CA2282839A1 - Device for time resetting in digital signal transmission for networks - Google Patents
Device for time resetting in digital signal transmission for networks Download PDFInfo
- Publication number
- CA2282839A1 CA2282839A1 CA002282839A CA2282839A CA2282839A1 CA 2282839 A1 CA2282839 A1 CA 2282839A1 CA 002282839 A CA002282839 A CA 002282839A CA 2282839 A CA2282839 A CA 2282839A CA 2282839 A1 CA2282839 A1 CA 2282839A1
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- CA
- Canada
- Prior art keywords
- time
- digital
- module
- transmission
- bouquet
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 230000008054 signal transmission Effects 0.000 title claims description 4
- 230000005540 biological transmission Effects 0.000 claims abstract description 28
- 238000006467 substitution reaction Methods 0.000 claims description 6
- 238000000605 extraction Methods 0.000 claims 1
- 230000004807 localization Effects 0.000 claims 1
- 230000001934 delay Effects 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
- H04N21/40—Client devices specifically adapted for the reception of or interaction with content, e.g. set-top-box [STB]; Operations thereof
- H04N21/43—Processing of content or additional data, e.g. demultiplexing additional data from a digital video stream; Elementary client operations, e.g. monitoring of home network or synchronising decoder's clock; Client middleware
- H04N21/434—Disassembling of a multiplex stream, e.g. demultiplexing audio and video streams, extraction of additional data from a video stream; Remultiplexing of multiplex streams; Extraction or processing of SI; Disassembling of packetised elementary stream
- H04N21/4344—Remultiplexing of multiplex streams, e.g. by modifying time stamps or remapping the packet identifiers
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04H—BROADCAST COMMUNICATION
- H04H20/00—Arrangements for broadcast or for distribution combined with broadcast
- H04H20/10—Arrangements for replacing or switching information during the broadcast or the distribution
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04H—BROADCAST COMMUNICATION
- H04H20/00—Arrangements for broadcast or for distribution combined with broadcast
- H04H20/18—Arrangements for synchronising broadcast or distribution via plural systems
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
- H04N21/20—Servers specifically adapted for the distribution of content, e.g. VOD servers; Operations thereof
- H04N21/23—Processing of content or additional data; Elementary server operations; Server middleware
- H04N21/236—Assembling of a multiplex stream, e.g. transport stream, by combining a video stream with other content or additional data, e.g. inserting a URL [Uniform Resource Locator] into a video stream, multiplexing software data into a video stream; Remultiplexing of multiplex streams; Insertion of stuffing bits into the multiplex stream, e.g. to obtain a constant bit-rate; Assembling of a packetised elementary stream
- H04N21/23608—Remultiplexing multiplex streams, e.g. involving modifying time stamps or remapping the packet identifiers
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
- H04N21/80—Generation or processing of content or additional data by content creator independently of the distribution process; Content per se
- H04N21/85—Assembly of content; Generation of multimedia applications
- H04N21/854—Content authoring
- H04N21/8547—Content authoring involving timestamps for synchronizing content
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04H—BROADCAST COMMUNICATION
- H04H2201/00—Aspects of broadcast communication
- H04H2201/10—Aspects of broadcast communication characterised by the type of broadcast system
- H04H2201/20—Aspects of broadcast communication characterised by the type of broadcast system digital audio broadcasting [DAB]
Landscapes
- Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- Multimedia (AREA)
- Computer Security & Cryptography (AREA)
- Electric Clocks (AREA)
- Television Systems (AREA)
Abstract
In a time-resetting device in a terrestrial digital transmission network of the type used by digital radio or television broadcasting, the time information of the digital signal is modified in the transmission site before the modulator in order to replace it by a time information that is computed on the basis of the UTC time given by a GPS receiver and that includes the transmission delay of the concerned site. The invention can be applied to terrestrial digital transmission networks for digital audio broadcasting (DAB) or digital video broadcasting (DVB-T).
Description
H6635, 6-399 DEVICE FOR 'TIME RESETTING IN DIGITAL SIGNAL
TRANSMISSION NETWORKS
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The invention relates to digital type transmission networks and, s more particularly, in such networks, to a device to reset the time at which the information is transmitted to the receivers.
