CMMB, or China Mobile Multimedia Broadcasting, is China's first mobile TV standard with independent intellectual property rights designed for mobile devices. It is a portable multimedia broadcasting service jointly developed by China Mobile and China Broadcasting Corporation, primarily aimed at small-screen devices such as mobile phones, PDAs, and car TVs. As mobile phones have evolved into multifunctional tools capable of handling both communication and multimedia tasks, integrating CMMB has become a natural progression. The system employs a combination of satellite and terrestrial transmission technologies, operating in the U-band (1.55–3.4 GHz) and S-band (470–860 MHz). Unlike traditional streaming services, CMMB delivers content without generating data charges, making it a cost-effective alternative to mobile internet-based TV. This unique feature has led to high market demand for CMMB-enabled devices. To support this growing need, this paper introduces the IF228, a dedicated CMMB chip designed to enable efficient reception of mobile multimedia broadcasts.
When selecting a CMMB chip, several technical trends must be considered. First, the chip should offer improved performance metrics such as better signal interference resistance, lower power consumption, smaller size, and more diverse interface options. Second, the overall cost and development complexity of the chip should be minimized to facilitate faster product deployment and broader market adoption. SIP-packaged chips are known for their compliance, stability, and reliability, making them a top choice. In the long run, all-in-one single-chip solutions that integrate functions like tuner, demodulator, decoder, and decryptor will dominate the market. Based on these considerations, the latest IF228 chip from Creative Video was chosen for designing a mobile multimedia broadcast receiver.
The IF228 chip stands out due to its high integration and compact design. It combines the tuner, demodulator, and UAM conditional access modules into one unit, fabricated using a 65 nm process and packaged in a TFBGA 5 mm × 5 mm format. Its small size and fine-pitch solder balls (0.65 mm spacing) make PCB design easier and more flexible. The IF228-based solution can be implemented in an area as small as 50 mm², significantly reducing development costs and complexity for terminal manufacturers.
In terms of demodulation performance, the IF228 supports high-speed mobility, including vehicles traveling over 800 km/h, such as high-speed trains and even aircraft. It also performs well in urban environments with multi-path interference, achieving a QPSK demodulation threshold below 7.3 dB under standard TU6 channel conditions. Additionally, when two paths have a maximum delay of 75 μs, the chip maintains a QAM 16 demodulation-to-noise ratio threshold of 12.5 dB. These capabilities ensure seamless reception in any single-frequency network environment.
The IF228 also excels in resisting single-frequency interference, a critical factor for CMMB systems that rely on time-domain synchronization. It can successfully receive signals even when in-band interference exceeds the received signal by 15 dB. More importantly, if the interference becomes too strong, the chip can quickly resume normal reception once the interference weakens, avoiding the so-called Schmitt effect. This ensures a smoother user experience, especially in crowded electromagnetic environments. Moreover, this feature reduces EMI requirements, simplifying PCB layout and eliminating concerns about interference from other components like the application processor or baseband chip.
Power efficiency is another key advantage of the IF228. Using CMMB’s time-slot receiving technology, it consumes only 36 mW on average when active for 1/10 of the time, with each time slot consuming less than 10 mW. In power-down mode, the current is extremely low, simplifying power management for device designers. The chip supports I/O voltages ranging from 1.6 V to 3.6 V without additional adjustments, and includes a PWM output pin for easy antenna integration.
Finally, the IF228 supports multiple clock frequencies, including 10, 12, 13, 18, 19.2, 20, 24, 26, 27, and 30 MHz. This flexibility allows it to share a crystal with the AP/BB, reducing costs and saving space on the PCB. Overall, the IF228 is a powerful and versatile solution for next-generation CMMB terminals.
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