Telefonini, la RF nel chip

Interessante questa corrispondenza di Electronics Times dalla conferenza ISSCC di San Francisco. I costruttori di componentistica per telefoni cellulari cercano il modo di ridurre all'osso i costi di fabbricazione dei telefonini, in modo da poter attaccare i mercati a bassissimo prezzo delle nazioni in via di sviluppo. La soluzione consiste nell'integrare il più possibile la radiofrequenza nei processori (ovviamente digitali) che elaborano la banda base. Uno degli ostacoli principali è il crosstalk, le reciproche interferenze tra le due a bordo dei minuscoli chip. Va da sé che a tali livelli di integrazione i dispositivi finali diventeranno ancora più flessibili e aperti a molteplici standard e modulazioni.

Engineers grapple with digital radio at ISSCC

Rick Merritt
(02/05/2008 4:50 PM EST)
URL: http://www.eetimes.com/showArticle.jhtml?articleID=206104558

SAN FRANCISCO, Calif. — Lowering cellphone costs by integrating radio components was a big theme for engineers at the International Solid-State Circuits Conference here Tuesday (Feb. 5). Several of the big cellphone chip makers came to ISSCC describing their current integrated digital RF devices, while others showed different techniques to eliminate external passive components.
Broadcom, Infineon and Texas Instruments described their latest devices for pulling more of the RF work into 2.5G digital devices, typically integrated with baseband processors. Separately Broadcom and the former cellular RF group of Analog Devoices Inc. (ADI), now owned by MediaTek (Hsinchu, Taiwan), described ways of eliminating passives from 3G phone designs.
These "very costly SoC developments" are motivated in part by the need to access huge new markets, said Bob Staszewski, a distinguished member of technical staff at TI.
"There is 100 percent saturation in mature markets such as Finland, Taiwan and Hong Kong, so continued growth depends on accessing emerging markets were you need something on the order of a $20 phone," Staszewski. "That requires integration to save costs," he added.
The TI engineer described a 90nm, 24mm-squared baseband with an integrated quad-band radio that TI is now shipping. The device still requires a 2W power amp, battery charger and SAW filters. Its integrated baseband includes a C54x DSP and ARM 7 running at 104 MHz.
"In the next few years the best we can do is bring into digital some RF and analog functions and integrate them with a baseband," said Staszewski.
Infineon went a step further. Its now-shipping chip includes a 250nm power management device integrated on a substrate with the 130nm baseband and digital radio on a system-in-package design. The baseband included a 260 MHz ARM and 178 MHz Teaklite DSP.
Engineers on both chips struggled with signal coupling and crosstalk issues. "Digital crosstalk effects are becoming more significant as the technology scales down, and digital noise will become increasingly significant," said Guiseppe Li Puma, a cellular RF system engineer at Infineon.
"You get a lot of signal coupling that is hard to predict and fix," said Staszewski.
"The more pressing design issue these days is removing external passives," said Tony Montalvo, a design center director for ADI who co-chaired the session on cellular transceivers.
"The big issue in WCDMA now is quad-band designs can require as many as seven SAW filters," he said. "These filters can dominate the board size and bill of materials costs of the phone," he added.
MediaTek described a tri-bandWCDMA/HSDPA transceiver that eliminated six SAW filers and three low-noise amplifiers. The device also reduces the cost of calibrating the radio to meet 3G standards.
For its part, Broadcom described a 65nm WCDMA transmitter using a feedback filter to suppress receiver noise while consuming just 65 mW. The design eliminated the need for a SAW filter.

HD Radio, nuovo silicio in arrivo

Uno dei nodi fondamentali della questione radio digitale continua a essere il mercato dei terminali utente, in italiano "ricevitori". EETimes si occupa in questo articolo del silicio che Samsung e SiPort http://www.siport.com/, azienda di progettazione "fabless", presenteranno in anteprima al CES di Las Vegas. Il focus è il mercato delle autoradio per il sistema Ibiquity.

Terrestrial digital radio goes mobile

Junko Yoshida
(12/31/2007 1:49 PM EST)
URL: http://www.eetimes.com/showArticle.jhtml?articleID=205205995

