JPH04120992A - Time synchronization system for catv center - Google Patents

Abstract

PURPOSE:To implement time matching automatically by all center equipments by providing a time setting means setting a time of a clock device based on a timing signal generated by a timing generating means to other center equipments. CONSTITUTION:When a timecast signal in a broadcast wave to be sent is inputted to each of center equipments 110, 120, 130, the center equipment 110 matches the time of a built-in clock device based on the inputted timecast signal, while a timing generating means of the center equipments 120, 130 generates a timing signal based on the inputted timecast signal. Then a time setting means sets the time of the built-in clock device based on the timing signal generated by the timing generating means. Thus, the built-in clock device of each center device is subjected to time matching accurately and automatically and each center equipment fulfills each function based on the clock devices synchronously with each other at all times.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a CATV system, and more particularly to a time synchronization method for centers constituting the CATV system.

[Conventional technology]

FIG. 3 shows an example of a conventional CATV system.

1 is a center, and includes an automatic program operating device 11 that controls switching of programs to be broadcast on each channel as a center device, and a terminal control device 12 that controls whether or not a terminal can select a channel.
and a transmission path monitoring device I3 that monitors the transmission path,
Furthermore, a video signal/control signal multiplexing device 14 is connected to these center devices and multiplexes video signals and control signals and outputs the multiplexed video signals and control signals to a transmission path. Each terminal 4 includes home terminals 411 to 41n and televisions 421 to 42 that receive video signals and control signals output from the terminal control device 12.
n, and is connected to the multiplexing device 14 of the center 1 through the transmission line 2. Repeaters 3 are provided at various locations on the transmission path 2 .

Each of the center devices 11 to 13 has a built-in clock device, and performs switching of broadcast programs, control of home terminals, monitoring of transmission paths, etc. at predetermined timings based on the time indicated by the clock device.

A broadcast wave time signal is input to the automatic program operating device 11, and the automatic program operating device 11 automatically adjusts the time of its built-in clock device based on this signal. However, in the terminal control device 12 and the transmission path monitoring device 13, which are other center devices, the time setting of the built-in clock devices is performed manually.

[Problem to be solved by the invention]

In this way, in the conventional time synchronization method, among the center devices,
In the automatic program operating device 11, the time of the clock device is automatically set based on the time signal of the broadcast wave, but in the other terminal control device 12 and the transmission path monitoring device 13, the time of the clock device is manually set. There must be.

Therefore, for center devices other than the automatic program management device 11, (1) it is necessary to adjust the time for each center device as many as the number of center devices, which is time-consuming.

(2) Since the time is set manually, there will be some lag between devices.

(3) Even if the clock device's time is out of order, it will remain that way until someone notices and corrects it.

There was such a problem.

SUMMARY OF THE INVENTION An object of the present invention is to provide a time synchronization method for CATV center equipment that solves these problems and makes it possible to automatically adjust the time in all center equipment.

[Means to solve the problem]

The present invention provides an automatic program operating device that automatically adjusts the time of a built-in clock device based on a broadcast wave time signal to determine the timing of the operation, and controls the switching of programs to be broadcast on each channel. In the time synchronization method of a center that is equipped with other center equipment that has a built-in clock device for timing, and that constitutes a CATV system with terminals connected through a transmission line, a timing signal is generated based on the time signal of the broadcast wave. and a time setting means for setting the time of the clock device based on the timing signal generated by the timing generation means, the other center device being provided.

〔Example) Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a CATV system based on the time synchronization method of the present invention.

Reference numeral 10 denotes a center, which includes an automatic program operating device 11 that serves as a center device and controls switching of programs to be broadcast on each channel;
Terminal control device 1 that controls whether or not a terminal can select a channel
20 and a transmission path monitoring device 130 that monitors the transmission path, and is further connected to these center devices and multiplexes video signals and control signals and outputs the video signals and control signals to the transmission path.
A control signal multiplexing device 14 is provided. Each terminal 4 includes home terminals 411 to 41n and televisions 421 to 41n that receive video signals and control signals output from the terminal control device 12.
42n, and is connected to the multiplexer 14 of the center 1 through the transmission line 2. Repeaters 3 are provided at various locations on the transmission path 2 .

