[opendtv] TI chips for IBOC radio

  • From: "Manfredi, Albert E" <albert.e.manfredi@xxxxxxxxxx>
  • To: "OpenDTV (E-mail)" <opendtv@xxxxxxxxxxxxx>
  • Date: Wed, 28 Jul 2004 16:48:08 -0400

The reason IBOC AM radio is problematic at night is exactly the
same reason why any idea of high fidelity AM radio, which covers
30 KHz of spectrum instead of only 10 KHz, is a problem at night.
These 30 KHz stations spill over into the frequency allocations
of other AM stations (which are spaced 10 KHz apart). At night,
when AM propagates long distances, this causes interference for
anyone not completely dominated by the broadband station's

Translated, this creates annoying squeals for anyone trying
to tune his AM radio to a somewhat weak signal, especially at

IBOC AM radio places the digital content in two bands adjacent
to the central 10 KHz analog AM station. Together, these two
bands and the analog take up 30 KHz vs 10 KHz for analog
stations. (Wideband analog AM also uses 30 KHz of spectrum,
so its should come as no surprise that this creates the
same problem.)

IBOC FM does something similar, taking up 400 KHz for an
IBOC FM station, compared with the 200 KHz assigned to an analog
FM station. The advantage is that FM stations only propagate
so far, day or night (if we ignore the occasional skip). So if
this works during the day, it will also work at night.

Seems to me that ATSC could also have been called "IBOC." In the
sense that stations are assigned what would otherwise have been
considered tabboo frequencies for transmission of their digital
signal. For instance, in principle, TV stations could have been
assigned the immediately adjacent channel for their DTV signal.
Some of the time, this might actually have worked. I'm really
not sure I see the difference between this and IBOC radio, with
respect to the term "IBOC" (in band, on channel)?


TI bets on chips to amplify digital radio market
By Junko Yoshida , EE Times
July 22, 2004 (10:31 AM EDT)
URL: http://www.eet.com/article/showArticle.jhtml?articleId=3D23904934

Paris - The emerging U.S. terrestrial digital radio market
will get a substantial boost this week when Texas Instruments
Inc. rolls out two HD Radio baseband processors that make up
its third-generation digital radio silicon. One chip will allow
radio manufacturers to add digital terrestrial HD Radio to
existing analog AM/FM radio designs; the other supports HD
Radio and analog AM/FM radio in a single chip. The sampling
price of each chip is $22 per unit.

John Gardner, digital radio marketing manager at TI, called the
TMS320DR350, which combines IF-sampled AM/FM and HD Radio
processing, "the industry's lowest-cost implementation of HD
Radio technology." Many consider cost reduction an imperative
for HD Radio to boom.

The rollout of HD Radio technology by iBiquity Digital Corp.,
the developer of the U.S. terrestrial digital broadcast
system-called in-band on-channel (IBOC)-has encountered a number
of obstacles over the last few years. iBiquity is the sole owner
of intellectual property for IBOC; TI is an investor in
iBiquity. The difficulties include iBiquity's last-minute switch
of the IBOC codec last summer to improve audio quality (see
www.eet.com/showArticle.jhtml?articleID=3D18309105); reduced
coverage and interference with adjacent analog channels reported
by a group of radio engineers, station owners and others; and
interference with nighttime AM broadcasts.

While iBiquity's IBOC technology has been approved by the Federal
Communications Commission for digital broadcasts by existing AM
and FM radio stations, the FCC hasn't yet approved digital
nighttime transmissions by AM stations due to interference

The FCC is accepting public comment on interference until Aug. 2,
but the delay and uncertainty over nighttime broadcasts has
crimped HD Radio's potential reach.

Nighttime AM IBOC broadcasts are "a fly in the ointment," said
Will Strauss, president of Forward Concepts Co. (Tempe, Ariz.).
Critics argue that sidebands might wipe out weak distant radio
stations, Strauss said, "and there are a lot of people who
simply like to log reception of distance, or DX, broadcasts."

The installed base for HD Radio in the United States is "very,
very limited," said Dan Benjamin, analyst at ABI Research Inc.
(Oyster Bay, N.Y.), "as just a handful of devices are even
available and those devices remain very expensive, on the order
of several hundred dollars." Analyst Strauss agreed, estimating
shipments of "only about 30,000 radios" for 2004. Assuming
approval of nighttime AM IBOC late this year, Strauss said, "We
expect 2005 will only see factory-installed IBOC-capable radios
in the 100,000 range." Forward Concepts doesn't expect the HD
Radio market to hit a million units before 2007.

That may explain chip makers' scant interest in HD Radio. Only
TI and Philips Semiconductors now offer HD Radio chips. Beyond
the imperative to cut costs, the industry agrees, HD Radio also
needs more features.

Samples of TI's DRI350 and DRI300 HD Radio basebands are
available now, with volume production scheduled in the fourth

Copyright 2003 CMP Media
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