JP2019146110A - Transmitter and method for control - Google Patents

Abstract

To provide a transmitter and a method for control which can maintain the reliability of switching demanded for broadcasting businesses while suppressing increase of the cost of the device.SOLUTION: The transmitter according to an embodiment includes: a first output unit; a second output unit; a switching unit; and a feedback unit. The first and second output units output a picture signal. The switching unit is connected to the first and second output units and switches the output system of the picture signal between the first and second output units on the basis of a predetermined switching system. The feedback unit feeds back the signal level of the picture signal output from the first output unit to the second output unit, and feeds back the signal level of the picture signal output from the second output unit to the first output unit. The first and second output units adjust the output level of the picture signal so that the difference in the level of the output picture signal will be within the acceptable range of the switching system, according to the fed-back level information.SELECTED DRAWING: Figure 1

Description

  Embodiments described herein relate generally to a transmitter and a control method.

  In a broadcasting business system, a video signal processing system is generally made redundant in order to ensure transmission quality of a program (content). Furthermore, if there is a large gap in the signal strength of each system (hereinafter referred to as “signal level”) during system switching, the program (content) may be stopped instantaneously or noise may occur in the video. High reliability is also required for system switching means. As such a system switching system, a quasi-seamless switching system is used in terrestrial digital broadcasting, which is currently mainstream. This switching method is a method of performing system switching on the transmission side at an appropriate timing that does not adversely affect the demodulation processing of the video signal on the reception side.

  Conventionally, as a method of determining the timing of system switching in quasi-seamless switching, the switching timing is determined based on the frequency difference, phase difference, level difference, envelope, etc. of the signals of each system input to the switch that switches the output system. There is a way. However, this method requires components such as a phase shifter and a mixer, and thus the transmitter becomes expensive. On the other hand, as a method for easily realizing quasi-seamless switching, there is a method for maintaining a level difference of signals output from each processing system within a specified range. However, in this method, the level difference between the signals output from the respective processing systems is not necessarily within the specified range at the input time of the switching unit. Therefore, even if the transmitter can be configured at low cost, there is a possibility that the switching timing cannot be properly determined.

JP 2004-120345 A JP 2003-309738 A JP 2002-76946 A

  The problem to be solved by the present invention is to provide a transmitter and a control method capable of maintaining the switching reliability required for the broadcasting business while suppressing an increase in the device price.

  The transmitter according to the embodiment is a transmitter that transmits a video signal, and includes a first output unit, a second output unit, a switch, and a feedback unit. The first output unit and the second output unit output the video signal. The switch is connected to the first output unit and the second output unit, and the output system of the video signal between the first output unit and the second output unit is based on a predetermined switching method. To switch. The feedback unit feeds back level information indicating the signal level of the video signal output from the first output unit to the second output unit, and indicates a level indicating the signal level of the video signal output from the second output unit. Information is fed back to the first output unit. In each of the first output unit and the second output unit, based on the level information fed back by the feedback unit, the level difference between the video signals output from each other falls within the allowable range of the switching method. As described above, the output level of the video signal is adjusted.

The figure which shows the structural example of the transmitter 1 of 1st Embodiment. The figure which shows the structural example of the switch 30 in 1st Embodiment. The figure which shows the structural example of the transmission converter 14 in 1st Embodiment. In the first embodiment, it will be described that the level difference between the video signals of each system input to the switch 30 is approximated by the level difference between the video signals output from the transmission converters 14 of each system. The figure explaining the level difference of the video signal of each system | strain input into the switch 30 approximated by the level difference of the video signal which the transmission converter 14 of each system | strain outputs in 1st Embodiment. The figure which shows the specific example of the method of adjusting the output level of the transmission converter 14 in 1st Embodiment. The figure which shows the specific example of the method of adjusting the output level of the transmission converter 14 in 1st Embodiment. The figure which shows the specific example of the method of adjusting the output level of the transmission converter 14 in 1st Embodiment. The figure which shows the modification of the transmitter 1 of 1st Embodiment. The figure which shows the modification of the transmitter 1 of 1st Embodiment. The figure which shows the modification of the transmitter 1 of 1st Embodiment. The figure which shows the structural example of the transmitter 1a of 2nd Embodiment. The figure which shows the structural example of the transmission converter 14a in 2nd Embodiment.

