JP2004320713A - Delay time measurement method, delay time measurement system, time information setting apparatus, and delay time measurement apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a delay time measurement method, a delay time measurement system, a time information setting apparatus, and a delay time measurement apparatus capable of measuring a transmission delay time by using only a single signal and measuring a delay time including a delay caused in a transmission path and a delay in an OFDM modulator-demodulator. <P>SOLUTION: External reference time information is set to an attached information transmission packet in a multiplex frame of a broadcast TS signal, the broadcast TS signal is transmitted, OFDM demodulation is applied to the broadcast TS signal subjected to OFDM modulation for broadcasting to demultiplex the multiplexed frame and to extract the time information of the attached information transmission packet, and a time difference between the extracted time information having been set and the external reference time information is obtained to measure a delay time. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a delay time measuring method, a delay time measuring system, a time information setting device, and a delay time measuring device, and relates to a delay time measuring method and a delay time measuring system for transmitting an OFDM modulated signal to a plurality of broadcasters in a single frequency network. The present invention also relates to a time information setting device and a delay time measuring device.

  Currently, as a transmission method of terrestrial digital television broadcasting, an OFDM (Orthogonal Frequency Division Multiplexing) standardized method for orthogonal frequency division multiplexing (OFDM) called ISDB-T (Integrated Services Digital Broadcasting-Terrestrial) is standardized. (For example, see Non-Patent Document 1).

  In terrestrial digital television broadcasting, each of a plurality of channels of television broadcast signals is digitally modulated by OFDM with a high frequency efficiency and broadcast. OFDM is also resistant to multipath interference, and by providing a temporal guard called a guard interval in the transmission signal, signal degradation due to multipath interference with a long delay time can be suppressed. A single frequency network (SFN) that broadcasts at a frequency becomes possible, which can greatly save the frequency.

  In order to construct a single frequency network, it is necessary for the modulators at each broadcasting station to emit the same OFDM signal at the same timing without any delay time difference. Since the OFDM signal is transmitted from a performance station to each broadcasting station via a transmission path such as wireless or wired, a delay time difference occurs due to the transmission path, and each broadcasting station passes through a component device such as a modulator, so that each configuration There will also be a delay time difference due to the equipment. For this reason, in order to perform timing adjustment at each broadcasting station, it is necessary to measure these delay times.

  FIG. 11 is a block diagram showing an example of a conventional delay time measuring method. In the figure, a specific signal and a delayed signal obtained by delaying the specific signal are supplied to the delay profile measuring apparatus 10. The delay profile measuring apparatus 10 calculates and outputs the delay time of the delay signal with respect to the specific signal by correlating the specific signal with the delayed signal.

  That is, by receiving OFDM modulated signals transmitted from a plurality of broadcast stations in the SFN service area and supplying them to the delay profile measuring apparatus 10, the received OFDM modulated signals from one broadcast station are received from other broadcast stations. The delay time of the received OFDM modulated signal is measured.

  FIGS. 12A and 12B show a configuration diagram of a transmission facility and a reception facility in another example of the conventional delay time measuring method, and FIG. 13 shows a flowchart of another example of the conventional delay time measuring method. .

  In FIG. 12A, the remultiplexer 20 is supplied with a normal TS signal obtained by multiplexing TS (Transport Stream) compliant with MPEG-2. The remultiplexer 20 gives a multiplex digital frame structure of the terrestrial digital television broadcast signal to the normal TS signal, and adds control information such as modulation information, mode information, network information, etc., and a delay time measuring device ( To the transmission unit) 21.

  The delay time measurement device (transmission unit) 21 creates STS information (time information) based on a reference time signal and a reference frequency signal obtained from a GPS (Global Positioning System) or the like, and creates an IIP (Transport Stream Packet) IIP (Transport Stream Packet) It is written in an ISDB-T Information Packet packet and supplied to the 64QAM modulator 22. The 64QAM modulator 22 performs 64QAM modulation on the broadcast TS signal and sends it to the transmission line. This process corresponds to step S10 in FIG.

  In FIG. 12B, the 64QAM modulated signal received from the transmission line is supplied to the 64QAM demodulator 25, and is demodulated into 64QAM to be a broadcast TS signal. The demodulated broadcast TS signal is supplied to an OFDM modulator 28 through a delay time measuring device (receiver) 26 and a delay adjuster 27.

