JP3275817B2 - Digital satellite broadcast receiving system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a digital satellite broadcast receiving system, and more particularly to a digital satellite broadcast receiving system for receiving a digital satellite broadcast signal of a desired channel by a plurality of digital tuners connected to one receiving antenna.

[0002]

2. Description of the Related Art In conventional analog satellite broadcasting, a plurality of channels are distributed with a single polarization, and a low noise converter (LNB) mounted on a receiving antenna is used.
The power supply to the ock downconverter is performed with only one type of voltage. For this reason, a plurality of analog tuners can be connected to one receiving antenna via a distributor, and channel tuning can be performed independently from each analog tuner to view satellite broadcasting.

Conventionally, there is also known a tuner for providing a satellite broadcast by connecting a second analog tuner to the output of a first analog tuner connected to one antenna and connecting a second analog tuner to each output. (For example, JP-A-4-335719). FIG. 2 is a block diagram showing an example of the satellite broadcast receiving tuner. In the figure,
The satellite broadcast signal received by the antenna 32 is transmitted to the LNB 31
, And is converted to a constant frequency of about 1 GHz and input to an RF signal input terminal 34 of a satellite broadcast receiving tuner 33 with a distributor via a coaxial cable.

In the tuner 33, an RF signal input terminal 34
Is amplified by an RF amplifier 36 and then divided into two by a distributor 36. One of the satellite broadcast signals is selected by a TV monitor 40 through a signal processing circuit 37 at a stage subsequent to the tuner. The other is output from an RF distribution output terminal 38 and supplied to an RF signal input terminal 41 of a tuner 39 via a coaxial cable.
The image of the satellite broadcast signal of the channel selected in 9 is displayed on the TV monitor 42.

Here, when the tuner 39 serving as the slave unit is set to the operating state and the tuner 33 serving as the master unit is turned off, the power supply 43 of the tuner is turned off, and the signal processing circuit 37 at the subsequent stage of the tuner is turned off. State. On the other hand, a tuner 39 is connected to an RF distribution output terminal 38 of the tuner 33.
The power supply voltage of the LNB is applied from the RF input terminal 41 through a coaxial cable.
4, the voltage is inputted to and detected by the voltage detection circuit 45, and it is detected that the tuner 39 is operating.

When the voltage is detected by the voltage detection circuit 45, the LNB power on / off switch 47 is turned on by a control signal from the LNB power on / off control terminal 46, and the LNB power supply is Supply terminal 4
The power supply voltage for LNB is applied to the power supply 9 and the power supply voltage is further applied to the LNB 31 via the RF signal input terminal 34 and the coaxial cable, so that the LNB 31 operates even though the tuner 33 is in the cutoff state. .

In the above case, the power supply switch 50 is switched by the output signal of the voltage detection circuit 45 to the stabilized power supply circuit 4.
8, the voltage of the output power supply voltage of the stabilized power supply circuit 48 is supplied to the RF amplifier 35 via the power supply changeover switch 50 and the power supply terminal 51 for the RF amplifier, and the RF amplifier 35 is brought into an operating state. . Thus, even if the tuner 33 serving as the master unit is in the cut-off state, when the tuner 39 serving as the slave unit is in the operating state, the RF amplifier 35 becomes active together with the LNB 31, and the distribution of the RF input signal by the tuner 33 is stopped. Normally done.

[0008]

On the other hand, digital satellite broadcasting differs from conventional analog satellite broadcasting in that it has two channels.
A plurality of channels are distributed using different types of polarization, and the polarization is switched by switching the supply voltage to the LNB according to the program selection information. In digital satellite broadcasting, in addition to channel selection, data for additional services such as introduction of channel and program contents and introduction of a time schedule are multiplexed and distributed to a specific channel.

[0009] For example, P which is currently broadcasting in Japan
The erfectTV multiplexes data such as program contents, time schedules, and the like on a vertically polarized specific channel.
For this reason, for example, when these additional service functions are selected while viewing a program on a horizontally polarized channel, the tuner temporarily selects a specific channel of the linearly polarized wave to collect information. become. That is, in digital satellite broadcasting, polarization switching is frequently performed every time a channel is selected or an additional service function is selected. Therefore, as in the case of conventional analog satellite broadcasting, a plurality of tuners are connected to one antenna. , And it is difficult to use each tuner independently.

