JPH08316856A - Converter - Google Patents

Abstract

PURPOSE: To avoid the adverse effect due to leaked spurious radiation. CONSTITUTION: A chassis 21 whose two sides opposite to each other are mounted with at least two boards, and circuits (high frequency amplifier circuit, frequency mixer circuit and intermediate frequency amplifier circuit) of the frequency mixer amplifier circuit group are provided to the converter using a PLL control circuit. Then the converter is provided with the board 22 fitted to one side of the chassis 21, the board 23 with the PLL control circuit mounted thereon and fitted to the other side opposite to the side on which the board 22 of the chassis 21 is fitted, 1st shield covers 27, 29 covering respectively the boards 22 and 23.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a PLL (phase-locked).
loop: For example, a broadcasting satellite (BS: broadcasting satellite), a communication satellite (C:
S: communication satellite) converter.

[0002]

2. Description of the Related Art Conventionally, a broadcasting satellite (BS: broa) using a PLL (phase-locked loop) circuit is used.
dcasting satellite, communication satellite (CS: communicatio)
A converter for n satellite) (hereinafter referred to as a BS / CS converter) has a structure as shown in FIG.

The BS / CS converter is formed so that two or more types of substrates can be attached to a chassis 1 provided with a microwave input waveguide section. In the example shown in FIG. 2, two boards 2 and 3 are provided on two opposite surfaces of the chassis 1.
Is attached. A high frequency amplifier circuit, a frequency mixing circuit, a PLL control circuit (the above circuits are not shown), a local oscillator 4 and the like are provided on one substrate 2. The other substrate 3 is provided with an intermediate frequency amplifier circuit, a power supply circuit and the like. The board 3 is connected to the external output coaxial connector 5 by a connecting portion 6.

A shield cover 7 is fixed to the chassis 1 by screws or the like so as to cover the substrate 2. As shown in FIG. 2, the shield lid 7 is provided with a partition plate 8 according to the arrangement of the circuits provided on the substrate 2, and each circuit block of the substrate 2 is provided with a partition plate 8 of the shield lid 7. It is divided by and is designed to shield each circuit from each other.

The BS / CS converter stabilizes a local oscillation frequency oscillated from the local oscillator 4 by using a PLL circuit. Therefore, the shield lid 7 (partition plate 8) is provided in order to prevent spurious in the PLL control circuit unit from leaking to the frequency mixing circuit and other circuits.

[0006]

As described above, the conventional BS
In the CS converter, the frequency mixing circuit and the PLL control circuit are provided on one substrate 2, and each circuit block is shielded by the shield lid 7 (partition plate 8).

However, since the frequency mixing circuit and the PLL control circuit are shielded only by the partition plate 8 of the shield lid 7, the loosening of the screwing for attaching the shield lid 7 to the chassis 1 and the production of the partition plate 8. The shield may be incomplete due to the above-mentioned variations in accuracy. In this case, from the gap between the substrate 2 and the partition plate 8, the PLL
Spurious in the control circuit section may leak to the frequency mixing circuit.

Further, if the spurious in the PLL control circuit is in the intermediate frequency band, it is amplified by the intermediate frequency amplification circuit of the substrate 3 on the opposite surface side. In this case, a signal amplified by, for example, about 40 dB is output from the external output coaxial connector 5 due to the leaked spurious.

The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a converter capable of avoiding an adverse effect due to leakage of spurious from the PLL control circuit section.

[0010]

SUMMARY OF THE INVENTION The present invention relates to a converter using a PLL control circuit, including a chassis formed so that at least two substrates are mounted on two opposing surfaces, and a frequency mixing amplifier circuit system. A circuit is provided and a first board is mounted on one surface of the chassis, and a PLL control circuit is provided and is mounted on the other surface of the chassis opposite to the surface on which the first board is mounted. A second substrate, the first substrate and the second substrate
And a shield cover that covers each of the substrates.

[0011]

According to such a configuration, a substrate provided with a circuit of a frequency mixing amplifier circuit system (including, for example, a high frequency amplifier circuit, a frequency mixing circuit, and an intermediate frequency amplifier circuit),
The board and the board on which the LL control circuit is provided are arranged such that the chassis is sandwiched therebetween. That is, the chassis performs the shield function, and the shield characteristic that the spurious from the PLL control circuit does not leak to the circuit of the frequency mixing amplifier circuit system is obtained. Furthermore, since each substrate is covered by the shield lid, more stable shield characteristics can be obtained.

[0012]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing the configuration of the converter according to this embodiment. The converter shown in FIG.
ase-locked loop: Phase locked loop)
It is a BS / CS converter for a broadcasting satellite (BS: broadcasting satellite) and a communication satellite (CS: communication satellite).

