KR20070095188A - Digital transmission device - Google Patents

Abstract

A digital transmission device is provided to determine the stability of a transmission state by transmitting information for visualizing the transmission state at high speed without using new image transmission line. An image signal is inputted to an MPEG(Moving Pictures Experts Group) encoder(5) and converted to a compressed data. The compressed data is delivered to a first transmitter(Tx1) and modulated to a microwave signal. The modulated signal is amplified and transmitted as a microwave(W1) by a first antenna(1). The microwave is received by a second antenna(2) and reproduction compression data is restored, which is inputted to a specific TS(Time Slice) replacing unit(7). The specific TS replacing unit replaces specific data except for NULL data in the TS signal with a reception state TS signal, and delivers the TS signal to a second transmitter(Tx2). The TS signal is modulated and converted to a microwave. The microwave is received at a third antenna(4) of a broadcasting system. The third antenna receives the microwave signal and reproduces the compression data. A reception state display(8) displays reception state information.

Description

Digital Transmission Device {DIGITAL TRANSMISSION DEVICE}

1 is a system configuration diagram (TS multiplexed reception state and output and transmission) showing an example of a digital relay system having a reception status display function of the present invention.

Fig. 2 is a system configuration diagram (ENC setting with lots of NULL data in the direction adjustment mode) showing another example of the digital relay system with the reception status display function of the present invention.

3 is an explanatory diagram showing an example of a stream in which NULL data of the present invention is increased.

Fig. 4 is a system configuration diagram (transmission in the direction adjustment mode to another point) showing another example of the digital relay system with the reception status display function of the present invention.

Fig. 5 is a system configuration diagram (transmitting reception status on another line) showing another example of the digital relay system with the conventional reception status display function.

6 is a block diagram showing an example of a reception state transmitter common to the present invention and the prior art.

7 is a detailed block diagram of a writing unit which is common in the present invention and the prior art.

8s is a detailed block diagram of an initialization unit common to the present invention and the prior art.

9 is a detailed block diagram of a read display unit and a read transfer unit which are common in the present invention and the prior art.

10 is an explanatory diagram showing a transmission signal to which a header common to the present invention and the prior art are added.

11 is a detailed block diagram of a reception state display unit which is common to the present invention and the prior art.

12 is a detailed block diagram of a reception input unit common to the present invention and the prior art.

Explanation of symbols for main parts of the drawings

Tx1, Tx2, Tx3: Transmitter

Rx1, Rx2, Rx3, Rx4: Receiver

1, 2, 3, 4: Antenna

5, 12: MPEG encoder

6, 16: reception status transmission unit

7: specific TS replacement

8, 15: reception status display unit

11: mode setting unit

13: NULL generator

14: TS multipart

The present invention provides a digital transmission device that receives a signal modulated by a digital modulation method and performs relaying, wherein the reception state of the wireless transmission device is visualized, transmitted to the receiving device side, and assists stabilization of the transmission state. The technology is about improvement.

Although video and audio have been transmitted by analog FM many years ago for wireless transmission of video and audio signals, recently, digital transmission methods such as quadrature amplitude modulation (QAM) or Orthogonal Frequency Division Multiplexing (OFDM) have been used. It is supposed to be.

