CN102291193A - Digital single frequency synchronous coverage system and single frequency synchronous coverage method for amplitude modulation broadcast - Google Patents
Digital single frequency synchronous coverage system and single frequency synchronous coverage method for amplitude modulation broadcast Download PDFInfo
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- CN102291193A CN102291193A CN2011102108271A CN201110210827A CN102291193A CN 102291193 A CN102291193 A CN 102291193A CN 2011102108271 A CN2011102108271 A CN 2011102108271A CN 201110210827 A CN201110210827 A CN 201110210827A CN 102291193 A CN102291193 A CN 102291193A
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Abstract
The invention relates to a digital single frequency synchronous coverage system and a single frequency synchronous coverage method for amplitude modulation broadcast. The system comprises a Beidou/global positioning system (GPS) satellite receiving antenna, a Beidou/GPS synchronous source and an audio synchronous source, wherein both the Beidou/GPS synchronous source and the audio synchronous source are connected with a medium wave transmitter which is connected with a medium wave transmission antenna. In the system and the method, a frequency reference source with the short-term frequency stability of 10<-10> is output by a frequency residence technology as the frequency reference source of all transmitters in the medium wave synchronous broadcast single frequency coverage network system, the frequency error stability of all the transmitters is lower than 0.0001Hz by a digital phase locked loop, and the delay error stability of audio signals output by a digital satellite receiver is lower than 18 milliseconds by utilizing clock signals of the Beidou or a GPS and adopting a synchronous decoding technology. By the system and the method, the frequency error stability of coherent areas is lower than 0.0001Hz, and the delay error stability of the audio signals is lower than 17 milliseconds, so an amplification modulation broadcast single frequency network can be run stably and is actually practical.
Description
Technical field
The present invention relates to broadcast television signal digitlization transmission system, be specifically related to medium wave, the synchronous single-frequency covering system of shortwave amplitude modulation broadcasting and the synchronous covering method of single-frequency thereof.
Background technology
" covering of self adaptation phase place system medium wave synchronized broadcasting single-frequency " is a kind of medium wave broadcast single-frequency soverlay technique under the condition of broadcast singal analogue transmission, just carry out the synchronous of synchronous platform tranmitting frequency, two errors are not carried out the specific descriptions (seeing " progress and the application of medium wave synchronized broadcasting single frequency network " literary composition) of time delay less than 0.001Hz.After China's broadcast television signal transmission all realizes digitlization, this technology can not adapt to, someone propose medium wave synchronized broadcasting single frequency network to realize three with, with frequency, homophase and modulation together, be that difference on the frequency is 0.015Hz, phase difference is 70 microseconds, and the modulation degree error is seen " building perfect medium wave synchronized broadcasting network " literary composition less than 15%().
There are the following problems in the above-mentioned prior art:
1) uses GPS as a reference source signal, have unsteadiness and unreliability, can not eliminate because a reference source frequency accuracy that signal jitter of GPS a reference source or the variation of gps receiver acceptable conditions are brought and the transient change of stability.
2) can not satisfy the requirement of amplitude modulation broadcasting signal to the real-time frequency stability, the stability index of frequency is 24 hours frequency error and a stability, is mid-term or long-term frequency stability index.
3) platform frequency accuracy difference can not satisfy the seamless requirement of medium wave single-frequency nerve of a covering less than 0.001Hz synchronously.
4) after broadcast signal source adopts Digital Transmission, technical conditions owing to audio signal in the single frequency network change (and randomness is arranged) greatly, make that the audio signal of coherence area can not be synchronous in real time, when normal design was used, audio signal may satisfy less than 70 microsecond delay inequalities.But during practical application, each condition of accepting the audio signal of digitlization transmission changes greatly, and the differing greatly of numerous factors such as each transmitting station transmitting power, antenna gain, transmission and condition of acceptance, guarantee that at coherence area the audio delay difference of maximum 70 microseconds is very difficult at last, and show very big randomness, make medium wave single-frequency nerve of a covering exist in name only, can not effectively use.
5) broadcast television signal transmitting digitized after, medium wave synchronized broadcasting single-frequency covers has requirement to modulation degree, requires adjacent synchronous platform modulation degree error less than 15%.
Summary of the invention
At above-mentioned problems of the prior art, the objective of the invention is to propose a kind of synchronous covering system of amplitude modulation broadcasting digitlization single-frequency and the synchronous covering method of single-frequency thereof, it guarantees to be issued to the stable synchronous effect of the synchronous nerve of a covering real time execution of amplitude modulation broadcasting single-frequency in the condition of broadcast television signal digitlization transmission, realizes the seamless covering of single-frequency.