  Hereinafter, a transmitter and a control method according to an embodiment will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a diagram illustrating a configuration example of the transmitter 1 according to the first embodiment. The transmitter 1 is a device that receives a video signal from a video signal output device (not shown) that outputs a video signal for broadcasting, and transmits the received video signal to a receiver (not shown) that is a display device. is there. The transmitter 1 includes a CPU (Central Processing Unit), a memory, an auxiliary storage device, and the like connected by a bus, and executes a program. The transmitter 1 functions as a device including the first transmission unit 10, the second transmission unit 20, the switch 30 and the controller 40 by executing a program. All or some of the functions of the transmitter 1 may be realized using hardware such as an application specific integrated circuit (ASIC), a programmable logic device (PLD), or a field programmable gate array (FPGA). The program may be recorded on a computer-readable recording medium. The computer-readable recording medium is, for example, a portable medium such as a flexible disk, a magneto-optical disk, a ROM, a CD-ROM, or a storage device such as a hard disk built in the computer system. The program may be transmitted via a telecommunication line.

  The first transmission unit 10 and the second transmission unit 20 receive the video signal, perform various signal processing on the received video signal, and output the processed signal to the switch 30. The first transmission unit 10 and the second transmission unit 20 have the same configuration and make the internal transmission path of the transmitter 1 redundant. Specifically, the same video signal made redundant is input to the first transmission unit 10 and the second transmission unit 20, and the same internal transmission processing (reception to output) is performed on each of them.

  Specifically, the first transmission unit 10 and the second transmission unit 20 include a reception converter 11, a demodulation unit 12, a modulation unit 13, and a transmission converter 14, respectively. Hereinafter, as necessary, these function units are distinguished from each other by the first transmission unit 10 and the second transmission unit 20 by adding “−1” or “−2” to the reference numerals of the respective function units. For example, the reception converter 11 included in the first transmission unit 10 is described as “reception converter 11-1”, and the reception converter 11 included in the second transmission unit 20 is described as “reception converter 11-2”. The two are distinguished by.

  The reception converter 11 receives the video signal transmitted from the video signal output device, performs frequency conversion processing on the received video signal, and outputs the result to the demodulation unit 12. For example, when a video signal converted into a broadcast frequency band (RF: Radio Frequency) is output, the reception converter 11 changes the frequency of the received video signal to a frequency in an intermediate frequency band (IF: Intermediate Frequency). The data is converted and output to the demodulator 12.

  The demodulator 12 demodulates the intermediate frequency band video signal output from the reception converter 11 and outputs the demodulated video signal to the modulator 13. For example, modulation methods such as QAM (Quadrature Amplitude Modulation) and OFDM (Orthogonal Frequency-Division Multiplexing) are used for wireless transmission of video signals. The demodulator 12 demodulates the video signal based on these modulation methods, and outputs the data signal (TS), clock signal (CLK), and synchronization signal (Fsync) obtained by the demodulation to the modulator 13.

  The modulation unit 13 converts the frequency of the demodulated video signal output from the demodulation unit 12 into a frequency in the intermediate frequency band and outputs the frequency to the transmission converter 14. Note that the modulation unit 13 may perform signal processing for the purpose of improving quality, removing noise, or the like on the video signal before modulation as necessary.

  The transmission converter 14 converts the video signal in the intermediate frequency band output from the modulation unit 13 into a broadcast frequency band and outputs it to the switch 30. Note that the transmission converter 14 may perform signal processing for the purpose of improving quality, removing noise, or the like on the unmodulated video signal as necessary.

