JP3067296B2 - Transmission switching control method for multiple transmitting stations - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission switching control system capable of automatically and accurately switching transmissions of a plurality of transmitting stations without interruption.

SUMMARY OF THE INVENTION The present invention relates to switching control of a plurality of transmitting stations sharing a transmission line in communication or broadcasting, and automatically switches a plurality of transmitting stations at a specified time. In order to achieve this, a method is proposed that enables stable and accurate switching control by adding time data up to the switching time to conventional switching information, even if a signal loss such as a burst error occurs. It is.

[0003]

2. Description of the Related Art As a conventional technique for controlling switching between a plurality of transmitters having a shared transmission line, for example, "NH
A multi-access control system described in K-Technical Monthly Report -Vol.22 No.7 (July 1979) is known.

In this prior art, a transmission end signal is multiplexed and transmitted from a transmitting transmitting station a fixed time before a transmission end time, and a transmitting station to be transmitted next receives the transmission end signal.
The transmission is started after a fixed time from the detected time.

[0005]

However, according to the above-mentioned prior art, when detection is delayed or accurate reception cannot be performed due to the influence of noise or the like on a transmission line, a switching delay occurs, and such switching is performed. There has been a problem that an intermittent time is generated in the transmission signal due to the delay or switching cannot be performed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a transmission switching control method for a plurality of transmitting stations, which enables reliable switching control without being affected by noise or the like generated on a transmission line. Is to provide.

[0007]

SUMMARY OF THE INVENTION To achieve the above object, the present invention relates to a system for controlling transmission switching of a system in which a plurality of transmitting stations transmit signals via a shared transmission line. Generates a timing signal indicating the remaining time until the end of the transmission a predetermined time before the end of the transmission, and transmits a multiplexed signal including the timing signal via the transmission path. Upon receiving the signal, the timing signal is extracted and transmission of the own station is started based on the timing signal.

[0008]

According to the above arrangement, a timing signal indicating the remaining time until the end of transmission is transmitted a predetermined time before the end of transmission, and when the transmitting station scheduled to transmit next receives this timing signal, the timing signal is used as a base point. And the remaining time until the start of transmission is counted. When the counting is completed, transmission by the transmitting station is started. As a result, transmission switching between a plurality of transmitting stations is performed continuously without interruption.

[0009]

FIG. 1 is a block diagram showing an embodiment of a broadcasting system to which the present invention is applied. In this embodiment, the transmission switching control of the two transmitting stations A and B is taken as an example. Since the transmitting stations A and B have the same configuration, only the configuration of the transmitting station A is numbered. Will be explained.

The transmission system of the transmission station A includes a remaining time generation circuit 1 for generating a timing signal as remaining time data up to the transmission switching time, and an information signal encoding circuit 2 for encoding the timing signal and the switching information signal. And a multiplexing circuit 3 for multiplexing the coded signal with the main signal. The multiplexed signal is transmitted from the transmission / reception circuit 4 via a transmission path. One receiving system includes a demodulation circuit 5 that separates the multiplexed signal received via the transmission / reception circuit 4 into the main signal and an encoded signal, and decodes the switching information signal and the timing signal from the encoded signal. And a remaining time counting circuit 7 for counting the remaining time from the decoded timing signal to the end of transmission by another station.

Next, the operation of this embodiment will be described with reference to the time chart of FIG.

When a transmission control trigger is input from outside during a predetermined time before the end of transmission during transmission by the transmitting station A (time t _{n in} FIG. 2), the remaining time generation circuit 1 sets the transmission end time to 0. to generate a timing signal of the countdown that, the transmission end time (time t ₀ in FIG. 2) outputs a transmission stop signal to the transmission and reception circuit 4. Upon receiving the transmission stop signal, the transmission / reception circuit 4 immediately stops transmission and enters a reception standby state.

When the information signal encoding circuit 2 receives the timing signals, it encodes these signals together with the switching information signal. The coded signal is multiplexed with the main signal by the multiplexing circuit 3 and then transmitted to a transmission path shared by a plurality of transmitting stations via the transmission / reception circuit 4.

On the other hand, the transmitting station B to be transmitted next receives the multiplexed signal transmitted from the transmitting station A via the transmitting / receiving circuit 4. The received multiplex signal is separated by the demodulation circuit 5 into a main signal and an encoded signal. The separated encoded signal is decoded by the information signal decoding circuit 6, and a timing signal and a switching information signal are extracted.

The timing signal extracted in this manner is used as a timing signal for counting the time until the transmission of the transmitting station A currently transmitting by the remaining time counting circuit 7, and the built-in timer is started by this timing signal.
When the count value of the timer becomes 0 (time t _{0 in} FIG. 2), the remaining time counting circuit 7 outputs a transmission start signal to the transmission / reception circuit 4. As a result, the transmission / reception circuit 4 immediately starts transmitting the signal of the time station. The reception period of the timing signal can be from the time t _n shown in FIG. 2 to t _1.

As described above, according to this embodiment, in addition to the currently used switching information data, time data for determining the switching timing is transmitted, so that a plurality of standby broadcasting stations can be continuously connected without interruption. It is possible to automatically switch automatically. Therefore, the effective use of the transmission path and the reliability and economy of the broadcasting system and the communication system are improved.

In this embodiment, transmission switching between the transmitting station A and the transmitting station B has been described as an example. However, the number of transmitting stations is not limited to two. It can be applied to switching.

[0018]

As described above, according to the present invention, a transmitting station that is transmitting transmits a timing signal indicating the remaining time until the end of the transmission a fixed time before the end of the transmission, and then the transmitting station that is scheduled to transmit Is configured to start transmission of its own station based on this timing signal, so that transmission switching between a plurality of transmitting stations can be performed continuously and accurately without being affected by noise or the like.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a time chart showing the operation of one embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 remaining time generation circuit 2 information signal encoding circuit 3 multiplexing circuit 4 transmission / reception circuit 5 demodulation circuit 6 information signal decoding circuit 7 remaining time counting circuit

Continuation of front page (72) Inventor Zenichiro Misawa 2-2-1 Jinnan 2-chome, Shibuya-ku, Tokyo Inside the Japan Broadcasting Corporation Broadcasting Center (56) References JP-A 1-212141 (JP, A) JP-A 4-181836 (JP, A) JP-A-1-245634 (JP, A) JP-A-4-26247 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04L 12/28

Claims (1)

(57) [Claims] In a system for controlling transmission switching in a system in which a plurality of transmitting stations transmit signals via a shared transmission path, the transmitting station during transmission has a remaining time until the end of transmission a predetermined time before the end of transmission. And transmitting a multiplexed signal including the timing signal through the transmission path, and when the transmitting station to be transmitted next receives the multiplexed signal, extracts the timing signal and converts the timing signal into this timing signal. A transmission switching control method for a plurality of transmitting stations, based on which the transmission of the own station is started.