[0010] Even if a plurality of tuners (slaves) are connected in addition to the first tuner (slave) for supplying power to the LNB using the distributor, the master is selected by the master. You can only watch the channel with the same polarization as the channel you are using. In the above-described example of Perfect TV, if the parent device selects the additional service function while viewing a horizontally polarized channel, for example, the polarization is switched to the vertical polarization. The slave unit that was viewing the polarization channel cannot receive the signal.

The conventional satellite broadcast receiving tuner shown in FIG. 2 cannot be applied to digital satellite broadcast reception. This is because, in digital satellite broadcasting, the content of the above-mentioned additional service data is periodically updated, so that power is always supplied to the LNB even if the main power of the tuner is turned off. .

As described above, conventionally, when receiving a digital satellite broadcast using a receiving antenna equipped with an LNB with a polarization switching function, it is necessary to connect the antenna and the tuner in a one-to-one manner in principle. However, if one-to-many connection is made using a distributor, there is a problem that the slave unit cannot freely select a channel even if the main power of the master unit is off.

The present invention has been made in view of the above points,
It is an object of the present invention to provide a digital satellite broadcast receiving system capable of freely selecting a channel from a slave even when the main power of the master is off.

[0014]

In order to achieve the above object, the present invention provides a receiving antenna equipped with an LNB having a polarization switching function, which receives a digital satellite broadcast wave, converts it into an intermediate frequency signal, and converts the intermediate frequency signal into an intermediate frequency signal. A signal is input from a first digital tuner via an IF signal input terminal to a second digital tuner connected to an IF signal input terminal via a coaxial cable to an IF distribution output terminal of the first digital tuner. A digital satellite broadcast receiving system comprising: a first divider and a second digital tuner; a two divider, an input unit, a signal processing circuit, an LNB supply power supply unit, and an
And an F distribution output terminal.

Here, the two divider splits the IF signal input through the IF signal input terminal into two. The input unit inputs a channel selection signal and a command. The signal processing circuit has a function of generating an on / off identification signal for identifying whether the power of the digital tuner is on or off, and outputs channel selection information based on a channel selection signal from the input unit. At the same time, one of the split output IF signals of the splitter is input and demodulated and reproduced. The LNB power supply receives channel selection information from the signal processing circuit,
The power supply voltage supplied to the LNB via the two divider and the IF signal input terminal is controlled to receive the polarization of the selected channel. Further, an IF distribution output terminal is used to extract the other distribution output IF signal of the two divider.

Here, in the present invention, the LNB power supply unit receives the on / off identification signal together with the channel selection information from the signal processing circuit, and transmits the master unit / slave unit mode selection signal from the input unit. When the power of the first digital tuner is on, the L of the first digital tuner is
Power is supplied from the NB power supply unit to the LNB, and when the power of the first digital tuner is off, the presence or absence of a voltage at the IF distribution output terminal of the first digital tuner is detected. Power supply from the LNB supply power supply unit of the digital tuner to the LNB is stopped, and the power supply from the LNB supply power supply unit of the second digital tuner input to the IF distribution output terminal is changed to the power supply in the first digital tuner. It is configured to supply to the LNB through a two-way distributor.

According to the present invention, an LNB having a polarization switching function is provided.
When receiving a digital satellite broadcast by connecting a plurality of digital tuners to a single receiving antenna equipped with an LNB, the first antenna connected to a single receiving antenna equipped with an LNB with a polarization switching function is connected via a coaxial cable. Although power is supplied from the first digital tuner to the LNB, when the power of the first digital tuner is off, the power from the power supply unit of the second digital tuner can be supplied to the LNB. As a result, the channel of the second digital tuner can be freely selected.