In this case, the data to be transmitted is a transmission signal such as TS (Transport Stream) in which a video or audio signal is compressed by MPEG processing. In this case, in general, the digitally modulated transmission signal is mapped to two-dimensional data. And a digital transmission device of a method of transmitting from the transmitting side and reproducing the transmission signal by identifying two-dimensional data at the receiving side. By the way, in the analog system described above, the S / N of the video or audio changes depending on the received electric field level. Therefore, in the case of mobile transmissions in which the electric field level is severely changed, such as a marathon relay, the relayed video is noisy. It was easy to be a low quality image with a lot of distortion. However, according to the digital transmission method, since the digitized information is transmitted, an error correction process can be applied. Therefore, even in a transmission environment in which the reception electric field level is changing, the same can be applied to the electric field level range where error correction works. You can relay quality video. On the other hand, in the digital transmission system, when the electric field level falls below a certain threshold, error correction is not heard. In this case, video signal reproduction is suddenly impossible, but the lower limit of the electric field level at this time is the identification determination process at the receiving end. It is possible to grasp to some extent by the signal state in. For example, in the case of a 64 QAM scheme with a relatively high transmission rate of 60 Mbps, the minimum value of the received electric field level is about -70 dBm since the minimum value of C / N is about 27 dB, so that a higher level is required for image reproduction. do. In the case of the 16 QAM2 system with a relatively small transmission rate of 35 Mbps, the minimum value of the C / N is about 18 dB, so the lower limit of the received electric field level is about -80 dBm. Therefore, in the digital transmission device to which such data correction processing has been applied, it has conventionally been known that the lower limit value of the received electric field level can be grasped from the transmission state or the synchronized reproduction state (see, for example, Patent Documents 1 and 3). .

An example of such a digital transmission device will be described below with reference to FIG. 5. Fig. 5 is a block diagram showing an example of the prior art when a digital transmission device to which data correction processing has been applied is applied to relaying a video. In this case, for example, a moving vehicle capturing an image of a running marathon runner. For example, a radio transmission format using a radio wave of a microwave band is provided between a shooting spot and a broadcasting station. In addition, when a shooting site is far from a broadcasting station, or when there is an obstacle to radio waves on the way, it is necessary to provide a relay in the middle of the broadcast station. In this case, the reception base is installed in the relay unit, for example, on a hill slightly higher, so that two-stage relay transmission is performed.

First, at the shooting site, a video signal captured by a television camera (not shown) is input to the MPEG encoder 5, which is converted into compressed data TS, and then supplied to the transmission unit Tx1. Then, the signal is modulated, frequency-converted into a microwave band signal, power amplified, transmitted by the antenna 1 as the microwave W1, and transmitted toward the antenna 2 at the reception base. In this way, the microwave W1 transmitted to the receiving known antenna 2 is inputted to the receiving unit Rx1, demodulated and restored to the reproduction compressed data TSr, modulated by the transmitting unit Tx2, and converted into microwaves, and the antenna The radio wave W2 is received by the antenna 4 of the broadcasting station from (3). The antenna 4 receives the radio wave W2 of the microwave, and reproduces the main line compressed data TSb signal containing the video and the audio in the receiver Rx2.

At this time, as described above, since there is a lower limit on the reception electric field level, it is necessary to grasp the reception state, and the low-speed line such as the reception state transmission unit 6 and the telephone line and the reception state display unit 8 are required. In addition, the reception state can be observed. In this way, it is anticipated that the reception of the image transmission may be interrupted, and it is possible to take measures such as switching to a separate program prepared in advance (see Patent Document 4).

In addition, it is also proposed to secure an auxiliary information transmission means by replacing NULL data in the reproduced TS signal with auxiliary information at the time of transmission of the TS signal (see Patent Document 2).

Next, the details of the reception state transmission unit 6 and the reception state display unit 8 will be described. First, FIG. 6 is an embodiment of the reception state transmission unit 6, and as shown in the drawing, FIG. The signal I, which is an in-phase component of the two-dimensional data Dd demodulated at Rx1, and the signal Q, which is an orthogonal component, are input. At this time, a video signal is also input. These signals I and Q are input to the AD converters 201 and 202, respectively, and are digitally converted and then input to the writing unit 203.

7 is a detailed view of the writing unit 203. First, the signal I and the signal Q inputted therein are first converted into a two-dimensional address in the display space by the synthesizer 203-1. The conversion result at this time is held by the pulse S1 supplied from the WE generator 203-2, and outputs the address. In addition, the synthesizer 203-1 performs a logical sum of the change point of the signal I and the change point of the signal Q, so as to indicate the timing of the change point of the signal I and the signal Q. Is generated and supplied to the gate 203-4 and the gate 203-5.