In analog type transmission networks, the period of transmission of the analog signals are brief and are practically not detectable by a radio station listener or a television station viewer.
io In the case of dilrital type transmission networks, whether these are radio or television networks, the analog signals are encoded in binary numbers on which a certain number of digital processing operations are carried out. These processing operations give rise to delays which accumulate from the beginning to the end of the transmission chain or is sequence.
H6635, 6-339 DESORIPTION OF THE PRIOR ART
Figure 1 is a drawing of a digital type transmission sequence that begins with radio or television studios 10, 20 and 30 whose audio and/or video analog signals are encoded in binary numbers by encoders 12, 22 s and 32 respectively. '.Chese binary codes come from the studios 10, 20 and 30 and are transmitted: to a multiplexing site 40 by means of collection networks 14, 24 and 34.
In the multiplexing site 40, the binary codes coming from the different studios are "mixed" to form what is called a digital "bouquet".
io This bouquet is distributed to transmission sites 16, 26 and 36 by means of a distribution network 42 known as a "primary" network. In these transmission sites 16, 26 and 36, each of which includes a modulator/transmitter assembly 18, 28 and 38, the bouquet is sent to the receivers of the users o~f the radio or television broadcasting network by a is distribution network knows as a «secondary» network.
In one structure accordilig to the drawing of Figure 1, each encoding, multiplexing and trmsmission site carries out a digital processing operation whose duration is not negligible while each primary distribution, secondary distribution and collection network introduces a 2o variable delay that too is not negligible.
H6635, 6-339 The adding up of these digital processing periods and these transmission periods leads to a time lag between the instant at which the sound or the image is picked up and the instant at which this sound or this image is received by the user's receiver.
Furthermore, the new radio or television RF digital broadcasting standards stipulate the integration, .into the bouquets, of service information in addition to the audio and/or video programs. Now this service information, known as SI, includes the date and time which is usually introduced into the studio 10, 20 and 30 or by the operator of the io multiplexing site 40 using information given by a receiver knows as the GPS (Global Positioning System) receiver.
This information given by the GPS receiver includes a one-pulse-per-second time reference, a frequency reference given by a 10 MHz frequency signal and the UTC date and time information, UTC being the is acronym for Universal Time Coordinated or Greenwich Mean Time using the Julian calendar. Furthermore, to take account of the fact that the UTC
information corresponds to the Greenwich Mean Time, the «time lag»
or «time offset» between the Greenwich meridian and the zone served by the bouquet is taken into account by using the local time information 2o given by the "LTO" (Local Time Offset) signal.
d if.'.
' 4 H6635, 6-339 When this date and time information reaches the user's receiver, the earlier it has been introduced into the transmission sequence, the more erroneous will it be.
The aim of the present invention therefore is to obtain a device that can be used to reset the information on time that is transmitted to the user's receiver so that it corresponds to the real time of the place of reception.
This aim is achieved by implementing a time-resetting device positioned in each transmission site 16, 26 and 36 and more particularly at io the input of the modulator of each site, this time-resetting device using the UTC information given by the GPS receiver as well as the information on the duration of processing in the transmission site and on the duration of transmission to the user's receiver.
is SUMMARY OF THE INVENTION
The invention therefore relates to a device for resetting the time in a digital signal transmission network, the network comprising studio digital encoding sites, collection networks, a multiplexing site that sets up the "digital bouquet", a network for the primary distribution of the digital ao bouquet and transmission sites, each transmission site comprising a H6635, 6-339 modulator, a radio frequency amplifier and a GPS receiver, wherein the time-resetting device is position in the modulator and comprises:
means for computing the time to be transmitted to the users, means for extracting the time in the digital bouquet, and means for substituting the computed time for the extracted time.
BRIEF' DESCRIPTION OF THE DRAWINGS
Other features and advantages of the present invention shall appear from the following description of a particular embodiment, said description io being made with reference to the appended drawings, of which:
Figure 1 is a drawing of a structure of a digital type transmission system to which the invention can be applied, Figure 2 is a functional drawing of a modulator/transmitter comprising a time-.resetting device according to the invention, is Figure 3 is a. functional drawing of the time-resetting device according to the invention, Figure 4 is a. functional drawing showing the computation of the time that will be transmitted to the user, and Figure 5 is a functional drawing of the substitution module 72 of Zo Figure 3.
