JPH06105880B2 - Satellite broadcasting receiving system - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a satellite broadcast receiving system for directly receiving satellite broadcasts.

[Technical background of the invention and its problems]

2. Description of the Related Art In recent years, so-called satellite broadcasting, in which television satellite radio waves are emitted from an artificial satellite toward the earth and a terrestrial viewer directly receives and listens to the radio waves with a parabolic antenna, has come into practical use and spread in various countries.

Although the situation of such broadcasting satellites varies depending on the country, it is generally within a receivable range when viewed from the receiving point, and a plurality of satellites are arranged in a geostationary orbit.

Therefore, in order to receive the broadcast from these satellites, the viewer needs to change the direction of the antenna in the geostationary orbit plane. By the way, in order to change the direction of the parabolic antenna, an actuator which can be expanded and contracted by controlling the rotation of the motor is usually used between the supporting column for supporting the antenna and the antenna as described later, and the number of rotations of the motor is counted and the antenna Know the orientation and remember this value.

When the antenna is aimed in the specific direction, the count value corresponding to the direction is read from the memory and the motor is rotated by this value. Therefore, as long as the direction of the antenna is determined by the stored count value, the direction should always be constant. However, in reality, the orientation of the antenna may be shifted depending on the conditions, although the angle is small. This is mainly due to mechanical errors, play and hysteresis of the antenna. By the way, such a deviation is hardly a problem with an antenna having a relatively wide directivity, but a parabolic antenna used for reception of a broadcasting satellite uses a very sharp directivity from the viewpoint of efficiency. In such antennas, the above-mentioned shift has a great influence on the reception state.

That is, there may be a case where the antenna cannot be properly received even though the antenna orientation is properly set.

For example, a parabolic antenna for actual satellite broadcasting reception shows directional characteristics as shown in FIG. In the figure, the horizontal axis is the angle from the center of the pointing direction, and the vertical axis is the C / N ratio. Generally, in a normal parabolic antenna device, the above-mentioned shift is about 0.5 ° to 1 °. However, as is clear from the above figure, if the orientation of the antenna deviates by 0.5 ° to 1 °, the C / N ratio drops significantly. Therefore, in satellite broadcasting with low transmission power, the C / N quality of the image may deteriorate significantly, and in some cases, the signal may not be received.

Moreover, the deviation as described above changes depending on the conditions and does not always result in a constant angle error. Therefore, it is very inconvenient because it is impossible to automatically move the parabolic antenna by a certain angle when the vehicle is stopped.

[Object of the Invention]

The present invention has been made in view of the above problems,
It is an object of the present invention to provide a satellite broadcast receiving system that can always perform good reception even if there is a direction deviation due to a mechanical error of an antenna or the like.

[Outline of Invention]

According to the present invention, when changing the broadcast satellite to be received, the antenna is directed in a direction corresponding to the count value read from the memory, and the direction is finely changed within a predetermined angle range centered on this direction. The antenna is oriented so that the automatic gain control voltage of the intermediate frequency amplifier becomes maximum. Further, the count value stored in the memory at this time is not changed.

Example of Invention

An embodiment of the present invention will be described below. FIG. 1 shows the overall configuration of an embodiment of the present invention in which the direction of the antenna and the receiving channel operate in tandem.

Reference numeral (11) is a parabolic antenna, which comprises a reflector (12) and a primary radiator (14) held by a holder (13) so as to face the reflector. Parabolic antenna (1
1) is attached to a pillar (15) fixed to the ground so as to be rotatable in azimuth and elevation directions.

By the way, it is necessary to change the azimuth angle and the elevation angle to direct the parabolic antenna (11) to the broadcasting satellite in the geostationary orbit, but in reality, if the angle is changed only in one direction in the geostationary orbit plane, Good. The adjustment of the angle is performed by an actuator (16) provided between the support column (15) and the parabolic antenna (11) and capable of suppressing the length depending on the rotation direction and amount of the built-in DC motor.

On the other hand, the radio wave received by the primary radiator (14) enters the outdoor unit (17) connected to the primary radiator (14), where high frequency amplification and first frequency conversion are performed, and then the cable (18 ) Signal processing section (22) of the indoor unit (21)
Sent to.

