CN102025944A - Demodulator and mobile digital television information receiving device - Google Patents
Demodulator and mobile digital television information receiving device Download PDFInfo
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- CN102025944A CN102025944A CN2009103068768A CN200910306876A CN102025944A CN 102025944 A CN102025944 A CN 102025944A CN 2009103068768 A CN2009103068768 A CN 2009103068768A CN 200910306876 A CN200910306876 A CN 200910306876A CN 102025944 A CN102025944 A CN 102025944A
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Abstract
The invention relates to a mobile digital television information receiving device comprising a radio frequency antenna, a tuner, a demodulator and an application provider/content provider (AP/CP) master control chip which are connected in sequence, wherein the radio frequency antenna receives a radio frequency input China mobile multimedia broadcasting (CMMB) signal including mobile digital television information and transmits the radio frequency input CMMB signal to the tuner; the tuner converts the radio frequency input CMMB signal into a zero intermediate frequency in-phase/quadrature phase (I/Q) signal and transmits the zero intermediate frequency I/Q signal to the demodulator; the demodulator carries out analog/digital conversion on the zero intermediate frequency I/Q signal and carries out corresponding demodulation according to the demodulation mode of the zero intermediate frequency I/Q signal and descrambles a scrambled CMMB signal to obtain an original CMMB signal including the mobile digital television information, and the original CMMB signal is transmitted to the AP/CP master control chip; and the AP/CP master control chip decodes the original CMMB signal to obtain the mobile digital television information. In the invention, the mobile digital television information receiving device integrates a descrambling function in the demodulator, thereby, the AP/CP master control chip needs working at overfrequency, therefore, the power consumption of the AP/CP master control chip is reduced and the system power consumption of the whole mobile digital television information receiving device is reduced.
Description
Technical field
The present invention relates to the mobile digital TV technical field, relate in particular to a kind of demodulator and a kind of digital television information receiving system.
Background technology
Mobile TV is commonly called as mobile TV, it is support with the digital technology, play and received television program by the mode that the broadcasting of ground or satellite TV signal, ground installation receive, at present manyly realize that by terminal equipments such as mobile phone, multimedia player, vehicle-mounted, USB (UniversalSerial BUS, USB) receivers TV signal receives.The characteristics of its maximum are to keep the stable and clear of TV signal being on the vehicles of mobile status.
CMMB (ChinaMobileMultimedia Broadcasting, China Mobile multimedia broadcasting) industry standard has been stipulated in the broadcasting service frequency range, frame structure, chnnel coding and the modulation of mobile multimedia broadcast system broadcast channel transmission signals, this standard is applicable to that 30MHz is to the interior broadcasting service frequency of 3000MHz frequency range, via satellite and/or the broadcast system of multi-media signals such as terrestrial wireless emission TV, broadcasting, data message, can realize whole nation roaming.
By the CMMB network, the user can see existing TV programme, special TV programme by mobile TV, and obtains stock, meteorology, traffic or the like value-added information.Simultaneously, the CMMB network can be supported functions such as the national roaming of control and management, user of mass users, multimode authorization control way to manage, user management, user's customer service support.We can say that CMMB from satisfying the angle of operation demand, has realized powerful technical support.