  The delay time measurement device (reception unit) 26 compares the time information obtained based on the reference time signal and the reference frequency signal obtained from the GPS and the like with the STS (Synchronization Time Stamp) information of the IIP packet, The delay time is obtained, and the delay time of the delay adjuster 27 is adjusted according to the delay time. The above processing corresponds to step S12 in FIG.

The OFDM modulator 28 performs OFDM modulation of the television broadcast signal according to control information added to the broadcast TS signal. The OFDM modulated signal output from the OFDM modulator 28 is transmitted from the broadcaster 30 after the delay time is adjusted by the delay adjuster 29. The OFDM modulation signal is sent to a transmission path for transmission to another broadcast station by an IF-TTL (Intermediate Frequency-Transmitter Transmitter Link) transmission unit 31.
Digital Terrestrial Television Broadcasting Transmission Standards (ARIB STD-B31): Radio Industry Association

  In the conventional method of obtaining the correlation between the specific signal and its delay signal shown in FIG. 11, the transmission delay time of a single signal cannot be measured. In addition, the OFDM modulation signals transmitted from a plurality of broadcast stations must actually be received in the SFN service area, and there is a problem in that it takes time for measurement.

  12A and 12B, the delay time measurement method using the STS information of the IIP packet can measure the delay time in the transmission path between the 64QAM modulator 22 and the 64QAM demodulator 25. Since the IIP packet is sometimes discarded and the STS information is lost, the delay time occurring after the OFDM modulator 28 cannot be measured, so that the delay time setting of the delay adjuster 29 cannot be performed. In addition, there is a problem that it is impossible to measure the delay time of an OFDM modulated signal transmitted to another broadcasting station using the IF-TTL transmission method.

  The present invention has been made in view of the above points, and can measure a transmission delay time using only a single signal, and can measure a delay time including a delay occurring in a transmission path and a delay in an OFDM modulator / demodulator. It is an object to provide a delay time measuring method, a delay time measuring system, a time information setting device, and a delay time measuring device.

According to the first aspect of the present invention, external reference time information is set in an additional information transmission packet in a multiplex frame of a broadcast TS signal, the broadcast TS signal is transmitted, and the broadcast TS signal modulated by OFDM for broadcasting is used. By demultiplexing and performing demultiplexing to extract time information of the additional information transmission packet, by measuring a delay time by obtaining a time difference between the extracted set time information and external reference time information,
The transmission delay time can be measured with only a single signal, and the delay time including the delay in the transmission path and the delay in the OFDM modulator / demodulator can be measured.

According to a second aspect of the present invention, there is provided a time information setting device for setting external reference time information in an additional information transmission packet in a multiplex frame of a broadcast TS signal, and the broadcast TS signal OFDM-modulated for broadcasting. By providing a delay time measuring device that performs OFDM demultiplexing and demultiplexing to extract time information of the additional information transmission packet, and obtains a time difference between the set time information extracted and external reference time information,
The transmission delay time can be measured with only a single signal, and the delay time including the delay in the transmission path and the delay in the OFDM modulator / demodulator can be measured.

According to a fifth aspect of the present invention, external reference time information is set in an area allocated to a dummy byte portion in a TS packet constituting a multiplex frame of a broadcast TS signal, the broadcast TS signal is transmitted, The broadcast TS signal that has been OFDM-modulated for OFDM is subjected to OFDM demodulation, demultiplexing is performed, time information written in the dummy byte portion in the TS packet is extracted, and the set time information thus extracted and an external reference time are extracted. By measuring the delay time by finding the time difference from the information,
The transmission delay time can be measured with only a single signal, and the delay time including the delay in the transmission path and the delay in the OFDM modulator / demodulator can be measured.

According to a sixth aspect of the present invention, there is provided a time information setting device for setting external reference time information in an area allocated to a dummy byte portion in a TS packet constituting a multiplex frame of a broadcast TS signal, OFDM broadcast-modulated broadcast TS signal is demultiplexed by demultiplexing, and time information written in the dummy byte portion in the TS packet is extracted, and the set time information and external reference time information extracted are extracted. With a delay time measuring device that calculates the time difference between
The transmission delay time can be measured with only a single signal, and the delay time including the delay in the transmission path and the delay in the OFDM modulator / demodulator can be measured.

Further, in the invention according to claim 9, the delay time measuring device further includes a delay adjuster, and by inputting the obtained delay time to the delay adjuster as setting information,
The delay adjustment of the OFDM modulation signal can be performed.

