JP2008258940A - Digital broadcasting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology for allowing a mobile relay car side to easily discriminate how a transmission wave outputted from an FPU transmitter is received on a receiving side. <P>SOLUTION: The FPU transmitter 14 mounted on the mobile relay car 12 transmits a digitally modulated transmission wave toward a base station 20. A receiver 40 of a head office 30 receives a digital modulated wave transmitted from the FPU transmitter 14 via the base station 20 and demodulates and decodes the digital modulated wave. The receiver 40 also evaluates a receiving state of the transmission wave by ranking it and outputs an evaluation result from a speaker 62 or the like by voice. The outputted voice is transmitted to a radio terminal 19 of an operator of the mobile relay car 12 through a radio terminal 39. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a digital broadcasting device, and more particularly to a digital broadcasting device having a function of evaluating a reception state of a digital modulated wave.

  As a relay means from outside the station for television broadcasting, an outside relay using an FPU (Field Pick-up Unit) transmitter mounted on a mobile relay vehicle is often used. At the interview site, the antenna of the FPU transmitter mounted on the mobile relay vehicle is directed to the FPU receiving base station (hereinafter simply referred to as “base station”), and the interviewed video is transmitted to the broadcast station via the base station.

  In order to realize high-quality data transmission to the base station, the antenna direction of the FPU transmitter needs to be properly oriented with respect to the base station. Therefore, antenna direction adjustment (hereinafter also simply referred to as “tone”) is very important.

  In the antenna tone, for example, an accurate position of a relay point (FPU transmitter) is obtained using GPS or the like, and the antenna direction is determined from the positional relationship between the FPU transmitter and the base station. By the way, the problem in this tone work is that the FPU transmitter cannot determine the reception state at the base station. Between the FPU transmitter and the base station, data transmission is only one-way due to regulations of the Radio Law. Therefore, it is necessary to notify the reception state from the base station to the FPU transmitter, and several techniques have been proposed as a notification method.

  For example, in a conventional analog modulation transmission system, an indication value of an input wave reception level (electric field strength; BL value) at a base station is converted into an audio signal that changes in accordance with a change in the indication value, and is transmitted to the FPU transmitter side. On the other hand, a technique of transmitting with a contact radio is disclosed (see Patent Document 1). That is, the level of the electric field strength is converted into an audio signal that changes intermittently and notified to the FPU transmitter, and the operator of the FPU transmitter makes a tone depending on the change in the audio signal.

  Also, in the digital modulation transmission method used in recent years, the transmission quality is not determined only by the BL value unlike the analog modulation transmission method, and even when the BL value is high, there is a large amount of reflected waves. The transmission quality deteriorates, and the decoded BER (Bit Error Rate) value (hereinafter simply referred to as “BER value”) at the time of decoding the encoded and digitally transmitted data, that is, the rate at which the data cannot be correctly decoded increases. End up. By tuning the antenna on the base station side, it is possible to improve the transmission quality to some extent, but finally, the antenna of the FPU transmitter on the transmission side needs to be tuned.

Therefore, a technique has been proposed in which at least any two states of the reflected wave mixing state, the BL value of the received wave, and the BER value state are reflected in a predetermined characteristic of the voice, and the reception state is notified by a voice that changes intermittently. (See Patent Document 2). In addition, a margin (CN value) for noise of the input wave is also taken into account.
JP 59-104837 A JP 2006-54915 A

  As described above, in the digital modulation transmission method, the antenna of the FPU transmitter is tuned while confirming the sound that changes intermittently according to the level of the BER value, CN value, BL value, etc. Yes. However, it is difficult for the operator of the FPU transmitter to determine in what state the signal is received at the base station from intermittently changing sounds, and a certain level of proficiency is required. Sufficient personnel are not always arranged at the relay point, and in some cases, it may be operated by an operator who has rarely operated, and the reception status is notified by the pitch of the sound or the change in pitch. In the case of a device, it may be practically difficult for an operator to properly grasp the reception state.

