JP4234258B2 - Television broadcast transmitter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is, without interrupting the television signals broadcast relates to a TV broadcasting transmission equipment which can be switched transmitter.
[0002]
[Prior art]
The television broadcast transmitting apparatus is usually provided with a spare transmitter so that the broadcast of the television signal is not interrupted even if the current transmitter fails. In addition, a master station that transmits a television signal uses a high-power transmitter of kW class to expand the service area. And the antenna which transmits a television signal in the air uses the high-gain feed method with a high gain in which two antennas are positioned up and down.
[0003]
Here, a conventional television broadcast transmission apparatus will be described with reference to FIG.
Reference numeral 60 is a current television transmitter, and reference numeral 70 is a spare television transmitter. Each of the two transmitters 60 and 70 is connected to a four-terminal coaxial switch 61. The coaxial switch 61 has first to fourth four terminals T1, T2, T3, and T4. For example, the current transmitter 60 is connected to the terminal T1, and the spare transmitter 70 is connected to the terminal T3. It is connected. A 3 dB coupler 12 is connected to the terminal T2, and a termination resistor R1 is connected to the terminal T4. The terminals T1 and T2 of the coaxial switch 61 are connected by a connection piece A, and the terminals T3 and T4 are connected by a connection piece B.
[0004]
Therefore, in the case of FIG. 6, the output of the transmitter 60 is input to the terminal T <b> 1 of the coaxial switch 61 and is input from the connection piece A to the 3 dB coupler 62 through the terminal T <b> 2. The output of the transmitter 70 is terminated with a termination resistor R1 via a terminal T3 and connection pieces B and T4.
[0005]
The 3 dB coupler 62 is provided with four terminals t1, t2, t3, and t4. The 3 dB coupler 62 has a structure in which a signal input from the terminal t1 or the terminal t2 is output to the terminals t3 and t4 with a phase difference of 90 degrees. A terminal resistor R2 is connected to the terminal t2.
[0006]
The output of the transmitter 60 input to the terminal t1 of the 3 dB coupler 62 is output to the terminals t3 and t4 with a phase difference of 90 degrees. The signal output to the terminal t3 is transmitted from the upper antenna 631. The signal output to the terminal t4 is transmitted from the lower antenna 632.
[0007]
In the above configuration, when a failure such as a decrease in output or modulation abnormality occurs in the current transmitter 60 or when the current transmitter 60 is maintained, the standby transmitter 70 is switched to continue broadcasting. It can be configured.
[0008]
Here, the switching operation from the transmitter 60 to the transmitter 70 will be described with reference to FIGS. FIG. 7A shows the connection state of the coaxial switch 61 when the output of the working transmitter 60 is transmitted. Terminals T1 and T2 are connected by a connection piece A, and terminals T3 and T4 are connected by a connection piece B.
[0009]
In this case, inside the coaxial switch 61, the terminals T1 and T2 are connected by the connection piece A as shown in FIG. The connection piece A is fixed to a fixed base C, and the fixed base C is connected to a motor M via a shaft J. For example, when the motor M is driven, the connection piece A rotates about the axis J, and the terminal connected by the connection piece A can be switched. Although not shown in FIG. 8, the connection piece B also rotates together with the connection piece A by driving the motor M so that the terminals connected by the connection piece B can be switched.
[0010]
When the active transmitter 60 is switched to the spare transmitter 70, first, as shown in FIG. 8B, the fixing base C is mechanically lowered, and the connection piece A connecting the terminals T1 and T2 is disconnected. . Next, as shown in FIG. 8C, the fixing base C is rotated 90 degrees by driving the motor M, and at the same time, the connection piece A is rotated. And as shown in FIG.8 (d), the fixed stand C is moved upwards and the terminal 2 and the terminal 3 are connected with the connection piece A. As shown in FIG. At this time, the connection piece B also rotates at the same time, and the connection piece B connects between the terminal 1 and the terminal 4. This state is shown in FIG.