  The invention according to claim 10 includes the extracted delay control basic information by extracting delay control basic information from an IIP packet in which reference time information from outside is embedded in a multiplex frame of a broadcast TS signal. By writing the delay control information into the AC packet, the AC packet can be used effectively.

  The invention according to claim 11 includes the extracted delay control basic information by extracting delay control basic information from an IIP packet in which reference time information from the outside is embedded in a multiplex frame of a broadcast TS signal. By writing the delay control information in the AC data area assigned to the dummy byte portion in the TS packet, the dummy byte portion can be effectively used.

Further, the invention according to claim 12 is to demultiplex and demultiplex a broadcast TS signal that is OFDM-modulated for broadcast, extract time information and delay control information set from an AC packet in a multiplex frame, A delay time is measured by obtaining a time difference between the extracted time information and external reference time information, a delay adjustment time is determined from the delay time and the extracted delay control information, and the OFDM modulation is performed by the delay adjuster. By adjusting the delay of the broadcast TS signal
Delay adjustment of an OFDM-modulated broadcast TS signal can be performed.

According to the thirteenth aspect of the present invention, a broadcast TS signal that is OFDM-modulated for broadcasting is OFDM demodulated, demultiplexed, and time information and delay control information written in a dummy byte portion in the TS packet are extracted and extracted. The delay time is measured by obtaining a time difference between the time information obtained and the external reference time information, a delay adjustment time is obtained from the delay time and the extracted delay control information, and the OFDM is modulated by the delay adjuster. By adjusting the delay of the broadcast TS signal
Delay adjustment of an OFDM-modulated broadcast TS signal can be performed.

  According to the first and fifth aspects of the present invention, the transmission delay time can be measured using only a single signal, and the delay time including the delay generated in the transmission path and the delay in the OFDM modulator / demodulator can be measured.

  According to the second and sixth aspects of the invention, the transmission delay time can be measured using only a single signal, and the delay time including the delay in the transmission line and the delay in the OFDM modulator / demodulator can be measured. it can.

  According to the ninth aspect of the invention, it is possible to adjust the delay of the OFDM modulated signal.

  According to the tenth aspect of the invention, the AC packet can be effectively used by writing only the delay control information necessary for the delay time measurement into the AC packet.

  According to the eleventh aspect of the present invention, the dummy byte portion can be effectively utilized by writing only the delay control information necessary for delay time measurement into the dummy byte portion in the TS packet.

  In addition, according to the inventions of claims 12 and 13, it is possible to adjust the delay of a broadcast TS signal subjected to OFDM modulation.

  1 (A), (B), and (C) show a configuration diagram of a transmission facility, a reception and relay facility, and a reception facility in an embodiment of the delay time measurement method of the present invention. FIG. The flowchart of 1st Example of the delay time measuring method is shown.

  In FIG. 1A, a remultiplexer 40 is supplied with a normal TS signal obtained by multiplexing TS conforming to MPEG-2. The remultiplexer 40 gives the normal TS signal a multiplex digital frame structure of a terrestrial digital television broadcast signal, and adds control information such as modulation information, mode information, and network information. To the delay time measuring device (transmitting unit) 41 as a broadcast TS signal shown in FIG.

  The delay time measurement device (transmission unit) 41 obtains the reference time signal (1 PPS) and the reference frequency signal (10 MHz) shown in FIGS. 3A and 3C from the GPS or the like, and starts the multiplexed frame of the broadcast TS signal. The time difference from the timing to the rising timing of the reference time signal (1PPS) is counted by the reference frequency signal (10 MHz), and this count value is added to the NSI (Network Synchronization Information) of the IIP packet shown in FIG. The STS information is written, and the contents of the IIP packet are copied to an AC (auxiliary channel) packet that is an additional information transmission packet to form a multiplexed frame, which is supplied to the 64QAM modulator 42. Alternatively, the contents of the IIP packet are written in the AC data area assigned to the dummy byte portion in the TS packet and supplied to the 64QAM modulator 42.

  3C and 3D show the time axes of FIGS. 3A and 3B in an enlarged manner. The 64QAM modulator 42 performs 64QAM modulation on the broadcast TS signal and sends it to the transmission line by light or radio. The processing so far corresponds to steps S20 and S22 in FIG.

