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Spread Spectrum Scene Online

Issue 13, Fall 2004


Inside This Issue:

Review our Previous Issues

SSS is proud to present our Thirteenth Online issue.

We are now soliciting ideas and articles for our fourteenth issue, which is tentatively scheduled for spring 2005. Please send your comments and suggestions to:

What's New At Pegasus Technologies
and SSS Online

Our Upcoming Move: Progress Report

As we reported in our last issue, we have signed a lease on a new building that is being constructed on a 4.6 acre parcel in the Roane Regional Industrial and Business Park, less than a mile away from Interstate 40, close to both Knoxville and Oak Ridge, Tennessee. When we have moved in, we'll all finally be in one spot -- for now, we're scattered in 4 different locations in a 20-mile radius.

Construction is underway. We broke ground on October 18th in a pouring rainstorm -- and rain has plagued us ever since. Despite the soggy conditions, the walls are completed and work on the roof has begun. We are very excited about this move, which is currently scheduled to take place in early March (if it stops raining long enough to get the building under roof...). Check our facilities page for updates.

Groundbreaking ceremony
Groundbreaking Ceremony, 10/18/04
building walls
Pegasus Technologies building, 12/3/04, side view

We Helped Record History! (Part 2)

By now everyone knows that Burt Rutan's Spaceship One won the Ansari X prize on October 4 for its two flights to space within a fourteen-day period. We played a small part in recording this historic event -- the pictures of the takeoff and landing taken at the runway were transmitted over a Pegasus Technologies wireless video link design! You can see the videos here.

The End of a Good Year; Thoughts for the Next

At this time of year, it's good to take a moment to reflect and think about the future. 2004 was a really good year for us. On the Pegasus Technologies side, we added three new staff members, outgrew our facilities, doubled our 2003 gross sales, and completed development of two new products (see our RF Module Sales page for a description and pricing). For 2005, we have some very exciting developments in the works, but it would be premature to mention them until plans are finalized. However, we anticipate that 2005 will be a strong growth year for us. In today's uncertain world, we are very grateful for your continued support and confidence, and we will continue to strive to deserve your trust.

On the SSS Online side, we have completed our fourth year operating the Spread Spectrum Scene website. Our statistics have increased substantially during the year, both in the number of hits and the number of visits. Our Google ranking and placement on top search engines has continued to improve and we are now at or near the top on most of our search terms. We have updated every one of the more than 400 active pages at least once during the year, and have added a huge amount of new material as well as finishing the upload of the old 1992 and 1993 paper issues. We plan for more of the same in 2005.

We hope that each and every one of you has a peaceful, safe, and successful year in 2005. As always, we welcome any comments or suggestions on any aspect of our website.

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Chip Review: The Toshiba TB31262F
Wireless Telephone Chip

By Jim Pearce

Jim Pearce is Chief Technical Editor of SSS Online, and President of of Pegasus Technologies, Inc., a provider of electronic RF and advanced electronic design services and RF modules.

Sometimes you find a chip that does so much more than its original intended function that it is hard to keep from using it. This is how I felt about the Toshiba TB31262F wireless telephone chip. The '262 is a complete RF section for a full duplex analog FM transceiver that also has data communications capability. It is intended to operate in the US 902 MHz to 928 MHz license-free band but with a minor change in external components it can also operate in the European 868 MHz band.

You can download its datasheet here:

Note that even though the datasheet is all English, the pdf file contains codes for Japanese characters and Acrobat Reader will complain. Go ahead and load the Japanese character set when Acrobat complains.


Lets take a look at the transmit side of the '262.

The transmitter uses a phase locked loop frequency synthesizer. Frequency modulation of a PLL can be performed either by summing the modulation voltage with the VCO control voltage, or by varying the reference frequency for the PLL. Which of these techniques is used has a direct impact on the choice of the loop bandwidth of the PLL. The '262 uses the first method of modulation since it must simultaneously transmit and receive, and having the referee frequency modulated would make receiving using the same reference impossible.

This means that the loop bandwidth of the PLL must be lower than the lowest desired modulation frequency. Modulation with frequencies lower than the loop bandwidth will be cancelled out by the feedback action of the PLL. This is the reason for the relatively large values of the components the make up the transmit loop filter, C11 (1uF), R6 (1K), and C12 (2.2uF).

The voltage controlled oscillator for the transmitter operates at half the desired output frequency and is completely integrated except for two inductors. These inductors have a suggested value of 2.2 nH but for operation at lower frequencies such as the European 868 MHz band you may need to use 2.7 nH.

The '262 includes two stages of amplification for the audio signal prior to its application to the VCO modulation varactors. The first stage is a straightforward op-amp that is AC coupled on its input. The output of this stage is available to the designer, but it is also internally connected to a audio level compressor.

The compressor on the transmit side works in conjunction with a matched expander on the receive side to increase the apparent dynamic range of the FM communications channel. A compressor and expander together is called a compandor. More information on the theory and operation of compandors can be found in Philips Application Notes AN174 and AN176.

If compression of the audio signal isn't desired, the output of the first amplifier can be connected to the second amplifier without going through the compressor. On the schematic this would involve connecting C8 to pin 8 instead of pin 7.

