JP2004048120A - Down-converter for receiving satellite broadcast - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a down-converter for receiving satellite broadcast that is structurally simple and downsized by simplifying the assembling of a circuit board in a state that interference between two oscillators is avoided. <P>SOLUTION: The down-converter for receiving satellite broadcast is provided with: a metallic enclosure 1; a circuit board 5 contained in the metallic enclosure 1; and first and second frequency conversion sections 31, 32 configured on the circuit board 5 and down-converting a satellite broadcast signal at a received satellite broadcast band into an intermediate frequency band. The first frequency conversion section 31 has a first oscillator 31c and down-converts a satellite broadcast signal at lower frequencies of the satellite broadcast band by using a local oscillation signal of the first oscillator 31c, and the second frequency conversion section 32 has a second oscillator 32c and down-converts a satellite broadcast signal at higher frequencies of the satellite broadcast band by using a local oscillation signal of the second oscillator 32c, and a shield case 6 contains either the first oscillator 31c or the second oscillator 32c. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a down converter for receiving satellite broadcasting.
[0002]
[Prior art]
A conventional satellite broadcast receiving downconverter will be described with reference to FIGS. FIG. 4 is a perspective view. A rectangular parallelepiped metal housing 41 is formed by casting or the like, and a waveguide 42 for receiving a satellite signal radiated from a satellite is attached to one end of one side. Satellite broadcast signals are arranged in a satellite broadcast band of 10.7 GHz to 12.75 GHz. Further, two connectors 43 and 44 are mounted on the other side surface away from the side where the waveguide 42 is mounted.
[0003]
As shown in FIG. 5, a partition 41c for dividing the internal space into two compartments 41a and 41b is integrated with the housing 41 inside the housing 41 in a state perpendicular to the axial direction of the waveguide 42. Is formed. Each of the compartments 41a and 41b is opened with a partition 41c interposed therebetween, and circuit boards 45 and 46 attached to the partition 41c are provided therein. After the circuit boards 45 and 46 are attached to the compartments 41a and 41b, a metal cover (not shown) is attached to the opening and sealed. On each of the circuit boards 45 and 46, a circuit for converting the frequency of the satellite broadcast signal into an intermediate frequency band of 1 to 2 GHz is configured.
[0004]
The horizontally polarized and vertically polarized satellite broadcast signals that have entered the waveguide 42 are guided to one circuit board 45. The frequency-converted intermediate frequency signals are output from the circuit boards 45 and 46 to the connectors 43 and 44, respectively. FIG. 6 shows a circuit configured on each of the circuit boards 45 and 46.
[0005]
First, a circuit configured on one circuit board 45 will be described. The first low-noise amplifier 51 and the second low-noise amplifier 61 to which horizontal polarization and vertical polarization are respectively input are connected to the waveguide 42. A first distributor 52 and a second distributor 62 are provided at the next stage, respectively. A first band-pass filter 53 and a second band-pass filter 63 are connected to one output terminals of the first distributor 52 and the second distributor 62, respectively. The first band-pass filter 53 and the second band-pass filter 63 pass a satellite broadcast signal on the low band side (10.7 GHz to 11.7 GHz) of the satellite broadcast band.
[0006]
A first mixer 55 is connected to the first bandpass filter 53, and a second mixer 57 is connected to the second bandpass filter 63. The first mixer 55 and the second mixer 57 are supplied with a first local oscillation signal from a first oscillator 56. The local oscillation frequency is 9.75 GHz. A first switching circuit 58 is connected to the first mixer 55 and the second mixer 57. The first switching circuit 58 has four input terminals and one output terminal, and is switched so that the output terminal is connected to any one of the input terminals. Then, the first mixer 55 and the second mixer 57 are respectively connected to one input terminal. The output end is connected to one connector 43.