Fig. 1 is existing mobile digital TV information receiver structure chart.As shown in Figure 1, the receiving system of existing mobile digital TV comprises radio-frequency antenna 11, tuner 12, first demodulator 13, an AP/CP (master/coprocessor) main control chip 14 and CA (Conditional Access, the condition receives) deciphering module 15 that links to each other in turn.Wherein, the receive frequency range of radio-frequency antenna 11 is 470～862MHz, radio-frequency antenna 11 sends RF-IN (radio frequency input) the CMMB signal that reception comprises mobile digital TV information to tuner 12, it is zero intermediate frequency I/Q (in the same way/quadrature) signal (i/q signal is an analog signal) that tuner 12 is imported the CMMB conversion of signals with radio frequency, send between first demodulator, 13, the first demodulators 13 and the tuner 12 and pass through I
2C bus transfer control command and data, 13 pairs of i/q signals of first demodulator carry out mould/number conversion and carry out demodulation according to its corresponding modulation system, obtain scrambling CMMB signal, contain ECM (EntitlementControl Message in this scrambling CMMB signal, Entitlement Control Message) information, by SPI (SerialPeripheral Interface, serial peripheral interface) sends an AP/CP main control chip 14 to, H.264,14 couples of scrambling CMMB of the one AP/CP main control chip signal is decoded, cooperate CA deciphering module 15 simultaneously, finish CMMB signal descrambling function, AP/CP main control chip 14 is done descrambling earlier, do decoding again, wherein the detailed process of descrambling is: EMM (the EntitleManage Message that an AP/CP main control chip 14 will obtain from base band, Entitlement Management Message) information, perhaps import the EMM information that obtains the CMMB signal from radio frequency, and the ECM information that obtains from first demodulator 13 sends CA deciphering module 15 to, CA deciphering module 15 is at first used PDK (PersonalDistribute Key, the individual subscriber distributing key) EMM is deciphered, from EMM, take out SK (Service Key, business cipher key) information, with SK ECM is decrypted then, from ECM, take out CW (Control Word, control word), CA deciphering module 15 sends CW to an AP/CP main control chip 14 then, the one AP/CP main control chip 14 usefulness CW carry out descrambling to scrambling CMMB signal, obtain original CMMB signal.The shortcoming of this scheme is that the AP/CP main control chip generally all is RISC (ReducedInstructionSet Computing, a reduced instruction set computer) instruction set, finishes H.264 decoding function and CMMB signal descrambling function, generally needs overclocking work, and chip power-consumption is very high.
Summary of the invention
Technical problem to be solved by this invention provides a kind of demodulator, reduces the system power dissipation of mobile digital TV information receiver.
For solving the problems of the technologies described above, the present invention proposes a kind of demodulator, comprise demodulation module, described demodulation module is used for the zero intermediate frequency i/q signal is carried out mould/number conversion and carries out corresponding demodulation according to the modulation system of described zero intermediate frequency i/q signal, also comprise descrambling module, described descrambling module is used for scrambling CMMB signal is carried out descrambling.
Further, above-mentioned demodulator also can have following characteristics, described demodulation module further comprises demodulating unit and demultiplexing unit, described demodulating unit is used for the zero intermediate frequency i/q signal is carried out mould/number conversion and carries out corresponding demodulation according to the modulation system of described zero intermediate frequency i/q signal, and described demultiplexing unit is used for the zero intermediate frequency i/q signal demultiplexing after the demodulation.
For solving the problems of the technologies described above, the invention allows for a kind of mobile digital TV information receiver, comprise the radio-frequency antenna, tuner, demodulator and the AP/CP main control chip that link to each other in turn, wherein:
Described radio-frequency antenna is used to receive the radio frequency input CMMB signal that comprises mobile digital TV information, sends described tuner to;
Described tuner, being used for described radio frequency input CMMB conversion of signals is the zero intermediate frequency i/q signal, sends described demodulator to;
Described demodulator, be used for described zero intermediate frequency i/q signal is carried out mould/number conversion and carries out corresponding demodulation according to the modulation system of described zero intermediate frequency i/q signal, and scrambling CMMB signal carried out descrambling, obtain comprising the original CMMB signal of mobile digital TV information, send described AP/CP main control chip to;
Described AP/CP main control chip is used for described original CMMB signal is decoded, and obtains mobile digital TV information.
Further, above-mentioned mobile digital TV information receiver also can have following characteristics, and the receive frequency range of described radio-frequency antenna is 470～862MHz and/or 2635～2660MHz.
Further, above-mentioned mobile digital TV information receiver also can have following characteristics, and described radio frequency input CMMB signal packet contains Entitlement Control Message ECM and Entitlement Management Message EMM.
