JP2014171081A - Broadcasting transmission system and transmission control method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a broadcasting transmission system and a system control method, capable of preventing failure of a device due to broadcasting signals outputted from a plurality of transmitters.SOLUTION: A broadcasting transmission system including a plurality of transmitters, and adopting a signal synthesis system in which broadcasting signals outputted from the respective transmitters are combined with each other to transmit a combined signal, includes a phase-difference detecting device, and a transmitter control device. The phase-difference detecting device detects a phase from the broadcasting signal outputted from each of the plurality of transmitters to detect a phase difference among the plurality of transmitters from the phases. The transmitter control device instructs to the plurality of transmitters so that the output phases of the broadcasting signals match with each other and the output during phase control is reduced less than the rating, on the basis of the phase-difference detection result by the phase-difference detecting device in accordance with a change in delay time of the broadcasting signals.

Description

  Embodiments described herein relate generally to a broadcast transmission system used in television broadcast, radio broadcast, and the like and a transmission control method thereof.

  In general, a broadcast transmission system that requires high output includes a plurality of transmitters, and synthesizes broadcast signals output from the respective transmitters to generate and transmit one broadcast signal. The method is adopted. In this system, it is important to manage the phase of a broadcast signal output from each transmitter, and an exciter is used for the phase management. This exciter has a delay time setting function for changing the delay time of the signal, and manages the transmitter sending time by changing the delay time according to the transmission time and processing time until the input of the exciter.

  However, in the signal transmission system for broadcasting as described above, since the output phase of the exciter changes when the delay time is changed, a phase difference occurs between transmitters. In a broadcast transmission system, when signals are combined with a phase difference between transmitters, a combination loss increases. That is, the broadcast transmission system needs to control the phase each time the delay time is changed. If the signal is output at the rated value from the transmitter without changing the phase after changing the delay time, excessive power may be output to the termination side during combined output, leading to equipment failure.

JP-A-8-265066

  As described above, in the conventional broadcast transmission system using the signal synthesis method, when the delay time is changed by the exciter, it is necessary to control the phase each time, and if the delay time is changed, the phase control is performed. If the signal is output from the transmitter at the rated value, there is a risk of failure of the subsequent equipment.

  Therefore, the purpose is for broadcasting that can synthesize the broadcasting signals output from each transmitter even when the delay times of a plurality of transmitters are changed, in a state where the phases of each transmitter are matched, and output the rated output. It is to provide a transmission system and a transmission control method thereof.

  According to the present embodiment, the broadcast transmission system includes a plurality of transmitters, and the broadcast transmission system adopts a signal combining method that combines and transmits broadcast signals output from the respective transmitters. And a phase difference detection device and a transmitter control device. The phase difference detection device detects a phase from a broadcast signal output from each of the plurality of transmitters, and detects a phase difference between the plurality of transmitters from the phase. The transmitter control device matches the plurality of transmitters with the output phase of the broadcast signal based on the phase difference detection result of the phase difference detection device in accordance with the change in the delay time of the broadcast signal. And instruct to reduce the output during phase control from the rated value.

The block diagram which shows the structure of the transmission system for broadcasting which employ | adopts the signal-synthesis method which concerns on embodiment. The block diagram which shows the structure of the exciter shown in FIG. The flowchart which shows the control method of the transmission system for broadcasting which concerns on embodiment.

  Hereinafter, embodiments will be described with reference to the drawings.

  FIG. 1 is a block diagram illustrating a configuration of a broadcast transmission system that employs a signal synthesis method according to an embodiment.

  The broadcast transmission system shown in FIG. 1 is a system for outputting a broadcast signal such as a television broadcast or a radio broadcast and transmitting it via an antenna or the like. A phase difference detection device 4 and a transmitter control device 5 are provided. In the present embodiment, a configuration example in which two transmitters are used and a broadcast signal output from each transmitter is combined and output is shown. Moreover, in this embodiment, since the structure of the transmitters 1 and 2 is the same, description of the transmitter 2 is abbreviate | omitted and only the transmitter 1 is demonstrated.