  The switch 30 is referred to as a video signal output from the first transmission unit 10 (hereinafter referred to as “first video signal”) and a video signal output from the second transmission unit 20 (hereinafter referred to as “second video signal”). ), And selectively output one of the video signals. The video signal output from the switch 30 is input to an antenna device (not shown) and wirelessly transmitted to the receiver by the antenna device.

  In addition, the switch 30 monitors a level difference (that is, an intensity difference) between the signal level of the first video signal and the signal level of the second video signal, and between the first video signal and the second video signal. It has a function of determining whether or not semi-seamless switching is possible and notifying the controller 40 of the determination result. The switch 30 continuously executes the determination process and the notification process during the transmission of the video signal, and the video is transferred from one of the first transmission unit 10 and the second transmission unit 20 to the other according to an instruction from the controller 40. Switch the signal output system.

  Further, in the transmitter 1 of the first embodiment, the switch 30 feeds back information indicating the signal levels of the first video signal and the second video signal (hereinafter referred to as “level information”) to each transmission converter 14. It has a function. Based on the level information fed back in this way, each transmission converter 14 maintains the level difference between the video signals output from each other within a range in which quasi-seamless switching is possible (hereinafter referred to as “quasi-seamless switching possible range”). The function of adjusting the output level of the video signal is provided.

  The controller 40 is a functional unit that controls the transmitter 1. Specifically, the controller 40 is electrically connected to each functional unit included in the transmitter 1, and inputs / outputs signals related to the control of the functional units (hereinafter referred to as “control signals”) between the functional units. To do. By such control signal input / output, the controller 40 grasps the state of each functional unit and gives a control instruction according to the state of each functional unit to each functional unit.

  FIG. 2 is a diagram illustrating a configuration example of the switch 30 in the first embodiment. The switch 30 includes a switch 31, a level information acquisition unit 32, and a determination unit 33. The switch 31 switches the video signal output system in accordance with an instruction from the controller 40. FIG. 2 shows a situation where the output system is the first transmission unit 10. When the controller 40 notifies the switching instruction in this situation, the switch 31 switches the video signal output system from the transmission converter 14-1 to the transmission converter 14-2.

  The level information acquisition unit 32 acquires a signal level (hereinafter referred to as “input level”) when the video signals output from the transmission converter 14-1 and the transmission converter 14-2 are input to the switch 30. . Specifically, the input level of the first video signal is acquired from the signal level detector 321 provided in the internal transmission path of the first video signal, and the signal level detector provided in the internal transmission path of the second video signal. From 322, the input level of the second video signal is acquired. The level information acquisition unit 32 generates level information indicating a level difference between the video signals based on the signal levels of the first video signal and the second video signal, and transmits the generated level information to the transmission converters 14-1 and 14 -2 and the determination unit 33.

  Based on the level information output from the level information acquisition unit 32, the determination unit 33 determines whether the level difference between the first video signal and the second video signal is within a semi-seamless switchable range. If the level difference between the video signals is not within the quasi-seamless switchable range, the determination unit 33 notifies the controller 40 that the quasi-seamless switching is not possible. Hereinafter, this notification is referred to as an abnormality notification.

  FIG. 3 is a diagram illustrating a configuration example of the transmission converter 14 in the first embodiment. The transmission converter 14 includes an attenuator 141, a local oscillator 142, a mixer 143, a BPF (Band Pass Filter) 144, an HPA (High Power Amplifier) 145, a DA (Digital to Analog) converter 146, a level information converter 147, and a level. An adjustment unit 148 is provided.

  Among these functional units, the local oscillator 142, the mixer 143, and the BPF 144 are configured to be generally provided in a transmitter that generates a transmission signal in a radio band. Further, the attenuator 141, the HPA 145, and the DA converter 146 are generally provided in a transmitter that assumes system switching by a semi-seamless switching method. In such a transmitter, the video signal is attenuated by the attenuator 141 and input, and the HPA 145 amplifies the video signal in order to keep the output level within a specified range. The DA converter 146 inputs a control signal of an FET (Field Effect Transistor) (not shown) that controls the amplification process of the video signal to the HPA 145.