[0007]
On the other hand, on the other circuit board 46, a third band-pass filter 54 and a fourth band-pass filter 64 are provided in parallel. Then, the other output end of the first distributor 52 formed on one circuit board 45 is connected to the third band-pass filter 54, and the other output end of the second distributor 62 similarly formed on the circuit board 45. The other output terminal is connected to the fourth band pass filter 64. Therefore, in this connection, a through hole (not shown) is provided in the partition wall 41c, and the partition 41c is connected by a conducting wire passing through the through hole. The third and fourth bandpass filters 54 and 64 pass satellite broadcast signals on the high band side (11.7 GHz to 12.75 GHz) of the satellite broadcast band.
[0008]
A third mixer 65 is connected to the third bandpass filter 54, and a fourth mixer 67 is connected to the fourth bandpass filter 64. A second local oscillation signal is supplied from a second oscillator 66 to the third and fourth mixers 65 and 67.
The local oscillation frequency is 10.6 GHz. Further, a second switching circuit 68 is connected to the third mixer 65 and the second mixer 67. The second switching circuit 68 has the same configuration as the first switching circuit 58. Then, the third mixer 65 and the fourth mixer 67 are respectively connected to one input terminal. Further, the first mixer and the second mixer are connected to the remaining inputs of the second switching circuit 68, and similarly, the third mixer 65 and the fourth mixer 67 are also connected to the first switching circuit. It is connected to the remaining input of circuit 58. Therefore, also in the connection between the first and second mixers 55 and 57 and the second switching circuit 68 and the connection between the third and fourth mixers 65 and 67 and the first switching circuit 58, the partition wall 41c is provided. Are provided with through holes (not shown), and are connected by conducting wires passing through the through holes. The output terminal of the second switching circuit 68 is connected to the other connector 44.
[0009]
In the above configuration, the first mixer 55 receives a horizontally polarized low-bandwidth satellite broadcast signal, and the second mixer 57 receives a vertically polarized low-bandwidth satellite broadcast signal. You. Its bandwidth is 1 GHz. Then, by being mixed with the first local oscillation signal of 9.75 GHz supplied from the first oscillator 56, it is block-converted into an intermediate frequency band of 0.95 GHz to 1.95 GHz. Similarly, the third mixer 65 receives a satellite signal on the high band side of horizontal polarization, and the fourth mixer 67 receives a satellite broadcast signal on the high band side of vertical polarization. Its bandwidth is 1.05 GHz. Then, by being mixed with the second local oscillation signal of 10.6 GHz supplied from the second oscillator 66, the signal is block-converted into an intermediate frequency band of 1.1 GHz to 2.15 GHz.
The converted four intermediate frequency signals are input to the respective switching circuits 58 and 68, and one selected intermediate frequency signal is output from each of the connectors 43 and 44.
[0010]
In the above configuration, the first oscillator 56 for frequency-converting the low-frequency side satellite broadcast signal and the second oscillator 66 for frequency-converting the high-frequency side satellite broadcast signal are provided on different circuit boards 45 and 46. In addition, since the two circuit boards 45 and 46 are provided in the separate compartments 41a and 41b separated by the partition 41c, there is no interference between local oscillation signals.
[0011]
[Problems to be solved by the invention]
However, since the two oscillators 56 and 66 are configured on different circuit boards 45 and 46, two types of circuit boards need to be assembled, and there is a problem that the assembling work becomes complicated. In addition, in order to guide the low frequency side satellite broadcast signal and the high frequency side satellite broadcast signal to separate circuit boards for both horizontal polarization and vertical polarization, one circuit board and the other circuit board are interconnected via a partition. The structure for connection was complicated. Furthermore, two compartments for accommodating two circuit boards are required, and the shape (thickness) of the product is increased, and it is difficult to reduce the size.
[0012]
It is an object of the present invention to solve these problems, to simplify the assembly of a circuit board in a state where interference between two oscillators is eliminated, to achieve a simple structure, and to reduce the size. .