' 6 H6635, 6-339 MORE DETAILED DESCRIPTION
Each transmission site 16, 26 or 36 respectively comprises a modulator/transmitter 18, 28 or 39 which consists (Figure 2) of a modulator 50, a transmitter 52, a transmission antenna 54 and a GPS
receiver 56. The transmitter comprises a power amplifier 66 and, as the case may be, a filter 68. In the known way, the modulator 50 comprises an input interface 58 for the uiput of the digital signal given by the primary distribution network 42, and OFDM (Orthogonal Frequency Division Multiplex) type modulator 60 proper that carries out baseband modulation io and a frequency converter 62 that carries out a baseband frequency change.
According to the invention, a time-resetting device 63 is positioned between the input interface 58 and the modulator 60 and carries out a resetting of the time contained in the digital signal of the distribution is network by introducing the current time or real time after having corrected it by the duration of processing in the transmission site.
The GPS receiver 56 gives the modulator 50 the following information in order that it may be used in a manner that is known: the one-pulse-per-second tame reference information and the 10 MHz Zo frequency reference information. According to the invention, the GPS
~ ~ ~ ~.~
~z ; . I
' ~ H6635, 6.39 receiver furthermore gives the UTC time information which is used only by the time-resetting device 64.
The time-resettilig device 64 comprises (Figure 3) a module 70 to compute the time information to be transmitted on the basis of the UTC
time information, the one-pulse-per-second time information elements given by the GPS receiver 56 and the information on duration of processing Td in the transmission site. This correct time information replaces the information contained in the digital signal of the bouquet in a module 72.
io The time information of the bouquet is localized in the input digital signal by the modules 74 and 76, the module 74 being used to localize the Service Information elements SI while the module 76 is used for the demarcation, in these Service Information elements SI, of those information elements that correspond to the information of the received is bouquet.
As can be seen in Figure 4, the module 70 comprises a first register 78 for the memorizing, at each second, of the real UTC time information, a second register 80 for the memorizing of the processing duration Td of the transmission site considered, an adder 82 to add up the contents of the first 2o and second registers 78,, 80 and a third register 84 to store the result of the addition which constitutes the substitution time information.
H6635, 6-339 The modules 74 and 76 are adapted to the digital signals of the bouquet to be broadcast. Tlus bouquet is given to the modulator in a form known as the "transport multiplex" which is defined by the ETI standard (ETS 300 799) for digital audio broadcasting (DAB) and by the MPEG-TS
s (ISO/IEC 13818-1) standard to digital video broadcasting television (DVB-T).
The Service Information elements SI and their transport envelope are constituted by information elements that are defined by the ETS
standard 300 401 for digital audio broadcasting (DAB) and by the ETS
io standard 300 468 for digital video broadcasting (DVB-T).
The localizing module 74 is designed to identify the envelope of the Service Information elements SI in the transport multiplex. For digital audio broadcasting, the envelope is conveyed by the frame ETI to a fixed location. For digital video broadcasting, the transport envelope is defined is by a TDT (Time and Date Table) that is conveyed in packets provided with an identifier having the value 14.
The UTC time demarcation module is designed for the identification in the envelope SI, localized beforehand by the module 74, of the information element conveying the UTC time. For digital audio 2o broadcasting, this is a group having the identifier 0/9 (FIG 0/9, FIG being H6635, 6-339 the acronym for "Fast Information Group"). For digital video broadcasting, it is a TDT table having the identifier OX70.
The substitution module 72 essentially comprises a multiplexer 86 that is controlled by a substitution signal given by the localizing module 74. Tlus substitution module 72 replaces the UTC bytes of the distribution network by the bytes of the UTC value computed by the module 70.
The description that has just been given of the invention shows that the time-resetting device comprises:
means 70 to compute the time to be transmitted to the users, io means 74 and 7~5 to extract the time in the digital bouquet, and means 72 to substitute the computed time for the extracted time.
TRANSMISSION NETWORKS
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The invention relates to digital type transmission networks and, s more particularly, in such networks, to a device to reset the time at which the information is transmitted to the receivers.