[0011]
When the connection state of the coaxial switch 61 is FIG. 7B, the output of the transmitter 70 in FIG. 6 is input to the terminal t 1 of the 3 dB coupler 62 through the terminals T 3 and T 2 of the coaxial switch 61. And it outputs to terminal t3 and t4, and is each transmitted from the upper stage antenna 131 and the lower stage antenna 132, and the switch to the transmitter 70 is completed.
[0012]
[Problems to be solved by the invention]
A conventional television broadcast transmitting apparatus has a redundant configuration and is provided with a working transmitter and a spare transmitter. The transmitter and the transmitting station where the transmitter is installed are usually operated unattended. Therefore, an output detector or the like for detecting the output of the transmitter is provided, and when the output of the transmitter is cut off, it is automatically switched to the spare transmitter. In the case of a conventional television broadcast transmitter, the active transmitter and the spare transmitter are connected to a common coaxial switch. For this reason, if the coaxial switch breaks down, the transmitter cannot be switched and transmission is interrupted. In addition, if a failure occurs in the coaxial switch, the operator must go to the transmitting station for repair. For this reason, the wave is unavoidable until the repair is completed.
[0013]
Also, when switching to a spare transmitter, the connection piece and terminal of the coaxial switch are temporarily opened. Therefore, when switching is performed, a method is employed in which the output of the transmitter is interrupted once, and after the switching is completed, the transmitter is operated again. Therefore, the broadcast is interrupted although it is a short time of about several seconds. Also, when the transmitter is maintained, broadcasting is interrupted because the transmitter needs to be switched.
[0014]
In order to avoid such interruption of broadcasting, a pause time during which transmission stops is used. Therefore, time for maintenance work and the like is limited. In addition, when the antenna is maintained, the same problem occurs because it is performed during the broadcast pause time.
[0015]
The present invention is intended to solve the drawbacks mentioned above, it aims to provide a television broadcasting transmission equipment that can maintain the antenna without such can be switched transmitter without interrupting the broadcast, and to interrupt the broadcast And
[0016]
[Means for Solving the Problems]
The television broadcast transmitting apparatus of the present invention includes a first transmitter and a second transmitter that output a television signal, a first terminal to which the first transmitter is connected, and a second transmitter to which the second transmitter is connected. 2 dB, a 3 dB coupler having four terminals of a third terminal and a fourth terminal that output a signal input from the first terminal or the second terminal with a phase difference of 90 degrees, and the third terminal of the 3 dB coupler A first coaxial switch connected to the second coaxial switch connected to the fourth terminal of the 3 dB coupler, one terminal connected to one terminal of the first coaxial switch, and the other terminal A third coaxial switch connected to one terminal of the second coaxial switch, a fourth coaxial switch connected to one terminal of the first coaxial switch, and one terminal. Is connected to one terminal of the second coaxial switch. The fifth coaxial switch and one terminal connected to one terminal of the fourth coaxial switch and the other terminal connected to one terminal of the fifth coaxial switch A first transmission line connected between the first coaxial switch and the fourth coaxial switch; a second transmission line connected between the second coaxial switch and the fifth coaxial switch; A third transmission line connected between the third coaxial switch and the sixth coaxial switch, the line length being ¼ wavelength longer than the first transmission line and the second transmission line, and the fourth coaxial line. A first antenna connected to the switch and a second antenna connected to the fifth coaxial switch , wherein the first transmitter and the second transmitter each modulate a television signal; And a phaser that changes phase by 90 degrees, a modulated television signal It consists of amplified power amplifier, the phase shifter is connected between the power amplifier and the modulator.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to FIG. Reference numeral 10 denotes an active television transmitter, and reference numeral 20 denotes a spare television transmitter. Each of the active and standby television transmitters 10 and 20 includes a modulator 11 that modulates a television signal, a phase shifter 12 that changes the phase by 90 degrees, a power amplifier 13 that amplifies the modulated television signal, and the like. Has been.