[0013]
[Means for Solving the Problems]
In the present invention, in order to solve the above problems, a metal housing, a circuit board housed in the metal housing, a first frequency conversion unit and a second frequency conversion unit configured on the circuit board The first frequency conversion unit has a first oscillator that outputs a local oscillation signal for down-converting a satellite broadcast signal on a low frequency side of a satellite broadcast band to an intermediate frequency band, and the second frequency converter includes the second oscillator. The frequency converter has a second oscillator that outputs a local oscillation signal for down-converting the satellite broadcast signal on the high frequency side of the satellite broadcast band to the intermediate frequency band, and the first oscillator or the second oscillator Is housed in a shield case.
[0014]
Further, the first frequency conversion unit is supplied with a first mixer to which the horizontal-polarized satellite broadcasting signal on the lower frequency side is input, and receives the vertical-polarized satellite broadcasting signal on the lower frequency side. A second mixer is provided, and the second frequency converter has a third mixer to which the horizontally polarized satellite broadcast signal on the high frequency side is input, and a third mixer on the high frequency side of the vertical polarization. A fourth mixer to which a satellite broadcast signal is input is provided, and both the first oscillator and the second oscillator are activated.
[0015]
Further, an intermediate frequency signal output from each of the first to fourth mixers is input, and one of the four types of intermediate frequency signals is selected and independently output to two output terminals. A switching circuit of two poles and four throws for outputting was provided, and the two output terminals were respectively connected to two connectors attached to the metal housing.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
The downconverter for receiving satellite broadcasting according to the present invention will be described with reference to FIGS. FIG. 1 is a perspective view, and a bottomed metal housing 1 having a rectangular parallelepiped shape is made by casting or the like, and a waveguide 2 for receiving a satellite signal radiated from a satellite is provided at an end of the bottom 1a. Attach. Satellite broadcast signals are arranged in a satellite broadcast band of 10.7 GHz to 12.75 GHz. Further, two connectors 3 and 4 are mounted on another side surface away from the side where the waveguide 2 is mounted. As shown in FIG. 2, a single circuit board 5 is mounted on the bottom 1a inside the housing 1 with its surface perpendicular to the axial direction of the waveguide. After the circuit board 5 is attached, a metal cover (not shown) is attached to the opening and sealed. A circuit for amplifying the satellite broadcast signal and converting the frequency to an intermediate frequency signal of 1 to 2 GHz is formed on the circuit board 5.
[0017]
The satellite broadcast signal converted into horizontal polarization and vertical polarization in the waveguide 2 is guided to the circuit board 5. The frequency-converted intermediate frequency signal is output from the circuit board 5 to the connectors 3 and 4. FIG. 3 shows a circuit configured on the circuit board 5.
[0018]
The first low-noise amplifier 11 and the second low-noise amplifier 21 to which the horizontal polarization and the vertical polarization converted by the waveguide 2 are respectively input are provided closer to the waveguide 2, and A first distributor 12 is provided next to the low noise amplifier 11. A first band-pass filter 13 is connected to one output terminal of the first distributor 12, and a second band-pass filter 14 is connected to the other output terminal. The first band-pass filter 13 passes a satellite broadcast signal on the low band side (10.7 GHz to 11.7 GHz) of horizontal polarization in the satellite broadcast band, and the second band filter 14 has a high band side (11.7 GHz). １２12.75 GHz).
[0019]
Similarly, a second distributor 22 is provided next to the second low noise amplifier 21. A third bandpass filter 23 is connected to one output terminal of the second distributor 22, and a fourth bandpass filter 24 is connected to the other output terminal. The third band-pass filter 23 passes a satellite broadcast signal on the low frequency side (10.7 GHz to 11.7 GHz) of vertical polarization in the satellite broadcast band, and the fourth band filter 24 transmits the high frequency side (11.7 GHz). １２12.75 GHz).
[0020]
Frequency converters 31 and 32 for frequency-converting the satellite broadcast signal on the low frequency side and the satellite broadcast signal on the high frequency side of each polarization into an intermediate frequency band are provided adjacent to each other. , 23, and 24.
First, the first frequency converter 31 has a first mixer 31a, a second mixer 31b, and a first oscillator 31c, and the first mixer 31a is connected to the first bandpass filter 13. , The second mixer 31 b is connected to the third bandpass filter 23. Accordingly, the first mixer 31a receives a low-frequency side satellite broadcast signal of horizontal polarization, and the second mixer 31b receives a low-frequency side satellite broadcast signal of vertical polarization. Then, a local oscillation signal of 9.75 GHz is supplied to the two mixers 31a and 31b from the first oscillator 31c.