  The level information conversion unit 147 converts the level information output from the switch 30 into information necessary for the level adjustment unit 148 to adjust the output level (hereinafter referred to as “adjustment information”), and the level adjustment unit 148. Output to.

  Based on the adjustment information output from the level information conversion unit 147, the level adjustment unit 148 causes the level difference between the video signals output from the transmission converters 14-1 and 14-2 to be within a semi-seamless switchable range. The feedback control is performed for the amplification processing of the video signal. Specifically, the level adjustment unit 148 controls the DA converter 146 and causes the HPA 145 to output a control signal reflecting the above feedback control.

  Specifically, the level information conversion unit 147 acquires the following two pieces of information based on the signal levels of the first video signal and the second video signal indicated by the level information, that is, the input level of each video signal in the switch 30. To do. The first information is the difference between the input level of the video signal output from the transmission converter 14 of its own system and the input level of the video signal output from the transmission converter 14 of the other system (hereinafter referred to as “first level difference”). It is said.) The second information is the difference between the output level of the video signal from the transmission converter 14 of the own system and the input level of the video signal output from the transmission converter 14 of the own system (hereinafter referred to as “second level difference”). ). The level adjustment unit 148 adjusts the output level of the transmission converter 14 based on the first and second level differences acquired in this way.

  4 and 5, in the first embodiment, the level difference of the video signal of each system input to the switch 30 is approximated by the level difference of the video signal output from the transmission converter 14 of each system. It is a figure explaining this. As shown in FIG. 4, generally, the signal level of the video signal is attenuated by the influence of the transmission path (for example, a coaxial cable) from the output from the transmission converter 14 to the switch 30. For this reason, feedback of the input level of the switch 30 for the purpose of adjusting the output level of the transmission converter 14 basically feeds back information including more influences other than the control target. It is not preferable.

However, in a broadcasting business system that requires high reliability, it is often the case that each system has the same equipment configuration so as not to cause a performance gap between the systems as much as possible. Therefore, the grade and length of the transmission medium connecting the transmission converter 14 and the switch 30 are often configured to be the same. If there is such a configuration premise, it can be considered that the degree of attenuation of the signal level in the transmission line is the same in each system. Therefore, as shown in FIG. 5, under such a premise, the level difference of the video signal of each system input to the switch 30 is determined by the level difference of the video signal output from the transmission converter 14 of each system. Can be approximated. In other _words, it can be regarded as a _{w1 out -w1 in ≒ w2 out -w2} in.

  FIGS. 6-8 is a figure which shows the specific example of the method of adjusting the output level of the transmission converter 14 in 1st Embodiment. FIG. 6 shows a method of adjusting the output level so that the output level of each system approaches a certain reference value common to both as a first method of adjusting the output level. FIG. 6 shows that in the transmission converter 14 of each system, the specified range of the output level is within the range of the reference value ± 1.0 [dB], within the range of the reference value ± 1.5 [dB] and out of the specified range. An example is shown in which a range that is outside the range of the reference value ± 1.5 [dB] and outside the range of the caution range is defined as the danger range.

  FIG. 6A shows the output level of each system before adjustment. FIG. 6A shows that the output level of the first system and the output level of the second system are both within the specified range, but the level difference between them (first level difference) is larger than the quasi-seamless switching range. Represents the situation. In this case, the transmission converter 14 of each system detects that the first level difference is outside the quasi-seamless switchable range based on the level information output from the switch 30, Adjust the output level so that it is closer. For example, the following processing is performed in the transmission converter 14-1.

  First, the level information conversion unit 147 obtains the first level difference by subtracting the input level of the second video signal indicated by the level information from the input level of the first video signal indicated by the level information. Further, the level information conversion unit 147 subtracts the input level of the first video signal indicated by the level information from the output level of the first video signal output from the transmission converter 14-1 of its own system (first system). To obtain the second level difference. The level information conversion unit 147 outputs adjustment information indicating the acquired first level difference and second level difference to the level adjustment unit 148.

