JP2010171681A - Digital multistage transmission system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a digital multistage transmission system for performing multistage relay, which can secure a receiving state at each relay place from received support information and controlling the receiving state at the each relay place. <P>SOLUTION: The digital multistage transmission system creates a TS signal by an encoded processing signal obtained by encoding a video signal or a sound signal, and performs multistage transmission by radio. A digital transmission system includes a first step transmitting part 101, several step relay receiving and transmitting parts 102 to 104 for receiving a transmission signal from the first step transmitting part 101 and performing signal processing, and the last receiving part 105 of the relay receiving and transmitting part, wherein the relay receiving and transmitting parts 102 to 104 replace a null packet with an identification signal of the each relay place and the received support information, and each frame of the receiver of the each relay place and the last-step receiver is controlled on the basis of an output of the received support information multiplexing means for multiplexing an output of the last step received support information generating means of the last receiving part 105 and an output of a restoring means. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a digital multi-stage transmission system, and more particularly to a digital multi-stage transmission system that transmits TS signals such as video signals via multi-points. The present invention relates to a digital multi-stage transmission system that superimposes and transmits.

  The digital transmission system encodes video and audio signals of broadcast program material with MPEG-TS (Moving Pictures Experts Group-Transport Stream), and the encoded signal is a wireless transmission device such as FPU (Field Pick-up Unit). It is a system that uses and transmits wirelessly.

  In a digital transmission system, when transmitting program material, it is not only transmitted from a transmitter to a receiver but also transmitted via a plurality of relay points. In such a case, encoded data is transmitted. Is transmitted from a transmitter to a receiver at a certain relay point, and then transmitted again to a receiver at another relay point by the transmitter at that relay point. Such a transmission operation is performed a plurality of times and transmitted to the FPU base station serving as the base station.

  In addition, transmission by FPU is a microwave relay, and there is no obstacle to the transmission of radio waves, and it is impossible to send and receive unless a relay point is set in a place where the line of sight is clear. In many cases, a plurality of relay stations are required. Such a multi-stage transmission method is also used in STL (Studio to Transmitter Link) and TTL (Transmitter to Transmitter Link).

  Conventionally, digital FPU receivers display the current reception status as reception support information. The reception support information includes constellation / spectrum, delay profile, CH, BL value, MER, BER, MARGIN, modulation scheme, and coding rate. Using these pieces of information, transmission / reception point arrangement determination, antenna direction adjustment, and monitoring during operation are performed.

  Referring to FIG. 10, a conventional multistage transmission system will be described. A mobile relay station uses a radio wave W1 to Wn of a video signal from an imaging site to receive a plurality of relay stations (reception from a transmitter Tx1 on a transmission side). Wireless transmission to the broadcasting station via the parts Rx1 to Rxn, the multiplexing parts MUX1, MUX2... SEL, and the transmission parts Tx2 to Txn). At the first stage of the relay station, 00 is assigned as the ID value of the TS signal (information for specifying the relay station), NULL data is replaced with ID00, and the received decoded signal is passed to the next-stage transmitter as a TS signal. Even in the relay stations after the second stage, when the received decoded signal is passed as a TS signal to the transmitter of the next stage, the ID detector for reception status information and the ID control unit check the ID, and if the ID is 00, ID = 01 is assigned to the second-stage received decoded signal, and NULL data is replaced with ID01. In the third-stage relay station, when the received decoded signal has an ID of 00 and an ID of 01, the NULL data is replaced with ID02 using ID = 02, and the received decoded signal of the third stage is This is a system in which a TS signal is delivered to a transmitter at the next stage, and NULL data is replaced with an ID value of the relay point and reception status information is superimposed on a video signal and transmitted (for example, see Patent Document 1).

  As another conventional example, there is a multi-stage transmission system that transmits data according to the DVB (Digital Video Broadcast) standard. In this multi-stage transmission system, the DVB encoding processing unit of the transmission side processing unit uses a TS packet structure (the packet structure is header information). 4 bytes, payload information 184 bytes, and dummy information 16 bytes (204 bytes) (transmission system that superimposes reception auxiliary information on the dummy information area) and the reception auxiliary information is rewritten as a null packet in the NULL information area of the TS signal. There is a transmission system (see, for example, Patent Document 2).