Since the priority of channel selection is on the first digital tuner side, which is the master unit, it is returned to the initial setting state when the power of the first digital tuner is turned on. Be programmed. Also,
When the power of the second digital tuner is off,
No power is supplied from the LNB power supply of the digital tuner. Further, the second digital tuner has a LN
The power supply to the LNB is recognized by the B power supply unit, and the display of the master / slave mode detection unit is switched to the master.

Further, according to the present invention, the first and second digital tuners receive a master unit / slave unit mode selection signal from an input unit and a voltage from an LNB power supply unit, and Each having a mode display section for displaying
The mode display section in the digital tuner of the first digital tuner reverses the display from the initial setting by stopping the voltage supply from the LNB power supply section in the first digital tuner, and the mode display section in the second digital tuner The display is inverted from the display at the time of initial setting by a voltage input from the LNB power supply unit in the second digital tuner.

In the present invention, when the power from the power supply unit of the second digital tuner is supplied to the LNB when the power of the first digital tuner is off, the mode display unit of the second digital tuner uses the mode display unit. It can be displayed that the second digital tuner is the master unit.

According to a fourth aspect of the present invention, two or more second digital tuners are connected in cascade. The LNB power supply in the second digital tuner includes a first digital tuner. Is off and
When one or more digital tuners of the plurality of second digital tuners are powered on, the LNB power supply in the second digital tuner closest to the first digital tuner is powered on. The power is supplied from the unit to the LNB.

According to the present invention, even if the power of the first digital tuner is off, the LNB supply in the second digital tuner closest to the first digital tuner whose power is on among the second digital tuners is provided. Since power can be supplied from the power supply unit to the LNB, channel selection can be performed by the second digital tuner whose power is on.

[0023]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a digital satellite broadcast receiving system according to the present invention. In FIG. 1, a receiving antenna 12 equipped with an LNB 11 with a polarization switching function is connected to an IF signal input terminal 14a of a first digital tuner (master) A via a coaxial cable 13.

The first digital tuner (master unit) A is
2 divider 15a, DC blocking capacitors 16a and 22
a, high frequency blocking choke coils 17a and 23a, a signal processing circuit 18a, an LNa power supply unit 19a, a channel selection and command input unit 20a, a master unit / slave unit mode display unit 21a, and an IF distribution output terminal 24a. It has a configuration.

One distribution output terminal of the two-way distributor 15a has
Signal processing circuit 18a via DC blocking capacitor 16a
Of the LNB supply power supply 19a2 via the high frequency blocking choke coil 17a, and the other distribution output terminal via the DC blocking capacitor 22a. In addition to being connected to the output terminal 24a, it is further connected to the LNB output voltage control section 19a1 of the LNB supply power supply section 19a via the high frequency blocking choke coil 23a.

The channel selection and command input section 20a is an operation button or a remote control device provided on the front panel of the tuner A, and receives a master / slave mode selection signal from a terminal 20a1. Mode display section 2
1a to indicate whether the mode is the master unit or the slave unit, and to the LNB output voltage control unit 19a1.

The signal processing circuit 18a is connected to a terminal 18a based on a signal taken out from a terminal 20a2 of the channel selection and command input section 20a and inputted to a terminal 18a4.
2, the LNB output voltage control unit 19
a1 and a power on / off identification signal
It supplies to the B output voltage control unit 19a1. Further, the signal processing circuit 18a outputs the demodulated video signal and audio signal from the terminals 18a5 and 18a6, respectively.

The IF distribution output terminal 24a is connected to a second digital tuner (slave unit) via a coaxial cable 25.
B is connected to the IF signal input terminal 14b. The second digital tuner (slave unit) B has the same configuration as the first digital tuner (parent unit) A, and the same parts have the same numbers with the suffix b added thereto. That is, the second digital tuner (slave unit) B includes a splitter 15b, DC blocking capacitors 16b and 22b, high-frequency blocking choke coils 17b and 23b, a signal processing circuit 18b, and an LNB.
The power supply unit 19b, a channel selection and command input unit 20b, a master / slave mode display unit 21b, and an IF distribution output terminal 24b are provided.

The master / slave mode display sections 21a and 21b and the LNB output voltage control sections 19a1 and 19b1
Is assumed to be always operable by the backup power supply irrespective of the on / off state of the main power supply of the master unit A and the slave unit B provided respectively.

