JP2007318718A - Low-noise down converter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-noise down converter capable of reducing a level of a spurious signal as much as possible in case two local oscillation circuits are simultaneously operated, and capable of carrying out down convert of the normal signal from satellite without receiving interference. <P>SOLUTION: A wiring substrate 34 is attached to an upper surface of a chassis 32. A frame 42 is attached so as to cover the wiring substrate 34 and the frame 42 is formed so as to cover a region of the wiring substrate 34 corresponding to a local oscillation circuit 12. Moreover, a wiring substrate 36 is attached to an lower surface of the chassis 32 and a frame 46 is formed so as to cover a region of a wiring substrate 36 corresponding to a local oscillation circuit 18. Furthermore, with respect to a location of the local oscillation circuits 12 and 18, the local oscillation circuits 18 provided with the wiring substrate 36 is arranged not to the position just under the local oscillation circuit 12 provided with the wiring substrate 34. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a low noise converter, and more particularly to a low noise down converter (LNB) that operates two or more types of local oscillation circuits simultaneously used in satellite communication of a satellite broadcast receiver.

  A coaxial cable is usually used to receive a radio wave with an antenna for satellite broadcasting and guide a signal to an indoor BS tuner. However, the radio wave received by the antenna cannot be guided indoors by a direct coaxial cable.

  It is necessary to use a metal tube called a waveguide to guide satellite broadcast radio waves with a very high frequency. In the case of using a waveguide, it is not practical to lead a signal from an antenna to an indoor satellite broadcast receiver because a large hole needs to be made in the wall and there is much attenuation. Therefore, usually, using the LNB installed near the antenna, the frequency of the received signal is lowered to a frequency that can be guided even by a coaxial cable, and the signal is transmitted to the indoor satellite broadcast receiver. The indoor satellite broadcast receiver has a built-in scramble decoder, which releases the scramble and displays an image on the display.

  In a mixture of analog broadcasting and digital broadcasting, a broadband LNB is required to receive both signals. A local oscillation circuit is used to convert a received signal from a satellite into a band received on the ground. However, the band of the received signal from the satellite is wider than the output band of one local oscillation circuit. Therefore, reception is normally performed using two local oscillation circuits having different oscillation frequencies.

  For example, for a band of signals 10.7 to 11.7 GHz of a received signal from a satellite, an LNB output frequency of 950 to 1950 MHz is covered with a first local oscillation circuit having an oscillation frequency of 9.75 GHz. For the band of received signals 11.7 to 12.75 GHz, the second local oscillation circuit having an oscillation frequency of 10.6 GHz is used, and the output frequency of 1NB to 2150 MHz of LNB is covered.

  In this LNB structure, conventionally, two wiring boards are used, and one local oscillation circuit is provided for each to avoid interference between the local oscillation circuits.

  Specifically, a metal chassis (sheet metal) is inserted between two wiring boards to separate the two wiring boards. However, when the thickness of the sheet metal is about 2 mm, for example, 2 It could not be said that the distance between the two wiring boards was sufficiently large.

  For this reason, when two local oscillation circuits are operated simultaneously, a strong spurious signal is generated based on the difference between the local oscillation frequencies of the two local oscillation circuits, resulting in a problem that harmonics appear in the reception band. Due to the influence of the harmonics, a normal signal from the satellite cannot be sent to an indoor satellite broadcast receiver or the like, and there is a problem that an image on a TV screen or the like may be disturbed. Therefore, it has been attempted to improve the thickness.

FIG. 7 is a diagram showing a cross-sectional structure of a conventional satellite broadcast receiving apparatus.
Referring to FIG. 7, wiring board 234 is attached to one surface of metal chassis 232 having a thickness d2, and wiring board 236 is attached to the other surface. Local oscillation circuits 212 and 218 are mounted on the wiring boards 234 and 236, respectively. A frame 242 is attached so as to cover the wiring board 234. On the other hand, the wiring board 236 is covered with a chassis 232.

Conventionally, as described above, a method of reducing the mutual influence of two local oscillation circuits by separating the wiring boards 234 and 236 by the thick chassis 232 has been adopted.
JP 2002-246925 A

  However, if a thick chassis is used, there is a problem that the entire apparatus naturally becomes large.