Mobile digital TV information receiver of the present invention is integrated descrambling function in demodulator, thereby need the work of AP/CP main control chip overclocking, therefore not only reduce the power consumption of AP/CP main control chip, and reduced the system power dissipation of whole mobile digital TV information receiver.
Description of drawings
Fig. 1 is existing mobile digital TV information receiver structure chart;
Fig. 2 is demodulator structure figure of the present invention;
Fig. 3 is a mobile digital TV information receiver structure chart of the present invention;
Fig. 4 is the part-structure figure except that the AP/CP main control chip in the mobile digital TV information receiver specific embodiment of the present invention;
Fig. 5 is the descrambling data flow diagram of mobile digital TV information receiver of the present invention.
Embodiment
Below in conjunction with accompanying drawing principle of the present invention and feature are described, institute gives an actual example and only is used to explain the present invention, is not to be used to limit scope of the present invention.
Fig. 2 is demodulator structure figure of the present invention, by shown in Figure 2, demodulator of the present invention comprises demodulation module 21 and descrambling module 22, wherein, demodulation module 21 is used for the zero intermediate frequency i/q signal is carried out mould/number conversion and carries out corresponding demodulation according to the modulation system of this zero intermediate frequency i/q signal, and descrambling module 22 is used for scrambling CMMB signal is carried out descrambling.Demodulation module 21 can further include demodulating unit and demultiplexing unit, demodulating unit is used for the zero intermediate frequency i/q signal is carried out mould/number conversion and carries out corresponding demodulation according to the modulation system of this zero intermediate frequency i/q signal, and demultiplexing unit is used for the zero intermediate frequency i/q signal demultiplexing after the demodulation.Like this, demodulator of the present invention has just had the dual-use function that demodulation is disturbed, when it is used for the mobile digital TV information receiver, AP/CP main control chip in this mobile digital TV information receiver needn't be carried out descrambling work, therefore do not need overclocking work, thereby not only reduced the power consumption of AP/CP main control chip, and can reduce the system power dissipation of whole mobile digital TV information receiver.
The invention allows for a kind of mobile digital TV information receiver.Fig. 3 is a mobile digital TV information receiver structure chart of the present invention, by shown in Figure 3, mobile digital TV information receiver of the present invention comprises radio-frequency antenna 31, tuner 32, second demodulator 33 and the 2nd AP/CP main control chip 34 that links to each other in turn, wherein, radio-frequency antenna 31 is used to receive the radio frequency input CMMB signal that comprises mobile digital TV information, send tuner 32 to, radio-frequency antenna 31 is the same with the function of radio-frequency antenna 11, and the receive frequency range of radio-frequency antenna 31 is 470～862MHz and/or 2635～2660MHz; It is the zero intermediate frequency i/q signal that tuner 22 is used for radio frequency is imported the CMMB conversion of signals, sends second demodulator 23 to, and tuner 32 is the same with the function of tuner 12; Second demodulator 33 is used for the zero intermediate frequency i/q signal is carried out mould/number conversion and carries out corresponding demodulation according to the modulation system of this zero intermediate frequency i/q signal, and scrambling CMMB signal carried out descrambling, obtain comprising the original CMMB signal of mobile digital TV information, send the 2nd AP/CP main control chip 34 to, as seen, second demodulator 33 is integrated descrambling function on the basis of first demodulator 13, thereby second demodulator 33 is different from first demodulator 13; The 2nd AP/CP main control chip 34 is used for original CMMB signal is decoded, obtain mobile digital TV information, as seen the 2nd AP/CP main control chip 34 is compared with an AP/CP main control chip 14 and has been lacked the descrambling function, and therefore the 2nd AP/CP main control chip 34 is different from an AP/CP main control chip 14.
Descrambling process in the mobile digital TV information receiver of the present invention is as follows: second demodulator 33 at first obtains EMM information from base band, perhaps from radio frequency input CMMB signal, obtain EMM information, and acquisition ECM information is deciphered EMM with PDK then from radio frequency input CMMB signal, from EMM, take out SK, with SK ECM is decrypted then, from ECM, take out CW, with CW scrambling CMMB signal is carried out descrambling then, obtain original CMMB signal (for scrambling CMMB signal, also can be described as CMMB clear stream signal).