The indoor unit (21) sends the control signal to the signal processing section (22) and the actuator (16) through the cable (19) and detects the length of the actuator, that is, the tilt of the parabolic antenna (11) ( 23), an operation unit (24) manually operated by the viewer in the storage mode, the viewing mode and the fine adjustment mode, and a maximum sensitivity direction detection unit (24) that detects the direction of the maximum sensitivity in the fine angle range in the fine adjustment mode. 25) and.

The signal processing unit (22) of the indoor unit (21) processes the received signal as described later, supplies the video signal and the audio signal to the display device (26), and reproduces the satellite broadcast.

The rotation structure of the indoor unit (21) in FIG. 1 is shown in FIG.

As shown in FIG. 2, the antenna control unit (23) of the indoor unit (21) includes a DC power supply (31) for generating a DC voltage applied to a DC motor (not shown) of the actuator (16), A relay (32) that switches the polarity of the DC voltage generated by this DC power supply (31) and applied to the actuator DC motor, and an up-down counter (3) that counts the pulses that detect the rotation of the DC motor by the Hall effect.
3), a non-volatile memory (34) that stores the count value of the up / down counter (33) in storage mode, and a rotation pulse display that displays the count value of the up / down counter (33)
Antenna control CPU (36) for switching the LED (35) and relay (32), controlling the counting direction of the up-down counter (33), controlling each circuit of the maximum sensitivity direction detection unit (25) described later, and the like. It consists of and.

The operation unit (24) of the indoor unit (21) has a memory key (M) and number keys of 0 to 9 and inputs a desired label (number of 0 to 9) in the storage mode. The label input section (37) for selecting and inputting the desired label number, the direction indicator section (38) for indicating the direction within the geostationary orbit plane of the antenna, and the maximum sensitivity direction detection section (25) are activated to optimize the antenna direction. A fine adjustment instruction section (39) for instructing the start of the fine adjustment mode to be moved to and a channel instruction section (40) for instructing a channel to be described later.

On the other hand, the signal processing section (22) of the indoor unit (21) has the first
A frequency conversion circuit (41) for converting a signal from an outdoor unit (17) in the figure to a second intermediate frequency, and a local oscillator (42) for supplying a local oscillation signal to this frequency conversion circuit (41).
A non-volatile memory (43) for storing the channel instructed by the channel instructing section (40) of the operation section (24), a channel display LED (44) for displaying this channel,
These non-volatile memory (43), channel display LED (4
4), a CPU for channel selection (45) for controlling the local oscillator (42), an intermediate frequency amplifier (46) for amplifying an intermediate frequency signal output from the frequency conversion circuit (41), and an intermediate frequency amplifier A signal meter that displays the automatic gain control (AGC) voltage at (46) as the strength of the received signal (47)
And an FM demodulator (48) that demodulates the intermediate frequency signal by FM,
The video processing circuit (49) and the audio processing circuit (50) each process the demodulated video signal and audio signal.

The outputs of the video processing circuit (49) and the audio processing circuit (50) are
The video and audio are supplied to the display device (26) and the viewer views them.

By the way, the indoor unit (21) shown in FIG. 2 has a maximum sensitivity direction detecting section (25) corresponding to the characteristic part of the present invention. The maximum sensitivity direction detector (25) includes a sample hold circuit (51) for sampling and holding the AGC voltage of the intermediate frequency amplifier (46), an AD converter (52) for AD converting the held voltage, This digital AGC voltage is used for antenna control C
Random access memory (RA that stores the count value of the up / down counter (33) in association with it via the PU (36)
M) (53) and a fine adjustment counter (54) for defining an angle range for searching the optimum direction of the antenna in the fine adjustment mode.

The operation of the satellite broadcasting receiving system is roughly divided into two modes: a storage mode for pre-storing a broadcasting channel from a broadcasting satellite and a viewing mode for subsequently watching the pre-stored broadcasting. To be If the image is not reproduced well in the viewing mode, the fine adjustment instruction section (39) can instruct the fine adjustment mode.

First, the operation of the above embodiment in the storage mode will be described.

When the direction instructing unit (38) instructs the direction to change the direction of the parabolic antenna in the geostationary orbit plane, the antenna control CPU (36) switches the relay (32) to the DC power source (3
The voltage of 1) is applied to the DC motor of the actuator (16), and the parabolic antenna (11) changes its direction.