At this time, the WE generator 203-2 generates the above-mentioned pulse S1 in accordance with the EN (enable) output supplied from the control unit 204, and at the same time serves as a source of WE (light enable). The pulse W1 is generated, and the pulse W1 is supplied to the gates 203-4 and 203-5. Here, the gate 203-4 turns on and off the pulse W1 in response to the pulse h1. When the pulse h1 is not shown, the gate 203-4 outputs the pulse W1 as WE as it is and outputs the pulse. When the input timing of (W1) and the pulse h1 coincide, the pulse W1 is turned off so that it is not output as WE.

In addition, when the input timing of the pulse W1 and the input of the pulse h1 coincide with each other, the gate 203-5 supplies the pulse EN1 to the WE generator 203-2, and the control unit ( From 204, the input of EN supplied to the WE generator 203-2 is turned off to change the timing of WE generation.

The writing unit 203 outputs the level H as data at all times, and supplies it to the control unit 204, and as a result, the level H in the memory space according to the values of the signals I and Q. Allow data to be entered. From this writing unit 203, an address output, a data output, and a WE output for control are supplied to the control unit 204.

The reception state transmission unit 6 also includes an initialization unit 205, a read display unit 206, and a read transfer unit 207. First, from the initialization unit 205, an address output, a data output, and a WE output are input to the control unit 204. At this time, the video signal is input to the control unit 204 as it is.

8 is a detailed view of the initialization unit 205. Here, the address generator 205-1 and the WE generator 205-2 are controlled to operate and stop in accordance with the input of EN, and the address generator 205 -1) outputs an address, and the WE generator 205-2 outputs WE. The level L is output as data.

Therefore, the overall operation is an operation of inputting data of level L into the memory address space according to the address generator 205-1 in accordance with the EN input, resulting in a black display space in which constellation has accumulated. It can be initialized in the form of black.

On the other hand, from the read display unit 206 and the read transfer unit 207, an address output and a RE (lead enable) output are input to the control unit 204, and at this time, the address output of the read transfer unit 207 is a transmitter. 208 is also supplied, and the read data from the controller 204 is also supplied to the transmitter 208. The output of this transmitter 208 is then output as the transmission signal TDt.

9 is a detailed view of the read display unit 206 and the read transfer unit 207. First, the address generator 206-1 and the RE generator 206-2 control operation and stop according to the input of EN. do. Then, the address generator 206-1 outputs an address according to the display screen, and the RE generator 206-2 outputs RE.

As a general operation, data in the memory address space according to the address generator 206-1 for display is read in accordance with the EN input. That is, the display space in which the constellation is accumulated is output in accordance with the scanning line timing for display.

First, the control unit 204, based on the input video signal, receives a signal EN for allowing the write unit 203, the initialization unit 205, the read display unit 206, and the read transfer unit 207 to operate. Output

At this time, the address output and data output supplied from each of the writing unit 203, the initialization unit 205, the read display unit 206, and the read transfer unit 207, and WE and RE which are signals for control, The A memory 209 and the B memory 210 are switched to be selected and output, and the data read from the A memory 209 and the B memory 210 are output to the adder 211. Therefore, the adder 211 adds the data read out from the A memory 209 and the B memory 210 to the video signal to create a constellation superimposed video signal CV, and outputs it.

Here, the read transmission unit 207 functions to enable reading at a speed that matches the transmission speed of the low speed line M. At this time, the transmitter 208 reads as shown in FIG. 10. The header is added to the data read in accordance with the read address of the transfer unit 207, and transmitted as the transmission signal TDt to the low speed line M. FIG.

Next, this reception state display part 8 is demonstrated with reference to FIG. In FIG. 5, the auxiliary signal TSm is supplied to the reception state display unit 8, but this is input to the reception writing unit 212 as shown in FIG. 11.