[0018]
In addition, the modulated television signal output from the modulator 11 of the current television transmitter 10 is switched by the switch SW so that the phase shifters 12 of the current television transmitter 10 and the spare television transmitter 20 respectively. It is configured to be supplied to. The modulated television signal output from the modulator 11 of the standby television transmitter 20 is switched by the switch SW so that the phase shifters 12 of the current television transmitter 10 and the standby television transmitter 20 respectively. It is configured to be supplied to. Therefore, in this case, the modulated television signal output from either the modulator 11 of the current television transmitter 10 or the modulator 11 of the standby television transmitter 20 is used as the current television transmitter. 10 or as the output of the spare television transmitter 20.
[0019]
Further, the current television transmitter 10 and the spare television transmitter 20 are each connected to the 3 dB coupler 14. The 3 dB coupler 14 has two input terminals t1 and t2, and two output terminals t3 and t4. The current television transmitter 10 is connected to the terminal t1, and the spare television transmitter 20 is connected to the terminal. connected to t2. The 3 dB coupler 14 has a structure in which a signal input from the terminal t1 or a signal input from the terminal t2 is output to the terminals t3 and t4 with a phase difference of 90 degrees. The terminal t 3 of the 3 dB coupler 14 is connected to the first terminal T 11 of the four-terminal first coaxial switch 151, and the terminal t 4 of the 3 dB coupler 14 is connected to the first terminal T 21 of the four-terminal second coaxial switch 152. It is connected to the.
[0020]
The first coaxial switch 151 and the second coaxial switch 152 have the same structure and operation as the coaxial switch described in FIGS. 7 and 8, and are provided with first to fourth terminals in the arrangement order. ing. And a pair of adjacent terminals are connected by two connection pieces A and B. Also, the two connection pieces A and B rotate so that the terminals connected by the connection pieces A and B can be switched. The other coaxial switching units described below also have the same structure as the first and second coaxial switching units 151 and 152, and include four terminals and two connection pieces.
[0021]
In the configuration of FIG. 1, in the first coaxial switch 151, the terminal T <b> 11 and the terminal T <b> 14 are connected by the connection piece A, and T <b> 12 and T <b> 13 are connected by the connection piece B. In the second coaxial switching device 152, the terminal T21 and the terminal T24 are connected by the connection piece B, and T22 and T23 are connected by the connection piece A.
[0022]
A third coaxial switch 153 is connected between the first coaxial switch 151 and the second coaxial switch 152. The third coaxial switch 153 has a terminal T32 connected to the terminal T14 of the first coaxial switch 151 and a terminal T34 connected to a terminal T22 of the second coaxial switch 152. In the third coaxial switch 153, the terminal T31 and the terminal T34 are connected by the connection piece A, and T32 and T33 are connected by the connection piece B.
[0023]
The terminal T42 of the fourth coaxial switch 154 is connected to the terminal T12 of the first coaxial switch 151. In the fourth coaxial switch 154, the terminal T41 and the terminal T42 are connected by the connection piece A, and T43 and T44 are connected by the connection piece B. The upper antenna 161 is connected to the terminal T43.
[0024]
Further, the terminal T54 of the fifth coaxial switch 155 is connected to the terminal T24 of the second coaxial switch 152. In the fifth coaxial switch 155, T51 and T52 are connected by a connection piece A, and T53 and T54 are connected by a connection piece B. The lower antenna 162 is connected to the terminal T53.
[0025]
A sixth coaxial switch 156 is connected between the fourth coaxial switch 154 and the fifth coaxial switch 155. In the sixth coaxial switch 156, T61 and T62 are connected by a connection piece A, and T63 and T64 are connected by a connection piece B. In the sixth coaxial switch 156, the terminal T62 is connected to the terminal T44 of the fourth coaxial switch 154, and the terminal T64 is connected to the terminal T52 of the fifth coaxial switch 155.