In the mobile digital TV information receiver of the present invention, the radio frequency input CMMB signal packet that radio-frequency antenna 31 receives contains Entitlement Control Message ECM, can also comprise Entitlement Management Message EMM.
Fig. 4 is the part-structure figure except that the AP/CP main control chip in the mobile digital TV information receiver specific embodiment of the present invention.As shown in Figure 4, radio-frequency antenna 41 receive frequency ranges are the radio frequency input CMMB signal of 470～862MHz, radio-frequency antenna 42 receive frequency ranges are the radio frequency input CMMB signal of 2635～2660MHz, the radio frequency input CMMB signal that radio-frequency antenna 41 receives sends tuner 44 to through filter 43, the radio frequency input CMMB signal of radio-frequency antenna 42 directly sends tuner 44 to, it is to pass to demodulator 45 behind the i/q signal that tuner 44 is imported the CMMB conversion of signals with radio frequency, demodulator 45 transmits the tuner control signal by automatic gain control AGC bus to tuner 44, passes through I between demodulator 45 and the tuner 44
2Two transmission line serial data line SDA of C bus and clock line SCL transmit i/q signal, demodulator 45 links to each other with the SPI flash memory by SPI, link to each other with CA deciphering chip (being equivalent to the CA deciphering module among Fig. 1) by 7816 interfaces, SPI flash memory and CA are integrated in the demodulator 45, in order to represent to know both are placed on demodulator 45 outsides here.Power Management Unit PMU (PowerManagement Unit) is to tuner 44 and demodulator 45 power supplies, and supply standard is 1.2V, 1.8V and 3.3V respectively.CMMB Tuner (tuner) receives uhf band (the CMMB analog signal of 470MHz ~ 862MHz), output zero intermediate frequency i/q signal; CMMB Demodulator (demodulator) is the CMMB channel receiver chip of 8MHz bandwidth mode, based on broadcast industry standard GY/T220.1-2006 Mobile Multimedia Broadcasting first: the frame structure of broadcast channel, chnnel coding and modulation, and GY/T220.2-2006 Mobile Multimedia Broadcasting second portion: multiplexing.I/q signal by Tuner output carries out the ADC conversion, and then does the OFDM demodulation, and LDPC (low density parity check code) parity check sum RS error correction; CMMB Demodulator chip obtains CW by 7816 interfaces and the communication of CA deciphering chip, finishes CMMB descrambling function simultaneously.
Fig. 5 is the descrambling data flow diagram of mobile digital TV information receiver of the present invention.As shown in Figure 5, tuner 51 sends the CMMB analog signal to demodulator 52, demodulator 52 carries out CMMB demodulation, CMMB demultiplexing, CMMB descrambling successively, drive the SPI that the CMMB clear stream is sent to the AP/CP main control chip by interface then, in CMMB descrambling process, demodulator 52 drives by interface ECM and EMMM is passed to CA, and CA decrypts CW with ECM and EMMM then, demodulator 52 drives by interface and obtain CW from CA, finishes the descrambling function again.
Mobile digital TV information receiver of the present invention is integrated descrambling function in demodulator, thereby need the work of AP/CP main control chip overclocking, therefore not only reduce the power consumption of AP/CP main control chip, and reduced the system power dissipation of whole mobile digital TV information receiver.
The above only is preferred embodiment of the present invention, and is in order to restriction the present invention, within the spirit and principles in the present invention not all, any modification of being done, is equal to replacement, improvement etc., all should be included within protection scope of the present invention.
Claims (5)
1. demodulator, comprise demodulation module, described demodulation module is used for the zero intermediate frequency i/q signal is carried out mould/number conversion and carries out corresponding demodulation according to the modulation system of described zero intermediate frequency i/q signal, it is characterized in that, also comprise descrambling module, described descrambling module is used for scrambling CMMB signal is carried out descrambling.