12 is a detailed view of the reception writing unit 212, and the auxiliary signal TSm is supplied to the header detecting unit 212-1, where the header described with reference to FIG. 10 is captured. From the contents, the address AW of the memory division to be transmitted is detected, and it is supplied to the address generator 212-2. At this time, the header detection unit 212-1 detects the start and end of the transmission of the auxiliary signal TSm in response to the capture of the header, and the address detection unit 212-2 and the WE generator 212-3, And instructs EN generator 212-4. Here, the address generator 212-2 generates an address value corresponding to data to be received by the transfer in accordance with the address AW. On the other hand, the WE generator 212-3 and the EN generator 212-4 generate a WE output and an EN output, respectively, and function to inform the control unit 213 of the timing of transmission reception, display and initialization.

Returning to FIG. 11, the initialization unit 214 is the same as the initialization unit 205 described in FIG. 8, and the read display unit 215 is the same as the read display unit 206 described in FIG. 9, and the A memory. 216 and B memory 217 are the same as A memory 209 and B memory 210 of FIG. 6, respectively.

(Patent Document 1) Japanese Unexamined Patent Application Publication No. 6-326735

(Patent Document 2) Japanese Unexamined Patent Publication No. 2000-83216

(Patent Document 3) Japanese Unexamined Patent Publication No. 2002-94481

(Patent Document 4) Japanese Unexamined Patent Publication No. 2005-51755

However, since low-speed lines such as telephone lines have a small transmission capacity, the number of constellation points to be displayed is small, and the accumulation is long at 64QAM (64 points), 32QAM (32 points), and 16QAM (16 points), and the change reflection is slow. In BPSK (2 points) or QPSK (4 points), the number of expression dots is sufficient, but the display of the change of state is delayed due to the accumulation process. Therefore, it is difficult to judge whether the converged constellation or the scattered constellation is instantaneous. On high speed line, burden of the fee for use is large. In addition, a reception base station or the like far from the head office (broadcasting station) requires a new video transmission line in order to quickly transmit the above situation.

In addition, when the NULL data in the TS signal is replaced with auxiliary information, the amount of original NULL data is limited, and reception information cannot be sent at high frequency, resulting in a slow response response requiring rapid response.

In addition, the reception side does not know that it is a special setting for direction adjustment.

The present invention has been made in view of the above-described point, and an object of the present invention is to provide a digital transmission device which makes it possible to easily monitor the reception state at the intermediate point at the end point even in the case of multi-stage relay transmission.

In the transmission system which relays and transmits a TS signal by at least 1 stage, in order to solve the said subject, the reception state information detected by the said relay stage is prescribed | regulated to the at least 1 stage. Means for transmitting to a receiving end of a subsequent stage in a specific signal period other than the NULL data.

And means for extracting the reception state information from the TS signal received by the receiving end to display the reception state at the corresponding relay end.

And a transmission transmitter for digitally modulating and transmitting the TS signal and having a detector for detecting the direction adjustment mode indication flag and having a function of inserting a direction adjustment mode indication flag linked to the direction adjustment mode setting and receiving a digital modulated signal. And demodulating and demodulating, and performing the direction adjustment mode setting according to the detection result of the detector.

In addition, the direction adjustment further includes an encoding unit for lowering the overall signal rate in the TS signal.

In addition, the encoding unit reduces the overall signal rate in the TS signal by increasing the video signal compression ratio to increase the ratio of specific signals other than NULL data.

The transmission transmitter has a function of inserting the direction adjustment mode indication flag linked to the direction adjustment mode setting into a low layer modulation other than TMCC or AC, and the transmission receiver outputs an output device outputting a direction adjustment state. Equipped.

That is, in the present invention, the direction adjustment is given priority over the image quality during the direction adjustment, and the reception state information and the direction adjustment mode indication flag are multiplexed in the transmission signal TS and transmitted to the receiving end.

(Example)

The configuration and basic operation of the first, second, and third embodiments of the present invention will be described in detail with reference to FIGS. 1, 2, 3, and 4. 1 is a system configuration diagram showing an example of a digital relay system with a reception status display function of the present invention, and FIG. 2 is a system configuration showing another example of a digital relay system with a reception status display function of the present invention. FIG. 3 is an explanatory diagram showing an example of a stream in which NULL data of the present invention is increased, and FIG. 4 is a reception state display function of the present invention. It is a system block diagram (another transmission of the direction adjustment mode to another point) which shows another example of the equipped digital relay system.