In analog type transmission networks, the period of transmission of the analog signals are brief and are practically not detectable by a radio station listener or a television station viewer.
io In the case of dilrital type transmission networks, whether these are radio or television networks, the analog signals are encoded in binary numbers on which a certain number of digital processing operations are carried out. These processing operations give rise to delays which accumulate from the beginning to the end of the transmission chain or is sequence.
H6635, 6-339 DESORIPTION OF THE PRIOR ART
Figure 1 is a drawing of a digital type transmission sequence that begins with radio or television studios 10, 20 and 30 whose audio and/or video analog signals are encoded in binary numbers by encoders 12, 22 s and 32 respectively. '.Chese binary codes come from the studios 10, 20 and 30 and are transmitted: to a multiplexing site 40 by means of collection networks 14, 24 and 34.
In the multiplexing site 40, the binary codes coming from the different studios are "mixed" to form what is called a digital "bouquet".
io This bouquet is distributed to transmission sites 16, 26 and 36 by means of a distribution network 42 known as a "primary" network. In these transmission sites 16, 26 and 36, each of which includes a modulator/transmitter assembly 18, 28 and 38, the bouquet is sent to the receivers of the users o~f the radio or television broadcasting network by a is distribution network knows as a «secondary» network.
In one structure accordilig to the drawing of Figure 1, each encoding, multiplexing and trmsmission site carries out a digital processing operation whose duration is not negligible while each primary distribution, secondary distribution and collection network introduces a 2o variable delay that too is not negligible.
H6635, 6-339 The adding up of these digital processing periods and these transmission periods leads to a time lag between the instant at which the sound or the image is picked up and the instant at which this sound or this image is received by the user's receiver.
Furthermore, the new radio or television RF digital broadcasting standards stipulate the integration, .into the bouquets, of service information in addition to the audio and/or video programs. Now this service information, known as SI, includes the date and time which is usually introduced into the studio 10, 20 and 30 or by the operator of the io multiplexing site 40 using information given by a receiver knows as the GPS (Global Positioning System) receiver.
This information given by the GPS receiver includes a one-pulse-per-second time reference, a frequency reference given by a 10 MHz frequency signal and the UTC date and time information, UTC being the is acronym for Universal Time Coordinated or Greenwich Mean Time using the Julian calendar. Furthermore, to take account of the fact that the UTC
information corresponds to the Greenwich Mean Time, the «time lag»
or «time offset» between the Greenwich meridian and the zone served by the bouquet is taken into account by using the local time information 2o given by the "LTO" (Local Time Offset) signal.
d if.'.
' 4 H6635, 6-339 When this date and time information reaches the user's receiver, the earlier it has been introduced into the transmission sequence, the more erroneous will it be.
The aim of the present invention therefore is to obtain a device that can be used to reset the information on time that is transmitted to the user's receiver so that it corresponds to the real time of the place of reception.
This aim is achieved by implementing a time-resetting device positioned in each transmission site 16, 26 and 36 and more particularly at io the input of the modulator of each site, this time-resetting device using the UTC information given by the GPS receiver as well as the information on the duration of processing in the transmission site and on the duration of transmission to the user's receiver.
is SUMMARY OF THE INVENTION
The invention therefore relates to a device for resetting the time in a digital signal transmission network, the network comprising studio digital encoding sites, collection networks, a multiplexing site that sets up the "digital bouquet", a network for the primary distribution of the digital ao bouquet and transmission sites, each transmission site comprising a H6635, 6-339 modulator, a radio frequency amplifier and a GPS receiver, wherein the time-resetting device is position in the modulator and comprises:
means for computing the time to be transmitted to the users, means for extracting the time in the digital bouquet, and means for substituting the computed time for the extracted time.
BRIEF' DESCRIPTION OF THE DRAWINGS
Other features and advantages of the present invention shall appear from the following description of a particular embodiment, said description io being made with reference to the appended drawings, of which:
Figure 1 is a drawing of a structure of a digital type transmission system to which the invention can be applied, Figure 2 is a functional drawing of a modulator/transmitter comprising a time-.resetting device according to the invention, is Figure 3 is a. functional drawing of the time-resetting device according to the invention, Figure 4 is a. functional drawing showing the computation of the time that will be transmitted to the user, and Figure 5 is a functional drawing of the substitution module 72 of Zo Figure 3.