JP 2007-251705 A JP 2006-157337 A

  In the multistage transmission system, if only the identification information of each relay point is added, it can be handled by changing the PID (Packet Identification) value of the header area in the TS signal (hereinafter referred to as TS packet). May be changed when multiplexing is performed, and a method of rewriting the data in the PID area of the TS packet is adopted because there are restrictions when signal processing is performed several times as in a multistage transmission system. Can not do it. If it is adopted, it is difficult to construct a multistage transmission system system that can quickly cope with the reception state and failure of each relay station.

  The multi-stage transmission system of Patent Document 1 displays the reception state of the relay point by transmitting the reception state of the relay point to a studio or the like, but is the same technique as described above, and data transmission generated from some amount of information However, the NULL data is merely replaced with an ID value using the NULL data for preventing the unlocking of the data, and therefore, the technique is not a technique for replacing the NULL data with another packet signal capable of controlling the reception state. In the case of a transmission system, there is a drawback that it is impossible to accurately grasp and control the reception state and failure of each relay station.

Further, in the multistage transmission system of Patent Document 2 is shown in FIG. 11, consists of header information ₇₁ and a payload region 7 ₂ and parity information 7 ₃ which the first TS packet in the payload area 7 _2, video signal Although the information of the audio signal is transmitted, the next TS packet, to the NULL information ₈₁ and the dummy information _{7 3,} for example, a bit string of "1111 ..." is transmitted written and. In this conventional example, if the packet is used as it is without changing the data in the PID area, this bit string is determined to be a null packet and may be discarded depending on the system, which is not preferable.

  The present invention has been made in view of the above problems, and in a digital multi-stage transmission system that performs multi-stage relaying, the reception status of each relay point can be grasped from the reception support information, and the control of the reception state of each relay point can be performed. An object is to provide a possible digital multi-stage transmission system.

The present invention achieves the above-mentioned problems, and the invention of claim 1 is a digital multi-stage transmission system that performs multi-stage transmission by encoding a video signal or an audio signal to create a TS packet signal.
The digital transmission system wirelessly transmits a TS packet signal obtained by encoding the video signal or audio signal, and receives and processes the TS packet signal from the initial transmission unit, and performs several stages of wireless transmission. Consisting of a relay reception / transmission unit that performs relaying according to and a final reception unit of the relay reception / transmission unit,
The first-stage transmission unit creates a null packet by coding processing means for coding the video signal or audio signal, TS packet signal creating means for creating a TS packet signal from an output signal of the coding processing means, and A null packet generating means, a multiplexing means for multiplexing the output signal of the TS packet signal generating means with the null packet, and a transmitting means for wirelessly transmitting the output signal of the multiplexing means,
The relay reception / transmission unit receives a transmission signal from the transmission means of the first-stage transmission unit, outputs a TS packet signal including the null packet, and obtains data related to reception from the receiver to receive support information And receiving support information generating means for generating information including identification information of each relay point, and replacing a null packet output included in the output signal of the receiver with an output signal from the receiving support information generating means A null packet replacement means, and a transmission means for wirelessly transmitting an output signal from the null packet replacement means,
The final reception unit receives a signal transmitted from the transmission unit of the relay transmission unit, outputs a TS packet signal including the null packet, and outputs the output signal of the receiver to the video signal or the audio signal. Separating means for separating the TS packet signal and TS packet signal of the reception support information, decoding means for decoding a video signal or audio signal by the TS packet signal obtained from the separating means, and the obtained from the separating means A restoration means for restoring the reception assistance information at each relay point from the TS packet signal of the reception assistance information; a final stage reception assistance information generation means for producing reception assistance information including identification information at the last stage from the receiver; Receiving support information multiplexing means for multiplexing the output signal of the final stage receiving support information generating means and the output signal of the restoring means; The control means for controlling each receiver of each relay point and the last stage receiver from the output signal of the conversion means, and the output signal of the reception support information multiplexing means are converted into graphic signals of the reception support information A digital multistage transmission system comprising: a reception support information display signal creation means; and a graphic monitor that displays an output signal of the reception support information display signal creation means.