The technical scheme that the present invention is taked for its purpose of realization: the synchronous covering system of a kind of amplitude modulation broadcasting digitlization single-frequency, comprise the Big Dipper (or GPS) satellite earth antenna, the Big Dipper (or GPS) synchronisation source and audio sync source, the described Big Dipper (or GPS) satellite earth antenna connects the Big Dipper (or GPS) synchronisation source and audio sync source; The described Big Dipper (or GPS) synchronisation source all is connected with medium wave transmitter with the audio sync source, and described medium wave transmitter is connected with medium wave radiating antenna.
The synchronous covering method of single-frequency adopts the standard-frequency signal source of the Big Dipper (or GPS) system as medium wave synchronized broadcasting single-frequency nerve of a covering, receives by the Big Dipper (or GPS) receiver, uses the short-term frequency stability of technology export in the frequency to reach 10
-10The frequency reference source, as the reference frequency a reference source of all transmitters of medium wave synchronized broadcasting single-frequency covering network system, make all transmitter frequency errors stable less than 0.0001Hz by digital phase-locked loop.Utilize the clock signal of the Big Dipper or GPS, adopt the synchronous decoding technology, make that the audio signal delay inequality of digital satellite receiver output is stable less than 17 milliseconds.
Beneficial effect of the present invention: make that the difference on the frequency of coherence area is stable less than 0.0001Hz, the delay inequality of audio signal is stable less than 17 milliseconds.Medium wave synchronized broadcasting single-frequency nerve of a covering just can stable operation like this, guarantees that seamless covering connects, and has actual application value.
Description of drawings
Fig. 1 is a mono-frequency network system block diagram of the present invention.
Embodiment
Referring to Fig. 1, three emission websites shown in the figure, a plurality of websites are by that analogy.Each emission website comprise antenna 1(its for the Big Dipper or gps satellite reception antenna), Big Dipper synchronisation source 2(or GPS synchronisation source) and audio sync source 3, the Big Dipper (or GPS) satellite earth antenna connection Big Dipper synchronisation source 2(or GPS synchronisation source) and audio sync source 3.Big Dipper synchronisation source 2(or GPS synchronisation source) all be connected with audio sync source 3 with medium wave transmitter 4, medium wave transmitter 4 is connected with medium wave radiating antenna 5.
The synchronous covering method of single-frequency of the present invention is to use a Big Dipper (or GPS) satellite earth antenna to use for Big Dipper synchronisation source and audio sync source, also can use two reception antennas, uses for the Big Dipper (or GPS) synchronisation source and audio sync source respectively.The Big Dipper (or GPS) synchronisation source utilizes the Big Dipper (or GPS) signal, adopts the frequency of technology export in frequency short-term stability to reach 10 in order to eliminate the signal source shake that the satellite-signal transmission conditions change and crystal wears out and cause
-10The a reference source signal, the output reference source frequency can be 10MHz, also can be 72KHz, by the synthetic required tranmitting frequency of transmitter of frequency synthesizer (perhaps frequency multiplier), use for transmitter, thereby the Frequency Synchronization of all transmitters that use in the assurance medium wave synchronized broadcasting single-frequency nerve of a covering, the stabilized frequency difference of any two adjacent transmitters is less than 0.0001Hz.
Utilize the Big Dipper (or GPS) signal source, provide for isochronous audio source standard time information, audio signal difference in relative time delay by the comprehensive decoder of synchronous decoding technique guarantee digital satellite or optical fiber (or cable, other digital simulation transmission means differences) digital audio decoding device demodulation output is not more than 17 milliseconds, and (system is under the condition with a kind of transmission mode, all websites can insert the constant time lag device simultaneously or not connect simultaneously, insert the function that the constant time lag device can play the absolute delay inequality that reduces audio transmission), and be stabilized in the 17 milliseconds of states that are not more than.If the audio-source transmission means difference that the emission website adopts, other numerals, analogue transmission modes such as satellite transmits, optical fiber, cable are arranged, at this moment according to the inherent delay difference of audio transmission mode, inserting the constant time lag device behind the audio sync source, to reduce the fixed delay of audio signal source poor, and this is determined on a case-by-case basis.
When underway ripple or shortwave synchronized broadcasting single-frequency covered, the incoming frequency of transmitter and audio signal guaranteed synchronously 1 simultaneously) the frequency stability employing short-term stability index of platform synchronously; 2) short-term frequency stability must reach 1 * 10
-10,, platform tranmitting frequency difference is less than 0.0001 synchronously; 3) the audio signal delay time error is not more than 17 milliseconds; 4) modulation degree to system does not require.