[0026]
The coaxial line E is connected between the first coaxial switch 151 and the fourth coaxial switch 154, the coaxial line F is connected between the second coaxial switch 152 and the fifth coaxial switch 155, and the third A coaxial line G is connected between the coaxial switch 153 and the sixth coaxial switch 156. The coaxial line E and the coaxial line G have the same length, and the coaxial line F is longer than the coaxial lines E and G by a length of λ / 4 (λ is a wavelength).
[0027]
In the connection state of FIG. 1 described above, for example, when the current transmitter 10 is in an operating state, the output of the transmitter 10 is input to the terminal t 1 of the 3 dB coupler 14. This output is divided into two and appears at terminals t3 and t4. The output appearing at the terminal t4 is delayed by 90 degrees compared to the output at the terminal t3. The output of the terminal t3 is supplied to the coaxial line F via the coaxial switches 151 and 153. The signal is further supplied from the coaxial line F to the upper antenna 161 via the sixth coaxial switch 156 and the fourth coaxial switch 154 and transmitted from the upper antenna 161.
[0028]
The output of the terminal t4 is supplied to the coaxial line G through the coaxial switch 152. Then, the signal is supplied to the lower antenna 162 via the fifth coaxial switch 155 and transmitted from the lower antenna 162.
[0029]
The coaxial line F has a line length longer than the coaxial lines E and G by λ / 4. Therefore, the power supplied to the upper antenna 161 and the lower antenna 162 is in phase. Moreover, since it is divided into two by the 3 dB coupler 14, the amplitude is also the same.
[0030]
Next, another embodiment of the present invention will be described with reference to FIG. 2 taking as an example a case where the transmitter 20 is operated instead of the transmitter 10. In FIG. 2, parts corresponding to those in FIG.
[0031]
In this case, the terminals of the first coaxial switch 151 to the sixth coaxial switch 156 are connected to each other by the connection piece A and the connection piece B as shown in FIG. For example, the terminals T11 and T12 of the first coaxial switching device 151 are connected by the connection piece B, and the terminals T13 and T14 are connected by the connection piece A. At this time, the output of the transmitter 20 output to the terminal t3 of the 3 dB coupler 14 is supplied to the coaxial line E via the coaxial switch 151. Thereafter, the signal is transmitted from the upper antenna 161 via the coaxial switch 154. The output of the transmitter 20 output to the terminal t4 is supplied to the coaxial line F by the coaxial switches 152 and 153. Thereafter, the signal is transmitted from the lower antenna 162 via the coaxial switches 156 and 155. Also in this case, the output of the transmitter 20 is fed to the upper antenna 161 and the lower antenna 162 with the same amplitude and the same phase.
[0032]
With the above configuration, for example, when the transmitter 10 is switched to the transmitter 20, the output of the transmitter 10 is turned off, the coaxial switches 151 to 156 are switched, and the output of the transmitter 20 is turned on. Further, the coaxial switch connected to the upper antenna 161 and the coaxial switch connected to the lower antenna 162 do not use a common coaxial switch. Therefore, even if one coaxial switch breaks down, a television signal is transmitted from either the upper antenna 161 or the lower antenna 162, and the broadcast is not interrupted.
[0033]
Next, another embodiment of the present invention will be described with reference to FIGS. 1, 3, and 4, taking as an example a case where the transmitter is switched without turning off the output of the transmitter. 3 and 4, the same reference numerals are given to the portions corresponding to FIG. 1, and duplicate descriptions are omitted.
[0034]
First, the transmitter 20 is set to an operating state in the connection state of FIG. At this time, the phase shifter 12 causes the output of the transmitter 20 to have a phase of 90 degrees with respect to the output of the transmitter 10. At this time, a combined output obtained by combining the outputs of the transmitters 10 and 20 appears at the terminal t 4 of the 3 dB coupler 14. The output appearing at the terminal t4 is supplied to the lower antenna 162 via the coaxial switch 152, the coaxial line G, and the coaxial switch 155, and is transmitted from the lower antenna 162. Note that, since the outputs of the transmitters 10 and 20 are in reverse phase, they cancel each other and are not output to the terminal t3.