' 6 H6635, 6-339 MORE DETAILED DESCRIPTION
Each transmission site 16, 26 or 36 respectively comprises a modulator/transmitter 18, 28 or 39 which consists (Figure 2) of a modulator 50, a transmitter 52, a transmission antenna 54 and a GPS
receiver 56. The transmitter comprises a power amplifier 66 and, as the case may be, a filter 68. In the known way, the modulator 50 comprises an input interface 58 for the uiput of the digital signal given by the primary distribution network 42, and OFDM (Orthogonal Frequency Division Multiplex) type modulator 60 proper that carries out baseband modulation io and a frequency converter 62 that carries out a baseband frequency change.
According to the invention, a time-resetting device 63 is positioned between the input interface 58 and the modulator 60 and carries out a resetting of the time contained in the digital signal of the distribution is network by introducing the current time or real time after having corrected it by the duration of processing in the transmission site.
The GPS receiver 56 gives the modulator 50 the following information in order that it may be used in a manner that is known: the one-pulse-per-second tame reference information and the 10 MHz Zo frequency reference information. According to the invention, the GPS
~ ~ ~ ~.~
~z ; . I
' ~ H6635, 6.39 receiver furthermore gives the UTC time information which is used only by the time-resetting device 64.
The time-resettilig device 64 comprises (Figure 3) a module 70 to compute the time information to be transmitted on the basis of the UTC
time information, the one-pulse-per-second time information elements given by the GPS receiver 56 and the information on duration of processing Td in the transmission site. This correct time information replaces the information contained in the digital signal of the bouquet in a module 72.
io The time information of the bouquet is localized in the input digital signal by the modules 74 and 76, the module 74 being used to localize the Service Information elements SI while the module 76 is used for the demarcation, in these Service Information elements SI, of those information elements that correspond to the information of the received is bouquet.
As can be seen in Figure 4, the module 70 comprises a first register 78 for the memorizing, at each second, of the real UTC time information, a second register 80 for the memorizing of the processing duration Td of the transmission site considered, an adder 82 to add up the contents of the first 2o and second registers 78,, 80 and a third register 84 to store the result of the addition which constitutes the substitution time information.
H6635, 6-339 The modules 74 and 76 are adapted to the digital signals of the bouquet to be broadcast. Tlus bouquet is given to the modulator in a form known as the "transport multiplex" which is defined by the ETI standard (ETS 300 799) for digital audio broadcasting (DAB) and by the MPEG-TS
s (ISO/IEC 13818-1) standard to digital video broadcasting television (DVB-T).
The Service Information elements SI and their transport envelope are constituted by information elements that are defined by the ETS
standard 300 401 for digital audio broadcasting (DAB) and by the ETS
io standard 300 468 for digital video broadcasting (DVB-T).
The localizing module 74 is designed to identify the envelope of the Service Information elements SI in the transport multiplex. For digital audio broadcasting, the envelope is conveyed by the frame ETI to a fixed location. For digital video broadcasting, the transport envelope is defined is by a TDT (Time and Date Table) that is conveyed in packets provided with an identifier having the value 14.
The UTC time demarcation module is designed for the identification in the envelope SI, localized beforehand by the module 74, of the information element conveying the UTC time. For digital audio 2o broadcasting, this is a group having the identifier 0/9 (FIG 0/9, FIG being H6635, 6-339 the acronym for "Fast Information Group"). For digital video broadcasting, it is a TDT table having the identifier OX70.
The substitution module 72 essentially comprises a multiplexer 86 that is controlled by a substitution signal given by the localizing module 74. Tlus substitution module 72 replaces the UTC bytes of the distribution network by the bytes of the UTC value computed by the module 70.
The description that has just been given of the invention shows that the time-resetting device comprises:
means 70 to compute the time to be transmitted to the users, io means 74 and 7~5 to extract the time in the digital bouquet, and means 72 to substitute the computed time for the extracted time.