  It is also necessary to avoid the problem that the two local oscillation circuits interfere with each other via the connection pins connecting the two wiring boards.

  An object of the present invention is to solve the above-described problems, and reduces the level of a spurious signal generated when two local oscillation circuits are operated simultaneously. To provide a low noise downconverter capable of downconverting a signal without being disturbed.

  A low-noise down-converter according to the present invention is a low-noise down-converter for receiving satellite broadcasting, and is a metal chassis having first and second surfaces facing each other, and a first attached to the first surface. 1 wiring board, a first local oscillation means provided on the first wiring board, a second wiring board attached to the second surface, and a second local part provided on the second wiring board Oscillating means and first and second frames provided corresponding to the first and second wiring boards, respectively, for covering the first and second wiring boards. At least a part of the first and second frames are molded so as to shield the areas of the first and second wiring boards with respect to the first and second local oscillation means, respectively. The second local oscillation means is separated and shielded from the first local oscillation means by a metal chassis. The second local oscillating means is arranged so as not to be provided directly below the first local oscillating means provided on the first wiring board.

  Preferably, a connection pin for connecting the first wiring board and the second wiring board is further provided. The connection pin is provided through the first wiring board, the chassis, and the second wiring board. The first and second frames are respectively formed so as to shield the regions of the first and second wiring boards through which the connection pins pass. The connection pin is not provided in the region for the first and second local oscillation means.

  Preferably, the first and second local oscillating means are provided in peripheral regions along the sides of the first and second wiring boards, respectively, and the interval between the first and second local oscillating means is maximized. So as to be displaced.

  Another low noise down converter according to the present invention is a low noise down converter for receiving satellite broadcasting, and is provided on a wiring board having first and second surfaces facing each other and a first surface. A first local oscillating means; a second local oscillating means provided on the second surface; a frame provided corresponding to the first surface of the wiring board; A metal chassis for mounting the wiring board, provided on the second surface side. At least a part of the frame is molded so as to shield a region of the wiring board with respect to the first local oscillation means. The metal chassis has a recessed area, and the second local oscillation means is shielded between the wiring board and the metal chassis by the recessed area. The second local oscillating means is arranged so as not to be provided directly below the first local oscillating means provided on the first surface of the wiring board.

  Preferably, the first and second local oscillating means are provided in peripheral regions along the side of the substrate of the wiring board, respectively, and are arranged so as to be shifted so that the interval between the first and second local oscillating means is maximized. The

  Another low noise down converter according to the present invention is a low noise down converter for receiving satellite broadcasting, and is provided on a wiring board having first and second surfaces facing each other and a first surface. A first local oscillating means; a second local oscillating means provided on the second surface; a frame provided corresponding to the first surface of the wiring board; A metal chassis provided on the second surface side for mounting the wiring board, and provided independently for each of the first and second local oscillation means, and connected to the corresponding local oscillation means for GND Are provided, and first and second GND supply lines.

  Preferably, at least a part of the frame is molded so as to shield an area of the wiring board with respect to the first local oscillation means, and the metal chassis has a recessed area, and the wiring board and the metal are formed by the recessed area. The second local oscillation means is shielded from the chassis.

  Preferably, the frame is grounded and one of the first and second local oscillating means and the frame are connected, and the frame forms part of the corresponding GND supply line.

  In the low noise down converter according to the present invention, at least a part of the first and second frames shields a region of the wiring board with respect to the first and second local oscillation means and is separated by a metal chassis, The second local oscillating means is arranged so as not to be provided directly below the first local oscillating means provided on the first wiring board, so that the influence of spurious signals on the peripheral circuit region is suppressed. In addition, since the interval between the first and second local oscillating means can be secured and interference with each other can be suppressed, the level of the spurious signal is reduced, and normal signals from the satellite are not disturbed. Can be down-converted.

  In another low-noise down converter according to the present invention, at least a part of the frame shields a region of the wiring board with respect to the first local oscillating means, and the second local oscillating means is formed by the metal chassis and the wiring board. Since the second local oscillating means is shielded and arranged so as not to be provided directly below the first local oscillating means provided on the first wiring board, the spurious signal for the peripheral circuit region is provided. And the interference between the first and second local oscillating means can be suppressed, so that the level of spurious signals can be reduced, and normal signals from satellites can be reduced. Can be downconverted without interference.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the following embodiment.