  In FIG. 1B, the 64QAM modulated signal generated by the 64QAM modulator 42 is supplied to the 64QAM demodulator 45 through the transmission line, and is demodulated to 64QAM to become a broadcast TS signal. The demodulated broadcast TS signal is supplied to the OFDM modulator 47. The OFDM modulator 47 performs OFDM modulation of the television broadcast signal according to the control information added to the broadcast TS signal. This OFDM modulation signal is provided with a guard interval at a frequency of 37.15 MHz, for example. The IIP packet is discarded at the time of OFDM modulation, but the AC data area of the dummy byte part in the AC packet and TS packet is not discarded, and OFDM modulation is performed, and the obtained OFDM modulated signal is sent to the delay time measuring device (receiving unit) 48 and This is supplied to the delay adjuster 49 and the IF-TTL transmitter 51.

  The delay time measurement device (reception unit) 48 includes an OFDM demodulation unit 48a and a delay time measurement unit 48b. The OFDM demodulator 48a demodulates the supplied OFDM modulation signal and extracts the AC packet after demultiplexing, or extracts the AC data area of the dummy byte portion in the TS packet and supplies it to the delay time measurement unit 48b. The delay time measurement unit 48b compares the time information obtained based on the reference time signal and the reference frequency signal obtained from GPS or the like with the STS information of the AC packet, or the time information and a dummy byte in the TS packet. The STS information written in the partial AC data area is compared to obtain a time difference, that is, a delay time, and the delay time of the delay adjuster 49 is adjusted according to this delay time. The above processing corresponds to steps S24, S26, and S28 in FIG.

  The OFDM modulated signal output from the OFDM modulator 47 is transmitted from the broadcaster 50 after the delay time is adjusted by the delay adjuster 49. Also, the OFDM modulated signal is converted into an IF-TTL transmission method by the IF-TTL transmission unit 51 and sent to a transmission path for transmission to another broadcasting station.

  In FIG. 1C, an IF-TTL transmission method signal output from the IF-TTL transmitter 51 and transmitted through the transmission path is received and supplied to the IF-TTL receiver 55. The OFDM modulated signal obtained from the IF-TTL receiver 55 is supplied to a delay time measuring device (receiver) 56 and a delay adjuster 57.

  The delay time measurement device (reception unit) 56 includes an OFDM demodulation unit 56a and a delay time measurement unit 56b. The OFDM demodulator 56a demodulates the supplied OFDM modulation signal and extracts an AC packet, or extracts the AC data area of the dummy byte portion in the TS packet and supplies it to the delay time measurement unit 56b. The delay time measurement unit 56b compares the time information obtained based on the reference time signal and the reference frequency signal obtained from GPS or the like with the STS information of the AC packet, or the time information and a dummy in the TS packet. The STS information written in the AC data area of the byte part is compared to obtain a time difference, that is, a delay time, and the delay time of the delay adjuster 57 is adjusted according to this delay time. The above processing corresponds to steps S24, S26, and S28 in FIG. The OFDM modulated signal output from the IF-TTL receiver 55 is transmitted from the broadcaster 58 after the delay time is adjusted by the delay adjuster 57.

  FIG. 4 shows a block diagram of an embodiment of a single frequency network using the method of the present invention. In the figure, a performance facility 60 is provided with a transmission facility shown in FIG. The broadcasting stations 62 and 64 are provided with the receiving and relay equipment shown in FIG. 1B, and the broadcasting station 66 is provided with the receiving equipment shown in FIG. Note that the broadcasting station 62 does not need to provide the IF-TTL transmission unit 51 in FIG.

  The 64QAM modulated signal transmitted from the performance station 60 is transmitted through the transmission path 61 and supplied to the 64QAM demodulator of the broadcasting station 62. The 64QAM modulated signal is transmitted through the transmission path 63 and supplied to the 64QAM demodulator at the broadcasting station 64. Further, the IF-TTL signal output from the IF-TTL transmitter 51 of the broadcasting station 64 is transmitted through the transmission path 65 and supplied to the IF-TTL receiving unit 55 of the broadcasting station 66.

  In this embodiment, signals sent from the performance place 60 at the same time are received by the broadcasting stations 62, 64, 66, and the broadcasting stations 62, 64 measure the delay time by the delay time measuring unit 48b, and the broadcasting station In 66, the delay time measurement unit 56b measures the delay time. By evaluating the relationship between the delay times measured at each broadcasting station and adjusting the delay time input to the delay adjusters 49 and 57, it is possible to transmit an OFDM modulated signal from the broadcaster 20 or 58 at the same timing.

