loss. it can. That is, this point also contributes to the improvement of the return loss.

FIG. 3 is a diagram showing that return loss characteristics are improved by the above structure. FIG. 3 shows the IF output frequency on the horizontal axis and the return loss value on the vertical axis, similarly to FIG. 9 (return loss characteristic diagram of the conventional example). As shown in FIG. 3, the conventional IF output frequency is 950 MHz to 1450.
In MHz (between arrow 1 and arrow 2), the value of the return loss is between −12 dB and −15 dB, and the currently required IF output frequency is 950 MHz to 1700 M
Between Hz (arrows 1 and 3), the return loss value of the arrow 3 is also about −10 dB.

Compared with the conventional example of FIG. 9, the return loss value at arrow 3 (IF frequency 1703 MHz) in FIG. 9 is about -7 dB, whereas in the present embodiment it is about -10 dB. It can be seen that the characteristics have been improved. In addition, in this embodiment, even when the IF output frequency is about 1600 MHz or more, the return loss value is about-
10 dB or more is obtained, and it is understood that the characteristics in the high band are superior to those of the conventional example shown in FIG. further,
It can be seen that characteristics superior to FIG. 9 are obtained not only in the high band but also in the entire frequency range from about 700 MHz to about 1700 MHz.

In the band of about 600 MHz or less, the conventional example shown in FIG. 9 has a portion where the return loss value is slightly larger, but this region is much lower than 950 MHz and is not involved in reception. Since this is a region, there is no effect on the characteristics as a converter.

By the way, in this embodiment, the F tangent 1
13 is about 3/4 of its line length by the silicone sealant 3.
Is covered.
As expected from the comparison between the conventional example of FIG. 3 and the present embodiment of FIG. 3, the return loss characteristics in the low frequency region may be further deteriorated. Therefore, the silicone sealant 3 is connected to the F tangent 1
By setting the area covering 13 to be not less than の and not more than ／ of the F tangent line 113, practically, problems in a low frequency region can be avoided, and improvement of return loss characteristics in a high frequency region can be guaranteed. .

As described above, according to the present embodiment,
The converter chassis structure is devised so as to be close to the bridge 114, and the return loss characteristic is improved without increasing the number of parts by a simple structure that only increases the amount of silicon sealant conventionally filled. Can be achieved.

In this embodiment, the extruding section 2
To the bottom side of the bridge 114 (the inner wall side of the chassis 118)
Provided on the chassis surface (chassis 11
8 back cover etc.). In the present embodiment, the partition wall 1 and the raised portion 2 are connected to the chassis 118.
Are formed integrally with each other.
8 may be soldered.

[0033]

As described above, according to the present invention,
A part of the chassis is brought close to the bridge connecting the circuit board inside the LNB converter and the F connector for connection to the outside, and the silicone sealant filled in the conventional structure is used. By a simple structural change that merely increases the amount, return loss characteristics in a wide band can be improved without increasing the number of components.

[Brief description of the drawings]

FIG. 1 is a partial bottom view of an LNB converter according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view of an LNB converter according to one embodiment of the present invention.

FIG. 3 is a return loss characteristic diagram for explaining the effect of the present invention.

FIG. 4 is a block diagram of a satellite broadcast receiving system according to a conventional example.

FIG. 5 is a schematic diagram of a conventional satellite broadcast receiving antenna.

FIG. 6 is a side view of a conventional LNB converter.

FIG. 7 is a partial bottom view of an LNB converter according to a conventional example.

FIG. 8 is a partial sectional view of a conventional LNB converter.

FIG. 9 is a diagram showing a return loss characteristic of an LNB converter according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Partition wall 2 Raised part 3 Dielectric material (silicone sealant) 112 F plug 113 F tangent 114 Bridge 115 Circuit board 118 Chassis

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H04B 1/08

Claims (3)

(57) [Claims] 1. A satellite broadcast receiving converter for converting a radio wave from a satellite received by an external antenna into a low-frequency IF output signal, comprising: a circuit board disposed in a converter chassis; And an F connector protruding outward from the converter for transmitting the output signal of the circuit receiver to the indoor receiver. The circuit board and the F connector are connected to the F connector, and the circuit board is connected to the F connector. A satellite broadcast receiving converter electrically connected by an F tangent protruding in a direction and a conductive bridge connecting the F tangent to the circuit board, wherein a ground portion is close to the bridge. A partition wall electrically connected to the chassis, and a raised portion electrically connected to the chassis is formed on at least one of the front and back sides of the bridge; The connecting portion of the F plug connector and F tangent, Ri Na filled with adhesive dielectric material so as to cover more than half of the F tangent, a silicon sealing agent as the adhesive dielectric material
Satellite converter, wherein Rukoto such by. 2. The system according to claim 1, wherein the partition wall and the raised portion are formed integrally with the chassis.
A satellite broadcast receiving converter as described in. 3. The satellite broadcast according to claim 1, wherein the adhesive dielectric material covers at least １ ／ and at most ／ of the line length of the F tangent line. Receive converter.