Off-air DTV reception wasn't the hot topic at CES this year, but a close look at displays showed that ATSC tuners were available in a wide range of products, ranging from USB DTV tuner sticks and a small Samsung portable media player to monster LCD TV sets. Effective this March, all TV sets sold in the United States will have to include ATSC DTV tuners. While I saw a few products that don't comply with this requirement--a DVD player with TV tuner for use in an automobile and some inexpensive small screen portable TV sets--the major manufacturers had medium-sized LCD TV sets with ATSC tuners. AudioVox showed a line of under-counter sets in screen sizes up to 10.5 inches, and with a DVD player and ATSC tuner.
One product attracting a lot of interest in the Samsung booth was a small screen portable media player with built-in ATSC tuner. The handheld unit was a prototype, but unlike the device shown at NAB2006, it didn't require any external cables or hardware. It featured battery life up to 4 hours, which Samsung hopes to increase to 20 hours in the production product. It receives ATSC signals using the proposed A-VSB standard (covered previously in my June 2006 RF Technology column in TV Technology).
I had an opportunity to play with the new receiver on a bus trip Samsung arranged to demonstrate how the receiver and the A-VSB standard worked for mobile reception in an urban environment. I was amazed with the performance--only once did I see the picture freeze (for a few seconds) and this was with the antennas (it uses two for diversity reception) collapsed and the near the floor of the bus. The signal returned quickly, even in this location. While it's hard to draw firm conclusions from such a short test on a course Samsung had previously checked out, the reception capability in a moving vehicle that I witnesses makes ATSC a strong competitor for DVB-T and perhaps even DVB-H and the DMB-T mobile standards.
For broadcasters, the cost in terms of bandwidth for transmitting a signal like the one transmitted on Channel 22 by KVMY for the demonstration may be more than they can afford. The demonstration used quarter rate coding, which meant 3 Mbps were needed to transmit a 750 Kbps media stream, In addition to that, an additional 2.8 Mbps was used by the supplemental reference signal (SRS). This barely leaves enough room to transmit one HDTV program. ATSC will be conducting tests of the proposed A-VSB standard, and acceptable reception may be possible with less error correction and less data devoted to the SRS. Given the quality of reception during the bus trip, I believe there is room to reduce the data used for error correction. During the demonstration of the A-VSB technology at NAB, an engineer from another company designing ATSC demodulators told me he felt his design would work well even without the SRS.
I'll have more information on this in a future RF Technology column in TV Technology magazine. Using the Pinnacle HD Stick Pro and TSReader Pro, in my hotel room I downloaded the data stream used for the Samsung demo from Channel 22 and will be analyzing it.