[0021]
The second frequency converter 32 has a third mixer 32a, a fourth mixer 32b, and a second oscillator 32c, and the third mixer 32a is connected to the second bandpass filter 14. , A fourth mixer 32 b is connected to the fourth bandpass filter 24. Accordingly, the third mixer 32a receives the satellite broadcasting signal on the high frequency side of the horizontal polarization, and the fourth mixer 32b receives the satellite broadcasting signal on the high frequency side of the vertical polarization. Then, a local oscillation signal of 10.6 GHz is supplied from the second oscillator 32c to the two mixers 32a and 32b.
[0022]
Therefore, a signal line 29 for connecting the second bandpass filter 14 and the third mixer 32a, a signal line 30 for connecting the third bandpass filter 23 and the second mixer 31b, Are merely crossed over on the circuit board 5, so that it is easy to ensure mutual insulation.
In addition, since the two oscillators 31c and 32c have different oscillation frequencies, at least one of them, for example, the second oscillator 32c is covered by the shield case 6 as shown in FIG.
[0023]
With the above configuration, the first mixer 31a performs block conversion of the horizontally polarized low frequency side satellite broadcast signal into an intermediate frequency band of 0.95 GHz to 1.95 GHz and outputs the intermediate frequency signal as an intermediate frequency signal. From the mixer 31b, the satellite broadcast signal on the lower side of the vertically polarized wave is block-converted into an intermediate frequency band of 0.95 GHz to 1.95 GHz and output as an intermediate frequency signal. Also, the third mixer 32a converts the satellite broadcast signal on the high frequency side of the horizontal polarization into an intermediate frequency band of 1.1 GHz to 2.15 GHz and outputs the intermediate frequency signal as an intermediate frequency signal. From 32b, the vertically polarized satellite broadcast signal on the high frequency side is block-converted into an intermediate frequency band of 1.1 GHz to 2.15 GHz and output as an intermediate frequency signal.
[0024]
A switching circuit 33 is connected to the first to fourth mixers 31a to 32b. The switching circuit 33 has a two-pole four-throw configuration having first to fourth input terminals 33a, 33b, 33c, 33d and first and second output terminals 33e, 33f. 33e, 33f are respectively connected to any one of the input terminals 33a, 33b, 33c, 33d. Then, the first mixer 31a is connected to the first input terminal 33a, the second mixer 31b is connected to the second input terminal 33b, and the third mixer 32a is connected to the third input terminal 33c. Connected, and the fourth mixer 32b is connected to the fourth input terminal. The first output terminal 33e is connected to one connector 3, and the second output terminal 33f is connected to the other connector 4.
[0025]
As described above, one of the above four types of intermediate frequency signals is output to one connector 3 and the other connector 4. Each of the connectors 3 and 4 is connected to an independent tuner, and the tuner selects an intermediate frequency signal of any channel in the intermediate frequency band.
[0026]
In the above configuration, both the first oscillator 31c for converting the frequency of the low frequency side satellite broadcast signal and the second oscillator 32c for converting the frequency of the high frequency side satellite broadcast signal are provided on the same circuit board 5. Even if configured, at least one is covered by the shield case 6, so that there is no interference between local oscillation signals. Also, when the horizontally and vertically polarized satellite broadcast signals are distributed to the low-frequency side and the high-frequency side and input to the two frequency converters, they are processed on the same circuit board, so that the structure is simplified. Become. Further, there is an advantage that one switching circuit 33 can be used.
[0027]
【The invention's effect】
As described above, the present invention includes a metal housing, a circuit board housed in the metal housing, and a first frequency converter and a second frequency converter configured on the circuit board. The one frequency converter has a first oscillator that outputs a local oscillation signal for down-converting a satellite broadcast signal on the lower band side of the satellite broadcast band to an intermediate frequency band, and the second frequency converter has a satellite broadcast signal. A second oscillator that outputs a local oscillation signal for down-converting the satellite broadcast signal on the high frequency side of the band to an intermediate frequency band, and at least one of the first oscillator and the second oscillator is provided in a shield case. Since they are housed, interference between the two oscillators can be avoided even if a circuit is formed on one circuit board. Further, since the circuit is formed on one circuit board, the assembling work is simplified and the thickness can be reduced.
[0028]
The first frequency converter has a first mixer to which a horizontally polarized low frequency side satellite broadcast signal is input, and a second to which a vertically polarized low frequency side satellite broadcast signal is input. A third mixer into which a horizontally-polarized high-bandwidth satellite broadcast signal is input, and a vertically-polarized high-bandwidth satellite broadcast signal input to the second frequency converter. Since a fourth mixer is provided and both the first oscillator and the second oscillator are operated, four intermediate frequency signals can always be taken out from each mixer.
[0029]
Also, an intermediate frequency signal output from each of the first to fourth mixers is input, and one of the four types of intermediate frequency signals is selected and output to two output terminals independently. Since a four-throw switching circuit is provided and the two output terminals are respectively connected to the two connectors attached to the metal housing, the intermediate frequency signal can be extracted to the two connectors using one switching circuit. Also, the connection between the connector and the switching circuit is simplified.
[Brief description of the drawings]
FIG. 1 is a perspective view of a satellite broadcast receiving downconverter of the present invention.
FIG. 2 is a sectional view of a main part of a down converter for receiving satellite broadcasting according to the present invention.
FIG. 3 is a circuit diagram of a satellite broadcast receiving downconverter of the present invention.
FIG. 4 is a perspective view of a conventional down converter for receiving satellite broadcasting.
FIG. 5 is a sectional view of a main part of a conventional downconverter for receiving satellite broadcasting.
FIG. 6 is a circuit diagram of a conventional down converter for receiving satellite broadcasting.
[Explanation of symbols]
Reference Signs List 1 housing 2 waveguide 3, 4 connector 5 circuit board 6 shield case 11 first low noise amplifier 12 first distributor 13 first bandpass filter 14 second bandpass filter 21 second low noise amplifier 22 second distributor 23 third band pass filter 24 fourth band pass filter 31 first frequency converter 31a first mixer 31b second mixer 31c first wave new 32 second frequency Converter 32a Third mixer 32b Fourth mixer 32c Second oscillator 33 Switching circuit 33a First input terminal 33b Second input terminal 33c Third input terminal 33d Fourth input terminal 33e First output Terminal 33f second output terminal

Claims (3)

A metal housing, a circuit board housed in the metal housing, and a first frequency converter and a second frequency converter configured on the circuit board, wherein the first frequency converter is a satellite A first oscillator that outputs a local oscillation signal for down-converting a satellite broadcast signal on a low band side of a broadcast band to an intermediate frequency band, wherein the second frequency conversion unit includes A second oscillator that outputs a local oscillation signal for down-converting the satellite broadcast signal to the intermediate frequency band, and at least one of the first oscillator and the second oscillator is housed in a shield case. A downconverter for receiving satellite broadcasting. A first mixer to which the horizontally polarized low frequency side satellite broadcast signal is input, and a second to which the vertically polarized low frequency side satellite broadcast signal is input to the first frequency conversion unit. A third mixer to which the horizontally polarized high-frequency side satellite broadcast signal is input to the second frequency conversion unit, and a vertically polarized high-frequency side satellite broadcast. 2. The down converter for receiving satellite broadcasting according to claim 1, wherein a fourth mixer to which a signal is input is provided, and both said first oscillator and said second oscillator are operated. An intermediate frequency signal output from each of the first to fourth mixers is input, and one of the four intermediate frequency signals is selected and output to two output terminals independently. 3. The down converter for receiving satellite broadcasting according to claim 2, wherein a switching circuit of two poles and four throws is provided, and said two output terminals are respectively connected to two connectors attached to said metal housing.

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