(Embodiment 1)
FIG. 1 is a block diagram showing a configuration of LNB 1 according to the embodiment of the present invention.

  Referring to FIG. 1, an LNB 1 includes a power supply circuit 20, an input horn 2 that receives a signal from a satellite, a low noise amplifier (LNA) 4 that amplifies the output of the input horn 2, and an LNA 4 A band pass filter (BPF) 8 connected to the output of the first local oscillation circuit 12, a local oscillation circuit 12 that outputs a predetermined first local oscillation frequency, an output of the band pass filter 8, and an output of the local oscillation circuit 12. And a mixer 10 for mixing.

  The LNB 1 further includes a band-pass filter 14 connected to the output of the LNA 4, a local oscillation circuit 18 that outputs a second predetermined local oscillation frequency, an output of the band-pass filter 14, and an output of the local oscillation circuit 18. A mixer 16 for mixing, a select circuit 22 for selecting one of the outputs of the mixers 10 and 16, an IF amplifier 24 for amplifying the output of the select circuit 22, and a capacitor 26 having one end connected to the output of the IF amplifier 24 And an F plug connector 28 connected to the other end of the capacitor 26.

  A power supply potential is supplied from the power supply circuit 20 to the LNA 4, the local oscillation circuits 12 and 18, and the F plug connector 28.

  FIG. 2 is a cross sectional view schematically showing a structure for separating the wiring boards on which the two local oscillation circuits of LNB 1 according to the embodiment of the present invention are mounted.

  Referring to FIG. 2, wiring boards 34 and 36 are attached to the upper and lower surfaces of chassis 32, respectively. Although not shown, the local oscillation circuits 12 and 18 are mounted on the wiring boards 34 and 36, respectively. An input unit horn 52 is attached to the chassis 32, and a frame 42 is attached so as to cover the wiring board 34. A frame 46 is attached so as to cover the wiring board 36. The chassis 32 is further provided with an F plug connector 54 that outputs a signal to an indoor satellite broadcast receiver.

  Thus, the wiring board 34 and the wiring board 36 are separated by the metal shield by the chassis 32, and the circuit on the wiring board is covered with the frame so that the radio waves do not fly outside.

FIG. 3 is a side view showing the structure of LNB according to the first embodiment of the present invention.
Referring to FIG. 3, a wiring board 34 is attached to the upper surface of the chassis 32. A frame 42 is attached to cover the wiring board 34, and the local oscillation circuit 12 provided on the wiring board 34 is shown. A frame 42 is formed so as to cover the area of the wiring board 34 corresponding to the local oscillation circuit 12. Specifically, the local oscillation circuit 12 is shielded by the side walls 42C and 42D.

  A wiring board 36 is attached to the lower surface of the chassis 32. A frame 46 is attached so as to cover the wiring board 36, and the local oscillation circuit 18 provided on the wiring board 36 is shown. A frame 46 is formed so as to cover a region of the wiring board 36 corresponding to the local oscillation circuit 18. Specifically, the local oscillation circuit 18 is shielded by the side wall portions 46A and 46B.

  Here, a case is shown in which connection pins 5 for connecting the wiring boards 34 and 36 are provided. Specifically, the connection pin 5 is provided through the wiring board 34, the chassis 32, and the wiring board 36. Frames 42 and 46 are provided so as to shield the areas of the wiring boards 34 and 36 through which the connection pins 5 penetrate. Specifically, the wiring board 34 is shielded by the side walls 42B and 42C, and the signal pin 5 is provided in a region different from the region where the local oscillation circuit 12 is shielded. And

  The wiring board 36 is shielded by the side walls 46B and 46C, and the signal pin 5 is provided in a region different from the region where the local oscillation circuit 18 is shielded.

  In this way, the local oscillation circuits 12 and 18 are separated by the metal shield by the chassis 32, and each circuit on the wiring board is divided by covering the wiring board 34 and the wiring board 36 with a frame. By shielding the area corresponding to 18 with a frame, it is possible to prevent radio waves, which are spurious signals, from jumping to circuit portions other than the circuit area of the local oscillation circuit. Further, regarding the signal pin 5, the signal pin is provided in a region different from the region corresponding to the local oscillation circuit and shielded by the frame, so that the radio waves of the local oscillation circuits 12 and 18 can hardly jump on the connection pin 5. Therefore, the two local oscillation circuits can be prevented from interfering with each other.