New York — The U.S. digital radio market is far from settled. The merger of rival satellite services Sirius and XM is still pending, iPod and MP3 players are proliferating, and Internet radio is fast becoming a viable option. Now iBiquity, a developer of free-over-the-air terrestrial digital radio broadcast systems, is pushing HD Radio.
IBiquity is neither content owner nor broadcaster; rather, its technology lets radio stations simulcast compressed digital audio and traditional analog audio without shifting to new frequency bands. As of today, according to iBiquity, 1,500 HD Radio stations are on the air, with 700 offering new FM multicast channels exclusively to HD Radio listeners, subscription-free.
IBiquity hopes to gain exposure for the concept at the Consumer Electronics Show, which opens Jan. 7 in Las Vegas. The company and its partners will demonstrate new HD Radio features at CES, including an "iTunes tagging" offering that it says will make it easier to purchase music, while unveiling chips and reference designs developed to let HD Radio go mobile in portable devices as well as car radio.
Among the new IC offerings is Samsung's HD Radio chip set, consisting of an RF-IF peripheral processor and a baseband processor and billed as the first low-power solution for portable HD Radio. Not to be outdone, fabless chip company SiPort (Santa Clara, Calif.) will demonstrate a single-chip HD Radio solution at CES that integrates the RF, baseband, memory, ADC and PLL. SiPort's chip, now in production-silicon form, will show up in commercial portable products by the third quarter, Sid Agrawal, SiPort's CEO, told EE Times.
IBiquity, which has been a CES regular for the past several years, believes the HD Radio infrastructure is finally in place to propel terrestrial digital radio's market penetration. A year ago, there were only 20 unique HD Radio products on the market, most notably a JVC car radio that sold for about $199. "Today, we have more than 60 unique HD Radio receivers, whose prices start as low as $99 and [scale] upward to $199," said Robert Struble, president and CEO of iBiquity. The company claims that HD Radio coverage reaches 80 percent of the population.
For their part, digital satellite radio services have been growing their subscription base: Sirius reported 7.7 million subscribers as of September, and XM touts nearly 8.6 million subscribers. But the satellite services continue to rack up financial losses, largely as a result of expensive deals to sign up high-end talent (such as Oprah Winfrey, Bob Dylan and Major League Baseball on XM, and Howard Stern and the National Football League games on Sirius).
Despite its latecomer status, HD Radio has potential, thanks to its free-over-the-air broadcast business model. HD technology enables multicast channels of programming, broadcast over a single FM frequency, which increases listener choice. The format has already garnered commitments from radio stations that produce or own content.
But not everyone is ready to predict that terrestrial digital radio can compete effectively in the U.S. market against satellite digital radio.
"HD Radio does not have commercial-free content or breadth of coverage like satellite radio," said Frank Dickson, chief research officer at MultiMedia Intelligence. "You also have to separate the satellite radio companies from the transmission medium."
The satellite radio players say that they are content aggregators first, distributors second. "This means they will license to Internet, mobile or any other distribution [medium]," Dickson said. "They already do Internet radio as part of the satellite subscription package. Content is king, so he who controls Howard Stern and Opera Winfrey has a multinetwork opportunity."
Indeed, iBiquity acknowledges it is neither content owner nor broadcaster. "We offer a patent portfolio, know-how and brand to chip vendors, receiver manufacturers, transmitter companies and broadcasters," explained Gene Parella, vice president of engineering at the company.
That means the HD Radio concept is reliant on the available content offered by broadcasters—as well as on cost-effective receivers and innovative services and applications—for success among consumers.
One new service that iBiquity is banking on is iTunes tagging, which the company states "makes listening, discovery and purchase of music easier." As a song is played on the air, the radio station broadcasts a metadata transmission of the iTunes store ID for the selection. A special iTunes tag button on the HD radio receiver lets users flag the song for subsequent preview and purchase on iTunes. At CES, Alpine Electronics, Polk Audio, JVC and others will demonstrate products with the tagging feature.
Like XM and Sirus, which bank on new car sales as the biggest generators of new subscriptions, iBiquity considers the in-car radio an essential market for HD Radio. But if iBiquity hopes to succeed, it needs to pay attention as well to the retail radio market. That's where portable designs enabled by chips from Samsung and SiPort come into play.
According to iBiquity's Parella, Samsung's HD Radio baseband processor, based on Tensilica's programmable core, integrates the baseband, memory, SDRAM and flash in a system-in-package measuring 9 x 9 mm. Including the companion RF chip, the chip set's total power consumption is 150 mW. Samsung developed the chip set based on iBiquity's design. Ibiquity intends to roll further reference designs that will let OEMs build tabletop radios and MP3 players capable of tuning and demodulating both HD Radio and its analog forebears.
Other IC vendors, such as Texas Instruments and NXP, have licensed iBiquity's technology and built chips based on a netlist from that company.
But SiPort designed its HD Radio chip on its own, claiming the first chip for the platform that is focused solely on nonautomotive applications.
SiPort's single-die solution is tailored for low-power, high-performance portables. Sunder Velamuri, vice president of marketing at SiPort, said power dissipation of the mixed-signal device is expected to be "around 100 mW in typical configurations." He added that the chip, essentially "a software radio," can tune and demodulate not only analog AM/FM and HD Radio but also DAB and DMB-T, making it ready for the global market. Taiwan Semiconductor Manufacturing Co. is fabricating the device.
The startup is betting the first application for its chip will be portable GSP devices, given HD Radio's ability to datacast real-time traffic information from local radio stations in far more detailed and comprehensive fashion than is currently available via the analog FM band.