(From Wikipedia, the free encyclopedia)
China Mobile Multimedia Broadcasting (CMMB) is a mobile television and multimedia standard developed and specified in China by the State Administration of Radio, Film, and Television (SARFT). It is based on the Satellite and Terrestrial Interactive Multiservice Infrastructure (STiMi), developed by TiMiTech, a company formed by the Chinese Academy of Broadcasting Science. Announced in October 2006, it has been described as being similar to Europe's DVB-SH standard for digital video broadcast from both satellites and terrestrial repeaters to handheld devices.
It specifies usage of the 2.6 GHz frequency band and occupies 25 MHz bandwidth within which it provides 25 video and 30 radio channels with some additional data channels. Multiple companies have chips that support CMMB standard - Innofidei who was the first with a solution March 28, 2007, Siano Mobile Silicon(with the SMS118x chip family, which support diversity and have superb performance).
Other manufacturers, such as Unique Broadband Systems, were quick to enter the race and grab a share of the handheld broadcasting market with their award winning hardware platform supporting both CMMB and DTMB (as well as others) standard waveforms based on their universal modulator hardware. While many other companies developed waveform specific hardware Unique broadband systems quickly cornered the Chinese market for CMMB and DTMB modulators.
RF Details
CMMB uses frequencies in the range 2635 - 2660 MHz (S-band) for satellite and "gap-filler" terrestrial broadcast, with additional terrestrial broadcast in the UHF band 470 – 862 MHz. The channel bandwidth can be either 2 or 8 MHz, depending on data rate.
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