Next, the operation of this embodiment will be described. First, when the mode setting of the master / slave unit is performed from the channel selection and command input unit 20a, the master / slave unit mode selection signal corresponding to the setting is transmitted to the LNB power supply unit 19a and the master / slave unit mode display. Parts 21a, respectively.
These states are automatically set according to the contents programmed in advance.

That is, when the main power supply of the base unit A is on, the power supply to the LNB 11 is performed from the power supply unit 19a1 built in the LNB supply power supply unit 19a of the base unit A to the current detection unit 19a.
2. High frequency blocking choke coil 17a, 2 distributor 15
a, via the IF signal input terminal 14a and the coaxial cable 13. The power supply voltage to the LNB 11 is a value according to the channel selection information from the signal processing circuit 18a.

As a result, the digital satellite broadcast wave distributed as both the vertical / horizontal linearly polarized waves or the right-handed / left-handed circularly polarized waves as the carrier wave is transmitted by the receiving antenna 12 equipped with the LNB 11 having the polarization switching function. After being received and converted into an intermediate frequency (IF) signal here, the signal is supplied to a two distributor 15a via a coaxial cable 13 and an IF signal input terminal 14a of a first digital tuner (master unit) A to be distributed into two. Is done.

One of the IF signals split into two by the splitter 15a is input to an IF signal input terminal 18a1 of a signal processing circuit 18a via a DC blocking capacitor 16a.
Here, based on the signal taken out from the terminal 20a2 of the channel selection and command input section 20a and input to the terminal 18a4, the signal of the selected desired channel is demodulated into a video signal and an audio signal, which are respectively It is taken out from the output terminals 18a5 and 18a6. Further, a power on / off identification signal is supplied to the LNB output voltage control unit 19a1 from the terminal 18a3 of the signal processing circuit 18a.

The other IF signal distributed by the two divider 15a is supplied to the IF signal input terminal of the second digital tuner (child device) B via the DC blocking capacitor 22a, the distribution output terminal 24a and the coaxial cable 25. 14b, the second digital tuner (slave unit) B performs the same signal processing as the first digital tuner (master unit) A, and outputs video signals of a desired channel from its output terminals 18b5 and 18b6. An audio signal is extracted.

However, in this case, the slave unit B can select only a channel having the same polarization as the reception polarization of the master unit A. Also, when the base unit A selects the additional service function,
Depending on the reception polarization of the master A, the slave B may not be able to receive.

Next, a case where the main unit A turns off the main power supply will be described. In this case, the LNB supply power supply unit 19a of the main unit A is connected to the LNB output voltage control unit 19a in the power supply unit.
1 to detect the presence or absence of a voltage at the distribution output terminal 24a, and if a voltage is detected, the power supply unit 1 in the power supply is detected.
The power supply from 9a3 is stopped, and the power is switched from the LNB power supply unit 19b of the slave unit B to the power input to the IF distribution terminal 24a via the two distributor 15b, the terminal 14b, and the coaxial cable 25.

At the time of this series of switching operations, the master unit A and the slave unit B are connected to the respective master / slave mode display sections 21a, 2a.
1b is switched. That is, the master / slave mode display unit 21a switches the display to the slave unit display by inverting the display at the time of the initial setting, triggered by the stop of the power supply from the power supply unit 19a3. On the other hand, master / slave mode display section 21
In the case of b, the display at the time of initial setting is reversed and switched to the parent device display, triggered by the detection of the current flow by the current detection unit 19b2.

As a result, the slave unit B recognizes that the channel operation from the slave unit B has become effective, performs the signal processing described above, and outputs the video signal and the audio signal of the desired channel from its output terminals 18b5 and 18b6. The signal is extracted. At this time, the slave unit B can freely select a channel regardless of the reception polarization of the master unit A.

If the main power supply of master unit A is turned on in this state, the master / slave unit mode setting is forcibly returned to the initial setting state according to the above-mentioned program contents. The initiative of the station shifts to the master A side. At this time, the master / slave mode display unit 21a switches to the master display at the time of initial setting, triggered by the start of power supply from the power supply unit 19a3. The unit 21b switches to the slave unit display at the time of the initial setting.