Claims (2)
1. the synchronous covering system of amplitude modulation broadcasting digitlization single-frequency comprises the Big Dipper or gps satellite reception antenna, the Big Dipper or GPS synchronisation source and audio sync source, and the described Big Dipper or gps satellite reception antenna connect the Big Dipper or GPS synchronisation source and audio sync source; It is characterized in that: the described Big Dipper or GPS synchronisation source all are connected with medium wave transmitter with the audio sync source, and described medium wave transmitter is connected with medium wave radiating antenna.
2. realize the synchronous covering method of single-frequency of the synchronous covering system of claim 1 described amplitude modulation broadcasting digitlization single-frequency, when underway ripple synchronized broadcasting single-frequency covers, utilize the Big Dipper or gps signal, guarantee that by the Big Dipper or GPS synchronisation source the incoming frequency of transmitter and audio sync source guarantee that audio signal synchronously simultaneously, it is characterized in that: adopt the Big Dipper or gps system standard-frequency signal source as medium wave synchronized broadcasting single-frequency nerve of a covering, receive by the Big Dipper or gps receiver, use the short-term frequency stability of technology export in the frequency to reach 10
-10The frequency reference source, as the reference frequency a reference source of all transmitters of medium wave synchronized broadcasting single-frequency covering network system, make all transmitter frequency errors stable less than 0.0001Hz by digital phase-locked loop; Utilize the clock signal of the Big Dipper or GPS, adopt the synchronous decoding technology, make that the audio signal delay inequality of digital satellite receiver output is stable less than 17 milliseconds.
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| Application Number | Priority Date | Filing Date | Title |
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| CN2011102108271A CN102291193A (en) | 2011-07-27 | 2011-07-27 | Digital single frequency synchronous coverage system and single frequency synchronous coverage method for amplitude modulation broadcast |
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| CN2011102108271A CN102291193A (en) | 2011-07-27 | 2011-07-27 | Digital single frequency synchronous coverage system and single frequency synchronous coverage method for amplitude modulation broadcast |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20100166042A1 (en) * | 2008-12-31 | 2010-07-01 | Ibiquity Digital Corporation | Synchronization of Separated Platforms in an HD Radio Broadcast Single Frequency Network |
| FR2943882A1 (en) * | 2009-03-27 | 2010-10-01 | Thomson Licensing | TRANSMITTING METHOD FOR WIRELESS NETWORK AND CORRESPONDING RECEPTION METHOD |
| CN102036123A (en) * | 2009-09-27 | 2011-04-27 | 科腾科技(北京)有限公司 | Synchronization method and system for single frequency network digital broadcast television system |
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- 2011-07-27 CN CN2011102108271A patent/CN102291193A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20100166042A1 (en) * | 2008-12-31 | 2010-07-01 | Ibiquity Digital Corporation | Synchronization of Separated Platforms in an HD Radio Broadcast Single Frequency Network |
| FR2943882A1 (en) * | 2009-03-27 | 2010-10-01 | Thomson Licensing | TRANSMITTING METHOD FOR WIRELESS NETWORK AND CORRESPONDING RECEPTION METHOD |
| CN102036123A (en) * | 2009-09-27 | 2011-04-27 | 科腾科技(北京)有限公司 | Synchronization method and system for single frequency network digital broadcast television system |
Non-Patent Citations (2)
| Title |
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| 《广播与电视技术》 20110315 杨霏等 "延时自动同步"音频传输系统在中波同步广播中的应用 第122-124页 1，2 , * |
| 杨霏等: ""延时自动同步"音频传输系统在中波同步广播中的应用", 《广播与电视技术》, 15 March 2011 (2011-03-15), pages 122 - 124 * |
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Inventor after: Ying Yuhai Inventor after: Han Daguo Inventor after: Lu Yan Inventor after: Li Haiyan Inventor after: Lv Peng Inventor after: Liu Xuefei Inventor before: Ying Yuhai Inventor before: Han Daguo Inventor before: Lv Peng Inventor before: Lu Yan Inventor before: Li Haiyan Inventor before: Liu Xuefei |
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Free format text: CORRECT: INVENTOR; FROM: YING YUHAI HAN DAGUO LV PENG LU YAN LI HAIYAN LIU XUEFEI TO: YING YUHAI HAN DAGUO LU YAN LI HAIYAN LV PENG LIU XUEFEI |
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Application publication date: 20111221 |