JP3117605B2 - Synchronous broadcasting 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 synchronous broadcasting system, and more particularly to a system for performing synchronous broadcasting of a medium-frequency radio at the same frequency at two or more transmitting stations.

[0002]

2. Description of the Related Art Synchronous broadcasting systems have been constructed in order to improve reception conditions in each region. FIG. 5 shows an overall configuration of a conventional synchronous broadcasting system. In FIG.
The broadcasting station 1 has a studio for producing broadcast audio, and a broadcasting signal is transmitted from the broadcasting station 1 to a plurality of transmitting stations 5 and 8. In that case, the broadcast signal is, for example, NT
Each transmission station 5 via the transmission equipment (network) 2 of T
8 is transmitted. Here, each line of the transmission equipment 2 is NT
T digital line 0 system (working line) 3a, 3b, N
TT digital line 1 system (backup line) 4a, 4b;
It consists of. That is, two lines are provided between the broadcasting station and each transmitting station.

[0005] Incidentally, in the conventional medium-wave synchronous broadcasting system, an analog line has been used, but with the background of digital networking in recent years, a digital line has been used as described above. The working line is generally used as the working line, but may be switched to the protection line depending on the circumstances of the line carrier (NTT) or the like.
The switching is done simultaneously and to the same type on each line.

The transmitting station A5 is located farther than the transmitting station B8, and includes a delay circuit 6 for compensating a signal arrival time difference (delay time difference) corresponding to a difference in path length between the lines 3a and 3b, and a delay circuit 6 for delaying the signal. And a transmitter A7 for transmitting the subsequent broadcast signal as radio waves. On the other hand, the transmitting station B8 has a transmitter B that transmits the transmitted broadcast signal as radio waves.

Next, the operation of the synchronous broadcasting system will be described. The program sound transmitted from the broadcasting station 1 is transmitted to the transmission equipment 2 and transmitted to the transmitting station A5 via the digital line 0 system 3a. At the transmitting station A5, the delay amount corresponding to the signal arrival time difference between the digital lines 0a 3a and 3b is set in the delay circuit 6 in advance, and the broadcast signal is delayed by the delay circuit 6 and then transmitted to the transmitter A7. Is modulated and amplified, and broadcast as radio waves from an antenna. On the other hand, at the transmitting station B8, a broadcast signal is transmitted by the digital line 0 system 3b and broadcast by the transmitter B9. Thereby, synchronous broadcasting is performed.

[0006] As described above, 0
The systems 3a and 3b and the first systems 4a and 4b can be switched without notice depending on the circumstances of the line carrier.

[0007]

Since the conventional synchronous broadcasting system is configured as described above, when the system (line type) of the digital line is switched, the digital lines 0 and 3a and 3b and 1 are switched. Due to the difference in the delay characteristics (transmission speed) between 4a and 4b, there is a time difference between the broadcasted sound from the broadcast from the transmitting station A5 and the broadcast from the transmitting station B8,
In particular, in an isoelectric zone, there is a problem in that an unnecessary echo is generated in a received signal and sound quality is deteriorated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to avoid sound quality deterioration in an equal electric field zone when synchronous broadcasting is performed at a plurality of transmitting stations. I do.

Another object of the present invention is to provide a highly reliable system that automatically determines switching of a line system and automatically changes a delay amount to secure synchronization.

[0010]

In order to achieve the above object, according to the present invention, there is provided a broadcasting station for transmitting a broadcast signal and a broadcasting station capable of switching between the broadcasting stations.
A plurality of transmission stations connected via a digital line having a number of systems and broadcasting a broadcast signal transmitted from the broadcasting station as radio waves of the same frequency , and a synchronous broadcasting system including: Transmitted to each transmitting station to compensate for the difference in arrival time of the broadcast signal for each system
Delay means for delaying a broadcast signal ;
Between at least one of the plurality of transmitting stations
Means for measuring the delay time of signal transmission in the,
The broadcast signal is transmitted from the broadcasting station to the transmitting station
A digital line and a monitor signal from the transmitting station to the broadcasting station
Are connected to the monitor lines through which
Measurement to measure delay time using signal loop
Means and the digital line based on the delay time.
System determining means for determining a system to be operated, and delaying means.
The broadcast with the delay amount corresponding to the determined system.
And delay selecting means for delaying the signal .