  FIG. 5 shows a flowchart of the second embodiment of the delay time measuring method of the present invention. FIG. 6 shows a block diagram of a delay time measuring device (transmission unit) 41 in the second embodiment of the delay time measuring method of the present invention, and FIG. 7 shows the delay in the second embodiment of the delay time measuring method of the present invention. A block diagram of time measuring devices (reception units) 48 and 56 is shown.

  In FIG. 6, the GPS 70 built in the delay time measurement device (transmission unit) 41 obtains a reference time signal (1 PPS) and a reference frequency signal (10 MHz) and supplies them to the counter 71. The broadcast TS signal from the most multiplexer 40 is supplied to the counter 71, the STS writing unit 73, and the AC carrier mapping unit 76 through the terminal 72.

  In FIG. 5, in step S30, the counter 71 counts the time difference from the start timing of the multiplex frame of the broadcast TS signal to the rising timing of the reference time signal (1PPS) using the reference frequency signal (10 MHz), and this count value is calculated as STS. This is supplied to the writing unit 73. The STS writing unit 73 writes the count value as STS information in the NSI (Network Synchronization Information) of the IIP packet shown in FIG. 3E in the multiplexed frame of the broadcast TS signal.

  Next, in step S32, the delay control basic information extraction unit 74 converts the AC data from the IIP packet in the multiplex frame of the broadcast TS signal supplied from the STS writing unit 73 to the information part of the invalid layer TSP and the dummy byte of each TSP. 1-bit AC multiplexing method identification information (AC_data_effective_position) indicating which of the 2-byte AC areas to be multiplexed, an IIP branch number (IIP_branch_number) indicating an IIP packet branch number, and a last branch number indicating an IIP packet An IIP branch number (last_IIP_branch_number) is extracted, and an identifier (synchronization_ID) indicating whether or not to perform delay time measurement from the NSI of the IIP packet, ST ECI for individually controlling the information, maximum delay amount (maximum_delay) from the play station to the transmitting antenna of the broadcaster, ELL (equipment_loop_length) information indicating the length of the entire equipment loop, offset of delay time of each device, etc. (equipment_Control_Information) information is extracted and supplied to the delay control information writing unit 75.

  Note that AC multiplexing method identification information, IIP branch number, last IIP branch number, identifier, STS information, maximum delay amount, ELL information, and ECI are called delay control basic information, which includes error detection code / user bit, etc. The information of the configuration shown in FIG. 8 or FIG. 9 is called delay control information.

  In step S34 or S36, the delay control information writing unit 75 converts the extracted information, that is, basic delay control information, into the AC (Auxiliary Channel) carrier format shown in FIG. The information portion of the invalid hierarchy TSP shown is sequentially written and multiplexed in the 2-byte AC area in the dummy byte of each TSP shown in FIG. 10B. 8 and 9 show the time domain, while FIG. 10 shows the frequency domain.

  FIG. 8 shows a first embodiment of an AC carrier format in mode 3. Here, the mode represents three OFDM carrier intervals and the number of carriers in different ISDB-T systems. In mode 3, the carrier interval is about 1 kHz and the number of carriers is 432. In mode 2, the carrier interval is about 2 kHz and the number of carriers is 216. In mode 1, the carrier interval is about 4 kHz and the number of carriers is 108.

  In the present embodiment, the AC carrier of the OFDM segment of segment number 11 whose AC carrier arrangement does not change in each mode is used, and the packet configuration 1 having no parity is used. 8 correspond to carrier numbers 10, 28, 161, 191, 277, 316, 335, and 425 in mode 3. AC carriers AC1-1 to AC1-8 shown in 8 columns in FIG. In mode 2, carrier numbers 10, 28, 161, 191 are valid, and in mode 1, carrier numbers 10, 28 are valid.

  The first 19 bits of each of the AC carriers AC1-1 to AC1-8 are a differential demodulation reference bit and a header, and data is stored in the remaining 185-bit area.