2. demodulator according to claim 1, it is characterized in that, described demodulation module further comprises demodulating unit and demultiplexing unit, described demodulating unit is used for the zero intermediate frequency i/q signal is carried out mould/number conversion and carries out corresponding demodulation according to the modulation system of described zero intermediate frequency i/q signal, and described demultiplexing unit is used for the zero intermediate frequency i/q signal demultiplexing after the demodulation.
3. a mobile digital TV information receiver is characterized in that, comprises the radio-frequency antenna, tuner, demodulator and the AP/CP main control chip that link to each other in turn, wherein:
Described radio-frequency antenna is used to receive the radio frequency input CMMB signal that comprises mobile digital TV information, sends described tuner to;
Described tuner, being used for described radio frequency input CMMB conversion of signals is the zero intermediate frequency i/q signal, sends described demodulator to;
Described demodulator, be used for described zero intermediate frequency i/q signal is carried out mould/number conversion and carries out corresponding demodulation according to the modulation system of described zero intermediate frequency i/q signal, and scrambling CMMB signal carried out descrambling, obtain comprising the original CMMB signal of mobile digital TV information, send described AP/CP main control chip to;
Described AP/CP main control chip is used for described original CMMB signal is decoded, and obtains mobile digital TV information.
4. mobile digital TV information receiver according to claim 3 is characterized in that, the receive frequency range of described radio-frequency antenna is 470～862MHz and/or 2635～2660MHz.
5. mobile digital TV information receiver according to claim 3 is characterized in that, described radio frequency input CMMB signal packet contains Entitlement Control Message ECM and Entitlement Management Message EMM.
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| Application Number | Priority Date | Filing Date | Title |
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| CN2009103068768A CN102025944A (en) | 2009-09-11 | 2009-09-11 | Demodulator and mobile digital television information receiving device |
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| CN2009103068768A CN102025944A (en) | 2009-09-11 | 2009-09-11 | Demodulator and mobile digital television information receiving device |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102497217A (en) * | 2011-11-28 | 2012-06-13 | 北京乾图方园软件技术有限公司 | Method for enhancing receiving signal of China mobile multimedia broadcasting (CMMB) chip |
| CN103124371A (en) * | 2013-01-23 | 2013-05-29 | 南京熊猫电子股份有限公司 | Conditional access device based on SMD (scheduling management display) mode |
| CN103248954A (en) * | 2012-02-14 | 2013-08-14 | 国民技术股份有限公司 | Receiving device of digital television |
| CN104866315A (en) * | 2015-05-29 | 2015-08-26 | 上海亿耀电子有限公司 | Scheme of multi-key combination communication control key and lamp based on TwinCAT platform |
| CN113163195A (en) * | 2021-03-31 | 2021-07-23 | 国家广播电视总局监管中心 | Demodulation board card |
-
2009
- 2009-09-11 CN CN2009103068768A patent/CN102025944A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102497217A (en) * | 2011-11-28 | 2012-06-13 | 北京乾图方园软件技术有限公司 | Method for enhancing receiving signal of China mobile multimedia broadcasting (CMMB) chip |
| CN103248954A (en) * | 2012-02-14 | 2013-08-14 | 国民技术股份有限公司 | Receiving device of digital television |
| CN103124371A (en) * | 2013-01-23 | 2013-05-29 | 南京熊猫电子股份有限公司 | Conditional access device based on SMD (scheduling management display) mode |
| CN104866315A (en) * | 2015-05-29 | 2015-08-26 | 上海亿耀电子有限公司 | Scheme of multi-key combination communication control key and lamp based on TwinCAT platform |
| CN104866315B (en) * | 2015-05-29 | 2018-11-09 | 上海亿耀电子有限公司 | Device based on TwinCAT platform multikey combined communication control button and lamp |
| CN113163195A (en) * | 2021-03-31 | 2021-07-23 | 国家广播电视总局监管中心 | Demodulation board card |
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Application publication date: 20110420 |