When the main power of both the master unit A and the slave unit B is off, power is not supplied from the LNB power supply unit 19b of the slave unit. Thus, in this embodiment,
Two digital tuners A are connected to one receiving antenna 12
When the main power of the digital tuner (master unit) that supplies power to the LNB is off when the digital satellite broadcast signal is received by connecting the digital satellite broadcast signal and the base station B to the LNB, a signal from the slave unit, which was conventionally impossible, is not possible. Free channel selection is possible.

Next, a second embodiment of the present invention will be described. In the first embodiment, the case where two digital tuners are used as the master unit A and the slave unit B has been described, but the third slave unit C is connected to the IF distribution output terminal 24b of the slave unit B. The same effects as those of the first embodiment can be obtained.

In this case, the priorities regarding the initiative of the channel selection of the slave units B and C are on the side closer to the master unit A, ie, the slave unit B when the slave units B and C are both powered on.
However, when the main power of one of the slave units B and C is turned on, the main power on side has priority. By cascading the slave units in this way, it is possible to connect more digital tuners. However, in this case, it is necessary to insert and connect a booster at a necessary point to compensate for the distribution loss.

[0043]

As described above, according to the present invention,
When receiving a digital satellite broadcast by connecting a plurality of digital tuners to one receiving antenna equipped with an LNB with a polarization switching function, the LNB with a polarization switching function is used.
Supplies power to the LNB from a first digital tuner connected via a coaxial cable to a single receiving antenna equipped with a digital tuner. When the power of the first digital tuner is off, the second digital tuner is turned off. Can supply power from the power supply unit to the LNB.
Free channel selection from the second digital tuner, which was conventionally impossible, can be performed. This is particularly effective when a digital tuner is installed in a living room and a bedroom in a general home.

Further, according to the present invention, when the power from the power supply unit of the second digital tuner is supplied to the LNB when the power of the first digital tuner is off, the mode of the second digital tuner is changed. Since the display unit can indicate that the second digital tuner is the master unit, it is possible to clearly notify the user which digital tuner can freely select a channel.

According to the present invention, when a plurality of second digital tuners are connected in cascade, even if the power of the first digital tuner is off, the power of the second digital tuner is on. Since power can be supplied to the LNB from the LNB supply power supply unit in the second digital tuner closest to the first digital tuner,
Channel selection can be freely performed by the second digital tuner whose power is on.

[Brief description of the drawings]

FIG. 1 is a block diagram of one embodiment of the present invention.

FIG. 2 is a block diagram of a conventional example.

[Explanation of symbols]

 Reference Signs List 11 Low noise converter (LNB) 12 Receiving antenna 13, 25 Coaxial cable 14a, 14b IF signal input terminal 15a, 15b Divider 18a, 18b Signal processing circuit 19a, 19b LNB supply power supply unit 20a, 20b Channel selection and command input Units 21a, 21b Master / slave unit mode display unit 24a, 24b IF distribution output terminal A master unit B Slave unit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04N 5/44 H04B 1/16 H04B 1/18 H04N 5/63 H04N 7/20

Claims (6)

