JP2001231034A - Joint receiving system, terminal device thereof, and frequency conversion device for terminal - Google Patents

Abstract

(57) [Problem] To provide a low-cost terminal frequency converter with a simplified power supply circuit. An input terminal is supplied with a converted signal obtained by frequency-converting a satellite digital broadcast intermediate frequency signal into a frequency band that can be transmitted by a transmission path of a joint receiving system. The converter 20 converts the frequency of the converted signal supplied from the input terminal 10 into a signal in a frequency band that can be processed by a digital television receiver. The output signal of converter 20 is supplied to output terminal 24. The output terminal 24 is also supplied with operating power from a television receiver. The operating power is supplied from the output terminal 24 to the constant voltage circuit 30.
Converter 20 operates according to the output voltage from.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joint receiving system for transmitting, for example, an intermediate frequency signal for satellite digital broadcasting, a terminal device used for the system, and a terminal frequency converter.

[0002]

2. Description of the Related Art In the near future, satellite digital broadcasting will be started from broadcasting satellites. It is conceivable to transmit this satellite digital broadcast to each terminal via an existing joint reception system. In this case, the satellite digital broadcast signal received by the satellite broadcast receiving antenna is frequency-converted into a satellite digital broadcast intermediate frequency signal by a converter attached to the satellite broadcast receiving antenna. This satellite digital broadcast intermediate frequency signal has a frequency band of about 1 GHz. Some of the already installed joint receiving systems have a low transmittable frequency of, for example, 70 to 450 MHz and cannot transmit the satellite digital broadcast intermediate frequency signal in the same frequency band. In this case, it is conceivable that the satellite digital broadcast intermediate frequency signal is frequency-converted to a frequency that can be transmitted in the joint receiving system and transmitted to the terminal side of the joint receiving system via the transmission path.

[0003]

However, in this case, since each terminal of the existing joint receiving system is provided with a television receiver or tuner compatible with satellite digital,
It is desirable to provide a frequency conversion device for converting the frequency to a receivable frequency.

An object of the present invention is to provide a frequency conversion device capable of receiving a satellite digital broadcast signal at low cost, and a joint reception system using the frequency conversion device.

[0005]

According to the present invention, there is provided a frequency conversion device for a terminal of a joint receiving system, which supplies a converted signal obtained by frequency-converting a satellite digital broadcasting intermediate frequency signal to a frequency band transmittable by a transmission line of the joint receiving system. Input terminal. In addition, a satellite analog broadcast signal or a terrestrial television broadcast signal in the UHF and / or VHF band may be transmitted to this input terminal.
The frequency converter converts the converted signal supplied from the input terminal into a signal in a frequency band that can be processed by the digital television receiver. This receiving means may be, for example, a digital tuner,
Alternatively, it may be a digital television receiver equipped with a digital tuner. An output signal of the frequency converting means is supplied to an output terminal, and an operating power is supplied to the output terminal from the television receiving means. The operating power is supplied to the power supply unit from the output terminal, and the frequency conversion unit is operated.

With this configuration, the frequency conversion means converts the frequency into a signal in a frequency band that can be processed by the television receiving means, so that the television receiving means can be used as it is, and the cost is reduced. In addition, since the frequency converter operates with the operating power supplied from the television receiver, the terminal frequency converter does not need to be provided with a power supply for converting commercial AC power to DC power. Further, the cost can be reduced.

[0007] It is possible to provide a display means that operates when the operation power is supplied. In this case, it can be confirmed by the operation of the display means that the terminal frequency converter is operating.

[0008] A control signal output terminal for outputting a control signal may be provided in the television receiving means or the terminal device in accordance with the supply of the operating power. As the control signal output terminal, for example, another output terminal for outputting the above-described satellite analog broadcast signal or the UHF band and / or VHF band terrestrial television broadcast signal can be used. As the control signal, for example, a signal based on a DC voltage supplied as an operation power supply can be output.

By outputting the control signal in this way, the television receiving means can be automatically set to a state in which satellite digital broadcasting can be received, and satellite digital broadcasting can be received from the terminal device toward the head end. It is possible to report and monitor the status of the communication using the joint reception system. In the case of this notification and monitoring, if the joint receiving system is bidirectional, it can be transmitted to the headend via the transmission path.

[0010] The joint receiving system according to the present invention has a transmission path. The head end includes a first frequency conversion device that converts the frequency of a satellite digital broadcast intermediate frequency signal into a converted signal in a frequency band that can be transmitted on the transmission line and supplies the converted signal to the transmission line. The conversion signal is supplied from the transmission path to a terminal frequency conversion device. The terminal frequency converter converts the converted signal into a signal in a frequency band that can be received by the digital-compatible television receiving means, and supplies the signal to the digital-compatible television receiving means via an output terminal. Furthermore, the terminal frequency converter is
Operated by operating power supplied from the television receiving means via the output terminal. A display means that operates when the operation power is supplied can be provided in the terminal frequency converter. When receiving the supply of the operating power, the terminal frequency converter outputs a control signal to the television receiving means or the terminal device from a terminal different from the output terminal. The control signal may be, for example, a voltage generated by the supply of the operation power, specifically, a DC voltage.