  According to a second aspect of the present invention, in the digital multistage transmission system according to the first aspect, the null packet replacement means includes delay means for delaying the TS signal of the output signal of the receiver by 1 TS time, It comprises detection means for detecting whether the TS packet signal of the output signal includes a null packet, and switching means for switching the output of the delay means and the output of the reception support information creation means by a predetermined number of times by the detection means. Is a digital multistage transmission system characterized by

  Further, the invention of claim 3 is the digital multistage transmission system according to claim 1, wherein the control means of the final reception unit is equipped with a receiver and an antenna of the relay reception transmission unit through a line different from the wireless transmission. The digital multistage transmission system is characterized in that the gantry and the gantry on which the receiver and antenna of the final receiving unit are mounted are controlled.

  According to a fourth aspect of the present invention, in the digital multi-stage transmission system according to the first aspect, when the reception support information display signal creating means displays the reception support information display signal on the graphic monitor, each relay A display mode for displaying the reception support information display signal at each relay point on the entire screen individually, a display mode for reducing the reception support information display signal at each relay point and displaying all on one full screen, and the decoding A digital multi-stage transmission system comprising display selection means for switching a display mode in which an output video signal of the means is also converted into a graphic signal and mixed and displayed.

  According to the first aspect of the present invention, the reception support information at each relay point is obtained simultaneously with the output video signal, so that the reception state at each relay point can be monitored in real time, and the reception at each relay point is received. By displaying support information in a list, it is possible to easily grasp a relay point where a failure is suspected by comparing information of each relay point, and it is possible to quickly cope with a failure. In addition, there are control means for controlling the receiver of each relay point and each mount of the final stage receiver from the output signal of the reception support information multiplexing means of the final receiver, and the relay point is in a mountainous area or the like There is an advantage that it is possible to adjust the reception state by remote operation and set to the best reception state without going out to the mountainous area and adjusting.

  Also, by replacing the null packet used to match the transmission speed with the identification information of the relay station (reception point) and the reception support information, transmission of unnecessary information is reduced, so transmission that occupies all transmission packets There is an advantage that the amount of information increases and as a result, the transmission efficiency is improved. Furthermore, since the reception point identification information is included in addition to the reception support information, a TS packet including only the identification information is not required, and the transmission efficiency is improved.

  Further, according to the invention of claim 2, since the null packet replacement circuit can be configured with a small circuit by configuring with a null packet detector, a delay device, a TS packet generator, and a switch, It is also possible to incorporate it into the machine, and there is an advantage that the transmitter / receiver of the relay station can be made compact.

  According to the invention of claim 3, the main transmission is performed by adjusting the direction angle (horizontal control, vertical control, etc.) of the receiver and antenna at each relay point by using a line different from the transmission line. There is an advantage that remote control is possible without being influenced by the characteristics of the road, and there is an advantage that control using a wired line is possible because high-speed control is not required.

  Further, according to the invention of claim 4, since it is possible to select the display mode of the reception information, usually all the reception information is monitored on one screen, and if any abnormality occurs, it is individually Therefore, it is possible to switch the display so that it is displayed on the screen and to construct an efficient monitoring system. In addition, since the received video signal can be converted into a graphic signal and mixed and displayed at the same time, there is an advantage that the received image can also be grasped.

