Communications: directive radio wave systems and devices (e.g. – Directive – Including antenna orientation
Reexamination Certificate
2000-10-26
2002-10-01
Blum, Theodore M. (Department: 3662)
Communications: directive radio wave systems and devices (e.g.,
Directive
Including antenna orientation
C343S761000
Reexamination Certificate
active
06459408
ABSTRACT:
RELATED PATENT APPLICATION
This application claims priority from Japanese patent application number 11-307241, filed Oct. 28, 1999, which is hereby incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method and apparatus for adjusting the direction of a satellite dish antenna, and a satellite receiver having a function to assist adjustment of the direction of a satellite dish antenna.
2. Description of Related Art
In order to receive a satellite broadcast signal from broadcasting satellite (BS) or communications satellite (CS), it is necessary to install a satellite receiver and a satellite dish antenna. In general, a parabolic antenna is used as the satellite dish antenna. The parabolic antenna receives a signal from a satellite, and a satellite receiver takes images and sounds from the received signal and then transfers them to an output device such as a television and a speaker.
In general, a parabolic dish antenna has very strong directivity. For this reason, when the direction of the parabolic dish antenna is displaced by approximately 2 degrees, the output to the satellite receiver is reduced to half or less. The reduction of output to the satellite receiver causes a harmful effect such as distortion of images and sounds, and in the worst case it may cause the receiver failure. Therefore, accurate adjustment of the direction of the antenna such as an elevation angle, a horizontal angle and a polarization angle is necessary. Rough adjustment of the direction is made first by using graduations provided on the antenna and then fine adjustment is made. Most of currently available satellite receivers have a function to display the intensity of a signal received by the antenna as a numerical value or a bar graph on a display screen of a television or the like. Alternatively, the intensity of a signal received by the antenna may be given as a sound volume output from a built-in speaker of the television or the like. The direction of the antenna is adjusted by using such a function of the receiver so that the signal received by the antenna can attain the maximum intensity.
FIG. 6
shows the structure of a satellite receiver
80
and an example of connection between a parabolic dish antenna
70
and an output device
76
, but
FIG. 6
mainly shows a part associated with the adjustment of the direction of the parabolic dish antenna
70
. The parabolic dish antenna
70
is connected to the satellite receiver
80
through a connection cable
74
. A coaxial cable is generally used as the connection cable
74
. Between the parabolic dish antenna
70
and the connection cable
74
, a low noise block converter (LNB)
72
is disposed. The LNB
72
has a function of, for example, converting a received signal having a frequency band of 10 GHZ into a signal having a band frequency of 1 GHz. The satellite receiver
80
includes a tuner
82
, an automatic gain control (AGC)
84
, a microprocessing unit (MPU)
86
and an output processing unit
88
.
The tuner
82
tunes the television to a channel of a desired broadcast program. The 1 GHz signal received from the LNB
72
through the connection cable
74
is sent from the tuner
82
to the AGC
84
. The AGC
84
generates an output in accordance with the received signal as well as stabilizes the output through gain control. The output of the AGC
84
is substantially in proportion to the intensity of a signal received by the antenna. Therefore, the output of the AGC
84
can be used as an index for adjusting the direction of the antenna
70
. For example, the direction of the parabolic dish antenna
70
is adjusted so as to maximize the output of the AGC
84
. The amplitude of the output of the AGC
84
can be measured with a measuring device such as a tester, which most homes do not own. Accordingly, in many cases, a numerical value corresponding to the amplitude of the output of the AGC
84
is displayed on the television screen or a sound in accordance with the amplitude of the output of the AGC
84
is output from the speaker. The output device
76
such as a television and a speaker is connected to the satellite receiver
80
through an output cable
78
.
The output of the AGC
84
is input to the MPU
86
. The MPU
86
outputs a received intensity signal in accordance with the output of the AGC
84
. The received intensity signal used herein is obtained by converting the output of the AGC
84
into a numerical value ranging from 1 to 30. The output processing unit
88
converts the received intensity signal into an image signal or a sound signal. The image signal is output to the television screen or the like, and the sound signal is output to the speaker or the like. The image signal is used, for example, for displaying the numerical value (1 to 30) corresponding to the received intensity signal as a numerical character or a bar graph. The sound signal is used, for example, for changing the frequency or the volume of a sound to be output in accordance with the numerical value (1 to 30) corresponding to the received intensity signal. Based on the image displayed on the television screen or the sound output from the speaker, the direction of the antenna
70
is adjusted so as to maximize the intensity of the signal received by the antenna
70
.
However, these adjustments are made only by peripheral equipment of the satellite receiver
80
. In order to display the received intensity on the television screen, the television screen should be seen from a place where the parabolic dish antenna is installed. For example, in the case where the antenna is installed near the window of a room where the satellite receiver is placed and the television screen can be seen from the place where the antenna is installed, the direction can be easily adjusted. However, in the case where the antenna is installed, for example, on the roof, the television screen cannot be seen from the place where the antenna is installed, and therefore the direction of the antenna cannot be accurately adjusted.
In such a case, the direction is generally adjusted by two persons: one is an adjuster of the direction; and the other is an instructor for instructing the adjuster on the direction while watching the television screen. In this case, however, it is difficult to make fine and accurate adjustment of the antenna to an optimal direction. In general, an antenna is installed outdoors on the roof of a house or a building, and the satellite receiver is installed indoors near a television. Thus, in many cases a satellite receiver is away from an antenna. When the direction is thus adjusted by two persons, the adjuster sometimes cannot hear the voice of the instructor. Similarly, when the received intensity is output from the speaker, the adjuster sometimes cannot hear the output sound.
A reliable method of seeing the television screen without fails is to bring a compact television and the satellite receiver near the antenna so that the direction can be adjusted while checking the image displayed on the television screen. However, this method requires a compact television, and it is necessary to bring the compact television and the satellite receiver to the place where the antenna is installed, for example, to the roof, which entails danger. In addition, since a coaxial cable for connecting the receiver to the antenna is already. installed, an additional coaxial cable has to be prepared to be connected to the satellite receiver moved to the place for installing the antenna when the readjustment of direction of the antenna is required.
On the other hand, an expert in installing an antenna uses special equipment for measuring the intensity of the received signal. In most of such equipment, the intensity of the signal received by the antenna is displayed as a numerical value or a bar graph on the screen. This equipment is connected to the end terminal of the antenna (LNB), and the direction of the antenna is adjusted so as to maximize the intensity of the received signal measured with this equip
Kubo Hiroaki
Murakami Masahiro
Blum Theodore M.
Cutter, Esq. Lawrence D.
Heslin Rothenberg Farley & & Mesiti P.C.
Radigan, Esq. Kevin P.
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