Interfax News reports that China's CMMB mobile TV commercial operation will be available nationally by July. In the meantime, TeamCast and its local partner Digital Horizon are demonstrating a single-frequency network (SFN) solution developed by TeamCast for CMMB transmission networks at CCBN 2009.
The live demonstration combines modulators meeting SARFT’s CMMB digital mobile TV standard all working at the same frequency. This simulates the operation of several CMMB transmitters operating in SFN mode with accurate frequency and timing synchronization.
The live demonstration also shows the performance of TeamCast’s embedded peak-to-average power reduction (PAPR) function, which increases amplifier efficiency for multicarrier modulation like CMMB.
The MMB-1000/2000 modulator delivers signals at IF level in the UHF band (Bands IV and V), and in the S-band dedicated to satellite transmission. All versions include comprehensive SFN synchronization and PAPR.
The live demonstration uses an MMB-2000 CMMB modulator to provide a sample signal and an RPX-1000 measurement probe for monitoring the quality of CCMB transmissions. The RPX-1000 measurement probe demodulates and measures transmission parameters in real time, including:
- Modulation error ratio — a key indicator of the quality of digitally modulated mobile TV signals;
- Output signal level for commissioning transmission networks;
- Shoulder levels to reflect transmitter “health” and to ensure that adjacent channels are not being jammed.
The probe also delivers data for displaying spectrum and constellation views of the modulation.
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