It is a block diagram which shows one Example of the digital multistage transmission system of this invention. It is a block diagram of the first stage transmission part of a present Example. It is a block diagram of the relay reception transmission part of a present Example. It is a block diagram of the last stage receiving part of a present Example. FIG. 4 is a block diagram of the TS packet replacement circuit of FIG. 3. (A)-(d) is the figure which showed the structure of the output stream of each transmission part in a present Example. (E), (f), and (g) are diagrams showing input and output of the reception support information multiplexing circuit in the present embodiment. It is a figure which shows the example which displayed graphically the reception assistance information of 1 receiving point in this embodiment. It is a figure which shows the example which displayed graphically the reception assistance information of 4 receiving points in this embodiment. It is a block diagram which shows an example of the conventional digital multistage transmission system. It is a figure which shows the frame structure of the transmission signal in the conventional digital multistage transmission system.

  Embodiments of a digital multistage transmission system according to the present invention will be described below with reference to the drawings. In the present embodiment, the digital multi-stage transmission system of the present invention is exemplified by four-stage transmission (from transmission to reception to one stage) from transmission to reception, and input signals include video signals and audio signals. Is described as a video signal.

  FIG. 1 is a block diagram of a digital multistage transmission system according to the present embodiment, in which 100 is a video input terminal to which a video signal from a TV camera or a video camera is input, and 101 is a video signal that is input and encoded. 102, 103 and 104 are relay reception / transmission units having transmission / reception and transmission / reception antennas, 105 is a final reception unit having receivers and reception antennas, and 106 is a final reception unit. 105 is a video output terminal for transmitting an output signal from the receiver 105. The video signal input from the video input terminal 100 is modulated from the first-stage transmission unit 101 using a microwave as a carrier wave, and the relay reception transmission units 102, 103, and 104 And the output of the final stage receiving unit 105 is sent out from the video output terminal 106. The relay transmission units 102, 103, and 104 are provided with a transmission / reception unit and transmission / reception antennas. The azimuth angle of these reception antennas and the adjustment value of the receiver are set in the final-stage reception unit 105. It is controlled by the gantry control signal from and is set to the best receiving state. In addition, (a) to (d) in the figure show output signals of the respective units, and details thereof will be described later.

  Subsequently, each component in the digital multistage transmission system of the present embodiment will be described. First, the first-stage transmission unit 101 will be described with reference to FIG. 2. Reference numeral 100 denotes a video input terminal, which is the same as FIG. Reference numeral 200 denotes an MPEG-TS creation circuit (encoding processing means) for encoding a video signal, 201 denotes a null packet generation circuit (null packet generation means) for sending invalid data, and 202 denotes a code from the MPEG-TS creation circuit 200. A multiplexing circuit (multiplexing means) for multiplexing and transmitting the multiplexed video signal and the null packet from the null packet generating circuit 201; and 203, a transmitter for wirelessly transmitting the multiplexed video signal (Transmitting means). The MPEG-TS creation circuit 200 performs a coding process on the video signal input from the video input terminal 100 based on the MPEG-2 standard to create a TS packet consisting of 188 bytes of the video signal.

  The null packet generation circuit 201 generates a null packet whose packet identification information (PID: Packet Identification) is 0x1FFF. The multiplexing circuit 202 multiplexes the output of the MPEG-TS creation circuit 200 and the output of the null packet generation circuit 201 and performs transmission encoding processing. Usually, since the transmission speed is high when the microwave is used with respect to the bit rate of MPEG-TS, the transmission speed is adjusted by adding a null packet because only the MPEG-TS packet is insufficient. The multiplexing circuit 202 performs a transmission encoding process to add a null packet to the shortage to make a constant packet length. The transmitter 203 modulates the output packet from the multiplexing circuit 202 into a microwave and outputs it.