  Therefore, the operator who prepares the tone may not be able to determine whether to finish the tone work, whether to make a fine adjustment, or whether to make a large adjustment. From such a background, there is an increasing demand for more easily grasping the transmission state in the field where the actual situation is being performed.

  The present invention has been made in view of the situation as described above. The purpose of the present invention is to notify a transmitting side of a reception state when a digital modulation transmission system broadcast wave is received and It is to provide a technique for simplifying the adjustment work.

  The apparatus according to the present invention relates to a digital broadcasting apparatus. The apparatus includes means for evaluating the reception state of the digitally modulated radio wave into a plurality of ranks, and means for outputting different sounds according to the plurality of evaluated ranks.

  According to the present invention, the reception state of digitally modulated radio waves (broadcast waves) is evaluated to a plurality of ranks, and different sounds are output according to the ranks of the evaluation, so that the transmission side transmits by acquiring the sounds. It is easy to understand with sound how the received radio waves are being received.

  Next, the best mode for carrying out the present invention (hereinafter simply referred to as “embodiment”) will be specifically described with reference to the drawings. In the embodiment described below, first, a digital modulation wave transmitted from an FPU transmitter is received by a broadcast station or a base station, and a BL value and a BER value are detected as parameters for evaluating the reception state. Subsequently, when the BER is equal to or higher than a predetermined value, the reception state is ranked and evaluated from the difference between the lowest received electric field set for each modulation method of the digital modulation wave and the BL value, and the evaluation result is evaluated by the FPU transmitter. To the side. In response to the notification, the operator on the FPU transmitter side performs the work of the work or changes the transmission rate.

  FIG. 1 is a diagram showing an outline of a relay system 10 for transmitting a broadcast wave from a mobile relay vehicle to a head office of a broadcasting station using a digital modulation transmission system according to the present embodiment.

  The relay system 10 includes a mobile relay vehicle 12, a head office (broadcast station) 30, and a base station 20 that relays a digitally modulated wave between the mobile relay vehicle 12 and the head office 30.

  The mobile relay vehicle 12 includes a vehicle main body 13 and an FPU transmitter 14 mounted on the vehicle main body 13. The FPU transmitter 14 includes an antenna 15 for transmitting a digitally modulated transmission wave toward the base station 20. There are cases where a single transmission wave is used as the transmission wave and a multiplexed transmission wave based on OFDM (Orthogonal Frequency Division Multiplexing). In each transmission wave, a plurality of types of modulation schemes having different coding rates (transmission rates) can be used, and the operator selects an appropriate modulation scheme from the plurality of types of modulation schemes according to the transmission state.

  The base station 20 is constructed on a hill such as a mountain 21 so that there are as many obstacles as possible on the path of the transmission wave, receives the transmission wave from the mobile relay vehicle 12, and transmits the received transmission wave to the head office 30 ( Forward. For this purpose, the base station 20 includes an FPU receiver 22 that receives a transmission wave from the mobile relay vehicle 12 and a TSL (Transmitter to Studio Link) transmitter 26 that transmits the transmission wave to the head office 30. It is attached to. The FPU receiver 22 includes an antenna 25 and is installed on an FPU rotary base 27 attached above the steel tower 29. The operator of the head office 30 rotates the FPU turntable 27 and controls the antenna 25 on the base station 20 side by using an FPU remote control terminal provided in the head office 30 described later.

  The head office 30 includes, for example, a TSL receiver 32 on a building roof, and the antenna 35 of the TSL receiver 32 receives a transmission wave transmitted from the TSL transmitter 26 of the base station 20. The transmission wave received by the antenna 35 is demodulated and decoded by the receiving device 40. In addition, the receiving device 40 evaluates by ranking the reception state of the transmission wave, and outputs the evaluation result from the speaker 62 or the like by voice. The output voice is transmitted to the radio terminal 19 of the operator of the mobile relay vehicle 12 via the radio terminal 39. Examples of the wireless terminals 19 and 39 include transceivers and mobile phones. Note that the function of the base station 20 is unnecessary when the head office 30 is on a hill and can directly receive the digital modulated wave transmitted from the FPU transmitter 14 of the mobile relay vehicle 13.