  In the data area of the AC carrier AC1-1, 32-bit ID identification information for identifying a medium for radio wave monitoring, an 8-bit IIP branch number, an 8-bit last IIP branch number, and a 2-bit identifier (sync_ID) , 24-bit STS information, 24-bit maximum delay amount (maximum_delay), 8-bit ELL information, and AC data are multiplexed into the information portion of the invalid layer TSP and the 2-byte AC area in the dummy byte of each TSP. 1-bit AC multiplexing method identification information (AC_data_effective_position in the figure), 40-bit ECI # 1, 37-bit error detection code / user for delay control of one broadcasting station A bit is stored. The error detection code / user bit is one or both of the error detection code and the user bit.

  In addition, in each data area of the AC carriers AC1-1 to AC1-8, four sets of 40-bit ECIs and 25-bit error detection codes / user bits are stored. In this embodiment, the number of ECIs that can be set in one multiplexed frame in mode 3 is 29, and the number of ECIs that can be set in 1 multiplexed frame in mode 2 is 13. When setting more than 29 sets of ECI in mode 3, a plurality of AC carriers shown in FIG. 8 are used.

  This is because the IIP packet has only one TSP per multiplexed frame, and the payload in the NSI has an area that can be used for ECI of 148 bytes. Therefore, the maximum number of ECIs that can be set per multiplexed frame is 29. (From ARIB STD-B31). For example, when it is necessary to perform delay control from one performance place to 30 or more broadcast stations (broadcasters), that is, when it is necessary to set 30 or more ECIs, ECI is set over a plurality of multiple frames. At this time, the last IIP branch number indicates the total number of IIP packets (total number of multiplexed frames), and the IIP branch number indicates what number of multiplexed frames is the IIP.

  Since the amount of information set in one multiplexed frame for AC data is as shown in FIG. 8, the last IIP branch number indicates the total number of multiplexed frames that AC data spans, and the IIP branch number is the number of multiplexed frames. Indicates whether there is.

  FIG. 9 shows a second embodiment of the AC carrier format in modes 2 and 3. In the figure, the same parts as those in FIG. In FIG. 9, the first 19 bits of each of the AC carriers AC1-1 to AC1-8 are a differential demodulation reference bit and a header, and data is stored in the remaining 185-bit area.

  The 19th to 26th bits of the data area of the AC carrier AC1-1 to AC1-4 are 32-bit ID identification information for identifying the medium for radio wave monitoring, and the 27th and 28th bits are the 8-bit IIP branch number. The 29th and 30th bits are the 8-bit last IIP branch number, the AC carriers AC1-1 and AC1-2 are the 31st bits, the 2-bit identifier (sync_ID), and the AC carriers AC1-1 to AC1-4 31-37 bits include 24-bit STS information, 37-43 bits include 24-bit maximum delay (maximum_delay), 43-45 bits include 8-bit ELL information, AC carriers AC1-3, AC1- 4th 45th bit is 1-bit AC multiplexing method identification information (indicated as “AC multiplexing” in the figure), AC carrier The 46th to 203rd bits of C1-1 to AC1-4 store 40 bits of ECI # 1 to # 15 and 32 bits of error detection codes / user bits for delay control of 15 stations. . In this embodiment, in both modes 2 and 3, the number of ECIs that can be set in one multiplexed frame is fifteen.

  In step S34, the delay control information writing unit 75 sequentially multiplexes the delay control information into the information portion 188 bytes of the invalid hierarchy TSP as shown in FIG. Whereas the IIP is a packet of layer_indicator = “1000”, the delay control information is written in the information portion 188 bytes of the invalid layer TSP (hereinafter referred to as “AC packet”) of layer_indicator = “0100”. An AC packet is one packet per multiple frame.

  On the other hand, in step S36, the delay control information writing unit 75 sequentially multiplexes the delay control information in the 2-byte AC area in the dummy byte of each TSP as shown in FIG. Note that the AC multiplexing method identification information of the AC carrier has a value when executing step S34, for example, “1”, and a value when executing step S36, is “0”.

  The carrier mapping unit 76 maps the delay control information written in the information part 188 bytes of the AC packet or 2 bytes in the dummy byte of each TSP in step S37 into the AC carrier format shown in FIG. 8 or FIG. Send to the transmission line.

  The broadcast TS signal multiplexed with the delay control information in this way is supplied from the AC carrier mapping section 76 to the 64QAM modulator 42 via the terminal 77, and is 64QAM modulated and transmitted to the transmission line by light or radio.