[0035]
At this time, the output of the transmitter does not pass through the coaxial switches 151, 153, 154, and 156. Accordingly, the connection pieces A and B of these coaxial switches 151, 153, 154, and 156 can be freely rotated. Therefore, the connection pieces A and B of the coaxial switches 151, 153, 154 and 156 are rotated, and the connection with each terminal is set as indicated by broken lines P and Q in FIG.
[0036]
Next, the phases of the transmitters 10 and 20 are adjusted by the phase shifter 12, and the phase of the output of the transmitter 10 is set to −90 degrees with respect to the output of the transmitter 20. At this time, a combined output obtained by combining the outputs of the transmitters 10 and 20 appears at the terminal t3 of the 3 dB coupler. The combined output appearing at the terminal t3 is guided to the upper antenna 161 through the coaxial switch 151, the coaxial line E, and the coaxial switch 154, and is transmitted from the upper antenna 161. Note that the outputs of the transmitters 10 and 20 are out of phase with each other at the terminal t4, so that they are not canceled out.
[0037]
At this time, the output of the transmitter does not pass through the coaxial switches 152, 153, 155, and 156. Therefore, the connection pieces of the coaxial switches 152, 153, 155, and 156 can be freely rotated. Therefore, the connection pieces A and B of the coaxial switches 152 and 155 are rotated, and the connection with each terminal is set as indicated by broken lines P and Q in FIG. Then, the output of the transmitter 10 is stopped. At this time, the output of the transmitter 20 appears at the terminal t4, is guided to the lower antenna 162 via the coaxial switches 152 and 153, the coaxial line F, and the coaxial switches 155 and 156, and is transmitted from the lower antenna 162.
[0038]
The output of the transmitter 20 that appears at the terminal t3 is supplied to the upper antenna 161 via the coaxial switch 151, the coaxial line E, and the coaxial switch 154, and transmitted from the upper antenna 161. Switching from the transmitter 10 to the transmitter 20 is performed by the above procedure. The transmitter 20 can be switched to the transmitter 10 by the same procedure.
[0039]
In the middle of the above procedure, the combined output of the two transmitters 10 and 20 is guided to the upper antenna or the lower antenna, and the output of the transmitter is substantially doubled. However, since the antenna operates in only one direction, the antenna gain is halved. Therefore, the power radiated from the antenna is kept constant. A phase shifter 12 is connected between the modulator and the power amplifier. In this case, since the phase shifter 12 is connected at a portion of low output power, the phase can be changed at high speed, and switching can be performed reliably without interrupting broadcasting.
[0040]
Next, another embodiment of the present invention will be described with reference to FIG. 5 by taking as an example the case of maintaining an antenna without stopping. In FIG. 5, parts corresponding to those in FIG.
[0041]
In this case, the two transmitters 10 and 20 are in operation. Then, the phase of the output of the transmitter 20 is advanced 90 degrees from the phase of the output of the transmitter 10, and the phase of the output of the transmitter 10 is −90 degrees with respect to the transmitter 20. At this time, a combined output obtained by combining the outputs of the two transmitters 10 and 20 is supplied to the upper antenna 161 and transmitted from the upper antenna 161. A dummy load K is connected to the terminal T1 of the coaxial switch 153. If there is a difference in amplitude or phase between the transmitters 10 and 20, the two outputs of the transmitters 10 and 20 are not erased, and power appears at the terminal t4 of the 3 dB coupler. Further, when one of the transmitters 10 and 20 fails, power appears at the terminal t4 of the 3 dB coupler. Therefore, the dummy load K absorbs the power that appears at the terminal t4.