Each center device 11, 120, and 130 has a built-in clock device, and based on the time indicated by the clock device, broadcast programs are switched at predetermined timings, home terminals are controlled, transmission paths are monitored, etc. . The center device 11 automatically adjusts the time of the built-in clock device based on the time signal of the broadcast wave as in the past. On the other hand, the center devices 120 and 130 include a timing generating means for generating a timing signal based on a time signal of a broadcast wave, and a time for setting the time of a built-in clock device using the signal generated by the timing generating means. A time setting means is provided.

Each center device then adjusts the time according to the procedure shown in FIG. That is, when the time signal of the broadcast wave transmitted at 00 minutes 00 seconds of every hour is input to each center device 11120, 130, the center device 11 adjusts the time of the built-in clock device based on the input time signal. The timing generating means of the center devices 120 and 130 generates a timing signal based on a manually inputted time signal, and the time setting means sets the time of the built-in clock device based on the timing signal generated by the timing generating means. In other words, in this CATV system, the built-in clock devices of each center device are all automatically and accurately synchronized, and each center device can always perform its respective functions based on the synchronized clock device. .

〔Effect of the invention〕

As explained above, the present invention provides automatic program operation that automatically adjusts the time of a built-in clock device for determining operation timing based on a time signal of a broadcast wave, and controls switching of programs to be broadcast on each channel. In the time synchronization method of a center that comprises a CATV system and other center equipment that has a built-in time opening device for determining operation timing, and that constitutes a CATV system together with terminals connected through a transmission line, The other center device is provided with a timing generating means that generates a timing signal based on the timing signal, and a time setting means that sets the time of the clock device based on the timing signal generated by the timing generating means.

Therefore, by configuring the center of the CATV system based on the time synchronization method of the present invention, the following effects can be obtained. That is, (1) there is no need to manually adjust the time of the center device, which saves time and effort;

(2) Since time adjustment is performed automatically without manual intervention, there is no difference in time between devices. Therefore, for example, it becomes possible to control the program switching timing by the automatic program management device and the home terminal by the terminal control device at the same time, and it becomes possible to accurately locate the beginning of the program.

(3) Since the clock device of each control device is set every time a time signal is input, even if the time signal goes out of order, the clock device can be immediately reset to the correct time.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a CATV system configured by a center based on the time synchronization method of the present invention; FIG. 2 is an explanatory diagram of an operation procedure for explaining the operation of the CATV system of FIG. 1; FIG. 3 is a block diagram showing an example of a CATV system configured by a center based on a conventional time synchronization method. 2... Transmission line 3... Repeater 4... Terminal 10... Center 11... Automatic program operating device 14... Video signal/control signal multiplexing device/terminal control device/transmission line monitoring Device~41n ・Home terminal~42n ・TV

Claims (2)

[Claims] (1) An automatic program operating device that automatically adjusts the time of a built-in clock device based on the time signal of the broadcast wave to determine the timing of the operation, and controls the switching of programs broadcast on each channel, and the timing of the operation. In the time synchronization method of the center, which is equipped with another center device that has a built-in clock device for timing, and which constitutes a CATV system together with terminals connected through a transmission line, a timing signal is generated based on the time signal of the broadcast wave. CAT characterized in that the other center device is provided with a timing generating means and a time setting means for setting the time of the clock device according to the timing signal generated by the timing generating means.
V center time synchronization method. (2) The center device including the timing generation means and the time setting means includes a terminal control device that controls whether or not the terminal can select a channel, and a transmission path monitoring device that monitors the transmission path. A time synchronization system for a CATV center according to claim 1.