  The relay reception / transmission units 102, 103, and 104 will be described with reference to FIG. FIG. 3 is a block diagram of the relay reception / transmission unit 102, in which 300 is a receiver having a reception antenna, 301 is equipped with the reception antenna and the receiver 300, and the azimuth and elevation angles of the reception antenna can be adjusted. A frame, 302 is a relay point reception support information generation circuit, 303 is a TS packet replacement circuit, and 304 is a transmitter having a transmission antenna. The receiver 300 receives the microwave transmitted from the transmitter 203 of the first-stage transmitting unit 101 or the preceding-stage relay receiving / transmitting units 102 and 103, demodulates it into a TS packet, and converts the output signal a based on the TS packet signal to a TS packet replacement circuit. It outputs to 303. Further, the relay point reception assistance information generation circuit 302 outputs output data b that is reception assistance information to the TS packet replacement circuit 303. The gantry 301 is equipped with a receiver 300 having a receiving antenna, and the azimuth and elevation angles of the receiving antenna and adjustment values of the receiver 300 are controlled by the gantry control from the final stage receiving unit 105. The relay point reception support information generation circuit 302 generates data b that is the basis of the reception support information based on the identification information unique to the relay point and the data obtained from the receiver 300, and outputs the data b to the TS packet replacement circuit 303. In the TS packet replacement circuit 303, a part of the null packet added by the first-stage transmission unit 101 is replaced with a TS packet (a packet whose PID is not 0x1FFF) including identification information and reception support information. The transmitter 304 again modulates the TS packet into a microwave and transmits it to the next stage.

  Next, the TS packet replacement circuit 303 will be described with reference to FIG. The TS packet replacement circuit 303 includes a null packet detection circuit 500, a 1TS delay circuit 501, a TS packet creation circuit 502, and a switch 503. The null packet detection circuit 500 detects whether or not the output a of the receiver 300 is a null packet. The detection method is determined by detecting whether the PID is 0x1FFF. When the packet is a null packet, the switch 503 is controlled to switch to the TS packet creation circuit 502 side. The 1TS delay circuit 501 delays the output a by 1 TS packet (1 TS time). Since the PID starts from the 11th bit from the beginning of the TS packet, not the beginning of the TS packet, a 1TS delay circuit 501 is provided to eliminate the delay in detecting the PID. The TS packet creation circuit 502 creates a TS packet from the output b of the relay point reception support information generation circuit 302. The TS packet is 188 bytes in total, but is created with 184 bytes excluding the header 4 bytes. That is, the TS packet creation circuit 502 creates 1 TS packet. A preset ID is used as the PID used for the TS packet. The switching unit 503 performs switching control based on a switching signal from the null packet detection circuit 500 that detects whether or not the output a is a null packet. Then, switch to the TS packet creation circuit 502 side. The switcher 503 switches only 1 TS packet as the output c, and then returns to the original state and sends a null packet.

  Next, the final stage receiving unit 105 will be described with reference to FIG. In the figure, 400 is a receiver, 401 is a receiving antenna and a frame on which the receiver 400 is mounted, 402 is a TS separation circuit, 403 is an MPEG decoding circuit, 404 is another point reception support information restoration circuit, and 405 is final stage reception. Support information generation circuit, 406 is a reception support information multiplexing circuit, 407 is a monitor PC (PC: Personal Computer), 408 is a display selector, 409 is a reception support information display signal generation circuit, 410 is a graphic monitor, and 106 Is a video output terminal. Note that the gantry 401 is a gantry capable of adjusting the azimuth and elevation angles of the receiving antenna of the receiver 400 by a gantry control signal.

  Next, the operation of the final stage receiving unit 105 will be described. The receiver 400 receives a microwave through an antenna, demodulates it, and outputs a TS packet to the TS separation circuit 402. The receiver 400 outputs data serving as a basis for reception support information such as MER (modulation error ratio) and MARGIN (margin) to the final-stage reception support information generation circuit 405. The gantry 401 is a gantry that operates according to the gantry control signal of the gantry monitoring PC 407. The TS separation circuit 402 separates the TS video packet (TS packet containing only video information) and the TS packet including the reception support information according to the PID of the TS packet, outputs the TS video packet to the MPEG decoding circuit 403, and receives the reception support information. The included TS packet is output to the other-point reception support information restoration circuit 404.