  FIG. 2 is a functional block diagram illustrating a configuration of a receiving device 40 that receives a digital modulated wave transmitted from the FPU transmitter 14 and transferred via the FPU receiver 22 and the TSL transmitter 26 of the base station 20. The receiving device 40 includes an AGC (Automatic Gain Controller) 42 connected to the antenna 35, a demodulation processing unit 44, a decoding processing unit 46, and a tone induction unit 50.

  The AGC 42 adjusts the reception level of the received transmission wave, that is, the BL value to an appropriate level and transmits the adjusted level to the demodulation processing unit 44. In addition, the BL value before adjustment is notified to the reception state detection unit 52 of the tone guidance unit 50.

  The demodulation processing unit 44 demodulates the modulated digital data according to the modulation method, and transmits the demodulated data to the decoding processing unit 46.

In the decoding processing unit 46, the demodulated data is subjected to error correction processing, frame reconstruction processing, and further encoded data is decoded and digitally output (D _out ) to a predetermined device. Also, the BER required in the error correction process is notified to the reception state detection unit 52 of the tone guidance unit 50.

  The tone induction unit 50 includes a reception state detection unit 52, a generated sound determination processing unit 54, an information transmission unit 56, an FPU remote control terminal 58, a sound generation unit 60, and a line connection unit 64.

  The reception state detection unit 52 acquires the BL value from the AGC 42 as described above, and acquires the BER value from the decoding processing unit 46.

  The generated sound determination processing unit 54 acquires the BL value and the BER value from the reception state detection unit 52, and ranks and evaluates the reception state according to an evaluation procedure described later based on these values. Here, the ranks of evaluation are five stages of “rank S”, “rank A”, “rank B”, “rank C”, and “rank D” in order of good condition. The generated sound determination processing unit 54 is realized by, for example, an LSI (Large Scale Integrated Circuit) such as a CPU (Central Processing Unit), a memory, or an arbitrary program loaded in the memory. The evaluation criteria are stored in a reference storage unit 66 provided in the generated sound determination processing unit 54.

  The reception state evaluation result is notified to the sound generation unit 60, and the sound generation unit 60 outputs a sound signal corresponding to the evaluation result from the speaker 62. The sound output from the speaker 62 is acquired by the wireless terminal 39 and transmitted to the wireless terminal 19 used by the operator of the mobile relay vehicle 12. The voice generation unit 60 is connected to a public telephone line via a line connection unit 64, and directly dials the wireless terminal 19 that is a mobile phone of an operator who controls the FPU transmitter 14 in the mobile relay vehicle 12. By making a call, the evaluation result can be notified by voice without using the speaker 62.

  FIG. 3 is a table showing a combination example of the above-described five-level evaluation ranks of the reception state and the generated sounds output in accordance with the evaluation ranks. Here, two types of combinations of generated sounds, “generated sound 1” that is different depending on the rank and “generated sound 2” that is an announcement by words instead of a simple sound, are illustrated. If it is determined that the rank is S, the sound generating unit 60 generates a sound “ping-pong pong ping-pong pong ping-pong” if “generated sound 1” is selected, and “generated sound 2” is If it is selected, the announcement “OK even if the batch rate is increased” is issued.

  In addition, when “generated sound 2” is selected, not only the reception state is merely evaluated as described above, but also the actual state of the reception state, for example, the modulation method should be changed to lower the transmission rate. Notify you. As a result, even an operator who is not proficient at the operation of the FPU transmitter 14 can immediately determine what operation should be performed.

Next, the evaluation criteria for the reception state will be described.
First, the generated sound determination processing unit 54 determines whether the BER value is equal to or less than a predetermined value, specifically 10 ⁻⁴ or less, and then, the lowest value predetermined for each modulation method. A margin for the received electric field (“current received electric field value−minimum received electric field value”) is calculated to evaluate the reception state. When the margin is 20 dBm or more, it is evaluated as rank S, when it is less than 20 dBm and is 12 dBm or more, rank A, and when it is less than 12 dBm and is 7 dBm or more, it is evaluated as rank C. When the BER value is 10 ⁻⁴ or more, that is, when the error rate is high, it is evaluated as rank D. The predetermined value of the BER value is stored in the reference storage unit 66 and may be changed according to actual use.

