Mobile TV is a prime target for manufacturers wanting to add some fun to the whole business of communications, and as is often the case, Japan was arguably first in commercial deployment.
The Sanyo W33SA is a cdma2000 EV-DO handset from carrier KDDI in Japan, Figure 1.
What makes the W33SA special is its first-mover status in the addition of OneSeg digital television reception. OneSeg is an offshoot of ISDB-T digital terrestrial television, with signals formatted in a manner suitable for the requirements of power-sensitive mobile applications. While DMB-T(errestrial), DMB-S(atellite), DVB-H(andheld) and MediaFLO are competing in other geographies for mobile TV, the OneSeg derivative of ISDB-T is the standard of choice in Japan.
The W33SA is a complex product, and only the tuner circuit board (one of many in the design) responsible for the W33SA's FM radio and TV reception is shown here, Figure 2.
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Elsewhere in the system, Qualcomm supplies the handset communications with its MSM6500 baseband and a receive-diversity radio, the latter comprising two receive chips and a transmit processor. A Renesas media processor is responsible for almost all audio, imaging and display interface functions.
In the busy tuner board, one finds three tuners, for FM radio, analog TV and digital TV. Each is contained on an individual surface-mount daughtercard,. The FM radio of the W33SA is handled by the single-chip Niigata Seimitsu NS953. The two TV solutions are provided by Sony in the CXA3651 and CXA3681 for digital and analog tuning, respectively. Accompanying the analog tuner is the M61102FP VIF/SIF (Video Intermediate Format/Sound Intermediate Format) signal processor by Renesas. Texas Instruments' TVP5150 provides the video decoder for the analog tuner, converting baseband analog signals from the M61102FP into digital component video for the Renesas media processor mentioned earlier.
But where, then, is the back end for the CXA3651 digital TV tuner? As it turns out, the ISDB-T demodulator/decoder chip from Fujitsu was discovered embedded in the internal layers of the digital tuner substrate. We found the Fujitsu part flip-chip attached and nested into an internal pocket of the digital tuner module pc board. The embedded chip allows for a smaller tuner module and probably paves the way for future cost reductions as even smaller overall mobile-TV products become the expectation.
While many other bells and whistles draw on analog content in the W33SA, the TV is perhaps the most intriguing. The OneSeg standard is considered digital television, but it still requires a sophisticated analog front end, complemented here by an embedded processor found only after we went deep into the design.
Talk about under the hood!
About the author
David Carey is president of Portelligent (www.teardown.com). The Austin, Texas, company produces teardown reports and related industry research on wireless, mobile and personal electronics.