  The MPEG decoding circuit 403 decodes the video signal from the TS video packet, and outputs the decoded signal (video signal) to the output terminal 106 and the reception support information display signal generation circuit 409. The other-point reception assistance information restoration circuit 404 separates the reception assistance information from the TS packet including the reception assistance information, restores the reception assistance information at each point, and outputs it to the reception assistance information multiplexing circuit 406. The final stage reception support information generation circuit 405 is the same circuit as the identification information and relay point reception support information generation circuit 302 in FIG. 3 and outputs the final stage information including the identification information to the reception support information multiplexing circuit 406. To do. The reception support information multiplexing circuit 406 multiplexes the other-point reception support information (e) and the final-stage reception support information (f) into one piece of information (g), and the gantry monitoring PC 407 and the reception support information display. The signal is output to the signal generation circuit 409.

  The display selector 408 outputs a selection signal for switching the display screen of the graphic monitor 410 to the reception support information display signal creation circuit 409, and the graphic monitor 410 displays the output. The reception support information display signal generation circuit 409 is a circuit that generates reception support information as a graphic signal. The reception support information display signal generation circuit 409 generates a graphic signal of reception support information according to the display mode of the display selector 408. The display modes that can be selected by the display selector 408 include the reception support information at each relay point (relay reception transmission units 102, 103, and 104) as a graphic signal, that is, the reception support information display signal at each relay point is full. A mode for individually displaying on the screen (for example, FIGS. 9 (A) to 9 (D)), a mode for separately displaying the reception support information for each relay point on one screen (for example, FIG. 8), There is a mode for displaying a graphic signal in which reception support information and main line video are mixed, and the display selector 408 can select these display modes according to the application. It is also possible to create a graphic signal mixed with the main line video signal according to the display mode. In this case, the main line video is converted into a graphic signal (for example, VGA (Video Graphics Array)).

  Note that the split display screen may be a full-screen reception support information graphic signal, the reception support information graphic signal may be reduced, and a split display screen may be generated and displayed by combining the reduced screens. Alternatively, a reception support graphic signal having a size obtained by dividing one screen into four at each point is created, and a split display screen is created by combining the reception support information graphic signals into one screen, and the reception support information graphic signal at each point is created. In the case of displaying a full screen, the display may be enlarged.

  The gantry monitoring PC 407 is installed and used in a different location from the display selector 408, the reception support information display signal generation circuit 409, the graphic monitor 410, and the like. Equivalent multi-display is also possible. The gantry monitoring PC 407 controls each of the relay points and the gantry 301 and 401 of the final receiver. In this case, the gantry is controlled by a line different from the transmission circuit, for example, a telephone line. Specifically, when the MARGIN (transmission margin) is extremely bad, the gantry monitoring PC 407 adjusts the direction of the receiving antenna of the receivers 300 and 400 mounted on the gantry 301 and 401 (related to the azimuth angle or elevation angle). The horizontal control or vertical control) is controlled so as to obtain a predetermined MARGIN by driving the bases 301 and 401, and the best reception state is ensured.

  Next, an output stream of each transmission unit according to the present embodiment will be described with reference to FIGS. The figure shows the structure of the output stream corresponding to the outputs (a) to (d) of each transmitter in FIG. 1, and (b) shows the output of the first-stage transmitter 101, and (b) in FIG. Is the output of the relay transmission unit 102, (c) is the output of the relay transmission unit 103, and (d) is the output of the relay transmission unit 104. The output stream of (a) is an output stream of the first-stage transmission unit 101, which is a stream in which a null packet of 1TS packet continues after a video packet, and is a video packet, a null packet,. The output stream of (b) is the output of the relay transmission unit 102, and the null packet next to the video packet of the output stream of (b) is replaced with the identification number of the relay transmission unit 102 and reception support information, The video packet, the identification number of the relay transmission unit 102 and reception support information, a null packet, and so on. The output stream of (c) is the output of the relay transmission unit 103, and the video packet, by replacing the first null packet of the output stream of (b) with the identification number of the relay reception transmission unit 103 and reception support information The identification number of the relay transmission unit 102 and the reception support information, the identification number of the relay reception transmission unit 103 and the reception support information, a null packet, and so on. The same operation is repeated, and the output stream (d) of the relay reception / transmission unit 104 is a video packet, the identification number of the relay reception / transmission unit 103 and reception support information, the identification number of the relay reception / transmission unit 103, reception support information, and relay reception. The identification number of the transmission unit 104, reception support information, a null packet, and so on. The reception support information of the final stage reception unit 105 is created by the final stage reception support information generation circuit 405, and the multiplexed information is added after the identification information of the output stream (d) of the relay transmission unit 104 + the reception support information. To the gantry monitoring PC 407 and the reception support information display signal generation circuit 409.

