JP3312060B2 - DBS tuner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DBS for receiving satellite broadcasting.
More particularly, it relates to an input / output terminal structure of a DBS tuner having an IF input / output terminal.

[0002]

2. Description of the Related Art A conventional technique will be described with reference to FIGS. FIG. 5 is a circuit block diagram of a DBS tuner with an IF input / output terminal according to a conventional example, FIGS. 6 and 7 are equivalent circuit and characteristic diagrams of an external circuit notch filter of the DBS tuner, and FIGS. Equivalent circuit and characteristic diagram of external short circuit, FIG.
FIG. 1 is a diagram showing a tangent method of an input / output terminal unit according to a conventional example.
1 is a diagram showing a tangential method of an input / output terminal unit according to another conventional example, and FIG. 12 is a diagram showing a tangential state of FIG.

In FIG. 5, an RF signal input from an input terminal 21 of a tuner is amplified by RF-AMPs 22 and 23, and after passing through an AMP 24, a voltage variable BPF 25 whose passing frequency band changes according to a reception frequency. After passing through, it is input to the mixer 26.

On the other hand, an oscillation signal of a local oscillator 28 oscillated at a frequency corresponding to a reception frequency is also amplified by an AMP 27 and input to a mixer 26. RF signal from mixer 2
6. The IF signal is converted to an IF signal by IF-AMP.
31, IF-BPF32, AGC-AMP33 and IF
-After passing through the AMP 34, it is output from the IF-OUT terminal 35.

[0005] A short circuit or a filter circuit is usually connected as an external circuit between the IF-OUT terminal 35 and the IF-IN terminal 36.

The signal that has passed through the external circuit connected between the IF-OUT terminal 35 and the IF-IN terminal 36 is again guided into the tuner, amplified by the AMP 37, input to the FM demodulator 38, and subjected to FM detection. After, Base Ba
The signal is output from the nd output terminal 42. Here, 29 is an amplifier, and 30 is a PLL synthesizer for controlling a local oscillator. 39 is an AGC detection diode, 4
0 and 41 are DC AMPs. An AGC circuit is configured by these, the 23 RF attenuator, and the 33 AGC-AMP, and the level of the IF signal input to the FM detector 38 is made constant.

[0007] When satellite broadcasting is received, especially in satellite broadcasting using the C band, terrestrial microwave communication or the like may be hindered. BPF32 of FIG.
Is set to be almost the same as the pass band in the channel band of satellite broadcasting, and 25 to 30 MHz is generally used in the band.

However, since the above-mentioned interference caused by terrestrial microwave communication or the like falls within the band of the reception channel, the BPF 32
Cannot be removed by Therefore, in order to remove this, a steep notch filter or the like as shown in FIG. 6 having a characteristic as shown in FIG. 7 is additionally required. However, this terrestrial microwave communication disturbance does not occur in all reception areas. Therefore, in an area where interference occurs, a filter for removing interference is added to the IF-OUT terminal 35 and the IF-IN terminal 36 shown in FIG. 1, and in an area where interference does not occur and a filter need not be added. A short circuit as shown in FIG. 8 having a characteristic as shown in FIG. 9 is added.

Here, the connection between an external circuit such as a filter and a short circuit and the tuner body is ensured.
It is necessary to take sufficient isolation between the tuner IF input / output terminals. If the connection is insufficient, the characteristics of the external circuit such as a filter may not be sufficiently obtained. Conventionally, for example, as shown in FIG. 10, a tuner main body 50 and an external circuit 51 are connected by a coaxial connector 52 and a coaxial cable 53. The ground connection is made in the same manner.

As another example, as shown in FIGS. 11 and 12, an IF-OUT terminal 55 comprising a pin terminal 54 is provided.
Pin terminal 57 for grounding between the
And connecting them.

[0011]

In the connection method shown in FIG. 10, the connection between the IF input / output terminal of the tuner and the input / output terminal of the external circuit is performed by the coaxial connector 52 and the coaxial cable 53. There has been a problem that it is complicated and it is difficult to reduce the size.

In the connection methods shown in FIGS. 11 and 12, since the connection is made using the pin terminals 54, the connection structure is simple, but the ground of the tuner and the ground of the external circuit are connected through the pins. As a result, the connection of the ground may be insufficient, and characteristics such as a filter of an external circuit may not be obtained.

It is an object of the present invention to provide a DBS tuner which can reliably connect the ground even if the signal is transmitted by a simple pin terminal.

[0014]

According to the present invention, there is provided a DBS tuner having a tuner body having an input / output pin terminal for connecting to an external circuit. A ground terminal for connecting to the external circuit is arranged, and the ground terminal is
A notch groove is formed around a portion of the chassis of the tuner main body to be the ground terminal so as to have an area larger than the side surface area of the input / output pin terminal, and the portion to be the ground terminal is bent. One of the input / output pin terminals located on both sides of the ground terminal passes through a portion including the cutout groove formed by bending a portion serving as the ground terminal.

[0015]

[Operation] The ground connection between the tuner body and the external circuit
Since the grounding terminal of the tuner chassis is connected to the ground terminal, a more reliable ground connection can be performed as compared with the method of simply connecting the ground to the pin terminal. As a result, the characteristics of the external circuit can be sufficiently obtained.