  FIG. 4 is a table showing the minimum received electric field for each modulation method in the case of a single carrier method in which transmission waves are not multiplexed. Four types of transmission methods of 64QAM, 32QAM, 16QAM, and QPSK can be selected in descending order of coding rate (transmission rate), and a minimum reception limit is provided for each. The set minimum reception limit is, for example, -79 dBm for 64QAM with the highest coding rate and -94 dBm for QPSK with the lowest coding rate, and the minimum reception limit as the coding rate increases. Is high. The contents of this table are stored in the reference storage unit 66.

  FIG. 5 is a table showing the minimum received electric field for each modulation method when transmission waves are multiplexed by the OFDM method. A total of eight types of transmission methods can be selected: four types in the QAM scheme and four types in the PSK scheme, and the minimum reception limit is provided for each as in the single carrier scheme. The set minimum reception limit is, for example, -75 dBm for 64QAM with the highest coding rate, and -96 dBm for BPSK with the lowest coding rate, and the lowest reception limit as the coding rate increases. Is high. The contents of this table are also stored in the reference storage unit 66, similar to the contents of the table of FIG.

FIG. 6 is a flowchart showing a processing procedure for ranking reception states. This process is performed by the generated sound determination processing unit 54. First, it is determined whether or not the BER is “GOOD” (S10). As described above, when the BER value is 10 ⁻⁴ or less, it is determined that the BER is “GOOD”.

  In the process of S10, if it is determined that the BER is “GOOD” (Y in S10), it is determined whether the margin (M) is 20 dBm or more (S12). If the margin (M) is 20 dBm or more (Y in S12), it is evaluated that the reception state is rank S (S14).

  When the margin (M) is less than 20 dBm (N in S12), it is further determined whether or not the margin is 12 dBm or more (S16). If the margin is 12 dBm or more (Y in S16), it is determined that the reception state is rank A (S18).

  When the margin (M) is less than 12 dBm (N in S16), it is further determined whether or not the margin is 7 dBm or more (S20). If the margin is 7 dBm or more (Y in S20), it is determined that the reception state is rank B (S22). If the margin is less than 7 dBm (N in S20), it is determined that the reception state is rank C. (S24).

  In the process of S10, when it is determined that the BER is not “GOOD” (N in S10), the reception state is determined to be rank D (S26).

  When the rank of the reception state is determined (S14, S18, S22, S24, S26), sound corresponding to each rank is generated from the sound generation unit 60 (S28). With the above processing, one cycle of processing related to reception state evaluation and sound generation is completed. The processing according to this flow is repeated until the operator of the receiving device 40 performs a stop operation for this processing.

  When the reception state is determined to be rank C (S24) and “generated sound 2” is selected as the sound to be generated, an announcement is made to urge the transmission rate to be lowered. When the operator on the mobile relay vehicle 12 (FPU transmitter 14) side changes the transmission rate in accordance with this announcement, part or all of the margin may be changed. For example, in the single carrier scheme, if it is determined that the modulation scheme is changed from 64QAM to 32QAM with a low transmission rate, the determination criterion margin (M) is increased from “7 dBm or more” to “12 dBm or more” in the process of S20. .

  When performing such processing, once the rank of the reception state is determined, the rank and the modulation method are associated with each other and temporarily stored in a memory or the like, and the association is referred to in the next rank evaluation process, Change the criteria margin as necessary. At this time, the reception state detection unit 52 acquires the modulation method of the reception wave from the demodulation processing unit 44.