  The 64QAM modulated signal is supplied to the 64QAM demodulator 45 through the transmission path, demodulated by 64QAM to be a broadcast TS signal, and supplied to the OFDM modulator 47. The OFDM modulator 47 performs OFDM modulation of the television broadcast signal according to the control information added to the broadcast TS signal. This OFDM modulation signal is provided with a guard interval at a frequency of 37.15 MHz, for example. The IIP packet is discarded at the time of OFDM modulation, but the AC data area of the dummy byte part in the AC packet and TS packet is not discarded, and OFDM modulation is performed, and the obtained OFDM modulated signal is sent to the delay time measuring device (receiving unit) 48 and This is supplied to the delay adjuster 49 and the IF-TTL transmitter 51.

  The OFDM demodulator 80 (corresponding to the OFDM demodulators 48a and 56a) of the delay time measuring devices (receivers) 48 and 57 shown in FIG. 6 demodulates the OFDM modulated signal supplied from the terminal 79 and converts the broadcast TS signal into an AC carrier. This is supplied to the playback unit 81 and the counter 84.

  In step S38 of FIG. 5, the AC carrier reproducing unit 81 demodulates the AC carrier and reproduces the AC data shown in FIG. 8 or FIG.

  In step S40, the delay control information reading unit 82 reads the STS information, the maximum delay amount, and the ECI for delay control of the own station from the basic delay control information of the reproduced AC data. Note that the ECI for delay control of the own broadcasting station is specified by equipment_id in the ECI.

  In FIG. 7, the GPS 83 built in the delay time measuring devices (reception units) 48 and 57 obtains the reference time signal (1 PPS) and the reference frequency signal (10 MHz) and supplies them to the counter 84. The time difference from the start timing of the multiple frames to the rising timing of the reference time signal (1PPS) is counted by the reference frequency signal (10 MHz), and this count value is supplied to the delay measurement and control unit 85 as time information.

  In step S42 of FIG. 5, the delay measurement and control unit 85 compares the time information with the STS information of the reproduction AC carrier delay control information to obtain a time difference, that is, a delay time. Then, the delay adjustment time is obtained by subtracting this delay time from the maximum delay amount (maximum_delay) of the delay control information of the reproduction AC carrier, this delay adjustment time is set in the delay adjuster 49 from the terminal 86, and the delay time is set. Adjust.

  By the way, when there is an ECI for delay control of the own broadcast station and the fixed delay flag (static_delay_flag) in this ECI is “1”, the delay measurement and control unit 85 sets the time offset for the maximum delay amount in the ECI. (Time_offset) is set in the delay adjuster 49 as the delay adjustment time.

  The delay time measuring device (transmitting unit) 44 corresponds to the time information setting device described in claims 2 and 6 and the delay time measuring devices (receiving units) 48 and 56 correspond to the delay time measuring device.

It is a block diagram of the transmission equipment, the reception and relay equipment, and the reception equipment in one embodiment of the delay time measuring method of the present invention. It is a flowchart of 1st Example of the delay time measuring method of this invention. It is a signal timing chart for demonstrating the delay time measuring method of this invention. It is a block diagram of one Example of the single frequency network using the method of this invention. It is a flowchart of 2nd Example of the delay time measuring method of this invention. It is a block diagram of the delay time measuring apparatus (transmission part) in 2nd Example of the delay time measuring method of this invention. It is a block diagram of the delay time measuring apparatus (reception part) in 2nd Example of the delay time measuring method of this invention. 4 is a first example of an AC carrier format in mode 3. FIG. It is 2nd Example of the AC carrier format in mode 2 and 3. FIG. It is a figure for demonstrating a delay control information multiplexing position. It is a block diagram of an example of the conventional delay time measuring method. It is a block diagram of the transmission equipment and the reception equipment in another example of the conventional delay time measuring method. It is a flowchart of another example of the conventional delay time measuring method.

Explanation of symbols

40 Remultiplexer 41 Delay Time Measurement Device (Transmitter)
42 64QAM modulator 45 64QAM demodulator 47 OFDM modulator 48, 56 Delay time measuring device (receiver)
48a, 56a OFDM demodulation unit 48b, 56b Delay time measurement unit 49, 57 Delay adjuster 50, 58 Broadcaster 51 IF-TTL transmission unit 55 IF-TTL reception unit 60 Performing stations 62, 64, 66 Broadcasting stations 61, 63, 65 Transmission path 70, 83 GPS
71, 84 Counter 73 STS writing unit 74 Delay control basic information extracting unit 75 Delay control information writing unit 76 AC carrier mapping unit 80 OFDM demodulating unit 81 AC carrier reproducing unit 82 Delay control information reading unit 85 Delay measurement and control unit