The TS signal contains NULL data due to the amount of information or the return period. Increasing the compression rate of the MPEG encoder reduces the amount of information, lowers the overall signal rate and increases the NULL data.

First, FIG. 1 which is a system block diagram which shows an example of the digital relay system provided with the reception state display function of 1st Embodiment of this invention is demonstrated. In the prior art of FIG. 5, this embodiment of FIG. 1 deletes low-speed lines M such as a telephone line, and instead, specifies other than NULL data or NULL data in a TS signal other than a video. A specific TS changer 7 is added to replace data with the received state TS signal. As a result, the head office also allows the monitoring of the reception state at the receiving base, which is the intermediate relay point, at high speed.

The configuration and function of the reception status transmitter 6 and the reception status indicator 8 are the same as the reception status transmitter 6 and the reception status indicator 8 of the prior art described above.

First, at the shooting site, a video signal captured by a television camera (not shown) is input to the MPEG encoder 5, which is converted into compressed data TS, and then supplied to the transmission unit Tx1. Then, the signal is modulated, frequency-converted into a microwave band signal, power amplified, transmitted by the antenna 1 as the microwave W1, and transmitted toward the antenna 2 at the receiver. In this way, the microwave W1 transmitted to the antenna 2 of the receiver is inputted to the receiver Rx1, demodulated, reconstructed into reproduction compressed data TSr, and input to the specific TS changer 7. As shown in FIG. The specific TS changer 7 generates the relay TS signal TSr by replacing the NULL data in the TS signal other than the image or the other specific data other than the NULL data with the reception state TS signal, and supplies it to the transmitter Tx2. The relay TS signal TSr is modulated by the transmitter Tx2, converted into microwaves, and received by the antenna 4 of the broadcasting station as the radio wave W2 from the antenna 3. The antenna 4 receives the radio wave W2 of the microwave and reproduces the main line compressed data TSb signal in which the video and audio are received by the receiver Rx2. Then, the reception state information is output from the reception state display unit 8.

Codecs such as MPEG2 operate to produce compressed data at a predetermined rate, but all TS packets cannot be compressed data. In order to match the predetermined rate, NULL data is generated and inserted at a rate of about 3% or less. This NULL data is not used during actual decoding. In the receiver, the output reception state TS signal is transmitted to the head office using this NULL data. This NULL data causes a case where the insertion rate decreases in accordance with the video content of the compression target, and a case where the insertion rate decreases. If there is much NULL data, the result of changing the antenna direction is continuously sent to the head office. In some cases, updating of the situation is delayed, which impairs operability.

Orientation adjustment is a preparatory step before the main broadcast, and the video signal compression ratio is increased to slightly reduce the main line image quality, and the ratio of NULL data can be increased. FIG. 2 is a system configuration diagram showing another example of the digital relay system with the reception status display function of the present invention, and FIG. 3 is an explanatory diagram showing an example of a stream in which NULL data of the present invention is increased. In the embodiment of FIG. 2, in the embodiment of FIG. 1, the mode setting unit 11 for setting the direction adjustment mode, the NULL generation unit 13 and the TS multiplexer 14 for generating NULL data are described. ), The MPEG encoder 5 has been replaced by the MPEG encoder 12. As a result, in the direction adjustment mode, the ENC setting with a lot of NULL data which raises the video signal compression ratio and slightly degraded the main line image quality is set, and monitoring of the reception state at the receiver is much faster than in the case of the main broadcast during the direction adjustment. Is to be obtained. Instead of NULL data with all bits equal to 0, the word of all bits equals 1, i.e., other specific data with bytes other than 7, may be increased to replace the specific specific data with the reception state TS signal. In the relay digital transmission system, in general, a transport stream composed of a plurality of error correction units (packets) each having a total of 204 words of 188 words and 16 words of parity of 8 bits, that is, 1 byte as 1 word, It takes the form called a TS) signal.