  The transmitter 1 is an apparatus that outputs an RF (Radio Frequency) signal that is a broadcast signal. The transmitter 11, the distributor 12, and a plurality of n (n is a natural number) power amplifiers (PA: Power Amplifier) 131. To 13n, a synthesizer 14 and a band pass filter (BPF) 15.

  The exciter 11 has a signal delay function, and the delay time can be changed to an arbitrary time. The exciter 11 has a function of adjusting the phase of the signal to an arbitrary phase. The exciter 11 has a function of inputting an RF signal output from the transmitter 1 as a feedback signal, detecting a distortion component from the input RF signal, and executing distortion compensation according to the distortion component.

  The distributor 12 receives the RF signal output from the exciter 11 and distributes the input RF signal to n systems.

  The plurality of power amplifiers 131 to 13n receive the RF signals of n systems distributed by the distributor 12, and amplify the power of each of the input RF signals. Each of the power amplifiers 131 to 13n outputs an RF signal whose power is amplified to the synthesizer 14.

  The synthesizer 14 receives a plurality of RF signals output from the power amplifiers 131 to 13n and synthesizes the input RF signals. The synthesizer 14 outputs the synthesized RF signal to the band pass filter 15.

  The band pass filter 15 receives the RF signal output from the synthesizer 14 and passes an RF signal in a predetermined frequency band from the input RF signal.

  The combiner 3 combines the RF signals output from the transmitters 1 and 2 having the above-described configuration, and outputs the combined RF signal as a transmission signal to a transmission unit such as an antenna. Here, when there is a phase difference between the RF signals to be combined, the RF signal to be combined is output to the terminal side and becomes a combination loss.

  The phase difference detection device 4 detects the phase of the RF signal output from each of the transmitters 1 and 2, and detects the phase difference between the transmitters from the detected phase. The phase difference detection device 4 transmits detected phase difference information to the transmitter control device 5.

  The transmitter control device 5 instructs the exciter 11 installed in the transmitters 1 and 2 to change the signal delay time. Further, the transmitter control device 5 instructs the exciter 11 to control the phase of the signal based on the phase difference information transmitted from the phase difference detection device 4. In addition, the transmitter control device 5 instructs the exciter 11 to output a reduced signal with the change in the signal delay time, and instructs the exciter 11 to output the rated signal after the phase control. To do. Further, the transmitter control device 5 performs on / off control of each of the plurality of power amplifiers 131 to 13n in accordance with the change of the signal delay time.

Here, the configuration of the exciter 11 will be described in detail. FIG. 2 is a block diagram showing the configuration of the exciter 11 shown in FIG.

  An exciter 11 shown in FIG. 2 includes an A / D converter (ADC1) 11-1, a delay unit 11-2, a down converter (D / C) 11-3, an A / D converter (ADC2) 11-4, It has a distortion detector 11-5, a distortion compensator 11-6, a D / A converter (DAC) 11-7, an up converter (U / C) 11-8, and a controller 11-9. Here, in the exciter 11 of the present embodiment, signals in the intermediate frequency band (hereinafter, collectively referred to as IF (Intermediate Frequency) signal), which are reference signals for detecting distortion, are A / D converted from the host device. An RF signal that is input to the transmitter 11-1 and fed back from the transmitter output is input to the down converter 11-3.

  The A / D converter 11-1 converts the input IF signal from an analog format to a digital format. The A / D converter 11-1 outputs the IF signal to be converted to the delay unit 11-2.

  The delay unit 11-2 receives the IF signal output from the A / D converter 11-1, and changes the delay time of the input IF signal. The delay unit 11-2 outputs the IF signal whose delay time is changed to the distortion detection unit 11-5.

  The down converter 11-3 converts the frequency of the input RF signal from a transmission frequency to an intermediate frequency based on a local signal output by an oscillator or the like. The down converter 11-3 outputs the RF signal to be converted to the A / D converter 11-4.

  The A / D converter 11-4 converts the RF signal output from the down converter 11-3 from an analog format to a digital format. The A / D converter 11-4 outputs the converted RF signal to the distortion detection unit 11-5.

  The distortion detector 11-5 detects distortion from the RF signal output from the A / D converter 11-4 using the IF signal output from the delay unit 11-2 as a reference signal.