  Subsequently, the level adjustment unit 148 subtracts the first level difference indicated by the adjustment information and adds the second level difference from the output level of the first video signal output from the transmission converter 14-1 of its own system. Thus, the output level of the second video signal output from the transmission converter 14-2 of the other system (second system) is acquired. The level adjustment unit 148 determines the difference between the output level of the first video signal output from the transmission converter 14-1 of its own system and the output level of the second video signal output from the transmission converter 14-2 of the other system. It is determined whether or not it is within the quasi-seamless switching range. If this difference exceeds the quasi-seamable switching range, the difference between the output level of the first system and the output level of the second system is quasi-seamless. The output level of the own system is adjusted to be close to the reference value so as to be within the switchable range.

  As a result of the processing similar to the above also being executed in the transmission converter 14-2, as shown in FIG. 6B, the level difference of the video signal output from the transmission converter 14 of each system is within the quasi-seamless switching range. It is adjusted to be inside. Further, according to the first adjustment method, the output level of each system is adjusted so as to approach the reference value, so that the transmission converter 14 of each system can be operated more stably.

  FIG. 7 shows a method of adjusting the output level so that the output levels of the respective systems are close to each other as a second method of adjusting the output level. FIG. 7A shows the output level of each system before adjustment. In FIG. 7A, as in FIG. 6A, while the output level of the first system and the output level of the second system are both within the specified range, the level difference between them (first level difference). Represents a situation in which is larger than the semi-seamless switching range. The difference between FIG. 7A and FIG. 6A is that the output level of each system is on the plus side of the reference value.

  In this case, the transmission converter 14 of each system detects that the first level difference is outside the quasi-seamless switchable range based on the level information output from the switch 30, and for example, outputs from other systems Adjust the output level of your system so that it is close to the level.

  As a result, as shown in FIG. 7B, the level difference of the video signal output from the transmission converter 14 of each system is adjusted to be within the quasi-seamless switchable range. Further, according to the second adjustment method, the output levels of the respective systems are adjusted so as to approach each other, so that the amount of adjustment of the output level of each system can be made substantially the same. Therefore, the risk by moving one system | strain output level more largely than another system | strain can be reduced.

  In FIG. 8, as a third method for adjusting the output level, the output level is adjusted so that the output level of the non-operating system approaches the output level of the system selected as the output system (hereinafter referred to as “operating system”). How to do. FIG. 8A shows the output level of each system before adjustment. FIG. 8A shows the same situation as FIG. Here, it is assumed that the second system is an operational system.

  In this case, the transmission converter 14 of the first system (non-operating system) detects that the first level difference is outside the quasi-seamless switchable range based on the level information output from the switch 30; For example, the output level of the own system is adjusted so as to approach the output level of the second system (operating system).

  As a result, as shown in FIG. 8B, the level difference of the video signal output from the transmission converter 14 of each system is adjusted to be within the quasi-seamless switchable range. In addition, according to the third adjustment method, since it is not necessary to change the output level of the operating system, it is possible to reduce the risk caused by changing the output level of the operating system. In general, in a redundant system, changing the operation of the operation system is often avoided in consideration of the possibility of some influence on the service being provided. For example, in a broadcasting business system, the possibility that a failure such as an instantaneous stop of a program or noise in a video occurs due to a change in the output level of the operation system is not zero. Therefore, by changing the output level for the non-operating system, it is possible to reduce the risk of failure due to the adjustment of the output level.

  In the first adjustment method and the second adjustment method, the adjustment amount of the output level may be weighted depending on whether each system is an operating system or a non-operating system. By doing so, it is possible to prevent the output level of the operational system from being significantly changed also in the first adjustment method and the second adjustment method. For example, the weighting coefficient of the first system is α (0 ≦ α ≦ 1), the weighting coefficient of the second system is β (0 ≦ β ≦ 1), and the adjustment amount in one control cycle is γ. In this case, the adjustment amount of the first system in one control cycle is αγ, and the adjustment amount of the second system is βγ. Here, when the first system is an operating system, the adjustment amount of the operating system can be made smaller than that of the non-operating system by setting α> β. If the weighting coefficient value of the operating system is 0 and the weighting coefficient value of the non-operating system is 1, the adjustment amount of the operating system is 0 and the adjustment amount of the non-operating system is γ. The third adjustment method may be realized based on such weighting.