[0011]

[0012] The invention according to claim 2 is characterized in that it comprises timer means for judging a non-broadcast time zone, and wherein the delay measuring means measures the delay time in the non-broadcast time zone.

According to a third aspect of the present invention, the delay measuring means transmits a time signal from the broadcasting station to the digital line at a regular time.
The time of transmission and the time
The time difference at which the time signal is monitored at the broadcast station is
It is characterized in that it is measured as a delay time .

The invention according to claim 4 further comprises a pilot signal generating means for generating a pilot signal inserted into an unused band of the broadcast signal, and wherein the delay measuring means comprises
Including the pilot signal from a sending station to the digital line
Using the time to send out the broadcast signal and the monitor line
When the returned monitor signal is monitored at the broadcasting station
The time difference is measured as the delay time .

[0015]

According to the configuration of the first aspect, the signal arrival time difference is compensated for each system by the delay means, so that synchronous broadcasting can be maintained even when the system is switched, and sound quality deterioration at the time of reception, etc. Can be avoided. Here, the delay means is:
For example, it is constituted by a plurality of delay circuits provided corresponding to each system, or is constituted by a variable delay circuit capable of switching a delay amount corresponding to each system. Switching delay time in the delay means is performed by automatic.

Further, according to the above configuration, the delay time is measured by sending some signal to the digital line by the delay amount measuring means and receiving the signal returned via the monitor line. That is, the signal transmission time is measured using the signal loop. The system determining means determines whether the used line is the working line or the protection line based on the measured delay time, and the delay selecting means controls the delay time, that is, selects the delay circuit according to the determination result. Therefore, according to this configuration, the amount of delay in the delay means can be automatically set, manual complexity can be eliminated, and reliable switching can be realized.

According to the configuration of the second aspect, the delay time is measured using the non-broadcast time zone, and the delay can be compensated before the start of the broadcast every morning.

According to the configuration of the third aspect , the delay time is measured by using the regular time signal, so that the delay can be compensated periodically.

According to the configuration of the fourth aspect , the pilot signal which does not affect the broadcast is superimposed on the broadcast signal,
Since delay compensation can be performed using the pilot signal, switching of the system can be always detected, and an appropriate delay amount can be always set.

[0020]

FIG . 1 shows the overall configuration of a medium-wave synchronous broadcasting system. In FIG. 1, a broadcasting station 1 has a studio for producing an audio signal, and a broadcasting signal is transmitted from the broadcasting station 1 to a plurality of transmitting stations 5 and 8. In that case,
Using the transmission equipment (network) 2 of NTT, the same broadcast signal is transmitted to each of the transmitting stations 5 and 8. Here, each line of the transmission facility 2 is composed of an NTT digital line 0 system (working line) 3a, 3b and an NTT digital line 1 system (protection line) 4a, 4b. Note that these systems have different transmission characteristics, that is, transmission speeds.

The transmitting station A5 is located farther from the transmitting station B8, and has a delay unit 100 as a delay unit and a transmitter A7 for transmitting a broadcast signal as radio waves. The delay unit 100 compensates for a signal arrival time difference (delay time difference) corresponding to the distance difference between the lines 3a and 3b, and compensates for a signal arrival time difference corresponding to the distance difference between the lines 4a and 4b. And a switch 102 for switching the delay circuit. On the other hand, transmitting station B8
Has a transmitter B that transmits a broadcast signal as radio waves.

The delay unit 100 may be constituted by a variable delay circuit, and the amount of delay may be switched stepwise in accordance with each system. In any case, an appropriate delay amount is set for each system so that synchronous broadcasting can be maintained.

Next, the operation of this system will be described. Program sound from studio is NT from broadcast station 1
The signal is transmitted to the T transmission equipment 2 and transmitted to the transmitting station A5 via the digital line 0 system 3a. At the transmitting station A5, a delay time for compensating for a delay time difference between the digital lines 0a and 3b is set in the delay circuit 6a.
The broadcast signal delayed in a is modulated and amplified by the transmitter A7 and broadcast as a radio wave from the antenna.

In synchronization with this, at the transmitting station B8, a broadcast signal is transmitted via the digital line 0 system 3b, and is broadcast as a radio wave by the transmitter B9. That is, transmitting station A
5 and the transmitting station B8, the same broadcast signal is simultaneously broadcast as radio waves at the same frequency.