  The distortion compensation unit 11-6 compensates for the distortion detected by the distortion detection unit 11-5. The distortion compensator 11-6 outputs an RF signal whose distortion is compensated to the D / A converter 11-7.

The D / A converter 11-7 converts the RF signal output from the distortion compensator 11-6 from a digital format to an analog format. The D / A converter 11-7 outputs the RF signal to be converted to the up-converter 11-8.

  The up-converter 11-8 converts the frequency of the RF signal output from the D / A converter 11-7 from the intermediate frequency to the transmission frequency based on the local signal. The up-converter 11-8 outputs the RF signal to be converted from the transmitter 1. Further, the up-converter 11-8 performs phase control of the RF signal in accordance with a phase control instruction from the transmitter control device 5 sent via the control unit 11-9 described later. Here, the up-converter 11-8 controls the phase of the RF signal because the phase of the RF signal output from the transmitter changes with a change in the delay time of the IF signal, and there is a phase difference between the transmitters. This is because it occurs. The up-converter 11-8 performs signal phase control so that the phase difference between the transmitters falls within a predetermined range.

  The control unit 11-9 instructs the delay unit 11-2 to change the signal delay time in response to an instruction from the transmitter control device 5. Further, the control unit 11-9 instructs the up-converter 11-8 to control the phase of the signal in response to an instruction from the transmitter control device 5. Further, the control unit 11-9 controls an operation in which the down converter 11-3 converts the frequency of the RF signal from the transmission frequency to the intermediate frequency. In addition, the control unit 11-9 controls an operation in which the distortion detection unit 11-5 detects distortion from the RF signal. In addition, the control unit 11-9 controls an operation in which the distortion compensation unit 11-6 compensates for distortion detected by the distortion detection unit 11-5. In addition, the control unit 11-9 controls an operation in which the up converter 11-8 converts the frequency of the RF signal from the intermediate frequency to the transmission frequency.

  Next, a control method of the broadcast transmission system by the transmitter control device 5 having the above configuration will be described.

  FIG. 3 is a flowchart illustrating a control method of the broadcast transmission system according to the embodiment.

  As illustrated in FIG. 3, the transmitter control device 5 instructs the control unit 11-9 of the exciter 11 to change the delay time (step ST1). As a result, the control unit 11-9 instructs the delay unit 11-2 to change the delay time. The delay unit 11-2 changes the delay time of the IF signal according to an instruction from the control unit 11-9.

  Next, the transmitter control device 5 instructs the control unit 11-9 to output a reduced RF signal according to the change in the delay time of the IF signal in step ST1 (step ST2). As a result, the exciter 11 outputs a reduced signal of the RF signal. At this time, the transmitter control device 5 performs on / off control of the power amplifiers 131 to 13n in accordance with the reduced output of the RF signal from the exciter 11 (step ST3).

  Next, the transmitter control device 5 determines whether or not the phase difference between the transmitters detected by the phase difference detection device 4 is within a predetermined range after the output of the RF signal is reduced (step ST4).

  In this determination, when the phase difference is not within the predetermined range, the transmitter control device 5 instructs the control unit 11-9 to perform the phase control of the RF signal (step ST5), and returns to step ST4. Return. The up-converter 11-8 controls the phase of the RF signal according to an instruction from the control unit 11-9.

  Further, in the above determination, when the phase difference is within the predetermined range, the transmitter control device 5 instructs the control unit 11-9 to output the RF signal at a rated output (step ST6). Thereby, the exciter 11 performs the rated output of the RF signal. At this time, the transmitter control device 5 performs on / off control of the power amplifiers 131 to 13n in accordance with the rated output of the RF signal from the exciter 11 (step ST7).

  As described above, according to the above configuration, the broadcast transmission system according to this embodiment includes the delay unit, the phase difference detection device, and the transmitter control device in each of the transmitters 1 and 2. Thereby, the broadcast transmission system can perform phase control in accordance with the change in the delay time. Further, the output can be automatically reduced so that an unnecessary signal is not transmitted during the phase control, and automatically returned to the rated output after the phase control is completed.