  Next, the multiplexing of the reception support information multiplexing circuit 406 will be described with reference to FIGS. FIGS. 7E to 7G correspond to the input signals (e) and (f) and the output signal (g) of the reception support information multiplexing circuit 406 shown in FIG. (E) in FIG. 7 is an output signal diagram of the other-point reception assistance information restoration circuit 404, (f) in FIG. 7 is an output signal diagram of the final stage reception assistance information generation circuit 405, and ( G) is an output signal diagram of the reception support information multiplexing circuit 406. The reception support information multiplexing circuit 406 multiplexes the identification information and the reception support information in the order of the relay transmission units 102, 103, 104 and the final stage, as shown in the output signal diagram of (g). The reception support information multiplexing circuit 406 outputs an output signal (g) and inputs this output signal (g) to the reception support information display signal generation circuit 409. A signal having the same contents as (G) is also output to the gantry monitoring PC 407. However, when connected via a LAN (Local Area Network), the signal format is followed.

  The reception support information display signal generation circuit 409 shows a display diagram based on the reception support information graphic signal generated based on the restored video signal and the output signal (g) in FIG. The display contents will be described with reference to the figure. The CH name “C11”, the modulation schemes “OFDM FULL” and “32QAM”, the coding rate “3/4”, and the bit rate of the input signal “44. 736 Mbps ”, interleave delay time“ 756 ms ”, modulation error ratio“ MER ”, margin“ MARGIN ”, and“ delay profile ”in the middle of the figure, the reception support information is based on the identifier of each relay point These are information. In this figure, identification information and reception support information are created for each reception point and displayed on the graphic monitor 410 according to the selection mode of the display selector 408.

  FIG. 9 is a display example when the reception support information graphic signal at four relay points (reception points) is displayed on one screen. Generally, as shown in Fig. 9, a reduced display of the reception support video at each relay point is displayed on one screen of a graphic monitor, and if there is something abnormal, the screen of the relay point that seems to be abnormal is displayed. 8 are used by switching to individual screens as shown in FIG.

  Note that FIG. 9 shows a display example in the case of four reception points. However, when there are five or more reception points, one screen is created for each of the four reception points and is switched on a multi-screen. It is also possible to do. However, in the case of five or more, the display mode of the display selector 408 also uses two or more types of divided display. The interleave delay time is effective when the transmission radio wave modulation scheme is OFDM, but nothing is displayed except for OFDM. Moreover, although it replaced with a null packet, it is good also as a structure which created by DVB-ASI specification and added reception assistance information as dummy information.

  As an application example of the present invention, it is used in a digital transmission system using a microwave band, and is suitable for transmission not in one-way communication but in multiple stages. In particular, it is used as a digital multi-stage transmission system for transmission via a mountainous area and the like, and the reception state at each relay point can be adjusted by remote control, which is effective for multi-stage transmission.