Here, when the system to be used is switched from the digital system 0 system 3a, 3b to the system 1 4a, 4b, in the transmitting station A, the delay unit 100 switches the switch 102
Is operated to switch from the delay circuit 6a to the delay circuit 6b to delay the broadcast signal.

As a result, even if different systems are used, an appropriate delay time can be set according to the system.
Synchronous broadcasting can be maintained. Therefore, it is possible to solve the problem that the received signal becomes unclear in the equal electric field region as in the related art. The switching of the delay circuit in the delay unit can be performed manually, but it is desirable to automate the processing to avoid complication and ensure smooth switching.

[0027] FIG. 2 shows the essential structure of the embodiment. In this embodiment, there is a delay control unit 13 that automatically detects system switching and controls the amount of delay. That is, the delay control unit 13 automatically detects that the digital line has been switched from system 0 to system 1 or from system 1 to system 0, and automatically selects an appropriate delay circuit based on the result. I have.

[0028] Hereinafter, detailed per Example with reference to FIG. During the broadcast, the broadcast signal 10 from the broadcast station 1 is transmitted to each transmitting station via the timer switch 11 and the digital line of NTT, and is broadcast. The broadcast contents broadcast at the transmitting station are sent back to the broadcasting station 1 through the monitor line as the monitor audio l2.

When the nighttime broadcast suspension time comes, a timer switch 11 as a timer means operates, and the delay control unit 1
3 delay measuring devices 104 are connected to the audio transmission path. Here, the delay measuring device 104 is composed of, for example, a network analyzer or the like, and measures the delay time using signal feedback.

It is sufficient to measure the delay time only for the line between the representative transmitting station, but it is sufficient to measure the delay time for each line between the broadcasting station and each transmitting station. Good. Then, the following determination can be made more accurately, and it can be confirmed that the same type of system is used in each line.

The system discriminator 106 compares the measured delay time with a predetermined value indicating the delay time of the 0-system and the 1-system, and, based on the result, determines whether the digital line of the NTT is the 0-system or the 1-system. Is determined. Then, the delay circuit selector 108
Controls the switch 102 of the delay unit 100 shown in FIG. 1 using the third line separately allocated, and operates the delay circuit corresponding to the used system.

[0032] Thus, according to this embodiment, by utilizing the broadcast pause time period can be performed system automatically discriminated, it is possible to further automatically changes the delay amount.
Note that the control of the delay unit 100 by the delay control unit 13 may use a digital line through which a broadcast signal is transmitted. By doing so, it is possible to avoid an increase in the number of necessary lines.

[0033] In the above Symbol embodiment, N during the night of the broadcast pause time
Although the method of detecting the switching of the TT digital line has been described, the switching can be detected by a time signal. In the method of such other embodiment, the delay control unit 1
3, the delay of the line is compensated for each regular time signal.

[0034] Hereinafter, description is per another embodiment with reference to FIG. The time signal sent from broadcast station 1 on a regular basis is broadcast station 1
And input to the delay measuring device 110 of the delay control unit 13. On the other hand, the time signal sent back to the studio 1 as the monitor sound 12 is also branched and input to the delay measuring device 110.

The delay measuring device 110 measures the time difference between the time signal sent to the transmitting station and the time signal returned, that is, the signal transmission time on the loop path. Thus, the system discriminator 106 determines the type of the NTT digital line.
That is, it is determined whether the digital line has been switched from the 0 system to the 1 system or from the 1 system to the 0 system. Then, similarly to the second embodiment, the delay circuit selector 108
By controlling the 0 switch 102, an appropriate delay circuit is selected.

[0036] Therefore, according to this embodiment, it is possible to automatically switch the delay circuit by the delay control unit 13. Further , according to this embodiment, since the discrimination and the like can be performed based on the time signal, the switching of the system can be periodically performed during the day without affecting the broadcast.

In another embodiment shown in FIG . 4, there is provided a delay control unit 13 for performing delay compensation using a pilot signal.
That is, the pilot signal is superimposed on the broadcast signal, and the
The switching of the digital line of T is constantly monitored and detected, and a frequency of 7.5 kHz or more, which is not used for normal broadcasting, is used as the pilot signal.

[0038] Hereinafter, elaborating per the embodiment with reference to FIG. The pilot signal output from the pilot signal generator 112 of the delay control unit 13 is superimposed on the broadcast signal 10 transmitted from the broadcasting station l, and the signal is transmitted to the transmitting station. On the other hand, the signal returned to the broadcasting station 1 as the monitor sound 12 is input to the delay measuring device 114 together with the pilot signal.