  The transmitter 1 of the first embodiment configured as described above feeds back the level information indicating the input level in the switch 30 of the first video signal and the second video signal to each transmission converter 14, and the transmission converter 14-1 and 14-2 maintain the reliability of semi-seamless switching required for the broadcasting business by adjusting the respective output levels so that the output level difference between them is within the semi-seamless switchable range. Can do. Further, the transmitter 1 configured as described above can adjust the output level without requiring additional components such as a phase shifter and a mixer. Therefore, according to the transmitter 1 of the first embodiment, it is possible to maintain the reliability of semi-seamless switching required for the broadcasting business while suppressing an increase in device price.

  Hereinafter, modifications of the transmitter 1 of the first embodiment will be described.

  In the first embodiment, the configuration in which the transmitter 1 is made redundant by the two transmission converters 14 is shown. However, the transmitter 1 is made redundant by three or more transmission converters 14 as shown in FIG. May be used. With this configuration, the reliability of the transmitter 1 can be further improved. FIG. 9 shows an example in which the transmitter 1 includes three transmission converters 14. In this case, the switch 30 feeds back the information indicating the input levels of the transmission converters 14-1 to 14-3 as level information to the transmission converters 14-1 to 14-3, respectively.

  In the first embodiment, the switching unit 30 directly feeds back the level information to each transmission converter 14. In this case, however, the level information is sent to both the transmission converter 14 and the switching unit 30. It is necessary to add a physical interface for input / output. For example, as a method of mounting a configuration for inputting and outputting level information, there are a method for inputting and outputting a detection voltage and a reference voltage of a video signal, and a method for inputting and outputting as a serial communication signal such as start-stop synchronization. In addition, operations such as addition of connector parts to each transmission converter 14 and switching device 30, securing of the space, and laying of a new cable are required.

  On the other hand, in a conventional broadcasting business system, the transmission converter and the switch are generally monitored and controlled by a controller, and a communication interface between the transmission converter and the switch and the controller is already installed. Often it is. Therefore, the transmitter 1 may be configured such that the switch 30 and the transmission converter 14 input and output level information via the controller 40, as shown in FIG. As described above, when the transmitter 1 according to the embodiment is configured by extending the conventional broadcasting business system, by inputting / outputting level information using an existing physical interface, an additional part for the existing transmitter can be obtained. The number can be reduced.

  In the first embodiment, the transmission converter 14 is configured to include both the level information conversion unit 147 and the level adjustment unit 148. However, in actual operation, the output level of the transmission converter is transmitted to the controller as telemetry data. It is common to input and output between them. Therefore, the transmitter 1 may be configured to output the level information acquired in one transmission converter 14 to the other transmission converter 14 via the controller 40. In this case, for example, as shown in FIG. 11, the transmission converter 14 further includes a signal level detector 1451 similar to the signal level detectors 321 and 322. The signal level detector 1451 acquires the output level of the transmission converter 14 by converting the voltage value or current value of the video signal output from the HPA 145 and input to the level adjustment unit 148 into a signal level [dBm]. The transmitter 1 is configured to include the output level detected by the signal level detector 1451 in the telemetry data and notify the controller 40. In this case, the controller 40 includes a level information conversion unit 147 that generates adjustment information based on the output level notified from each transmission converter 14, and the adjustment information generated for each transmission converter 14 is converted to each transmission conversion. Configured to output to the device 14. With this configuration, the feedback control of level information can be managed by the controller 40 in an integrated manner.

  11 shows an example in which the transmission converter 14 detects its own output level and notifies the controller 40, but when level information is acquired in the switch 30 as in the first embodiment. The switch 30 may be configured to output level information to the level information conversion unit 147 of the controller 40. Further, the transmitter 1 may be configured to include a level adjustment unit 148 on the controller 40 side in addition to the level information conversion unit 147.