4 is a system configuration diagram (transmitted to another point in the direction adjustment mode) showing another example of the digital relay system with the reception status display function of the present invention. In this embodiment of FIG. 4, in the embodiment of FIG. 2, in the embodiment of FIG. 2, there is a transmitter Tx3 instead of the transmitter Tx1, and the transmitter Tx3 sets a direction adjustment mode instruction flag to be interlocked with the direction adjustment mode setter. Inserted into low-layer modulation other than TMCC and AC, the receivers Rx3 and Rx4 of the receiver and the broadcasting station include a detector of the direction adjustment mode instruction flag in addition to the functions of the receivers Rx1 and Rx2, and set the flag in the direction adjustment state. By outputting and displaying the direction adjustment state, the device of the receiver and the head office are automatically matched to the direction adjustment mode. The direction adjustment mode indication flag may be transmitted by other digital modulation instead of TMCC or low layer modulation other than AC.

In addition, the relay point is not limited to one place, and the reception state information from the relay point may be aggregated at a separate monitoring point different from the final reception point of the video transmission signal.

Next, the details of the reception state transmission unit 6 and the reception state display unit 8 which are common in the present invention and the prior art have been described above, and thus description thereof will be omitted.

As described above, according to the present invention, it is possible to transmit information visualizing an adjacent state at high speed and to notify the direction adjustment state without using a new video transmission line, so that the stability of the transmission state can be easily determined. It can be said.

In addition, even when multiple results exceed a predetermined capacity, a link of some transmission data can be secured.

According to the present invention, since the number of dots displayed at all times increases and the transmission state by constellation or the like can be quickly transmitted, the reception state at the relay point can be easily monitored even at the final transmission point, making it easy to confirm the convergence state. . Specifically, the shape converging to a small point can be known at a moment.

Claims (8)

In a transmission system for relaying and transmitting at least one stage of a TS signal, at least one stage includes receiving state information detected by the relay stage in a specific signal period other than the predetermined NULL data in the TS signal. Means for transmitting to a receiving end of the Digital transmission system. The method of claim 1, Means for extracting the reception state information from the TS signal received by the reception end and displaying the reception state at the corresponding relay end; Digital transmission system. The method according to claim 1 or 2, A transmission transmitter for digitally modulating the TS signal and having a function of inserting a direction adjustment mode indication flag linked to a direction adjustment mode setting; And a digital transmission receiver for detecting and demodulating the digitally modulated signal, the detector having a detector for detecting the direction adjustment mode indication flag. Executing the direction adjustment mode setting according to the detection result of the detector; Digital transmission system. The method of claim 3, wherein The apparatus may further include an encoder configured to reduce an overall signal rate in the TS signal when adjusting the direction. Digital transmission system. The method of claim 4, wherein The coding unit reduces the overall signal rate in the TS signal by increasing the video signal compression ratio to increase the ratio of specific signals other than NULL data. Digital transmission system. The method of claim 3, wherein The transmission transmitter has a function of inserting the direction adjustment mode indication flag linked to the direction adjustment mode setting into low layer modulation other than TMCC or AC, The transmission receiving section includes an output device for outputting a direction adjustment state. Digital transmission system. The method of claim 3, wherein The apparatus further includes an encoder for lowering a signal rate in the TS when adjusting the direction. The transmission transmitter has a function of inserting the direction adjustment mode indication flag linked to the direction adjustment mode setting into low layer modulation other than TMCC or AC, The transmission receiving section includes an output device for outputting a direction adjustment state. Digital transmission system. The method of claim 4, wherein And an encoding unit for lowering a signal rate in the TS by increasing a video signal compression ratio to increase a ratio of a specific signal other than NULL data. The transmission transmitter has a function of inserting the direction adjustment mode indication flag linked to the direction adjustment mode setting into low layer modulation other than TMCC or AC, The transmission receiving section includes an output device for outputting a direction adjustment state. Digital transmission system.

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