[0042]
In the state described above, the outputs of the transmitters 10 and 20 are not supplied to the lower antenna 162. Therefore, maintenance work can be performed on the lower antenna 162 even while the television signal is broadcast from the upper antenna 161. Also, the upper antenna 161 can be maintained while broadcasting with the lower antenna 162 in the same procedure. In this case, the output of the terminal t3 of the 3 dB coupler is connected to the dummy load K of the terminal T3 of the coaxial switch 153.
[0043]
According to the configuration described above, when a transmitter in an operating state is switched to another transmitter, a switch common to the two transmitters is not used. For this reason, the interruption of broadcasting due to the failure of the coaxial switch can be reduced. Furthermore, it is possible to realize a television broadcast transmitting apparatus that can switch transmitters or maintain antennas without interrupting broadcasting.
[0044]
【The invention's effect】
According to the present invention, it is possible to realize a television broadcast transmission equipment capable of such switching of no transmitter interrupting the broadcast.
[Brief description of the drawings]
FIG. 1 is a circuit configuration diagram for explaining an embodiment of the present invention.
FIG. 2 is a circuit configuration diagram for explaining another embodiment of the present invention.
FIG. 3 is a circuit configuration diagram for explaining another embodiment of the present invention.
FIG. 4 is a circuit configuration diagram for explaining another embodiment of the present invention.
FIG. 5 is a circuit configuration diagram for explaining another embodiment of the present invention.
FIG. 6 is a circuit configuration diagram for explaining a conventional example.
FIG. 7 is a schematic structural diagram for explaining a switching operation of the coaxial switch.
FIG. 8 is a schematic structural diagram for explaining a switching operation of a coaxial switch.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... 1st transmitter 20 ... 2nd transmitter 11 ... Modulator 12 ... Phaser 13 ... Power amplifier 14 ... 3dB coupler 151 ... 1st coaxial switch 152 ... 2nd coaxial switch 153 ... 3rd coaxial switch 154 ... 4th coaxial switch 155 ... 5th coaxial switch 156 ... 6th coaxial switch 161 ... Upper stage antenna 162 ... Lower stage antenna E, F, G ... Coaxial line

Claims (2)

A first transmitter and a second transmitter for outputting a television signal; a first terminal to which the first transmitter is connected; a second terminal to which the second transmitter is connected; the first terminal; A 3 dB coupler having four terminals, a third terminal and a fourth terminal, in which a signal input from two terminals is output with a phase difference of 90 degrees, and a first coaxial switch connected to the third terminal of the 3 dB coupler; , A second coaxial switch connected to the fourth terminal of the 3 dB coupler, one terminal connected to one terminal of the first coaxial switch, and the other terminal connected to one of the second coaxial switch. A third coaxial switch connected to the terminal, a fourth coaxial switch whose one terminal is connected to one terminal of the first coaxial switch, and a single terminal that is one of the second coaxial switch. A fifth coaxial switch connected to the terminal and one terminal A sixth coaxial switch connected to one terminal of the fourth coaxial switch and another terminal connected to one terminal of the fifth coaxial switch; the first coaxial switch; and the fourth coaxial switch. A first transmission line connected between coaxial switches, a second transmission line connected between the second coaxial switch and the fifth coaxial switch, the third coaxial switch, and the sixth coaxial switch. A third transmission line that is connected between the first and second transmission lines and is ¼ wavelength longer than the first transmission line and the second transmission line; a first antenna connected to the fourth coaxial switch; A second antenna connected to a coaxial switch , wherein the first transmitter and the second transmitter each modulate a television signal, and a phase shifter that changes the phase by 90 degrees, A power amplifier for amplifying the modulated television signal; Phase vessel is a modulator connected to the television broadcast transmission apparatus between the power amplifier.   The television broadcast transmitter according to claim 1, wherein a dummy load is connected to a terminal of the third coaxial switch.

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