Claims (4)
1. A device for resetting the time in a digital signal transmission network, said network comprising studio digital encoding sites, collection networks, a multiplexing site that sets up the "digital bouquet", a network for the primary distribution of the digital bouquet and transmission sites, each transmission site comprising a modulator, a radio frequency amplifier and a GPS receiver, wherein the time-resetting device is positioned in the modulator and comprises:
means to compute the time to be transmitted to the users, means to extract the time in the digital bouquet, and means to substitute the computed time for the extracted time.
means to compute the time to be transmitted to the users, means to extract the time in the digital bouquet, and means to substitute the computed time for the extracted time.
2. A time-resetting device according to claim 1 wherein the computation means comprise:
a module to memorize the UTC time given by the GPS receiver, a module to memorize the delay introduced by the concerned transmission site, a module to add vup the UTC time memorized by the module and the delay memorized by the module, and a module to memorize the computed time.
a module to memorize the UTC time given by the GPS receiver, a module to memorize the delay introduced by the concerned transmission site, a module to add vup the UTC time memorized by the module and the delay memorized by the module, and a module to memorize the computed time.
3. A time-resetting device according to claim 1 or 2 wherein the means for the extraction of the time in the digital bouquet comprise:
a localization module to identify the envelope of the Service Information elements, and a demarcation module for the identifying, in the envelope of the Service Information elements, of that information element which conveys the UTC time.
a localization module to identify the envelope of the Service Information elements, and a demarcation module for the identifying, in the envelope of the Service Information elements, of that information element which conveys the UTC time.
4. A time-resetting device according to claim 1, 2 or 3 wherein the substitution means comprise a multiplexes.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR9811642 | 1998-09-17 | ||
| FR9811642A FR2783657B1 (en) | 1998-09-17 | 1998-09-17 | TIME DELAY DEVICE IN DIGITAL SIGNAL TRANSMISSION NETWORKS |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2282839A1 true CA2282839A1 (en) | 2000-03-17 |
Family
ID=9530560
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002282839A Abandoned CA2282839A1 (en) | 1998-09-17 | 1999-09-17 | Device for time resetting in digital signal transmission for networks |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0987845A1 (en) |
| JP (1) | JP2000174716A (en) |
| AU (1) | AU752659B2 (en) |
| CA (1) | CA2282839A1 (en) |
| FR (1) | FR2783657B1 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001221874A (en) | 2000-02-14 | 2001-08-17 | Toshiba Corp | Time synchronization system |
| CN1317844C (en) * | 2003-09-28 | 2007-05-23 | 中兴通讯股份有限公司 | Method for realizing GPS standard time |
| CN101807044B (en) * | 2009-12-18 | 2011-08-10 | 安徽鑫龙电器股份有限公司 | Clock timing method of multifunctional meter |
| CN112486013B (en) * | 2020-11-06 | 2023-04-14 | 北京明瑞之光科技有限公司 | Multi-node control system, regional wireless time service device thereof and landscape lighting system |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5566174A (en) * | 1994-04-08 | 1996-10-15 | Philips Electronics North America Corporation | MPEG information signal conversion system |
| US5642285A (en) * | 1995-01-31 | 1997-06-24 | Trimble Navigation Limited | Outdoor movie camera GPS-position and time code data-logging for special effects production |
| US6549242B1 (en) * | 1997-04-04 | 2003-04-15 | Harris Corporation | Combining adjacent TV channels for transmission by a common antenna |
-
1998
- 1998-09-17 FR FR9811642A patent/FR2783657B1/en not_active Expired - Fee Related
-
1999
- 1999-09-17 CA CA002282839A patent/CA2282839A1/en not_active Abandoned
- 1999-09-17 EP EP99402281A patent/EP0987845A1/en not_active Withdrawn
- 1999-09-17 AU AU48788/99A patent/AU752659B2/en not_active Ceased
- 1999-09-17 JP JP11263954A patent/JP2000174716A/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| AU752659B2 (en) | 2002-09-26 |
| FR2783657A1 (en) | 2000-03-24 |
| JP2000174716A (en) | 2000-06-23 |
| AU4878899A (en) | 2000-03-23 |
| FR2783657B1 (en) | 2000-11-17 |
| EP0987845A1 (en) | 2000-03-22 |
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