(Second Embodiment)
FIG. 12 is a diagram illustrating a configuration example of the transmitter 1a according to the second embodiment. The transmitter 1a includes a transmission converter 14a-1 instead of the transmission converter 14-1, a point including a transmission converter 14a-2 instead of the transmission converter 14-2, and a switch instead of the switch 30. It differs from the transmitter 1 of 1st Embodiment by the point provided with the device 30a. Since the other structure of the transmitter 1a is the same as that of the first embodiment, the same reference numerals as those in FIG.

  The transmission converter 14a transmits / receives information indicating the output level of the video signal of the own system (hereinafter referred to as “individual level information”) to / from the transmission converter 14a of the other system, and based on each individual level information, It differs from the transmission converter 14 in the first embodiment in that the output level is adjusted.

  The switch 30a is different from the switch 30 in the first embodiment in that it does not acquire level information and output level information to the transmission converter 14a. That is, the switch 30a is the same as the conventional configuration, and the switch of the existing transmitter can be used as it is.

  FIG. 13 is a diagram illustrating a configuration example of the transmission converter 14a according to the second embodiment. The transmission converter 14a is different from the transmission converter 14 in the first embodiment in that a level information conversion unit 147a is provided instead of the level information conversion unit 147, and an individual level information acquisition unit 149 is further provided. Since the other configuration of the transmission converter 14a is the same as that of the first embodiment, in FIG. 13, the same reference numerals as those in FIG.

  The individual level information acquisition unit 149 is connected to the output side of the HPA 145 and acquires the signal level of the video signal output from the transmission converter 14. The individual level information acquisition unit 149 outputs the acquired signal level to the level information conversion unit 147a and notifies the transmission converter 14 of another system.

  The level information conversion unit 147a performs the first implementation based on the individual level information of the own system output from the individual level information acquisition unit 149 and the individual level information of the other system notified from the transmission converter 14a of the other system. Level information similar to the form is generated. The level information conversion unit 147a generates adjustment information similar to that of the first embodiment based on the generated level information, and outputs the generated adjustment information to the level adjustment unit 148.

  According to the transmitter 1a of the second embodiment configured as described above, the transmission converter 14a of each system inputs and outputs the output level of each other, and therefore transmission for connecting the transmission converter 14a and the switch 30a. The output level can be adjusted without being affected by the medium. Therefore, the output level can be adjusted more accurately in the transmission converter 14a of each system.

  The configuration in which the transmitter 1 or 1a of the embodiment adjusts the output level of the video signal is a transmission of a fixed wireless line (STL: Studio to Transmitter Link) that transmits the video signal between the studio of the broadcasting station and the transmitting station. The present invention may be applied to a transmitter, or may be applied to a transmitter of a fixed wireless line (TTL: Transmitter to Transmitter Link) that transmits a video signal between a transmitter and a transmitter. Furthermore, in each of the above embodiments, an example of a transmitter having a video signal reception function and a received video signal transmission function has been described. However, the output level adjustment method described above is a transmission that does not have a reception function. It may be applied to the machine. For example, the adjustment method described above may be applied to a transmitter that reproduces video data and transmits a video signal generated by the reproduction.

  In the above embodiment, the transmission converter 14-1 is an example of a first output unit. Similarly, the transmission converter 14-2 is an example of a second output unit. The level information acquisition unit 32 or the individual level information acquisition unit 149 is an example of a feedback unit. The semi-seamless switching method is an example of a predetermined switching method. The individual level information output from the transmission converter 14a-1 is an example of the first level information. Similarly, the individual level information output from the transmission converter 14a-2 is an example of second level information. The individual level information acquisition unit 149 of the transmission converter 14a-1 is an example of a first feedback unit. Similarly, the individual level information acquisition unit 149 of the transmission converter 14a-2 is an example of a second feedback unit.