  Further, the local oscillation circuits 12 and 18 are arranged so that the local oscillation circuit 18 is not provided on the wiring board 36 directly below the local oscillation circuit 12 provided on the wiring board 34. In other words, the mutual positional relationship is shifted so as not to be perpendicular to the wiring boards 34 and 36.

  With this configuration, a sufficient distance d1 between the local oscillation circuit 12 and the local oscillation circuit 18 can be ensured without providing the thick chassis 32. Note that the local oscillation circuits 12 and 18 can reduce the level of the spurious signal and suppress the influence of the spurious signal as the distance is secured, so that the peripheral region of the end portions of the wiring boards 34 and 36 can be suppressed. It is desirable that the local oscillation circuits 12 and 18 are provided in such a manner that the interval between the local oscillation circuits 12 and 18 is maximized.

(Embodiment 2)
In the first embodiment, the configuration in which the two wiring boards 34 and 36 are provided and the local oscillation circuits 12 and 18 are provided for the respective wiring boards has been described. However, two local oscillation circuits are provided on one wiring board. The structure which provides is demonstrated.

FIG. 4 is a side view showing the structure of LNB according to the second embodiment of the present invention.
Referring to FIG. 4, a chassis 32 for attaching the wiring board 35 is provided. The chassis 32 is attached by being adhered to the lower surface side of the wiring board 35. Further, the local oscillation circuit 12 is provided on the upper surface of the wiring board 35, and the local oscillation circuit 18 is provided on the lower surface. Further, a frame 42 # for covering the upper surface of the wiring board 35 is provided.

  In the configuration according to the second embodiment, a recessed area is molded in chassis 32, and local oscillation circuit 18 is molded so as to be accommodated in the recessed area. When the local oscillation circuit 18 is housed in the recessed area, the local oscillation circuit 18 is shielded between the chassis 32 and the wiring board 35.

  For frame 42 #, side walls 42 # A and 42 # B are provided so as to cover a region corresponding to local oscillation circuit 18, and local oscillation circuit 18 is shielded.

  In this way, the local oscillation circuit 12 is covered and divided by the frame 42 #, and the local oscillation circuit 18 is shielded between the chassis 32 and the wiring board 35, so that a circuit portion other than the circuit area of the local oscillation circuit is provided. Since it is possible to prevent radio waves that are spurious signals from jumping, the two local oscillation circuits can be prevented from interfering with each other.

  Further, the local oscillation circuits 12 and 18 are arranged such that the local oscillation circuit 18 is not provided on the back surface side with respect to the local oscillation circuit 12 provided on the upper surface side of the wiring board 35. That is, the mutual positional relationship is shifted from the wiring board 35 so as not to be on the vertical line.

  With this configuration, a sufficient distance d1 between the local oscillation circuit 12 and the local oscillation circuit 18 can be secured. Since the local oscillation circuits 12 and 18 can reduce the level of the spurious signal and suppress the influence of the spurious signal as the distance is secured, the local oscillation circuits 12 and 18 are locally provided in the peripheral region at the end of the wiring board 35. It is desirable to provide the oscillation circuits 12 and 18 so that the interval between the local oscillation circuits 12 and 18 is maximized.

  In addition, since the configuration is a configuration using one wiring board instead of the two wiring boards as described in the first embodiment, the size of the entire apparatus can be reduced, and signal pins and the like are also provided. It is not necessary, and it is possible to realize an LNB capable of reducing costs by reducing the number of parts.

(Embodiment 3)
In the above-described embodiment, the method of reducing the level of the spurious signal by securing the distance between the local oscillation circuits 12 and 18 has been described. However, in the third embodiment, the influence of the spurious signal is different in another method. A method for suppressing this will be described.

  In the third embodiment, as described with reference to FIG. 4 of the second embodiment, in the single circuit board 35, the two local oscillation circuits 12 and 18 are arranged on the upper surface and the lower surface of the circuit board 35, respectively. The GNDs of the oscillation circuits 12 and 18 are separated from each other.