  Therefore, in this embodiment, even if the delay times of the transmitters 1 and 2 are changed, the broadcast signals output from the transmitters can be combined and output at rated output in a state in which the phases are matched. Thus, it is possible to provide a broadcasting transmission system and a system control method capable of preventing a failure of a device due to broadcasting signals output from the transmitters 1 and 2.

  In the present embodiment, a configuration example using two transmitters is shown, but a configuration using three or more transmitters may be used.

  As mentioned above, although embodiment of this invention was described, this embodiment is shown as an example and is not intending limiting the range of invention. This embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. This embodiment and its modifications are included in the scope of the present invention and the gist thereof, and are also included in the invention described in the claims and the equivalent scope thereof.

  DESCRIPTION OF SYMBOLS 1,2 ... Transmitter, 11, 21 ... Exciter, 11-1 ... A / D converter (ADC1), 11-2 ... Delay part, 11-3 ... Down converter (D / C), 11-4 ... A / D converter (ADC2), 11-5 ... distortion detector, 11-6 ... distortion compensator, 11-7 ... D / A converter (DAC), 11-8 ... up converter (U / C), DESCRIPTION OF SYMBOLS 11-9 ... Control part, 12, 22 ... Divider, 131-13n, 231-23n ... Power amplifier (PA), 14, 24 ... Synthesizer, 15, 25 ... Band pass filter (BPF), 3 ... Synthesizer 4... Phase difference detection device, 5... Transmitter control device.

Claims (4)

In a broadcasting transmission system that includes a plurality of transmitters and adopts a signal combining method that combines and transmits broadcasting signals output from each transmitter,
Detecting a phase from a broadcast signal output from each of the plurality of transmitters, and detecting a phase difference between the plurality of transmitters from the phase; and
Instructing the plurality of transmitters so that the output phases of the broadcast signals coincide with each other based on the phase difference detection result of the phase difference detection device as the delay time of the broadcast signal changes. And a transmitter control device for instructing to reduce the output during phase control from the rated value. The transmitter is
An exciter for changing the delay time of the broadcast signal and performing phase control;
A distributor for distributing a broadcast signal output from the exciter;
A plurality of power amplifiers for amplifying each broadcast signal distributed by the distributor;
A combiner for combining a plurality of broadcast signals amplified by the plurality of power amplifiers;
Among the broadcast signals synthesized by the synthesizer, a band pass filter that passes a broadcast signal of a predetermined frequency band,
The transmitter controller is
Delay time change instructing means for instructing the exciter to change the delay time of the broadcast signal;
A reduction output instruction means for instructing the exciter to output a reduction of the broadcast signal according to the change in the delay time;
Phase control instruction means for instructing the exciter to perform phase control of the broadcast signal based on the phase difference detected by the phase difference detection device;
After controlling the phase of the broadcast signal until the phase difference is within a predetermined range, the output signal indicating means for indicating the rated output of the broadcast signal to the exciter,
The exciter is
A delay unit for changing a delay time of the broadcast signal;
An output processing unit for controlling the output of the broadcast signal;
A phase control unit for controlling the phase of the broadcast signal;
The delay unit is controlled according to a delay time change instruction from the transmitter control device, the output processing unit is controlled according to the reduction output instruction and the rated output instruction, and according to the phase control instruction. The broadcast transmission system according to claim 1, further comprising a control unit that controls the phase control unit.   2. The broadcast transmission according to claim 1, wherein the transmitter control device causes the plurality of power amplifiers of the plurality of transmitters to perform on / off control according to the power reduction output instruction and the rated output instruction. system. In a transmission control method for a broadcast transmission system that includes a plurality of transmitters and adopts a signal combining method that combines and transmits broadcast signals output from each transmitter,
Detecting a phase from a broadcast signal output from each of the plurality of transmitters, detecting a phase difference between the plurality of transmitters from the phase;
Instructing the plurality of transmitters so that the output phases of the broadcast signals coincide with each other based on the detection result of the phase difference in accordance with the change in the delay time of the broadcast signals and during phase control. A transmission control method for a broadcast transmission system that issues an instruction to reduce the output from the rated value.

Images