Claims (13)

External reference time information is set in the additional information transmission packet in the multiplex frame of the broadcast TS signal,
Transmitting the broadcast TS signal;
OFDM broadcast-modulated broadcast TS signal for broadcast is subjected to OFDM demultiplexing to extract time information of the additional information transmission packet,
A delay time measuring method, characterized in that a delay time is measured by obtaining a time difference between the retrieved set time information and external reference time information. A time information setting device for setting external reference time information in an additional information transmission packet in a multiplex frame of a broadcast TS signal;
The broadcast TS signal that has been OFDM-modulated for broadcasting is OFDM demodulated and demultiplexed to extract the time information of the additional information transmission packet, and the time difference between the extracted set time information and external reference time information is calculated. A delay time measuring device to be obtained;
A delay time measuring system comprising: Write external reference time information to the NSI of the IIP packet in the multiplex frame of the broadcast TS signal, and copy the content of the IIP packet to the AC packet.
A time information setting device characterized by that. A broadcast TS signal that is OFDM-modulated for broadcasting is OFDM demodulated, demultiplexed to extract time information set from an AC packet in the multiplexed frame, and a time difference between the extracted time information and external reference time information To determine the delay time,
A delay time measuring apparatus characterized by that. External reference time information is set in the area allocated to the dummy byte part in the TS packet constituting the multiplex frame of the broadcast TS signal,
Transmitting the broadcast TS signal;
The broadcast TS signal OFDM-modulated for broadcasting is OFDM demodulated and demultiplexed to extract time information written in the dummy byte part in the TS packet,
A delay time measuring method, characterized in that a delay time is measured by obtaining a time difference between the retrieved set time information and external reference time information. A time information setting device for setting external reference time information in an area allocated to a dummy byte part in a TS packet constituting a multiplex frame of a broadcast TS signal;
The broadcast TS signal that is OFDM-modulated for broadcasting is OFDM demodulated and demultiplexed to extract the time information written in the dummy byte portion in the TS packet, and the set time information and the external reference extracted A delay time measuring device for obtaining a time difference with time information;
A delay time measuring system comprising: Write external reference time information to the NSI of the IIP packet in the multiplex frame of the broadcast TS signal, and write the content of the IIP packet in the AC data area assigned to the dummy byte part in the TS packet.
A time information setting device characterized by that. A broadcast TS signal that is OFDM-modulated for broadcasting is OFDM demodulated and demultiplexed to extract time information written in a dummy byte part in the TS packet, and a time difference between the extracted time information and external reference time information To determine the delay time,
A delay time measuring apparatus characterized by that. The delay time measuring apparatus according to claim 4 or 8,
The delay time measuring apparatus further includes a delay adjuster, and inputs the obtained delay time to the delay adjuster as setting information.
A delay time measuring apparatus characterized by that. Basic delay control information is extracted from an IIP packet in which reference time information from the outside in a multiplex frame of a broadcast TS signal is embedded,
Write delay control information including the extracted delay control basic information to the AC packet.
A time information setting device characterized by that. Basic delay control information is extracted from an IIP packet in which reference time information from the outside in a multiplex frame of a broadcast TS signal is embedded,
Write the delay control information including the extracted delay control basic information in the AC data area assigned to the dummy byte part in the TS packet.
A time information setting device characterized by that. The broadcast TS signal that is OFDM-modulated for broadcasting is OFDM-demodulated and demultiplexed to extract time information and delay control information set from the AC packet in the multiplexed frame, and the extracted time information and external reference time Measuring a delay time by obtaining a time difference from the information, obtaining a delay adjustment time from the delay time and the extracted delay control information, and performing a delay adjustment of the broadcast TS signal modulated by the OFDM by the delay adjuster;
A delay time measuring apparatus characterized by that. A broadcast TS signal that is OFDM-modulated for broadcasting is OFDM demodulated and demultiplexed to extract time information and delay control information written in a dummy byte portion in the TS packet, and the extracted time information and an external reference A delay time is measured by obtaining a time difference from the time information, a delay adjustment time is obtained from the delay time and the extracted delay control information, and a delay adjustment of the OFDM-modulated broadcast TS signal is performed by the delay adjuster. ,
A delay time measuring apparatus characterized by that.

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