JP2567452Y2 - CATV transmission system - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CATV (cable television) transmission system for broadcasting broadcast programs and self-produced programs via a cable.

[0002]

2. Description of the Related Art Generally, CATV broadcasting is widely used for detached houses, and the number of subscribers in apartment houses is very small.

[0003] That is, in a multi-family apartment, a terrestrial broadcasting joint receiving system is usually introduced. However, a user who wants to receive only terrestrial broadcasting and a user who has subscribed to CATV and wants to receive pay broadcasting are resident. Conventionally, there has not been an inexpensive transmission system that can receive both terrestrial broadcasts and CATV broadcasts without imposing a cost on receivers of only terrestrial broadcasts.

FIG. 2 shows the configuration of a multi-family reception system for receiving only terrestrial broadcasts. In FIG.
HF receiving antenna, 2 is VHF receiving antenna, 3 is UH
U that mixes the F signal and the VHF signal to compensate for the distribution loss
/ V mixing amplifier, 4 is a distributor, 5 is a television terminal installed in each dwelling unit, 6 is a VHF and UHF of a television receiver 7.
This is a demultiplexer that demultiplexes and connects each signal to a terminal.

That is, the UHF reception signal and the VHF reception signal received by the UHF antenna 1 and the VHF antenna 2 are guided from the U / V mixing amplifier 3 to a number of television terminals 5 via the distributor 4. The user separates the U / V mixed signal led out to the television terminal 5 into a UHF broadcast signal and a VHF broadcast signal via a splitter 6 and supplies the resulting signal to a television receiver 7 so that a desired terrestrial broadcast can be obtained. Can receive the program.

FIG. 3 shows a configuration of a receiving system in which the above-mentioned multi-family housing receiving system for terrestrial broadcasting is modified for CATV broadcasting. In FIG. 3, reference numeral 8 denotes a trunk branching amplifier for amplifying and branching a signal on a CATV trunk 9. Reference numeral 10 denotes a tap-off for further branching the branch line and connecting to a drop-in line.
Numeral denotes a security device, 12 denotes an indoor amplifier for amplifying VHF, mid-band and super-high band, and 13 denotes a home terminal incorporating a scramble decoder for enabling only a CATV subscriber to receive a CATV channel. FIG.
FIG. 7A shows the frequency arrangement of terrestrial broadcasting and CATV broadcasting, and FIG. 7A shows the frequency arrangement of terrestrial broadcasting, and FIG.
Indicates a frequency array of CATV broadcasting.

In the frequency arrangement of terrestrial broadcasting shown in FIG. 4A, between the VHF low channel and the VHF high channel and between the VHF high channel and the UHF channel are all used for wireless communication. .

In the frequency arrangement of the CATV broadcast shown in FIG. 4B, the VHF low channel and the VH
Mid-band between F high channel and
The channel between the VHF high channel and the UHF channel is used as a CATV exclusive channel up to 450 MHz as a super high band.

That is, C transmitted to the CATV trunk line 8
The ATV signal is fed from the main branch amplifier 9 to the tap-off 10,
The signal is output to a number of television terminals 5 via a protector 11, an indoor amplifier 12, and a distributor 4. The user can output the CATV signal output to the television terminal 5 to the home terminal 1.
By decoding at 3 and giving it to the television receiver 7,
A desired CATV channel can be received. In this case, the terrestrial broadcast is also transmitted by cable from the CATV station, and the UHF broadcast is converted into a free channel of the VHF broadcast and transmitted.

[0010]

However, in the conventional CATV receiving system as described above, the terrestrial broadcasting also requires C
Since the cable is transmitted from the ATV station, the user who wants to receive only the terrestrial broadcasting needs to pay a corresponding reception fee to the CATV station. Since a broadcast signal is transmitted via many trunk amplifiers, the image quality may be slightly reduced, which is disadvantageous for a receiver of only terrestrial broadcast.

On the other hand, in a newly-built apartment house, a method of wiring a double cable to each house in advance in the construction stage has been adopted. However, performing additional cable construction in an existing apartment house requires a large construction cost. It is necessary and often difficult to wire due to the structure of the house, and there is an unrealistic problem.

