What are the major advantages of the digital TV technology over the analogue TV technology?
A：
From digital TV operators’side, compared with the analogue TV, the digital TV system uses the advanced signal sources encoding &decoding techniques, latest channel FEC encoding &decoding techniques, modulating &demodulating techniques and scrambling &descrambling techniques.Those technigues greatly improve the frequency resources availability ratio,several programs,even several ten programs,can be transmitted over one single analogue TV channel.The techniques can accommodate larger program capacity with better video/audio quality and guarantee simple daily maintenance. The digital TV can easily implement conditional access(CA) and CA system can control each program and each subscriber in order to guarantee the quick return of capital investment.There are better program selectivity,better video/audio quality,and simpler operation controls for the subscribers. Moreover,digital TV can be integrated together with other data services like Internet,VOD,data broadcast,IP video.
What are the key techniques of the digital TV?
A：
The key digital TV techniques includes signal sources encoding &decoding techniques,channel FEC encoding &decoding techniques, modulating &demodulating techniques and scrambling &descrambling techniques,system softwares(for example: CSA,SMS,EPG and data broadcast),microwave wireless coverage technique except HFC network and STB.
The following is the key techniques adopted in our Gopell digital TV products : MPEG-2 encoding and decoding, video and audio digital processing, video display digital processing technology, digital broadcasting technology, CA technology, digital modulating technology, satellite/microwave/HFC digital transmitting technology, SDH access technology, DVB gateway and TCP/IP technology, computer network and communication technology, computer server technology, computer RTOS technology, API applications, SNMP protocol.
What are the major components of a digital TV system ?
A：Besides the basic TV watching service,the major value-added services of the digital TV include data broadcasting,NVOD,real time VOD, the stock trading ,online payment,interactive gaming,TV shopping,IP phone and personal broadband access and etc
What’re the frequently used modulation methods?
A：
The frequently used modulation methods in the digital TV system are QPSK,QAM and COFDM. Our Gospell HFC and MMDS digital TV systems mainly adopt QAM and QPSK,while our MUDS system uses QAM and COFDM.
What’re the major difference between MMDS and MUDS?
A：
The major differences between digital MMDS and MUDS are:1)different operating frequency. MMDS usually operates at 2.5-2.7GHz,while MUDS does at 470-860MHz and doesn’t need frequency upconvert transmitting and downconvert receiving, 2)MUDS’s electromagnetic waves have better diffraction and penetration abilities when encounting shelters or going along ground surface,(3)MMDS uses LNB and transmitting power is low,so the large area coverage can be easily implemented. MUDS’s transmitting power is relatively high,so the cost of the antenna is also high and the coverage area is comparatively small.(4)Signal repeat can be easily made in MMDS while it’s comparatively difficult to use the repeat in MUDS.
What are the major advantages of the wireless coverage over the wireline coverage?
A：
Compared with the wireline coverage,the wireless coverage has following advantages:1)with CAS the operator can manage each program and subscriber to guarantee the return and benefits of capital investment,while subscriber charging cann’t ensured for the analogue wireless TV.2)low transmitting power.Only 1% of the tranmitting power of analogue wireless TV.3)fast network deployment.It takes about 10 days to commission a system when the cabinet and iron tower are previously ready.4)quick benefit return with small capital investment.the investment size of wireless coverage is about 1/20 of that of HFC and it takes 1.5-2.0 years or so to refund all the investment.5)adopting cascade repeat technique can implement large area coverage over a several hundred kilometers distance.
Can the digital TV services be delivered by combining the wireline network and wireless network with one common digital headend?
A：
The digital TV services can be delivered by combining the wireline network and wireless network with one common headend,one common CAS and one common SMS. Except adopting QAM modulation over the output signals Gospell has also specifically developed its own QPSK modulation whose technical advantages is the same as those of satellite QPSK. Gospell’s QPSK operates at 250-1500MHz.So the HFC and MMDS/MUDS systems can be conveniently accessed.Moreover,because of lower C/N value of QPSK over QAM,operators should prefer our Gospell’s solution when HFC network is not good or space signal interference is big.The transmitting power of the solution is very low and STB is cheaper,so the solution is very cost-effective.
How many receiving modes are there when using MMDS/MUDS coverage?
A：
When deploying the MMDS/MUDS systems,the operators can use the following receiving modes for their subscribers:1)MMDS/MUDS receiving unit plus STB,2)MMDS/MUDS receiving unit plus local CATV network plus STB.3)STB demodulates the signals from MMDS/MUDS and sends the signals to analogue modulators,then the signals are delivered to subscribers’analogue TV sets over a small CATV network.
How to select the indoor or outdoor transmitting solution?
A：
For relatively small coverage area and good weather conditions or signal repeat the operator should chose the outdoor transmitting solution. For large coverage area and bad weather conditions or requirement of high reliability the operator should chose the indoor transmitting solution. Generally a few indoor transmitters are used simultaneously and the transmitting power is combined by the power combiner (one indoor broadband transmitter can be used if the requirement of power is low).Daily maintenance is more easy for the indoor transmitting solution.
How to cover a wider area by means of the wireless technology?
A：
When a wireless main station cann’t effectively cover the designated service area, GOSPELL has specifically-designed same frequency repeat,different frequency repeat and digital re-generation repeat products.Taking subscriber location,local terrain,frequency resources,space signal interferences and so on into consideration we can work out the detailed system design to guarantee effective signal coverage over several hundred kilometers area.
How many digital TV total solutions can GOSPELL offer?
A：
GOSPELL can offer the following digital TV total solutions:1)HFC total solution,2)MMDS total solution,3)MUDS total solution,4) wireless& HFC total solution with one common digital headend,5)SDH total solution.
What are the basic characteristics of GOSPELL digital TV systems?
A：
GOSPELL is a unique vendor supplying the complete suite of the digital TV system. The basic characteristics of GOSPELL digital TV systems are as follows:
* subject to various international and national technology and quality standards,
* the independent intellectual property rights, * high reliability in system design，and easy extension and maintenance of systems, * functions of network management (SNMP) with the local and remote supervision by Internet.
* provision of various value added services.
What’re the major value-added services of the digital TV?
A：
Besides the basic TV watching service,the major value-added services of the digital TV include data broadcasting,NVOD,real time VOD, the stock trading ,online payment,interactive gaming,TV shopping,IP phone and personal broadband access and etc
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