The rotation of the DC motor is counted by the up / down counter (33), and the count value of this counter is the parabolic antenna (1
It corresponds to the direction of 1) and is displayed on the rotation pulse display LED (35). When the direction button (38) for one direction is continuously pressed, the parabolic antenna (11) continues to change its direction. At this time, keep an eye on the signal meter (47) and stop at the position where the needle of the meter largely shakes.

Therefore, the channel designating section (40) sequentially switches channels 1 to 24, for example, and selects a desired channel number. Of course, if there is no desired channel, the direction of the parabolic antenna (11) is changed again by the direction indicator (38). The channel number being received is the channel display LE
Displayed on D (44).

When the desired channel of the specific satellite is determined, the viewer presses the memory key (M) in the label input section (37) and continues to the favorite 0
Press the number keys 9 to 9, for example the 3 key. At this time, the rotation pulse display LED (35) and the channel display LED (44) respectively indicate the count value of the up / down counter (33) (e.g. 56) indicating the direction of the specific satellite and the desired channel number (e.g. 8). Is displayed. These numerical values are labeled and stored in the non-volatile memory (34) and the non-volatile memory (43), respectively. After the memory key of the label input section (37) is pressed, the number of the key to be pressed next, that is, the label number, is displayed on the rotation pulse display LED (35) or channel display LED (44) at that time. May be. By doing so, it is possible to eliminate an error such that a label number different from the intended number is used.

With respect to the antenna direction and the data of the desired channel which are stored with labels as described above, the desired channel is selected by the viewing mode described below at the time of viewing. First,
When the operator (viewer) wants to watch a program on a certain channel, he or she presses the key of the label number already assigned to that channel, for example, 3 key in the label input section (37).

Then, the antenna control CPU (36) stores the data of the number of rotation pulses labeled 3 in the nonvolatile memory (34).
The read-out rotation pulse display LED (35) is displayed and the relay (32) is switched and controlled so that the count value of the up-down counter (33) becomes the number of rotation pulses labeled 3.

Since the count value of the up-down counter (33) corresponds to the orientation of the parabolic antenna (11), the fact that the count value of the up-down counter (33) becomes the value corresponding to label 3 means that the parabolic antenna (11) is labeled. It means that the antenna is attached to the antenna attached to 3.

On the other hand, when the 3 key of the label input section (37) is pressed, this is transmitted to the channel tuning CPU (45) through the antenna control CPU (36), and this CPU is labeled 3. The channel number 8 is read from the non-volatile memory (43) and displayed on the channel display LED (44), and the local oscillator (42) output is controlled to the corresponding local oscillation frequency. In this way, the program of the satellite broadcasting channel labeled 3 can be viewed on the display device (26).

By the way, normally, a satellite broadcast program should be normally received and reproduced according to the above-mentioned viewing mode, but there is a problem that the direction of the parabolic antenna is not always exactly in a fixed direction. You may not get it. In this case, the parabolic antenna can be oriented in the optimum direction by the fine adjustment mode described below.

In this embodiment, the direction in which the directivity (C / N) becomes large is detected by the AGC voltage of the intermediate frequency amplifier (46). That is, the third
As shown in the figure, the direction of the AGC voltage and the directivity are in a proportional relationship, so the directivity becomes large when the AGC voltage is directed in the direction in which it becomes large.

Therefore, the operator first presses the fine adjustment button of the fine adjustment instruction section (39) in the operation section (24) of the indoor unit (21) shown in FIG. 2 to start the fine adjustment mode. In this mode, the parabolic antenna (11) is swung within a range that is a value obtained by adding or subtracting the count value of the up-down counter (33) by the number preset in the fine adjustment counter (54), and the intermediate frequency amplifier (46 ), The value of the up-down counter (33) that maximizes the AGC voltage is obtained, and the correspondence relationship is set again assuming that the direction of the parabolic antenna (11) at this time is the direction of the previously set count value.

Detailed operation of the fine adjustment mode will be described with reference to the change diagram of the directivity direction of the parabolic antenna (11) in FIG. 4 and the flowchart in FIG.

In FIG. 2, the AGC voltage of the intermediate frequency amplifier (46) is sample-held by the sample-hold circuit (51) and AD.
It is converted into a digital value by the converter (52), and its value is V, the value of the up-down counter (33) at that time is C, and the value of the fine adjustment counter (54) is f. The direction of the parabolic antenna (11) is A.