The delay measuring unit 114 measures the time difference between the output pilot signal and the returned pilot signal, that is, the signal transmission time, and the system discriminator 106 determines the type of the NTT digital line system. That is, it is always determined whether the digital line has been switched from the 0 system to the 1 system or from the 1 system to the 0 system. Then, the delay circuit selector 108 controls the switch 102 of FIG. 1 to select the delay circuit corresponding to the determined system.

Thus, according to this embodiment, the line type can be always determined, and the delay circuit can be switched immediately when switching the line.

It should be noted that the synchronous broadcasting system of the present invention
The present invention is not limited to broadcasting, and can be applied to FM broadcasting and television broadcasting.

[0042]

According to the first aspect of the present invention, the signal arrival time difference is compensated for each system by the delay means, so that synchronous broadcasting can be maintained even when the system is switched, and the sound quality at the time of reception is maintained. Deterioration and the like can be avoided.

Further, the amount of delay by the delay means can be automatically set, manual complexity can be eliminated, and reliable switching can be realized.

According to the second aspect of the present invention, the delay time is measured using the non-broadcast time zone, and the delay can be compensated before the start of the broadcast every morning.

According to the third aspect of the present invention, the delay time is measured by using the regular time signal, so that the delay can be compensated periodically.

According to the configuration of the fourth aspect , the pilot signal that does not affect the broadcast is superimposed on the broadcast signal,
Since delay compensation can be performed using the pilot signal, switching of the system can be always detected, and an appropriate delay amount can be always set.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a medium-wave synchronous broadcasting system according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a delay control unit according to an embodiment of the present invention.

FIG. 3 is a configuration diagram of a delay control unit according to an embodiment of the present invention.

FIG. 4 is a configuration diagram of a delay control unit according to an embodiment of the present invention.

FIG. 5 is a configuration diagram of three conventional medium-wave radio broadcasts.

[Explanation of symbols]

6a, 6b delay circuit, l1 timer controller, l3
Delay control unit, 100 delay unit, 102 switch, 104,
110, 114 delay measuring device, 106 system discriminator, 1
08 Delay circuit selector.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04B 7/24-7/26 H04H 1/00 H04L 1/00 H04L 1/08-1/22 H04L 7 / 00-7/10 H04L 29/00-29/14 H04Q 7/00-7/38

Claims (4)

(57) [Claims] 1. A broadcasting station for transmitting a broadcasting signal, and a plurality of systems which can be switched and used for the broadcasting station.
It is connected through a digital line having an integrated, said plurality of transmitting stations broadcasting the broadcasting signal transmitted from the broadcast stations as a radio wave of the same frequency, in the synchronous broadcasting system including the broadcast signals between the transmitting station Broadcast signal transmitted to each transmitting station to compensate for the arrival time difference of each system
Delay means that performs a delay for, among the plurality of transmitting stations and the broadcast stations at least one
Measures the delay time of signal transmission to and from the transmitting station
The broadcast signal from the broadcasting station to the transmitting station.
A digital line through which the broadcasting station is transmitted,
Connected to the monitor line through which the monitor signal is
Measure the delay time using the signal loop of these lines
Delay measuring means, and a system in the digital line based on the delay time.
And a delay corresponding to the determined system.
Delay selecting means for delaying the broadcast signal by a delay amount
And a synchronous broadcast system comprising: 2. The synchronous broadcasting system according to claim 1 , further comprising timer means for judging a non-broadcast time slot, wherein said delay measuring means measures a delay time in the non-broadcast time slot. . 3. The system according to claim 1 , wherein said delay measuring means is provided from said broadcasting station to said digital line.
The time at which the regular time signal is sent to
When the time signal returned via the is monitored at the broadcast station
A synchronous broadcast system , wherein a time difference between the two is measured as the delay time . 4. The system according to claim 1 , further comprising: a pilot signal generating unit that generates a pilot signal inserted into an unused band of the broadcast signal, wherein the delay measuring unit transmits the digital signal from the broadcasting station. Line
To transmit a broadcast signal including the pilot signal to
And a monitor signal sent back using the monitor line
Is the time difference monitored by the broadcasting station
Synchronous broadcasting system characterized by measuring as an interval .