  As described above, according to the present embodiment, the reception state of the digital modulated wave transmitted from the FPU transmitter 14 is ranked and evaluated, and a different sound or audio signal is generated for each rank and transmitted to the FPU transmitter 14 side. Therefore, the operator on the FPU transmitter 14 side can easily grasp the reception state by viewing the sound or reproducing the sound from the audio signal. In addition, since the sound is clearly distinguished, even an operator who is not proficient at the operation of the FPU transmitter 14 can easily determine the reception state at the base station 20 or the head office (broadcast station) 30 side.

  In addition, since it is not necessary to grasp and visually recognize the reception state on the receiving side only by listening to the sound, the operator can concentrate on the work that requires manual work and can perform the work while listening to the sound. it can.

  In addition, when wireless terminals 19 and 39 such as transceivers and mobile phone lines are used as means for notifying the reception state, the connection of these lines is easy to check. Alternatively, the reception state can be reliably transmitted from the base station 20 side to the FPU transmitter 14 side, and whether or not the reception state is transmitted to the FPU transmitter 14 side can be confirmed.

  For example, the FPU transmitter 14 is mounted on a mobile body such as the mobile relay vehicle 12, and information (evaluation result, BL value, etc.) regarding the reception state is notified from the reception side (head office 30, base station 20) via the Internet. In this case, since a wireless transmission means such as a wireless LAN is required, the transmission speed may be extremely deteriorated. In that case, the reception state cannot be notified to the operator of the FPU transmitter 14 with good response, that is, substantially in real time. In particular, in a place where improvement is required in the transmission state (reception state) of a digital modulated wave, it is naturally assumed that wireless transmission conditions such as a wireless LAN also deteriorate. However, according to the present embodiment, even if the transmission state of the notification is not good, the operator on the FPU transmitter 14 side can be notified substantially in real time. Also, even if the notification transmission state is poor and cannot be clearly recognized, the evaluation results are clearly distinguished compared to the conventional notification with intermittently changing sound pitch or pitch. Therefore, the operator can appropriately estimate the receiving state of the receiving side (head office 30, base station 20).

  The present invention has been described based on the embodiments. However, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention. For example, in the evaluation of the reception state, the margin and the BER value for the lowest received electric field of the actually received radio wave are used, but a CN value may also be used.

  The present invention can be widely used in, for example, an apparatus that receives a broadcast wave of a digital modulation transmission method transmitted from an FPU transmitter and an FPU transmission / reception system including the FPU transmitter.

It is a figure which shows the outline | summary of the relay system for transmitting a broadcast wave from a relay vehicle to the head office of a broadcast station using the digital modulation transmission system of embodiment by this invention. It is a functional block diagram which shows the structure of the receiver which receives the digital modulation wave sent from the FPU transmitter of embodiment by this invention. It is the table | surface which showed the example of the combination of the generated sound output according to the evaluation rank of 5 steps | paragraphs of a receiving state of the embodiment by this invention, and the evaluation rank. It is the table | surface which showed the minimum received electric field for every modulation system in the case of the single carrier system with which the transmission wave is not multiplexed of embodiment by this invention. It is the table | surface which showed the minimum received electric field for every modulation system when the transmission wave of the embodiment by this invention is multiplexed with the OFDM system. It is a flowchart which shows the process sequence for evaluating a receiving condition by a rank of embodiment by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Relay system 12 ... Mobile relay vehicle 13 ... Vehicle main body 14 ... FPU transmitter 15, 25, 35 ... Antenna 19, 39 ... Wireless terminal 20 ... Base station 22 ... FPU receiver 26 ... TSL transmitter 27 ... FPU turntable 30 ... Head office 32 ... TSL receiver 40 ... Receiver 42 ... AGC
44 ... demodulation processing unit 46 ... decoding processing unit 50 ... tone induction unit 52 ... reception state detection unit 54 ... generated sound judgment processing unit 62 ... speaker 64 ... line connection Unit 66 ... reference storage unit

Claims (1)

Means for evaluating the reception state of the digitally modulated radio wave to a plurality of ranks; and means for outputting different sounds according to the plurality of evaluated ranks;
A digital broadcasting device comprising:

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