The orientation of the parabolic antenna when labeled 3 is A _{0 in} FIG.
Direction. When the fine adjustment button is pressed, the digital value V of the AGC voltage of the intermediate frequency amplifier (46) in this direction V
₀ and the value C of the up / down counter (33) at that time are passed through the antenna control CPU (36) to the areas D ₁ and D _{2 of the} RAM (53).
It is stored in each. At this time, the fine adjustment counter (54) is preset with an appropriate value corresponding to the range in which the parabolic antenna (11) is swung.

It is about 2 ° even at the position closest to the broadcasting satellite, and the deviation of the sensitivity of the parabolic antenna (11) is usually about 0.5 ° to 1.0 °. Also, for the difference 1 between the count values of the up / down counter (33). Considering that it is in the range of 0.2 to 0.3 °, the preset value of the fine adjustment counter (54) can be set to 5, for example. This value is preset in the fine adjustment counter (54) at the start of the fine adjustment mode ((61) in FIG. 5). Next, as shown in (62) of FIG. 5, n = 1, the value of the up / down counter (33) is set to C + 1 in (63), and the parabolic antenna (11) is increased by the count value 1 in the direction A ₁ . Turn. At this time, the digital value V ₁ of the AGC voltage of the intermediate frequency amplifier (46) is in the D ₁ area of the RAM (53) and C + 1 is the RAM (53).
It is stored in the D ₂ area of.

Next, in (64) of FIG. 5, the stored digital AGC voltage value V ₁ and the maximum digital AGC voltage value Vm up to that point (V ₀ because there is only V ₀ at this point) Are compared. When V ₁ is greater than V ₀ (65)
As shown in FIG. 5, V ₁ is Vm and the up / down counter C + 1 at that time is C + m. Next, the value of the fine adjustment counter (54) preset with 5 in (66) is decremented by one. As shown in (67), if the value f of the reduced fine adjustment counter (54) is not 0, as shown in (68), n +
1 is set to n. On the other hand, when V ₁ is smaller than V ₀ in (64), Vm and C + m are left as they are (66), (6
Pass 7) and (68).

Again, returning to (63), the value of the up / down counter (33) is set to C + 2, and the parabolic antenna (11) is directed in the direction of A ₂ in FIG. The digital AGC voltage value V _{2 at} this time is the RAM
In D ₁ region (53), also count C + 2 of the up-down counter (33) is stored in the D ₂ region of RAM (53).

At (64), V ₂ and Vm (the larger value of V ₀ and V ₁ ) are compared again. If V ₂ is larger than the latter, V ₂ becomes Vm and C + 2 becomes C + m. This is the satellite when the orientation of the parabolic antenna (11) is changed and A _0, A _1, A ₂ is received in the most favorable state means that the direction of A _2.

Similarly, since the value 4 of the fine adjustment counter (54) is 3 and not 0, n + 1 is set to n. Therefore, at (63), the up / down counter (33) is set to C + 3 and A _{3 in} FIG.
The antenna is pointed in the direction of
The C voltage value V ₃ is stored in the D ₁ area of the RAM (53). In this way, after the maximum AGC voltage value Vm and the count value C + m at that time when the parabolic antenna (11) is directed in the direction of A _{0 to} A ₅ are obtained, at (67) in FIG. Fine adjustment counter (54)
Is 0.

Therefore, the value of the fine adjustment counter (54) becomes 5 again in (71).
Is set to. Next, at (72), n = 1 is set, and the direction of the parabolic antenna (11) is changed so that the count value of the up / down counter (33) becomes C-1. The direction of the antenna is A (-1) and the digital AGC voltage value V at that time is V
(-1) is stored in the D ₁ area. C-1 is stored in the D ₂ area. Here, V (-1) and Vm are compared again and V (-
When 1) is larger than Vm, V (-1) is regarded as Vm and C-
1 is set to C + m. When Vm is larger than V (-1), Vm and C + m are left as they are (76), and the fine adjustment counter (54) becomes 4 at (77) and is not 0, so n + 1 is n, that is, n = 2 (73). ~ (77) is performed.