FIG. 5 is a side view showing the structure of LNB according to the third embodiment of the present invention.
Referring to FIG. 5, there is shown a configuration in which through holes CH <b> 1, CH <b> 2, and CH <b> 3 that electrically connect the upper surface and the lower surface are further provided in circuit board 35 as compared with the configuration described in FIG. 4. . Specifically, the local oscillation circuit 12 provided on the upper surface of the wiring board 35 is connected to a GND pattern (described later) provided on the lower surface through the through hole CH2. Further, as will be described later, a side wall portion 42 # B of the frame 42 is connected to a GND pattern provided on a lower surface, which will be described later, through a through hole CH3. Further, the local oscillation circuit 18 provided on the lower surface of the wiring board 35 is connected to the frame 42 # provided on the upper surface via the through hole CH1. The frame 42 # is grounded, and GND is supplied to the local oscillation circuit 18 through the frame 42 # and the through hole CH1. Although not shown, a power supply line for supplying power and a signal transmission line for transmitting signals are provided on the upper surface of the circuit board 35.

  FIG. 6 is a diagram illustrating the lower surface and the upper surface of circuit board 35 according to the third embodiment of the present invention.

  Referring to FIG. 6A, here, a layout of a GND pattern or the like on the lower surface of the circuit board 35 is shown.

  Specifically, most of the area of the circuit board 35 is provided as the GND pattern 62. The GND pattern 62 is in contact with the grounded chassis 32, and GND is supplied to the GND pattern 62 via the chassis 32. The GND pattern 62 is provided to supply GND to circuit elements other than the local oscillation circuits 12 and 18. In addition to the GND pattern 62, a region 60 for providing the local oscillation circuit 18 provided on the lower surface side of the circuit board 35 is shown, and the local oscillation circuit 18 is provided in the region 60. In the outside region 60, a case where a through hole CH1 provided for supplying GND to the local oscillation circuit 18 is provided is shown.

  On the other hand, a GND pattern 64 different from the GND pattern 62 is provided on the lower surface of the circuit board 35. In this example, a predetermined interval is provided between the GND pattern 64 and the GND pattern 62 so that the GND pattern 62 and the GND pattern 64 are not short-circuited. Two through holes CH2 and CH3 are provided.

  Referring to FIG. 6B, here, a layout of a GND pattern or the like on the upper surface of the circuit board 35 is shown.

  Specifically, a GND pattern 70 that is in contact with the grounded frame 42 # is provided. As described above, the local oscillation circuit 18 is connected to the GND pattern 70 through the through hole CH1 and supplied with GND.

  In addition, a GND pattern 70 that is in contact with the side wall 42 # A of the grounded frame 42 # is provided, and GND required for a circuit (not shown) on the upper surface of the circuit board 35 is supplied. And it connects with the side wall part 42 # B of the flame | frame 42 through through-hole CH3. Then, the GND pattern 64 described above and the local oscillation circuit 12 on the upper surface of the circuit board 35 are connected via the through hole CH2 to supply GND.

  That is, the local oscillation circuit 12 and the local oscillation circuit 18 are independent from each other with respect to the GND pattern of the circuit board 35, and have different GND supply lines.

  With this configuration, it is possible to suppress mutual interference based on leakage of the local oscillation signal transmitted to the GND supply line by separating GND, and the difference between the local oscillation frequencies of these two local oscillation circuits and their harmonics. It is possible to reduce the level of the spurious signal generated from the difference from the wave.

  In this example, the method of supplying GND to the local oscillation circuit 12 using the through holes CH2 and CH3 and the GND pattern 64 has been described. However, the grounded frame 42 is not provided without providing such a through hole. Although it is possible to form a GND pattern so that GND is supplied to the local oscillation circuit 12 from the side wall portion 42 # B, the GND pattern is mainly provided on the lower surface side of the circuit board 35, and the upper surface side is provided. By reducing the area of the GND pattern to be provided, it becomes easy to lay out a pattern such as a power supply line or a signal line on the upper surface side, and the layout efficiency of the signal line can be improved.

  Here, separation of GND has been described, but it is naturally possible to combine with the method described in the first and second embodiments. Further, although the case where GND is separated has been described, for example, the level of the spurious signal can be reduced by separating the supply of power.