In this joint receiving system, since the frequency conversion device for the terminal converts the frequency to a signal that can be processed by the television receiving means, the television receiving means can be used as it is, and the cost can be reduced. it can.
In addition, since the terminal frequency converter is operated by the power supplied from the television receiver, there is no need to provide a power supply unit independently for the terminal converter. Since the number of terminal frequency converters used is extremely large in the joint receiving system, a great cost reduction can be realized by not having the terminal frequency converter having its own power supply device.
In addition, in this terminal frequency conversion device, a control signal can be output to the outside in response to the supply of the operating power, so that the external television receiving means and the terminal device can be automatically controlled. .

The frequency converter according to the present invention has a first input terminal. A first input terminal is connected to a first group of second intermediate frequency signals obtained by frequency-converting a first group of multiple satellite digital broadcast signals into a frequency band that can be transmitted through a transmission path. A first group of third intermediate frequency signals obtained by frequency-converting the intermediate frequency signal into a frequency band receivable by the receiving means is supplied. The first group of first intermediate frequency signals is generated by, for example, a converter provided in a satellite broadcast receiving antenna. The first group of second intermediate frequency signals is generated by, for example, frequency conversion means provided at the head end. The first group of third intermediate frequency signals is generated, for example, by another frequency conversion device provided in the terminal device. This frequency converter also has a second input terminal. A second input terminal is capable of transmitting a second group of first intermediate frequency signals obtained by frequency-converting a second group of multiple satellite digital broadcast signals through a transmission line, and the first group of second intermediate frequency signals. A second group of second intermediate frequency signals, which have been frequency-converted into different frequency bands, are input. The second group of multi-satellite digital broadcast signals corresponds to, for example, an increased satellite broadcast. The first intermediate frequency signal of the second group is also the first intermediate frequency signal of the first group.
Similarly to the intermediate frequency signal, the second intermediate frequency signal of the second group is generated by the converter attached to the satellite broadcast receiving antenna, and the second group of second intermediate frequency signals is also generated by the frequency conversion means provided at the head end. In the frequency converter of the present invention,
Frequency conversion means is also provided. This frequency converting means is capable of receiving a second group of second intermediate frequency signals from a second input terminal by the receiving means and having a second group of second intermediate frequency signals different from the first group of third intermediate frequency signals. The frequency is converted to a third intermediate frequency signal of the group. The mixing means mixes the first group of third intermediate frequency signals from the first input terminal and the second group of third intermediate frequency signals from the frequency conversion means. An output signal of the mixing means is output to an output terminal. The output terminal is
Output to the receiving means.

Digital satellite broadcasting is scheduled to be performed on four channels at the beginning. In the future, the number of satellite digital broadcasting channels may be increased. In this case, the second
The frequency band of the intermediate frequency signal is different between the newly increased satellite digital broadcast signal and the existing satellite digital broadcast signal.
Different ones are used. Depending on the frequency band of the increased second intermediate frequency signal of the satellite digital broadcast, these may not be able to be frequency-converted to the third intermediate frequency signal by the existing frequency converter. This frequency conversion device can cope with such a problem.
This is used when a second group of satellite digital broadcast signals is newly transmitted while the group of satellite digital broadcast signals is being transmitted from broadcast satellites. The second group of second intermediate frequency signals is frequency-converted by the frequency conversion means of the frequency conversion device into a second group of third intermediate frequency signals receivable by the reception means. The third intermediate frequency signal of the group is mixed with the third intermediate frequency signal by the mixing means, and supplied to the receiving means from the output terminal. Therefore,
The receiving means can be used as it is, and the cost can be reduced. Further, after transmitting the first group of third intermediate frequency signals from the existing frequency conversion device to the receiving means via the transmission line, the second group of third intermediate frequency signals are separated from the frequency conversion device to the receiving means. It is not necessary to transmit the third intermediate frequency signal of the first and second groups to the receiving means by the transmission path from the frequency conversion device.

This frequency conversion device includes a power supply circuit for operating the frequency conversion means with a voltage generated based on a voltage supplied to the output terminal from the outside, and a power supply circuit for converting the voltage supplied to the output terminal to the output terminal. An energizing circuit for supplying one input terminal may be provided. The voltage to the output terminal can be supplied, for example, from the receiving means.

In this case, there is no need to provide a large DC power supply for rectifying and smoothing the voltage from the commercial AC power supply, and for example, the existing frequency converter does not require the large DC power supply as described above. It is.

A terminal device for a joint reception system according to the present invention has first and second frequency conversion devices. First
The first group of second intermediate frequency signals obtained by frequency-converting the first group of first intermediate frequency signals obtained by frequency-converting the first group of multiple satellite digital broadcast signals into a frequency band that can be transmitted on a transmission path. And frequency-converts it into a third intermediate frequency signal of a first group in a frequency band receivable by the receiving means. The second frequency converter receives the first group of third intermediate frequency signals from the first frequency converter, and further converts the second group of multiple satellite digital broadcast signals into a first group of first intermediate frequency signals. A second frequency-converted second frequency signal capable of transmitting an intermediate frequency signal through the transmission path and having a different frequency band from the second intermediate frequency signal of the first group.
A second intermediate frequency signal of the group is input. The first group of multi-satellite digital broadcast signals is, for example, an existing one,
The group of digital satellite broadcast signals is, for example, an expanded one. The first and second groups of first intermediate frequency signals are generated, for example, by a converter provided in a satellite broadcast receiving antenna. The first and second groups of second intermediate frequency signals are generated by, for example, frequency conversion means provided at the head end. The second frequency conversion device is capable of receiving a second group of second intermediate frequency signals by the receiving means and converting the first group of third intermediate frequency signals to a second group of third intermediate frequency signals in a different frequency band. Mixing means for frequency-converting the signals into signals, mixing and outputting the first group of third intermediate frequency signals and the second group of third intermediate frequency signals, And an output terminal for outputting a signal.

According to this terminal device, the first frequency converter is directly connected to the receiving means, and while the first group of satellite digital broadcast signals is being received, the second group of satellite digital broadcasting is newly added. When a broadcast signal is transmitted, only the second frequency converter is provided between the first frequency converter and the receiving means, so that not only the existing first group but also the added second group of satellites are provided. Digital broadcast signals can also be received by the receiving means. Therefore, the receiving means can be used as it is and the cost can be reduced, and the transmission path to the receiving means only needs to be from the second frequency converter.

The second frequency conversion device includes a power supply circuit for operating the frequency conversion means based on a voltage supplied to the output terminal of the second frequency conversion device, and a voltage supplied from the outside to the output terminal. And a power supply circuit for supplying the frequency conversion device. In this case, the first frequency conversion device is configured to operate based on the voltage supplied from the energizing circuit.

With this configuration, it is not necessary to incorporate a large-sized power supply for generating a DC power supply from a commercial AC power supply in each of the first and second frequency conversion apparatuses. The size can be reduced.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A joint receiving system according to one embodiment of the present invention has a head end 1 as shown in FIG. The head end 1 is supplied with UHF band and VHF band terrestrial television broadcast signals received by the UHF band receiving antenna 2U and the VHF band receiving antenna 2V, which are supplied to a transmission line, for example, a coaxial cable 3. Have been. The coaxial cable 3 is provided with an amplifier such as a branch amplifier 5 at predetermined intervals, and a signal branched therefrom is supplied to each terminal device 7 via a branch unit 6. In the figure, each of the branch amplifier 5 and the terminal device 7 is 1
Although only one is shown, in practice these are provided in large numbers.

A satellite analog broadcast signal received by the satellite broadcast receiving antenna 4 is frequency-converted into a satellite analog broadcast first intermediate frequency signal by a converter 4a attached to the antenna 4 and supplied to the head end 1, where the signal is supplied to the head end 1. The frequency is converted into a satellite analog broadcast second intermediate frequency signal in a frequency band that can be transmitted by the coaxial cable 3 by a frequency conversion device incorporated in the end 1, and transmitted to each terminal device 7 via the coaxial cable 3. Note that the satellite analog broadcast signal includes a plurality of channels.

In this state, when satellite digital broadcasts are newly started, these are also received by the satellite broadcast receiving antenna 4 and frequency-converted by the converter 4a into satellite digital broadcast first intermediate frequency signals. Although not shown, a frequency converter is newly incorporated in the head end 1, and a first intermediate frequency signal of a plurality of channels of satellite digital broadcasting is supplied to the frequency converter.
It is frequency-converted (down-converted) into a converted signal, for example, a satellite digital broadcast second intermediate frequency signal. The second intermediate frequency signal of the satellite digital broadcast has a constant frequency interval between the channels, is frequency-converted to a frequency band that can be transmitted by the coaxial cable 5, and is supplied to the terminal device 7 via the coaxial cable 5. The signal is transmitted from a so-called broadcast satellite, received by the antenna 4, supplied to the head end 1, and transmitted to the terminal device via the transmission path. During this transmission, PSK transmission in which the PSK modulation scheme is maintained is performed. . Of course, the frequency bands of the satellite and digital broadcast second intermediate frequency signals are selected differently.

The frequency converter 8 of the terminal device 7 has an input terminal 10 as shown in FIG.
Satellite analog and digital broadcasting second intermediate frequency signal and U
Terrestrial television broadcast signals in the HF and VHF bands are supplied. The satellite analog broadcast second intermediate frequency signal and the UHF and VHF terrestrial television broadcast signals are demultiplexed by a demultiplexer 12 and supplied to a signal output terminal 16 via a DC blocking capacitor 14. As shown, the signal is supplied from the signal output terminal 16 to the analog input terminal of the digital broadcast compatible television receiver 18 via a coaxial cable.

Returning to FIG. 1, the second intermediate frequency signal of the satellite digital broadcast is split by the splitter 12 and supplied to frequency conversion means, for example, a converter 20, where it is received by the digital television receiver 18. It is frequency-converted (up-converted) to a possible frequency band, for example, a satellite digital broadcast third intermediate frequency signal in the same frequency band as the satellite digital broadcast first intermediate frequency signal. Converter 20
For example, it has a simple configuration including one mixer and one local oscillator. Since the second intermediate frequency signal of the satellite digital broadcast is composed of a plurality of channels having a constant frequency interval, the frequency of the frequency is collectively controlled by a simple configuration including one mixer and one local oscillator. Is converted. Satellite digital broadcasting with frequency conversion 3
The intermediate frequency signal is supplied to the DC blocking capacitor 22, the output terminal 2
4 to a digital-compatible television receiving means, for example, a satellite digital broadcast tuner 26. The satellite digital broadcast tuner 26 demodulates the satellite digital broadcast third intermediate frequency signal into a video signal and an audio signal, and supplies the demodulated signal to the digital television receiver 18. In addition,
In some cases, the digital television receiver 18 has a built-in one corresponding to the satellite digital tuner 26.
In this case, the frequency-converted satellite digital broadcast 3
The intermediate frequency signal is supplied directly to the digital television receiver 18. Therefore, the satellite digital tuner 26
May be digital-compatible television receiving means, or a digital-compatible television receiver may be digital-compatible television receiving means.

The tuner 26 for satellite digital broadcasting has a circuit for generating a DC voltage of, for example, +15 V. When a specific channel is selected by, for example, a remote control transmitter, the DC voltage generating circuit supplies the DC voltage to the tuner 26. The voltage is supplied to the frequency converter 8 via the output terminal 24.
Supplied to This DC voltage is supplied to a power supply unit, for example, a constant voltage circuit 30 via a high-frequency blocking coil 28 connected to the output terminal 24. The constant voltage circuit 30 converts the input DC voltage of +15 V into a predetermined voltage, converts the voltage into a constant voltage, and supplies the voltage to the converter 20. Thereby, converter 20 operates. Therefore, a large power supply circuit for generating a DC voltage from a commercial AC power supply is not required in the frequency conversion device 8, and the cost can be reduced.
Further, the converter 20 has a simple configuration including one mixer and one local oscillator, and has a plurality of satellite digital broadcasting
Since the frequency conversion of the intermediate frequency signal can be performed, the cost can be further reduced.

The DC voltage supplied to the high frequency blocking coil 28 is supplied to a display means, for example, a light emitting diode 34 via a current limiting resistor 32. Light emitting diode 34
Is mounted in a position that can be seen from the outside. Accordingly, the light-emitting diode 34 emits light when a DC voltage of +15 V is supplied to the output terminal 24, indicating that the frequency converter 8 is operating.
It can be confirmed from the outside that the frequency converter 8 is operating.

The output voltage of the constant voltage circuit 30 is supplied to an on contact 36on of the changeover switch 36. The changeover switch 36 also has an off contact 36off and a contact 36c. The off contact 36off is an empty terminal,
The contact 36c is supplied to the output terminal 16 via the current limiting resistor 38. Therefore, in a state where the contact 36c of the changeover switch 36 is connected to the ON contact 36on, a DC voltage of +15 V is supplied to the output terminal 24,
A DC voltage is supplied from a signal output terminal 16 to a digital broadcast compatible television receiver 18. Although not shown, the digital television receiver 18 is provided with a detection circuit for this voltage. When the detection circuit detects this voltage and generates a detection signal, the television receiver 18 is set to the satellite digital broadcast reception state, and automatically enters the satellite digital broadcast reception state. The DC voltage output from the signal output terminal 16 functions as a control signal. As described above, since the output voltage of the constant voltage circuit 30 is used as it is as a control signal, it is not necessary to separately provide a control signal generator, and cost can be reduced. The contact 36c of the changeover switch 36 is the off contact 3
6off, the output terminal 2
Even when the DC voltage of +15 V is supplied to 4, the output voltage of the constant voltage circuit 30 is not supplied to the signal output terminal 16.

FIG. 3 shows a joint receiving system according to the second embodiment. In this joint receiving system, the signal output terminal 1
6 is a terminal device, for example, a CATV home terminal 40
The output signal of the home terminal 40 is supplied to the television receiver 18, where it is demodulated into a video signal and an audio signal.
Is supplied to

The CATV home terminal 40 detects a DC voltage as a control signal supplied from the frequency converter 8 via the signal output terminal 16, and in accordance with the detection, indicates that satellite digital broadcasting is being received. Is supplied from the signal output terminal 16 to the frequency converter 8. The frequency converter 8 transmits the upstream signal from the input terminal 10 to the head end 2 via the coaxial cable 6. In this case, the head end 2 includes an upstream signal receiving unit. That is, the joint receiving system is a two-way joint receiving system. Other configurations are the same as those of the joint receiving system according to the first embodiment, and thus detailed description is omitted.

With such a configuration, for example, the headend 2 can investigate and monitor the time during which satellite digital broadcasting is received as data.

In the first embodiment, the changeover switch 36
Was used, but an open / close switch may be used instead. Also, by removing the changeover switch 36, the output terminal 2
While the DC voltage is being supplied to 4, the DC voltage may be supplied from the signal output terminal 16 to the television receiver 18 or the CATV home terminal 40. In addition, although the constant voltage circuit 30 is used, the present invention is not limited to this.
A DC voltage of 15V may be reduced to a predetermined voltage. Although the converter 20 performs frequency conversion of a plurality of second intermediate frequency signals of satellite digital broadcasting using one mixer and one local oscillator, a plurality of second intermediate frequency signals of satellite digital broadcasting have been described. A converter may be provided for each channel constituting the signal. Although the output voltage of the constant voltage circuit 30 is output as a control signal as it is, when a +15 V DC voltage is supplied to the output terminal 24, a high-frequency or low-frequency oscillator configured to operate is controlled by a high-frequency or low-frequency oscillator. It can also be used as a generating means. In addition, although the duplexer 12 is used, if the converter 20, the digital television receiver 18, or the CATV home terminal 40 includes a filter for selecting a signal of a frequency band to be input, the splitter 12 is used. The distributor 12 can be replaced with a distributor or a branch.

The terminal device 10 according to the third embodiment of the present invention
2 is used as a terminal device of the joint receiving system shown in FIG. This joint receiving system has a headend 10
3 which are UHF receiving antennas 105U and V
UH received by HF band receiving antenna 105V
The terrestrial television broadcast signals of the F band and the VHF band are supplied to a transmission path, for example, a coaxial cable 108. In addition, a signal obtained by frequency-converting the satellite communication signal into a frequency band that can be transmitted by the joint reception system by the head end 103 is also transmitted by the coaxial cable 108. Coaxial cable 10
Between 8, the branch amplifier 109 is provided at predetermined intervals. The signals branched from these branch amplifiers 109 are supplied to the terminal device 102 via the branch unit 110. In the figure, the branch amplifier 109, the branch unit 110, and the terminal device 102 are shown one by one, but actually, a large number of branch amplifiers 109, the branch unit 110, and the terminal device 102 are provided. The signal received by the satellite broadcast receiving antenna 104 is also supplied to the head end 103. This satellite broadcast receiving antenna 104 includes a first group, for example, BS1,
The satellite digital broadcast signals of four channels of BS3, BS13 and BS15 are received. BS5, BS7, BS
9. The satellite analog broadcast signal of four channels of BS11 is also received. Originally, BS5, BS7, BS9, BS11
Although only the four-channel satellite analog broadcast signals have been received, since the transmission of the four-channel satellite digital broadcast signals BS1, BS3, BS13, and BS15 has been newly started, these are also received. The satellite digital broadcast signal has a modulation scheme of PSK, is frequency-converted as described later, and is transmitted to the terminal device. During this time, PSK is maintained as the modulation scheme. As shown in FIG. 5, a satellite analog and digital broadcast first intermediate frequency signal BS-IF in a 1 GHz band is converted into a satellite analog and digital broadcast signal by a converter 104a attached to this antenna 104.
The frequency is converted from 1 to BS-IF 15 and supplied to the head end 103. The center frequency of BS1-IF1 is 1049.48 MHz, the center frequency of BS3-IF1 is 1088.77 MHz, the center frequency of BS5-IF1 is 1122.60 MHz, the center frequency of BS7-IF1 is 1164.56 MHz, and the center frequency of BS9-IF1 is The center frequency is 1202.92 MHz, the center frequency of BS11-IF1 is 1241.28 MHz, the center frequency of BS13-IF1 is 1279.64 MHz, and the center frequency of BS15-IF1 is 1318.00 MHz.

In the head end 103, the first intermediate frequency signals BS1-IF1, BS3-IF1,
Multiple channels A in a frequency band in which BS13-IF1 and BS15-IF1 can be transmitted by the coaxial cable 108
Frequency conversion means (not shown) for converting the frequency into the second intermediate frequency signals of satellite digital broadcasts D to D of FIG.
The A channel is, as shown in FIG.
Is converted into a frequency, and the center frequency is 253.
34 MHz. B channel is BS13-IF1
Is frequency-converted, and its center frequency is 291.
70 MHz. The C channel is obtained by frequency-converting BS3-IF1, and its center frequency is 330.0%.
6 MHz. The D channel is obtained by frequency-converting BS1-IF1, and has a center frequency of 368.42.
MHz.

The satellite digital broadcast second intermediate frequency signals of the A to D channels are transmitted to the terminal device 1 as shown in FIG.
02, for example, to a block up converter 112. The first intermediate frequency signal of the satellite analog broadcast is also frequency-converted by the coaxial cable 108 in the head end 103 into a frequency band that can be transmitted.
The signal is transmitted via the branching amplifier 107, the branching device 110, and the coaxial cable 108 together with the UHF band and VHF band terrestrial signals, and supplied to the block up converter 112.

The block up converter 112 has the configuration shown in FIG.
As shown in the figure, the input terminal 114 is provided with a signal from the head end 103 described above. This signal is supplied to the duplexer 116. In the demultiplexer 116, the second intermediate frequency signals of the satellite digital broadcasting of the A to D channels are demultiplexed, and unnecessary signal components are removed by a band-pass filter 118 having a pass band that passes only these signals, and supplied to the converter 20. Is done. Although not shown, the converter 120 has one mixer and one local oscillator, and collectively converts satellite digital broadcast second intermediate frequency signals of channels A to D as shown in FIG. , The third intermediate frequency signal B of satellite digital broadcasting
The frequency is converted to S9-IF3, BS11-IF3, BS13-IF3, and BS15-IF3. Therefore, the oscillation frequency of the local oscillator is, for example, 1571.34 MHz.
Has been selected. Therefore, converter 120 converts the frequency of the input signal to a frequency obtained by subtracting the frequency of the input signal from the frequency of the local oscillation signal.

BS9-IF3 is a frequency-converted D channel, BS11-IF3 is a frequency-converted C channel, BS13-IF3 is a frequency-converted B channel, and BS15-IF3 is a A
This is a frequency-converted version of the channel. BS9-IF
3 is BS9-IF1 and BS11-IF3 is BS11-IF1.
IF1 and BS13-IF3 correspond to BS13-IF1 and B
S15-IF3 is the same frequency band as BS15-IF1. Therefore, the satellite digital broadcasting third intermediate frequency signal BS9-IF3, BS11-IF3, BS13-
The IF3 and the BS15-IF3 can be received by a receiving unit described later, for example, the satellite digital tuner 122.

Satellite digital broadcast third intermediate frequency signal BS9
-IF3, BS11-IF3, BS13-IF3 and B
The S15-IF3 is output to an output terminal 128 via a DC blocking capacitor 126 after unnecessary signal components are removed by a bandpass filter 124 having a pass band for passing only these components.

The output terminal 128 is connected to the satellite digital tuner 122 via a coaxial cable as shown by a dotted line in FIG.
9-IF3, BS11-IF3, BS13-IF3, and BS15-IF3 are demodulated by the satellite digital tuner 122 and viewed by the digital television receiver 130.

In the demultiplexer 116 of the block up converter 112, signals other than the satellite digital broadcast second intermediate frequency signal among the signals from the head end 103 are demultiplexed, output from the output terminal 132, and are indicated by the dotted line in FIG. Is supplied to the CATV home terminal 134 and demodulated here.
0 is supplied.

The satellite digital tuner 122 has a built-in DC power supply, and a DC voltage from the DC power supply is supplied to an output terminal 128 of the block up converter 112 via a coaxial cable. This voltage is further illustrated in FIG.
As shown in (1), the voltage is supplied to the constant voltage circuit 138 via the high-frequency blocking coil 136, where it is converted into a predetermined voltage.
Further, the voltage is converted to a constant voltage, supplied to the converter 120, and operated.

By the way, in the future, BS5, BS7, BS9
And the satellite analog broadcast signal of the BS 11 may be digitized. This is the second group of satellite digital broadcast signals. These are also frequency-converted by the converter 104a into the first digital intermediate frequency signal of the satellite digital broadcast in the same frequency band as the satellite analog broadcast signal, and supplied to the head end 103. In this case, depending on the co-reception system, frequency conversion of the satellite digital broadcast first intermediate frequency signal into H to K channel satellite digital broadcast second intermediate frequency signals that can be transmitted by the coaxial cable 108 as shown in FIG. There is. H channel is BS11
IF1 is frequency-converted and the center frequency is 52
1.86 MHz. The I channel is BS9-IF
1 is frequency converted, and the center frequency is 560.22.
MHz. The J channel is obtained by frequency-converting BS7-IF1, and has a center frequency of 598.58 MHz. The K channel is obtained by frequency-converting BS5-IF1, and has a center frequency of 636.94 MHz.

As is clear from FIG. 7, the frequency intervals of the first group A to D channels are constant, and the frequency intervals of the second group H to K channels are also constant. Moreover, both frequency intervals have the same value as the frequency interval of each transponder of the broadcasting satellite. However, D of the highest frequency band of the first group
The frequency interval between the channel and the H channel in the lowest frequency band of the second group is different. In addition, the H to K channels also need to be frequency-converted to a frequency band that can be received by the satellite digital tuner 22, and the BS 9-IF
3 to BS15-IF3 are used. Therefore, it is necessary to convert the H-K channel satellite digital broadcast second intermediate frequency signal into BS1-IF3 to BS7-IF3 in the same frequency band as BS1-IF1 to BS7-IF1, respectively.

If the frequency intervals of the D and H channels are also equal to the frequency intervals of the transponders, the H to K channels are also supplied to the block up converter 112 to be frequency-converted to BS1-IF3 to BS7-IF3. . However, in practice, the frequency intervals of the D and H channels are different from the transponder frequency intervals as described above. Therefore, as shown in FIG. 5, the second frequency converter, for example, the block up converter 140
2 and the satellite digital tuner 122.

The block converter 40 has a first input terminal 142, as shown in FIG.
As shown by a solid line in FIG.
, And the third intermediate frequency signals BS9-IF3 to BS15-IF3 of the satellite digital broadcasting are supplied.

The block converter 140 also has a second input terminal 144 as shown in FIG. 4, which is connected to the output terminal 132 of the block up converter 112 as shown by the solid line in FIG. The signal from the output terminal 132 includes, instead of the second analog frequency signal of the satellite analog broadcast, the second intermediate frequency signal of the H-K channel satellite digital broadcast, and further includes the terrestrial television broadcast signal and the like. ing. The signal from the output terminal 132 is supplied from the second input terminal 144 to the duplexer 146 as shown in FIG. The demultiplexer 146 demultiplexes the second digital intermediate frequency signals of the H to K channels of the satellite digital broadcasting, and removes unnecessary signal components by a band pass filter 148 having a band through which only these components pass. Supplied to converter 150.

The converter 150 includes one mixer and one
And two local oscillators. The second intermediate frequency signals of the satellite digital broadcasting of the H to K channels are converted into the third intermediate frequency signals BS1-IF3 to BS7-IF of the satellite digital broadcasting.
3 is frequency-converted collectively. Of course, H channel is B
S7-IF3, I channel to BS5-IF3, J
Channel is BS3-IF3, K channel is BS1
The oscillation frequency of the local oscillator is selected to be, for example, 1686.42 MHz so that the frequency is converted to −IF3. Therefore, converter 150 converts the frequency of the input signal to a value obtained by subtracting the frequency of the input signal from the frequency of the local oscillation signal.

Unnecessary signal components are removed from the third intermediate frequency signal of the satellite digital broadcast by a band pass filter 152 having a pass band for passing only the signal, and the signal is output to a mixing circuit 154. The mixing circuit 154 includes the first
, Are also supplied via the DC blocking capacitor 156 from the satellite digital broadcast third intermediate frequency signals BS9-IF3 to BS15-IF3. Accordingly, the output of the mixing circuit 154 is, as shown in FIG. 7, the satellite digital broadcast third intermediate frequency signals BS1-IF3 to BS15-IF.
3 which is a DC blocking capacitor 15
The signal is supplied to a first output terminal 160 via a digital cable 8 and then to a satellite digital tuner 122 via a coaxial cable, where it is demodulated and supplied to a digital television receiver 130. Thus, despite the use of two block upconverters 112 and 140, only the coaxial cable from block upconverter 160 is connected to satellite digital tuner 122.

In the demultiplexer 146 of the block up converter 140, a terrestrial television broadcast signal, a satellite communication signal, and the like are demultiplexed and supplied to a second output terminal 162, and from there, a CATV home terminal as shown in FIG. 13
4, where it is demodulated and supplied to a digital television receiver 130.

The DC voltage from the satellite digital tuner 122 is supplied to an output terminal 160 via a coaxial cable.
The voltage is supplied to the constant voltage circuit 166 via the high frequency blocking coil 164. Here, the voltage is converted to a predetermined voltage, and is converted into a constant voltage, supplied to the converter 150 and operated. This voltage is supplied to the first input terminal 142 via an energizing circuit, for example, an open / close switch 168 and a high-frequency blocking coil 170. Therefore, the open / close switch 1
When the block 68 is closed, this voltage is supplied to the output terminal 128 of the block up-converter 112 via the high frequency blocking coil 179 and the first input terminal 142, and the block up-converter 112
Is operated. Therefore, it is not necessary for both the two block up converters 112 and 140 to include a large-sized power supply device that rectifies and smoothes the commercial AC power and supplies the rectified and smoothed power to the converters 120 and 150.

In the third embodiment, the DC voltage from the satellite digital tuner 122 is supplied to the output terminal 160 of the block up converter 140 via the coaxial cable. Alternatively, a power supply output terminal may be provided in the satellite digital tuner 122, and these may be connected by a power supply line. Similarly, a power output terminal may be provided for the block up converter 140 and a power input terminal may be provided for the block up converter 112, and a power line may be provided therebetween. Further, in the above embodiment, the increased (second group) digital satellite broadcast second intermediate frequency signal is set to the H to K channels. However, the present invention is not limited to this, and transmission is possible by the joint receiving system. If it is within the frequency band of the downlink signal and the frequency intervals between the channels of the second group are equal, channels of other frequency bands can be used. Although the duplexers 116 and 146 are used in the block up converters 112 and 140, the band-pass filters 118 and 148 are used, and the band-pass filters are also provided in the CATV home terminal 134. Therefore, in some cases, a splitter or a distributor may be used instead of the duplexers 116 and 146.

[0051]

As described above, the use of the terminal frequency converter according to the present invention can reduce the cost,
The cost of a joint receiving system including such a terminal frequency converter can also be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram of a terminal frequency converter according to a first embodiment of the present invention.

FIG. 2 is a block diagram of an example of a joint receiving system using the terminal frequency converter of FIG. 1;

FIG. 3 is a block diagram of a second embodiment of a joint reception system using the terminal frequency converter of FIG. 1;

FIG. 4 is a block diagram of a terminal frequency converter according to a third embodiment of the present invention.

FIG. 5 is a block diagram of a joint receiving system using the terminal frequency converter of FIG. 4;

FIG. 6 is a block diagram of another terminal frequency conversion device used in the terminal device of the joint receiving system of FIG. 4;

FIG. 7 is a diagram illustrating a frequency relationship of signals of respective units of the joint receiving system of FIG. 5;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Head end 5 Coaxial cable (transmission line) 8 Frequency conversion device 10 Input terminal 18 Digital television receiver 20 Converter (frequency conversion means) 24 Output terminal 30 Constant voltage circuit (power supply part) 34 Light emitting diode (display means) 112 Block up converter (first frequency conversion device) 130 Satellite digital tuner (receiving means) 140 Block up converter (second frequency conversion device) 142 First input terminal 144 Second input terminal 150 Converter (frequency conversion device) 154 Mixing circuit (mixing means) 160 First output terminal (output terminal) 166 Constant voltage circuit (power supply circuit) 168 On / off switch (energizing circuit) 170 High frequency blocking coil (energizing circuit)

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroo Arada 2-2-1 Jinnan, Shibuya-ku, Tokyo Inside the Japan Broadcasting Corporation Broadcasting Center (72) Inventor Yasumi Shibata 2-2-2 Jinnan, Shibuya-ku, Tokyo No. 1 Japan Broadcasting Corporation Broadcasting Center F term (reference) 5C056 FA02 FA08 FA11 GA05 HA01 HA08 HA13 5C064 BA02 BB05 BC20 BC21 BD07 BD13

Claims (8)

[Claims] An input terminal to which a converted signal obtained by frequency-converting a satellite digital broadcast intermediate frequency signal into a frequency band that can be transmitted by a transmission path of a joint receiving system is supplied, and the converted signal supplied from the input terminal is converted into a digital signal. Frequency conversion means for converting the frequency into a signal in a frequency band that can be processed by the corresponding television reception means; an output terminal to which an output signal of the frequency conversion means is supplied, and an operation power supply is supplied from the television reception means; A frequency converter for a terminal, comprising: a power supply section to which the operating power is supplied from the output terminal and which operates the frequency converter. 2. The terminal frequency converter according to claim 1, further comprising a display unit that operates when the operation power is supplied. 3. The terminal frequency conversion device according to claim 1, further comprising: a control signal output terminal for outputting a control signal to a television receiving means or a terminal device in response to the supply of the operation power. Conversion device. 4. A transmission path, and a converted signal in a frequency band that can be transmitted through the transmission path,
A head end including a first frequency converter that converts the frequency of a satellite digital broadcast intermediate frequency signal and supplies the converted signal to the transmission path; and the conversion signal is supplied from the transmission path, and converts the converted signal into a digital television receiver. The frequency is converted to a signal in a frequency band that can be received by the digital-compatible television receiving means via an output terminal, and the operating power supplied from the television receiving means via the output terminal. A terminal frequency converter that operates, the terminal frequency converter receives a supply of the operating power, and receives a control signal from a terminal different from the output terminal to a television receiving means or a terminal device. Output joint receiving system. 5. A first group of second intermediate frequency signals obtained by frequency-converting a first group of a plurality of digital satellite broadcast signals into a frequency band that can be transmitted through a transmission path. A first input terminal to which a first group of third intermediate frequency signals obtained by converting the frequency of the digital signal into a frequency band receivable by the receiving means is supplied; A second input terminal capable of transmitting the first intermediate frequency signal through a transmission line, and receiving a second group of second intermediate frequency signals whose frequency has been converted to a frequency band different from that of the first group of second intermediate frequency signals. A second group of second intermediate frequency signals from a second input terminal can be received by the receiving means, and a third group of third intermediate frequency signals in a different frequency band from the first group of third intermediate frequency signals. Frequency conversion means for converting the frequency to an intermediate frequency signal; Mixing means for mixing the first group of third intermediate frequency signals and the second group of third intermediate frequency signals from the frequency conversion means; and an output terminal for outputting an output signal of the mixing means. A terminal frequency converter provided. 6. The frequency conversion device for a terminal according to claim 5, wherein a power supply circuit that operates the frequency conversion unit by a voltage generated based on a voltage externally supplied to the output terminal; And a current supply circuit for supplying the supplied voltage to the first input terminal. 7. A first group of second intermediate frequency signals obtained by frequency-converting a first group of multi-satellite digital broadcast signals into a frequency band that can be transmitted through a transmission path. Enter the first frequency band that can be received by the receiving means.
A first frequency converter for frequency-converting a group of third intermediate frequency signals; a first group of third intermediate frequency signals from the first frequency converter and a second group of multi-satellite digital broadcast signals; A second group of second intermediate frequency signals that are capable of transmitting a second group of first intermediate frequency signals through the transmission path and that have been frequency-converted to a different frequency band from the first group of second intermediate frequency signals are input. A second frequency conversion device, wherein the second frequency conversion device is capable of receiving a second group of second intermediate frequency signals by the receiving means and a first group of third intermediate frequency signals. Frequency converting means for frequency-converting the second intermediate frequency signal into a second intermediate frequency signal of a second group, a third intermediate frequency signal of the first operational group, and a third intermediate frequency signal of the second operational area. A mixing means for outputting, and an output terminal for outputting an output signal of the mixing means. A terminal device for a joint receiving system provided. 8. The terminal device according to claim 7, wherein the second frequency conversion device includes a power supply circuit for operating the frequency conversion means based on a voltage supplied to the output terminal of the second frequency conversion device, and the output terminal. And a current supply circuit for supplying a voltage supplied from the outside to the first frequency conversion device, wherein the first frequency conversion device is configured to operate based on the voltage supplied from the current supply circuit. Terminal device for joint receiving system.