Thus, the largest value V of the digital AGC voltage among the orientations of the antennas A (-5) ~A ₅ in Figure 4
m and the count value C + m at that time are detected. This count value is within the range of C + 5 to C-5, and the angle deviation of the parabolic antenna (11) is usually about 0.5 ° to 1.0 °. It will be evenly shaken around.

Next, the antenna control CPU (36) changes the direction of the parabolic antenna (11) so that the count value of the up / down counter (33) becomes C + m. Then, the value of the up / down counter (33) is set to C while the direction of the parabolic antenna (11) is fixed. In this way, the relationship between the count value of the up / down counter (33) and the orientation of the parabolic antenna (11) is readjusted.

Here, changing the direction of the parabolic antenna (11) without changing the count value of the up-down counter (33) means that if the reverse adjustment is performed, all other stored count values must be changed. Is very annoying.

Thus, the parabolic antenna (11) is oriented in the direction in which the AGC voltage of the intermediate frequency amplifier (46) is maximized, the fine adjustment mode is terminated, and a good image of satellite broadcasting is reproduced.

In the above-described embodiment, when the reproduced image is not good in the viewing mode, the fine adjustment instruction section (39) of the operation section (24) manually gives an instruction to enter the fine adjustment mode. However, the fine adjustment may be automatically performed at the time when the received image in the viewing mode is automatically reproduced.

Further, in the above embodiment, the case where the present invention is applied to the system in which the orientation of the antenna and the desired channel are labeled and stored is described. However, the present invention is not limited to this, and the orientation of the antenna is stored as a count value. Then, the present invention can be applied.

〔The invention's effect〕

According to the present invention, when the broadcast satellite to be received is changed, the antenna is directed in the direction corresponding to the count value read from the memory, and the direction is finely changed within a predetermined angle range centered on this direction, and this fixed position is fixed. The antenna is oriented so that the automatic gain control voltage of the intermediate frequency amplifier becomes maximum in the angular range, and the count value stored in the memory is not changed at this time. As a result, it is possible to obtain a satellite broadcast receiving system that can always perform good reception even if there is a direction deviation due to a mechanical error of the antenna.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an embodiment of the present invention, and FIG.
FIG. 3 is a circuit configuration diagram of the indoor unit of the embodiment shown in FIG. 3, FIG. 3 is a diagram showing a relationship between the AGC voltage and C / N of the intermediate frequency amplifier, and FIG. 4 is a state in which the orientation of the antenna is changed in the fine adjustment mode. 5 and 5 are flowcharts showing the operation in the fine adjustment mode, and FIG. 6 is a diagram showing an example of directional characteristics of the parabolic antenna. 11 …… parabolic antenna, 14 …… primary radiator 16 …… actuator, 17 …… outdoor unit 18,19 …… cable, 21 …… indoor unit 22 …… signal processing unit, 23 …… antenna control unit 24 …… Operating part, 25 …… Maximum sensitivity direction detection part 26 …… Display device, 33 …… Up / down counter 34,43 …… Nonvolatile memory, 35 …… Rotation pulse display LED 36 …… Antenna control CPU, 39 …… Fine adjustment instruction section 45 …… Channel transmitter CPU, 46 …… Intermediate frequency amplifier 51 …… Sample hold circuit, 52 …… AD converter 53 …… Random access memory, 54 …… Fine adjustment counter

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Claims (1)

[Claims] 1. An antenna for receiving satellite broadcasting, a direction adjusting means for changing the direction of the antenna, a counting means for counting the adjustment amount of the direction adjusting means, and the counting means corresponding to the position of a broadcasting satellite to be received. A memory for storing the count value of the signal, a conversion circuit for converting the signal received by the antenna into an intermediate frequency, an intermediate frequency amplifier for amplifying the output of the conversion circuit, and a satellite for processing the output of the intermediate frequency amplifier. The broadcasting satellite changing means comprises a reproducing means for reproducing a broadcast and a broadcasting satellite changing means for changing a broadcasting satellite to be received, and the broadcasting satellite changing means is arranged in a direction corresponding to the count value read from the memory by the direction adjusting means. Means for directing the antenna, means for changing the direction by the direction adjusting means within a range of a predetermined angle centered on the direction of the directed antenna, and Satellite broadcasting reception, characterized in that it has means for pointing the antenna in a direction in which the automatic gain control voltage of the intermediate frequency amplifier is maximized without changing the count value stored in the memory within a range of angles. system.