DESCRIPTION OF SYMBOLS 100 Video input terminal 101 First stage transmission part 102,103,104 Relay reception transmission part 105 Last stage reception part 106 Video output terminal 200 MPEG-TS preparation circuit (encoding process means)
201 Null packet generation circuit (null packet generation means)
202 Multiplexing circuit (multiplexing means)
203 Transmitter (Transmission means)
300 Receiver 301 Base 302 Relay Point Reception Support Information Generation Circuit (Reception Support Information Generation Unit)
303 TS packet replacement circuit (TS packet replacement means)
304 Transmitter (transmission means)
400 Receiver 401 Base 402 TS separation circuit (separation means)
403 MPEG decoding circuit (decoding means)
404 Other point reception support information restoration circuit (restoration means)
405 Final reception support information generation circuit (final reception support information generation means)
406 Reception support information multiplexing circuit (reception support information multiplexing means)
407 Base monitor PC (control means)
408 Display selector (display selection means)
409 Reception support information display signal generation circuit (reception support information display signal generation means)
410 graphic monitor 500 null packet detection circuit (detection means)
501 1TS delay circuit (delay means)
502 TS packet creation circuit (TS packet creation means)
503 switcher (switching means)

Claims (4)

In a digital multistage transmission system that performs multistage transmission by encoding a video signal or an audio signal to create a TS packet signal,
The digital transmission system wirelessly transmits a TS packet signal obtained by encoding the video signal or audio signal, and receives and processes the TS packet signal from the initial transmission unit, and performs several stages of wireless transmission. Consisting of a relay reception / transmission unit that performs relaying according to and a final reception unit of the relay reception / transmission unit,
The first-stage transmission unit creates a null packet by coding processing means for coding the video signal or audio signal, TS packet signal creating means for creating a TS packet signal from an output signal of the coding processing means, and A null packet generating means, a multiplexing means for multiplexing the output signal of the TS packet signal generating means with the null packet, and a transmitting means for wirelessly transmitting the output signal of the multiplexing means,
The relay reception / transmission unit receives a transmission signal from the transmission means of the first-stage transmission unit, outputs a TS packet signal including the null packet, and obtains data related to reception from the receiver to receive support information And receiving support information generating means for generating information including identification information of each relay point, and replacing a null packet output included in the output signal of the receiver with an output signal from the receiving support information generating means A null packet replacement means, and a transmission means for wirelessly transmitting an output signal from the null packet replacement means,
The final reception unit receives a signal transmitted from the transmission unit of the relay transmission unit, outputs a TS packet signal including the null packet, and outputs the output signal of the receiver to the video signal or the audio signal. Separating means for separating the TS packet signal and TS packet signal of the reception support information, decoding means for decoding a video signal or audio signal by the TS packet signal obtained from the separating means, and the obtained from the separating means A restoration means for restoring the reception assistance information at each relay point from the TS packet signal of the reception assistance information; a final stage reception assistance information generation means for producing reception assistance information including identification information at the last stage from the receiver; Receiving support information multiplexing means for multiplexing the output signal of the final stage receiving support information generating means and the output signal of the restoring means; The control means for controlling each receiver of each relay point and the last stage receiver from the output signal of the conversion means, and the output signal of the reception support information multiplexing means are converted into graphic signals of the reception support information A digital multi-stage transmission system comprising: a reception support information display signal creating means; and a graphic monitor for displaying an output signal of the reception support information display signal creating means.   2. The digital multistage transmission system according to claim 1, wherein the null packet replacement means includes delay means for delaying a TS signal of the output signal of the receiver by 1 TS time, and a TS packet signal of the output signal of the receiver is a null packet. A digital multi-stage transmission system comprising: a detecting means for detecting whether or not a signal is included; and a switching means for switching the output of the delay means and the output of the reception support information generating means a predetermined number of times by the detecting means.   2. The digital multistage transmission system according to claim 1, wherein the control unit of the final reception unit includes a receiver frame of the relay reception transmission unit and a receiver and an antenna of the final reception unit through a line different from the wireless transmission. A digital multi-stage transmission system characterized by controlling the mounting base.   2. The digital multistage transmission system according to claim 1, wherein the reception support information display signal creation unit displays the reception support information display signal at each relay point when displaying the reception support information display signal on the graphic monitor. A display mode for displaying on a full screen for each relay point, a display mode for reducing the reception support information display signal at each relay point to display all on a full screen, and an output video signal of the decoding means as a graphic signal A digital multistage transmission system comprising display selection means for switching between display modes for conversion, mixing and display.

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