(57) [Claims] 1. A digital satellite broadcast wave is received by a receiving antenna equipped with an LNB with a polarization switching function, converted into an intermediate frequency signal, and the intermediate frequency signal is input via an IF signal input terminal. A digital satellite broadcast receiving system comprising: a digital tuner; and a second digital tuner connected to an IF signal input terminal via a coaxial cable to an IF distribution output terminal of the first digital tuner, wherein: A second digital tuner, a two divider for dividing the IF signal input through the IF signal input terminal into two, an input part for inputting a channel selection signal and a command, and a power source for the digital tuner. It has a function of generating an on / off identification signal for identifying whether it is on or off, and based on a channel selection signal from the input unit. A signal processing circuit for outputting channel selection information and demodulating and reproducing one of the divided output IF signals of the two dividers, and receiving the channel selection information from the signal processing circuit, The L through a filter and an IF signal input terminal.
An LNB supply power supply unit for controlling the power supply voltage supplied to the NB to receive the polarization of the selected channel, and an IF for extracting the other distribution output IF signal of the two divider
A distribution output terminal, the LNB power supply unit receiving the on / off identification signal together with the channel selection information from the signal processing circuit, and selecting a master / slave mode from the input unit. Receiving a signal, when the power of the first digital tuner is on, supplying power to the LNB from an LNB power supply unit of the first digital tuner, and when the power of the first digital tuner is off, Detecting the presence or absence of a voltage at an IF distribution output terminal of the first digital tuner, and stopping the power supply from the LNB supply power supply unit of the first digital tuner to the LNB when the voltage is detected; Said I
Digital satellite broadcast reception, characterized in that power supplied from an LNB supply power supply section of the second digital tuner input to an F distribution output terminal is supplied to the LNB through a two divider in the first digital tuner. system. 2. The first and second digital tuners receive a master / slave mode selection signal from the input unit and a voltage from the LNB power supply unit, and determine whether the master / slave unit is a master unit or a slave unit. The first digital tuner has a mode display unit for displaying, and the mode display unit in the first digital tuner is inverted from the display at the time of initial setting by stopping the voltage supply from the LNB power supply unit in the first digital tuner. The mode display section in the second digital tuner reverses the display at the time of the initial setting by a voltage input from an LNB power supply section in the second digital tuner. Digital satellite broadcast receiving system. 3. When the power of the first digital tuner is turned on, the mode display sections in the first and second digital tuners are forcibly set to the display at the time of initial setting, respectively. 3. A digital satellite broadcast receiving system according to claim 2, wherein: 4. A first antenna which receives a digital satellite broadcast wave with a receiving antenna equipped with an LNB having a polarization switching function and converts it into an intermediate frequency signal, and the intermediate frequency signal is input via an IF signal input terminal. Digital tuner and IF
A digital satellite broadcast receiving system comprising: a plurality of second digital tuners having a signal input terminal connected to an IF distribution output terminal of a preceding digital tuner via a coaxial cable, wherein the first and second digital tuners are provided. A splitter for splitting the IF signal input through the IF signal input terminal into two, an input unit for inputting a channel selection signal and a command, and determining whether the power of the digital tuner is on or off. Has a function of generating an identification on / off identification signal, and outputs channel selection information based on a channel selection signal from the input unit; A signal processing circuit for demodulating and reproducing the received signal, receiving the channel selection information from the signal processing circuit, Via said terminal L
An LNB supply power supply unit for controlling the power supply voltage supplied to the NB to receive the polarization of the selected channel, and an IF for extracting the other distribution output IF signal of the two divider
A distribution output terminal, the LNB power supply unit receiving the on / off identification signal together with the channel selection information from the signal processing circuit, and selecting a master / slave mode from the input unit. When a signal is received and the power of the first digital tuner is on, power is supplied to the LNB from an LNB power supply unit of the first digital tuner, and the power of the first digital tuner is off and When one or more digital tuners of the plurality of second digital tuners are powered on, the power is on and the second digital tuner in the second digital tuner closest to the first digital tuner is powered on. A digital satellite broadcast receiving system, wherein power is supplied from an LNB power supply unit to the LNB. 5. The first and second digital tuners receive a master / slave mode selection signal from the input unit and a voltage from the LNB supply power unit, and determine whether the master / slave unit is a master unit or a slave unit. The first digital tuner has a mode display unit for displaying, and the mode display unit in the first digital tuner is inverted from the display at the time of initial setting by stopping the voltage supply from the LNB power supply unit in the first digital tuner. Each of the mode display units in the plurality of second digital tuners performs a reverse display from the display at the time of initial setting by a voltage input from an LNB power supply unit in the second digital tuner. Item 6. A digital satellite broadcast receiving system according to item 4. 6. When the power of the first digital tuner is turned on, the mode display sections in the first and second digital tuners are forcibly set to the display at the time of initial setting, respectively. The digital satellite broadcast receiving system according to claim 5, wherein: