JPH0752948B2 - Specific channel frequency setting device in CATV system - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a CATV system under certain circumstances.
It relates to a CATV system that can be forcibly tuned to any other general channel.

BACKGROUND OF THE INVENTION Generally, CATV systems include pay broadcasting and general free broadcasting, and pay broadcasting can be received only when a subscriber pays a predetermined contract fee. On the other hand, if an unsubscribed broadcast is selected, a so-called scrambled image with distorted images on that channel is displayed on the television screen.

Alternatively, when the viewer selects an empty channel that is not actually broadcast, a noise screen appears on the TV screen.

In either case, a screen that is not unpleasant for the viewer appears, and in such a case, the general free channel is forced to be tuned.

In addition to this, there is an emergency broadcast, for example, when it is forcibly tuned to another channel. This is to force the broadcasting station to be forced to receive the information of the earthquake or typhoon when it is necessary to immediately notify the subscriber of any program while listening to any program.

In the case of a two-way CATV system, when the subscriber desires a pay program, it is forcibly tuned to a notification channel that announces that "this program is paid".

[Description of Prior Art] Conventionally, the terminal shown in FIG. 3 has been used to achieve such an operation.

The signal transmitted from the center via the signal transmission line 1 is superposed with the data signal including the address information of the other terminal of the video / audio signal. Then, control data is transmitted as another OUTBAND data at another frequency. One of these signals is sent to the communication receiver 4 by the distributor 2 and the other is sent to the descrambler 11. Descrambler 11
An RF tuning circuit, a video detection circuit, an audio detection circuit, a bandpass filter, and the like are provided, and only the data signal of the sent signals is sent to the terminal control device 5. Terminal control device 5
Determines from the data signal whether the channel data sent from the operation unit 8 such as a remote controller is a contracted channel. For example, the address designated in advance in the terminal is compared with the address data in the data signal, and if they match, it can be determined that the channel is a contracted channel, and if they do not match, it is an uncontracted channel.

If it is determined that the channel is the contracted channel, the terminal control device 5 sends the input data to the RF in the descrambler 11.
An RF adjustment data converter 3 for converting into a data signal for tuning the tuning circuit, and a descrambler 11
Is operated to supply a normal image to the TV receiver 9.

If it is an uncontracted channel, give a command to the RF adjustment data converter 3 to receive general broadcasting, but RO
The frequency data of the general broadcasting station at this time is stored in M6. That is, when the terminal control device 5 determines that the channel is an uncontracted channel, the frequency data of the general broadcasting station in the ROM 6 is read regardless of the instruction from the operation unit 8 and the RF adjustment data converter is tuned to the frequency. Give command to 3.

If it is a contracted channel, it gives a command to synchronize with the announcement channel.

[Disadvantages of Prior Art] In the case of the system as described above, since the frequency data of the general broadcasting station in the ROM 6 is fixed, only the broadcasting station of the predetermined frequency can receive.

In the case of the United States, there are television frequency arrangements such as standard (STD), HRC, or IRC in each area, but with the transfer of subscribers,
When the television frequency array system is moved to a different area, it is necessary to change the frequency data in ROM6, but this requires ROM6 to be completely replaced.

Also, due to the system's convenience, for example, when a failure occurs, the broadcasting station of the frequency in the ROM 6 cannot be received.

In addition, if this system is applied to an alarm system, it can be switched to a news program that informs information such as earthquakes and typhoons as soon as possible, but since this frequency is also fixed, it is the broadcasting station that sends the earliest information. It is not possible to select a channel arbitrarily.

Furthermore, even if the announcement channel is broadcasted at a hotel etc. even if the announcement channel is broadcast, since many international races are gathered, it is not possible to understand the contents of the announcement channel due to different languages and listening to unintended pay programs. It was a cause of trouble when collecting fees.

[Outline of the Invention] The present invention has been made to solve the above-mentioned drawbacks of the prior art. In the ROM 6, a plurality of frequency data and an independent pointer are provided for each of the frequency data.
It is characterized in that a rewritable ROM (EAROM) different from M is provided, and a pointer is rewritten from the center to instruct the EAROM which frequency data in the ROM 6 to use.

[Construction of the Invention] Specifically, the present invention relates to a CATV in which a channel selected by a subscriber in a terminal and frequency information regarding a frequency to be actually tuned by the terminal are uniquely associated by a pointer rewritable from the center. A specific channel setting device in the system, wherein the center is provided with a sending means for sending pointer data for rewriting pointers indicating each channel in the terminal as a data signal to the terminal, and the terminal demodulates the pointer data from the data signal. Communication receiver, an operation unit for a subscriber to select a channel, a first memory in which a plurality of frequency information and a pointer indicating the frequency information are stored, and a second memory in which a pointer indicating each channel is stored. , Rewrite the second memory according to the demodulated pointer data, and Depending on the channel selected, it reads the pointer indicating the selected channel from said second memory, characterized by comprising a terminal controller for reading the frequency information indicating the read pointer from the first memory.

An embodiment of the present invention will be described below with reference to FIG. In addition to the ROM 6 as the first memory shown in FIG. 3, an EA ROM 10 capable of rewriting internal data is provided as a second memory in FIG.

In the ROM 6, at least a plurality of frequency data as frequency information regarding frequencies and independent pointers corresponding to the respective frequency data are stored. For example, these frequency data may be stored so as to include all the frequency array methods of the HRC, IRC, and STD methods.
One of the pointers of the ROM 6 is stored in the EAROM 10 for each channel, and the pointer in the EAROM 10 can be rewritten by the data from the center.

From the center, pointer data for rewriting the pointer in the EAROM 10 is superimposed on the data signal. This data signal is sent out-of-band and demodulated by the communication receiver 4. Its command form is as shown in FIG.
For example, an NRZ signal composed of 8 bits is converted into BPS (Bi-PhaseS
pace) conversion is performed and FSK modulation is performed to set the carrier frequency to around 110 MHz, which is then combined with other video signals and data signals and transmitted.

In addition, here, 1 bit of isolation is sandwiched,
The necessity of rewriting is shown as DATA1 and the binary number showing the pointer data is shown as DATA2, but needless to say, it is not limited to this data format, and may be set in a desirable form for the system.

When pointer data is sent from the center based on the above-mentioned data format, the terminal control device 5 writes the pointer data written in DATA2 into the EAROM 10 when the first 1 bit of DATA1 is "1". Naturally, an area for storing the data is prepared in advance in the EAROM 10, and the data obtained by BPS converting the FSK-modulated data signal by the terminal control device 5 and further demodulating it into the NRZ signal is stored in the EAROM 10. The storage area of can be rewritten.

In such a configuration, when the subscriber requests an uncontracted channel or a channel that is not actually used by the operation unit 8, the terminal control device 5 compares it with the address in the data signal and determines that viewing is not permitted. do. Next, the terminal control unit 5 reads the pointer stored in the EAROM 10,
The frequency data table in the ROM 6 according to the pointer is read, and the descrambler 11 is tuned to the general free broadcast via the RF adjustment data converter 3 according to the frequency data.

Also, when forcibly receiving emergency broadcasts such as earthquake and typhoon information, the center side investigates the broadcasting station that reports the content earliest and sends pointer data corresponding to the channel frequency of that broadcasting station to all terminals. At the same time as writing to the EAROM 10 of each terminal, the terminal controller is forced to receive the frequency. This forcibly received data is superimposed on the data signal, and when the forcibly received data is discriminated in the terminal control device 5, it can be forcibly received based on the pointer in the EAROM 10 regardless of whether the addresses match or mismatch. It will be possible.

In the two-way CATV system used in hotels, etc.,
Check the language used by the guest at the front desk and set the frequency of the announcement channel broadcast in that language.

[Advantages of the Invention] The present invention is configured as described above, and by using the present invention, when a subscriber selects an uncontracted channel or a channel that is not designated, a general broadcast that is forcibly received can be received. It can be set freely from the center, and since only the pointer data is sent from the center to the rewritable ROM instead of sending the frequency data as it is, the EA ROM area and transmission area can be minimized. In particular, the information can be notified as soon as possible even for forced reception of alarm emergency broadcasts.

Further, if the present invention is applied to a two-way CATV system, the pay program announcement channel can be arbitrarily changed from the center side, so that an appropriate language announcement can be made even when international users such as hotels alternate. Can supply channels.

[Brief description of drawings]

FIG. 1 is a block diagram showing a CATV terminal according to the present invention,
2 (a), (b) and (c) are simplified formats showing the command form of the pointer data sent from the center, the third format.
The figure is a block diagram showing a conventional terminal. 3 ... RF adjustment data converter 4 ... Communication receiver 5 ... Terminal control device 6 ... ROM, 10 ... EAROM

Claims (1)

[Claims] 1. A specific channel setting device in a CATV system, wherein a channel selected by a subscriber in a terminal and frequency information regarding a frequency to be actually tuned by the terminal are uniquely associated with each other by a pointer rewritable from a center. The center is provided with transmission means for transmitting pointer data for rewriting pointers indicating respective channels in the terminal as a data signal to the terminal, and the terminal is provided with communication for demodulating the pointer data from the data signal. A receiver, an operation unit for the subscriber to select a channel, a first memory storing a plurality of the frequency information and a pointer indicating the frequency information, and a second memory storing a pointer indicating each channel. And rewriting the second memory according to the demodulated pointer data. Both are provided with a terminal control device that reads out a pointer indicating the selected channel from the second memory and reads out the frequency information indicated by the read pointer from the first memory according to the channel selection of the operation unit. A specific channel setting device in a CATV system.