The present invention has been made in view of the above problems,
For example, it is an object of the present invention to provide a CATV transmission system capable of receiving a CATV broadcast at low cost with a small change of an existing reception system without requiring a burden on a receiver of only terrestrial broadcasting in an apartment house. And

[0013]

That is, the CATV transmission system according to the present invention comprises a UH antenna from a UHF antenna.
A terrestrial broadcast receiving system that derives an F broadcast signal and a VHF broadcast signal from a VHF antenna from a television terminal via a UHF / VHF mixer, and includes a CATV trunk line through which a CATV broadcast signal is transmitted, and a CATV trunk line And a main branch amplifier for amplifying and branching the CATV broadcast signal transmitted to the CATV main line, and a UHF frequency band for the CATV broadcast signal branched by the main branch amplifier.
CATV / U to convert to frequency band corresponding to terrestrial broadcasting
HF converter, UHF antenna and UHF / VH
UH interposed between the FHF mixer and the UHF antenna
UHF signal by F broadcast signal and the above CATV / UHF converter
UHF to mix with CATV broadcast signal converted to band
/ UHF mixer and UH derived from the TV terminal
It is provided with a duplexer for splitting the F / VHF mixed signal into a UHF signal and a VHF signal and supplying the split signal to a television receiver.

[0014]

In other words, a user who receives only terrestrial broadcasts can receive good signals directly inputted from UHF and VHF antennas as before, without having to make any major changes to the existing multi-family reception system. A CATV subscriber can receive a CATV broadcast using a UHF selected channel.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a configuration of a CATV transmission system in an apartment house.
The F reception signal and the VHF reception signal from the VHF antenna 1 are mixed and amplified by the U / V mixing amplifier 3, respectively, and then led out to the television terminal 5 installed in each of a large number of dwelling units via the distributor 4. Here, between the UHF antenna 1 and the U / V mixed amplifier 3, a UHF / UHF
The mixer 14 is interposed.

On the other hand, the CAT transmitted to the CATV trunk 9
The V signal is amplified and branched via the main branch amplifier 8, and further branched via the tap-off 10 to CATV /
It is supplied to the UHF converter 15.

The CATV / UHF converter 15 comprises an inexpensive heterodyne frequency converter, and converts a CATV channel frequency transmitted in the mid-band and super-high band into a channel frequency in the UHF broadcast band. / UHF converter 15
The CATV signal converted to the band channel is supplied to the UHF / UHF mixer 14 via the protector 11. Here, a power supply voltage for the CATV / UHF converter 15 is supplied from the main branch amplifier 8 via a current passing type tap-off 10.

The UHF / UHF mixer 14 uses the UHF
It mixes the CATV signal converted into a channel with the UHF reception signal obtained from the UHF antenna 1, that is, each TV terminal 5 mixed / distributed via the U / V mixing amplifier 3 and the distributor 4. The terrestrial broadcast signal received by the UHF antenna 1 and the VHF antenna 2 and the CATV broadcast signal obtained from the CATV trunk line 9 include the broadcast signal derived from
The channel is converted into an F broadcast band channel and mixed and derived.
Here, the CATV receiving equipment from the main branch amplifier 8 to the UHF / UHF mixer 14 is a CATV station-borne equipment.

The duplexer 6 is connected to the television terminal 5 in each user's house. The splitter 6 splits the U / V mixed signal derived from the television terminal 5 into a UHF band and a VHF band. If the user wants to receive only terrestrial broadcasts, the U / V splitter 6 Any of the wave signals may be directly supplied to the UHF input terminal and the VHF input terminal of the television receiver 7, respectively.

In this case, since the terrestrial broadcast can be directly received from the UHF antenna 1 and the VHF antenna 2 of the existing receiving system in the apartment house, the user who receives only the terrestrial broadcast does not need to pay the reception fee to the CATV station. In addition, reception with good image quality can be performed.

On the other hand, if the user wants to receive a CATV broadcast as well, the VHF reception signal split by the splitter 6 is directly supplied to the VHF input terminal of the television receiver 7, and the UHF reception signal is converted to the UHF reception signal. What is necessary is just to supply to the UHF input terminal of the television receiver 7 through the home terminal 16.

The UHF home terminal 16 bypasses the terrestrial broadcast portion of the UHF reception signal obtained through the demultiplexer 6 in accordance with the selection of the UHF channel in the television receiver 7, and a scramble code corresponding to the CATV broadcast. Which decodes C
If the UHF home terminal 16 is connected only to the ATV subscriber, the UHF antenna 1 and V
Along with normal terrestrial broadcasting obtained from HF antenna 2, C
ATV broadcasting can be received. That is, CAT
Only those who wish to subscribe to V can receive CATV broadcasts, for example, by paying the usage fee of the UHF home terminal 16 or the CATV reception fee.

Therefore, according to the CATV transmission system having the above configuration, the CATV branched from the CATV trunk 9
The channel signal is converted into a channel corresponding to the UHF terrestrial broadcast frequency band through a CATV / UHF converter 15, and a UHF terrestrial broadcast reception signal obtained from the UHF antenna 1 of the existing receiving system by a UHF / UHF mixer 14 TV terminal 5 for mixing and individual user
UHF through the duplexer 6 of the U / V mixed signal derived to
UH to decode CATV scramble signal
By supplying the television receiver 7 to the television receiver 7 through the F home terminal 16, the user receiving only the terrestrial broadcast can receive the signals from the UHF and VHF antennas 1 and 2 in the same manner as before, without having to make a major change to the existing multi-family reception system. Good reception directly input is possible, and CATV
Applicants wishing to connect to UHF Home Terminal 16
ATV pay broadcasting can be received.

[0025]

As described above, according to the present invention, the UHF broadcast signal from the UHF antenna and the VHF signal from the VHF antenna
A terrestrial broadcast receiving system that derives an HF broadcast signal from a television terminal via a UHF / VHF mixer is provided, and a CATV trunk line through which a CATV broadcast signal is transmitted, and a CATV trunk line interposed between the CATV trunk line and A trunk branch amplifier for amplifying and branching the transmitted CATV broadcast signal, a CATV / UHF converter for converting a frequency band of the CATV broadcast signal branched by the trunk branch amplifier into a frequency band corresponding to UHF terrestrial broadcasting, and the UHF UHF interposed between an antenna and the UHF / VHF mixer
UHF broadcast signal from antenna and CATV / UHF
A UHF / UHF mixer for mixing a CATV broadcast signal converted to a UHF band by a converter, and a television receiver for separating a UHF / VHF mixed signal derived from the television terminal into a UHF signal and a VHF signal For example, in a multi-family house, a CATV broadcast can be received at a low cost by a small change of an existing receiving system without requiring a burden on a receiver of only a terrestrial broadcast in an apartment house. It becomes possible.

[Brief description of the drawings]

FIG. 1 shows C in an apartment house according to an embodiment of the present invention.
FIG. 1 is a diagram illustrating a configuration of an ATV transmission system.

FIG. 2 is a diagram showing a configuration of an apartment house receiving system that receives only terrestrial broadcasts.

FIG. 3 shows the above-mentioned multi-family reception system for terrestrial broadcasting as C
The figure which shows the structure of the conventional receiving system modified for ATV broadcasting.

FIG. 4 is a diagram showing a frequency arrangement of terrestrial broadcasting and CATV broadcasting.

[Explanation of symbols]

1: UHF antenna, 2: VHF antenna, 3: U / V
Mixing amplifier, 4 ... Distributor, 5 ... TV terminal, 6 ... Diplexer, 7 ... TV receiver, 8 ... Main branch amplifier, 9 ... CA
TV main line, 10: tap off, 11: protector, 14: U
HF / UHF mixer, 15 ... CATV / UHF converter,
16 ... UHF home terminal.

Claims (3)

(57) [Scope of request for utility model registration] 1. A UHF broadcast signal from a UHF antenna and a VHF broadcast signal from a VHF antenna are converted to UHF / VH
In a CATV transmission system having a terrestrial broadcast receiving system derived from a television terminal via an F mixer, a CATV trunk line through which a CATV broadcast signal is transmitted, and a CATV broadcast line interposed in the CATV trunk line and transmitted through the CATV trunk line A main branch amplifier for amplifying and branching a signal, a CATV / UHF converter for converting a frequency band of a CATV broadcast signal branched by the main branch amplifier into a frequency band corresponding to UHF terrestrial broadcasting, the UHF antenna and the UHF / A UHF / UHF mixer interposed between the VHF mixer and mixing a UHF broadcast signal from the UHF antenna and a CATV broadcast signal converted into a UHF band by the CATV / UHF converter; The derived UHF / VHF mixed signal is split into a UHF signal and a VHF signal. CATV transmission system, characterized by comprising a supplying demultiplexer, to the television receiver. 2. A UHF broadcast signal from a UHF antenna and a VHF broadcast signal from a VHF antenna are converted into UHF / VH
In a CATV transmission system having a terrestrial broadcast receiving system derived from a television terminal via an F mixer, a CATV trunk line through which a CATV broadcast signal is transmitted, and a CATV broadcast line interposed in the CATV trunk line and transmitted through the CATV trunk line A main branch amplifier for amplifying and branching a signal, a CATV / UHF converter for converting a frequency band of a CATV broadcast signal branched by the main branch amplifier into a frequency band corresponding to UHF terrestrial broadcasting, the UHF antenna and the UHF / A UHF / UHF mixer interposed between the VHF mixer and mixing a UHF broadcast signal from the UHF antenna and a CATV broadcast signal converted into a UHF band by the CATV / UHF converter; The derived UHF / VHF mixed signal is split into a UHF signal and a VHF signal. A duplexer for supplying to a television receiver, and a duplexer interposed between the television receiver of the CATV subscriber and the duplexer for bypassing a terrestrial broadcast portion of the UHF signal split through the duplexer and CATV. And a UHF home terminal for decoding a scramble code corresponding to a broadcast. 3. The CATV transmission system according to claim 1, wherein a power supply of the CATV / UHF converter is supplied from the trunk branch amplifier.