  The embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is shown not by the above-described embodiment but by the scope of claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

It is the block diagram which showed the structure of LNB1 according to embodiment of this invention. It is sectional drawing which showed roughly the structure which isolate | separates the wiring board which each mounts two local oscillation circuits of LNB1 according to embodiment of this invention. It is the figure which showed the structure of LNB according to Embodiment 1 of this invention from the side surface. It is the figure which showed the structure of LNB according to Embodiment 2 of this invention from the side surface. It is the figure which showed the structure of LNB according to Embodiment 3 of this invention from the side surface. It is a figure explaining the lower surface and upper surface of the circuit board 35 according to Embodiment 3 of this invention. It is the figure which showed the cross-section of the conventional satellite broadcast receiver.

Explanation of symbols

  1 LNB, 2 input horn, 5 connection pin, 8, 14 band pass filter, 20 power supply circuit, 22 select circuit, 24 amplifier, 26 capacitor, 10, 16 mixer, 28, 54 F plug connector, 12, 18 local oscillation Circuit, 32 chassis, 42, 42 #, 46 frame, 52 input horn, 34, 35, 36 wiring board, 62, 64, 70, 71 GND pattern.

Claims (8)

A low noise down converter for receiving satellite broadcasts,
A metal chassis having opposing first and second surfaces;
A first wiring board attached to the first surface;
First local oscillation means provided on the first wiring board;
A second wiring board attached to the second surface;
Second local oscillation means provided on the second wiring board;
Provided corresponding to the first and second wiring boards, respectively, and first and second frames for covering the first and second wiring boards,
At least a part of the first and second frames are respectively molded so as to shield regions of the first and second wiring boards with respect to the first and second local oscillation means,
The second local oscillation means is separated and shielded from the first local oscillation means by the metal chassis,
The low-noise down-converter, wherein the second local oscillating means is arranged so as not to be provided directly below the first local oscillating means provided on the first wiring board. A connection pin for connecting the first wiring board and the second wiring board;
The connection pin is provided through the first wiring board, the chassis, and the second wiring board,
The first and second frames are respectively formed to shield regions of the first and second wiring boards through which the connection pins penetrate,
2. The low noise down converter according to claim 1, wherein the connection pin is not provided in a region for the first and second local oscillation means.   The first and second local oscillating means are provided in peripheral regions along the sides of the first and second wiring boards, respectively, and the interval between the first and second local oscillating means is maximized. The low noise down converter according to claim 1, wherein the low noise down converter is arranged so as to be offset. A low noise down converter for receiving satellite broadcasts,
A wiring board having first and second surfaces facing each other;
First local oscillation means provided on the first surface;
Second local oscillating means provided on the second surface;
A frame provided corresponding to the first surface of the wiring board and covering the wiring board;
A metal chassis provided on the second surface side of the wiring board for attaching the wiring board;
At least a part of the frame is molded so as to shield a region of the wiring board with respect to the first local oscillation unit,
The metal chassis has a recessed area, and the second local oscillation means is shielded between the wiring board and the metal chassis by the recessed area,
The low-noise down-converter, wherein the second local oscillating means is arranged so as not to be provided immediately below the first local oscillating means provided on the first surface of the wiring board.   The first and second local oscillating means are respectively provided in peripheral regions along the side of the substrate of the wiring board, and are arranged so as to be shifted so that the interval between the first and second local oscillating means is maximized. The low noise down converter according to claim 4. A low noise down converter for receiving satellite broadcasts,
A wiring board having first and second surfaces facing each other;
First local oscillation means provided on the first surface;
Second local oscillating means provided on the second surface;
A frame provided corresponding to the first surface of the wiring board and covering the wiring board;
A metal chassis provided on the second surface side of the wiring board for mounting the wiring board;
Low noise reduction provided with first and second GND supply lines that are independently provided corresponding to the first and second local oscillation means and connected to the corresponding local oscillation means and supplied with GND. converter. At least a part of the frame is molded so as to shield a region of the wiring board with respect to the first local oscillation unit,
The low noise down according to claim 6, wherein the metal chassis has a recessed area, and the second local oscillation means is shielded between the wiring board and the metal chassis by the recessed area. converter. The frame is grounded;
One of the first and second local oscillation means and the frame are connected;
The low noise down converter of claim 6, wherein the frame forms part of a corresponding GND supply line.

Images