The BS / CS converter is formed so that two or more types of substrates can be attached to a chassis 21 provided with a microwave input waveguide section. In the example shown in FIG. 1, two boards 2 are provided on two opposite surfaces of the chassis 21.
2, 23 are attached. On one of the substrates 22,
A high frequency amplification circuit, a frequency mixing circuit, an intermediate frequency amplification circuit (the above circuits (the circuits of the frequency mixing amplification circuit system are not shown), a local oscillator 24 and the like are provided. Board 22
Are connected to the external output coaxial connector 25 by a connecting portion 26. The other board 23 is provided with a PLL control circuit, a power supply circuit and the like.

A first shield lid 27 is fixed to the chassis 21 by screws or the like so as to cover the substrate 22. As shown in FIG. 1, a partition plate 28 is provided on the first shield lid 27 in accordance with the arrangement of each circuit provided on the substrate 22, and each circuit block on the substrate 22 is provided with a first shield. It is partitioned by a partition plate 28 of the lid 27 so as to mutually shield each circuit.

Further, a second shield lid 29 is fixed to the chassis 21 or the housing so as to cover the substrate 23 provided on the surface facing the substrate 22. Next, the function and effect of this embodiment will be described.

In the converter of this embodiment, as shown in FIG. 1, the intermediate frequency amplifier circuit is provided on the side of the substrate 22 where the high frequency amplifier circuit and the frequency mixer circuit included in the circuit of the frequency mixture amplifier circuit system are provided. A connection portion 26 for connecting to the external output coaxial connector 25 is also provided on the substrate 22 side. On the other hand, the PLL control circuit is provided on the side of the substrate 23 where the circuit of the frequency mixing amplifier circuit system is not provided.

That is, since the two boards 22 and 23 are provided on the two facing surfaces of the chassis 21, the PLL control circuit and the frequency mixing circuit provided on the boards 22 and 23 are The circuit board and the chassis 21 are sandwiched between them and separated.

The substrate 22 is covered with a first shield lid 27 that mutually shields the circuits provided on the substrate 22, and the substrate 23 provided with the PLL control circuit is provided with a second shield lid. Covered by 29.

Therefore, even if there is loosening of the screws for attaching the first shield lid 27 to the chassis 21 and variations in the manufacturing precision of the partition plate 28, stable shield characteristics that are not affected by these factors can be obtained. To be Therefore, there is no possibility that spurious in the PLL control circuit section will leak to the frequency mixing circuit.

Further, since the intermediate frequency amplifier circuit is also provided on the substrate 22, stable shield characteristics can be obtained between the intermediate frequency amplifier circuit and the PLL control circuit provided on the substrate 23 with the chassis 21 interposed therebetween, similarly to the frequency mixing circuit. , PLL control circuit and frequency mixing circuit. Therefore, even if the spurious in the PLL control circuit is in the intermediate frequency band, there is no possibility that the spurious signal is amplified and output by the intermediate frequency amplifier circuit.

In the present invention, the frequency mixing amplifier circuit system and P
The local oscillator 24 and the power supply circuit may be provided on any of the substrates 22 and 23 as long as the structure separates from the LL control circuit unit.
May be provided in.

[0022]

As described above in detail, according to the present invention, the frequency mixing / amplifying circuit system and the PLL control circuit are structured so as to be positioned so as to sandwich the chassis, and the shield lid for covering the substrate on which each circuit is provided. By providing the above, it is possible to obtain stable shield characteristics and avoid the adverse effect due to spurious leakage.

[Brief description of drawings]

FIG. 1 is a sectional view showing a configuration of a BS / CS converter according to an embodiment of the present invention.

FIG. 2 is a sectional view showing the structure of a conventional BS / CS converter.

[Explanation of symbols]

21 ... Chassis, 22, 23 ... Board, 24 ... Local oscillator, 25 ... External output coaxial connector, 26 ... Connection part, 2
7 ... 1st shield lid, 28 ... partition plate, 29 ... 2nd shield lid.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Hiroaki Ohata 1406 Hasunuma, Omiya City, Saitama Yagi Antenna Co., Ltd. Omiya Factory

Claims (1)

[Claims] 1. A converter using a PLL (phase-locked loop) control circuit, and a chassis formed so that at least two substrates are mounted on two opposing surfaces, and a frequency mixing amplifier circuit. A first circuit board provided with a system circuit and attached to one surface of the chassis, and a PLL control circuit provided on the other surface of the chassis opposite to the surface provided with the first circuit board. A converter comprising: a mounted second substrate; and a shield lid that covers each of the first substrate and the second substrate.