  According to at least one embodiment described above, level information indicating the signal level of the video signal output from the first output unit is fed back to the second output unit, and the video signal output from the second output unit is output. A feedback unit that feeds back the level information indicating the signal level to the first output unit, and the first output unit and the second output unit output each other based on the fed back level information. By adjusting the output level of the video signal so that the level difference of the video signal is within the allowable range of the predetermined switching method, the switching reliability required for the broadcasting business is maintained while suppressing the rise in the equipment price. can do.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1, 1a ... Transmitter, 10 ... 1st transmission part, 20 ... 2nd transmission part, 11 ... Reception converter, 12 ... Demodulation part, 13 ... Modulation part, 14, 14a ... Transmission converter, 141 ... Attenuator, DESCRIPTION OF SYMBOLS 142 ... Local oscillator, 143 ... Mixer, 144 ... Band pass filter, 145 ... High power amplifier, 1451 ... Signal level detector, 146 ... DA (Digital to Analog) converter, 147 , 147a ... level information conversion unit, 148 ... level adjustment unit, 149 ... individual level information acquisition unit, 30, 30a ... switch, 31 ... switch, 32 ... level information acquisition unit, 321, 322 ... signal level detector, 33 ... Determining unit, 40 ... Controller

Claims (10)

A transmitter for transmitting a video signal to a receiver,
A first output unit and a second output unit for outputting the video signal;
A switch connected to the first output unit and the second output unit and configured to switch an output system of the video signal between the first output unit and the second output unit based on a predetermined switching method. When,
Level information indicating the signal level of the video signal output from the first output unit is fed back to the second output unit, and level information indicating the signal level of the video signal output from the second output unit is returned to the second output unit. A feedback unit that feeds back to one output unit;
With
In each of the first output unit and the second output unit, based on the level information fed back by the feedback unit, the level difference between the video signals output from each other falls within the allowable range of the switching method. Adjust the output level of the video signal,
Transmitter. The feedback unit feeds back information indicating an input level of the video signal output from the first output unit and the second output unit in the switch as the level information.
The transmitter according to claim 1. The feedback unit is provided in the switch, and outputs the level information to the first output unit and the second output unit.
The transmitter according to claim 2. The transmitter further includes a controller that controls the first output unit, the second output unit, and the switching unit,
The feedback unit is provided in the switch,
The feedback unit outputs the level information to the controller;
The controller outputs the level information output from the feedback unit to the first output unit and the second output unit;
The transmitter according to claim 2. The feedback unit includes a first feedback unit that feeds back first level information indicating an output level of the video signal output from the first output unit to the second output unit, and the second output unit. A second feedback unit that feeds back second level information indicating an output level of the video signal output from the first output unit;
The transmitter according to claim 1. The first feedback unit is provided in the first output unit, and outputs the first feedback information to the second feedback unit,
The second feedback unit is provided in the second output unit, and outputs the second feedback information to the first feedback unit.
The transmitter according to claim 5. Each of the first output unit and the second output unit adjusts its output level so as to approach a predetermined reference value.
The transmitter according to any one of claims 1 to 6. Each of the first output unit and the second output unit adjusts its output level so as to approach the other signal level,
The transmitter according to any one of claims 1 to 6. Each of the first output unit and the second output unit does not adjust the output level when it is an output system, and approaches the other signal level when it is a non-output system. Adjust your output level to
The transmitter according to any one of claims 1 to 6. A first output unit that outputs a video signal to be transmitted to a receiver, and a second output unit, wherein the first output unit or the output system of the video signal to the receiver is based on a predetermined switching method; A transmitter control method for switching to a second output unit, comprising:
Level information indicating the signal level of the video signal output from the first output unit is fed back to the second output unit, and level information indicating the signal level of the video signal output from the second output unit is returned to the second output unit. Feeding back to the output of 1;
Based on the level information fed back by each of the first output unit and the second output unit, the video signal so that the level difference between the video signals output from each other is within the allowable range of the switching method. Adjusting the output level of the
A control method.

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