Further, since the ground terminal is arranged between the input / output pin terminals and is formed so as to have an area larger than the area of the side surface of the input / output pin terminals, the isolation between the two terminals is ensured. Can be improved.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. 1 (a) to 1 (c) are respectively
FIG. 2A is a top view, a side view, and an AA ′ cross-sectional view of FIG. 2A showing an earth terminal according to an embodiment of the present invention. FIG. 2A is a top view of the earth terminal before bending the chassis angle, and FIG.
And (c) are a top view and a side view, respectively, of the ground terminal after bending the chassis angle, FIG. 3 is a view showing a ground connection structure between the tuner body and an external circuit, and FIG. 4 is a ground according to another embodiment of the present invention. It is a figure showing a terminal structure.

In FIG. 1, reference numeral 1 denotes a tuner IF-OU.
T terminal, 2 is a ground terminal, 3 is an IF-IN terminal, 4 and 5 are a PWB pattern inside the tuner connected to the IF-OUT terminal 1 and a PWB pattern of the tuner connected to the IF-IN terminal 3, respectively. is there. Reference numeral 6 denotes a PWB inside the tuner, and 7 denotes a chassis angle of the tuner body (hereinafter simply referred to as a chassis angle), and this chassis angle is connected to the ground inside the tuner.

In FIG. 1, a part of the chassis angle 7 is bent to form the ground terminal 2. This ground terminal 2 is formed, for example, as shown in FIGS. That is, as shown in FIG.
A notch groove 8 is formed around the portion to be the ground terminal 2, and then the ground terminal portion is bent at a substantially right angle as shown in FIGS. 2 (b) and 2 (c). Here, ground terminal 2
Are formed to be larger than the area of the side surfaces of the terminals such as the IF-OUT terminal 1 and the IF-IN terminal 3.

Next, the ground terminal 2 obtained by bending a part of the chassis angle 7 is connected to an external circuit 9 such as a filter as shown in FIG. At this time, the ground terminal 2
It is arranged at a position sandwiched between the F-OUT terminal 1 and the IF-IN terminal 3.

As described above, in this embodiment, in the structure in which the connection between the IF input / output terminal of the tuner and the external circuit is connected by the pin terminal, a part of the chassis angle 7 of the tuner is used as the ground terminal 2. Since there is no need for extra terminal mounting work, the grounding can be strengthened. Therefore, the characteristics of the external circuit can be sufficiently brought out.

Further, the ground terminal 2 is disposed between the IF-OUT terminal 1 and the IF-IN terminal 3, so that both terminals are separated by the ground terminal 2, and FIG. As is apparent, since the ground terminal 2 has a larger area than the side surfaces of both terminals, the isolation between both terminals can be reliably improved.

Further, as shown in FIG. 4, the ground pattern 11 formed on the PWB substrate 6 inside the tuner and the chassis angle 7 are fixed by soldering with solder 10, thereby further strengthening the ground and improving the isolation. Can be planned.

In FIG. 4, the soldering between the ground of the PWB substrate 6 and the chassis angle 7 is performed by the ground pattern 11 on the terminal insertion side of the PWB 6, but is connected to the ground pattern on the surface opposite to the terminal insertion side. You may do it.

[0025]

As described above, according to the present invention,
The ground between the IF input / output terminal of the tuner and the external circuit can be sufficiently strengthened, and the characteristics of the external circuit can be sufficiently brought out. Also, the isolation between the input and output terminals can be improved.

[Brief description of the drawings]

FIGS. 1A to 1C are a top view and a side view of a ground terminal according to an embodiment of the present invention, and FIG.
It is A 'sectional drawing.

2A is a top view of the ground terminal before bending the chassis angle, and FIGS. 2B and 2C are a top view and a side view of the ground terminal after bending the chassis angle, respectively.

FIG. 3 is a diagram showing a ground connection structure between a tuner body and an external circuit according to an embodiment of the present invention.

FIG. 4 is a diagram showing a positional relationship between a ground terminal and another input / output terminal according to one embodiment of the present invention.

FIG. 5 is a circuit block diagram of a conventional DBS tuner with input / output terminals.

FIG. 6 is an equivalent circuit diagram of a notch filter of a conventional DBS tuner.

FIG. 7 is a characteristic diagram of the notch filter of FIG. 6;

FIG. 8 is an equivalent circuit diagram of a short circuit of a conventional DBS tuner.

FIG. 9 is a characteristic diagram of the short circuit of FIG. 8;

FIG. 10 is a diagram showing a tangent method of an input / output terminal unit according to a conventional example.

FIG. 11 is a diagram showing a tangent method of an input / output terminal unit according to another conventional example.

FIG. 12 is a diagram showing a tangent state of FIG. 11;

[Explanation of symbols]

 1 IF-IN terminal 2 Ground terminal 3 IF-OUT terminal 7 Chassis angle 9 External circuit

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

Claims (1)

(57) [Claims] 1. A DBS tuner having an input / output pin terminal for connecting to an external circuit on a tuner body, wherein a ground terminal for connecting to the external circuit is arranged between the input / output pin terminals. Wherein the ground terminal forms a cutout groove around a part of the chassis of the tuner main body which becomes the ground terminal so as to have an area larger than a side surface area of the input / output pin terminal; A terminal portion is bent, and a portion including the cutout groove formed by bending the ground terminal portion is formed by bending one of the input / output pin terminals located on both sides of the ground terminal. A DBS tuner characterized by passing through.