If you want to send data using the '262 you simply sum in the data signal with an additional resistor to pin 6. The value of this resistor must be sized so that the digital signals voltage modulates the signal an appropriate amount. You should also keep in mind that the op-amp between pins 4 and 5 will invert the data signal so that a data high level will cause a shift to the low frequency and a data low level will cause a shift to the high frequency.

The format of the digital data that you use to modulate the transmitter with will have an impact on how well the system works. Since the system is AC coupled, you should give serious consideration to using Manchester encoding. For more information of Manchester encoding see: Wikipedia's Article.

We have used low bit rates of about 2400 bps, though the '262 should be capable of much higher rates.

The modulated PLL signal passes through a frequency doubler stage and then a power amplifier stage. The power amplifier has a differential output which must use external components to perform the function of a balun (balanced-to-unbalanced). This RF output must then be fed through a bandpass filter. We at Pegasus have found that a SAW filter works best for this. In a cordless telephone application a SAW duplexer is often used.

A duplexer is a pair of filters and a RF combiner. It has two inputs and one output. The inputs are responsive to frequencies at opposite ends of the 902 - 928 MHz band. So you might have the transmit side operate at 903 MHz and the receive side operate at 927 MHz.

Receiver RF Section:

The receiver in the '262 is amazingly sensitive. We have had good luck with it at signal levels of less than -90 dBm! The input signal is amplified by a low noise amplifier stage and then fed to a double balanced mixer. The local oscillator for the mixer is supplied by a phase locked loop that operates off of the same reference frequency as the transmitter PLL. The receiver PLL does not need to be modulated so its loop bandwidth can be higher so that the phase noise can be reduced. Notice the smaller values of the loop components, C28 and C27.

The output of the mixer is a 10.7 MHz intermediate frequency (IF) signal. This signal is routed through standard ceramic filters like the Toko SK107 series or the Murata SFECS10M7 series or SFECV10M7 series, and is amplified by three stages of IF amplifiers. The amplified IF signal is then routed to the demodulator.

Receiver Baseband:

The IF signal is demodulated using a quadrature demodulator stage. The quadrature coil can be a standard IF can with a tuning slug or a ceramic demodulator. We have had good performance using the Murata CDSCB10M7 series of ceramic demodulators. The advantage to using these is that no turning is needed.

The demodulated audio signal is available on pin 47. Filtering of this signal is performed by R13 and C35 before it is amplified and expanded. The output of the expander goes through a volume control stage whose gain can be set digitally. This signal can them be further amplified by the speaker driver amplifier.

The audio signal also can be routed into pin 45 to perform data slicing. This gives a digital output signal on pin 24 that can be routed into your microcontroller for further processing.

Getting Started with the TB31262F

I have found that this chip is popular in 900 MHz cordless telephones. When I first started using it, I bought a Radio Shack® catalog number 43-3534 cordless telephone for less than $20. I used its FCC identifier on the FCC equipment authorization database to find its certification data and was able to download the phone's schematic.

I could then remove the microcontroller that is in the phone and connect my own. This made a very inexpensive development evaluation board for the TB31262F!

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UWB Update: Fall 2004

by Karen Edwards, Pegasus Technologies, Inc.

At press time, there is no movement on either side of the standards debate over multiband OFDM vs. direct sequence spread spectrum as the path forward for UWB. Both camps are proceeding as quickly as possible to churn out silicon and get them into products -- and on this front, the direct sequence camp has the lead. There's lots of activity going on right now, especially with the FCC weighing in on UWB with a second Report and Order that expands wideband use in certain frequency bands. Below is a compendium of press releases, FCC releases, and other news items on this topic.

FCC Amends Rules to Permit Wider Application of UWB in Non-Restricted Frequency Bands

On December 15, the FCC issued a Second Report and Order on UWB. In response to a Multispectral Solutions petition, the FCC agreed to permit new unlicensed wideband devices in the 6 GHz, 17 GHz and 24 GHz bands. This gives MSSI a huge leap forward in its ability to go forward on a wide variety of applications. Carefully distinguishing these wideband devices from UWB, the Second Report and Order dismissed a Petition for Reconsideration filed by the Satellite Industry Association, stating that it would continue to monitor the situation in the 4 GHz band, and also denied the Petition for Reconsideration filed by Cingular, Inc. In so doing, the FCC reaffirmed its decisions regarding UWB adopted in the first UWB Report and Order.

For more information, click on the links below:

Current UWB Industry News

MBOA Ultrawideband Techzone Showcases UWB Products and Applications at CES

LAS VEGAS, Dec. 16, 2004 - Sixteen of the world's leading semiconductor, personal computing and consumer electronics companies along with four key wireless industry organizations will appear together in the MultiBand OFDM Alliance (MBOA) Ultrawideband TechZone in the Innovations Plus area of the 2005 International Consumer Electronics Show (CES), Jan. 6-9, in Las Vegas. The intent of this cooperative appearance is to excite and educate the CES audience about ultrawideband (UWB), a revolutionary high-speed, short-range wireless technology with enormous potential for consumer electronics slated for release as early as the second half of 2005. The TechZone will also show the broad industry support for MBOA ultrawideband technology.

"By collaborating today, the 170-plus members of the MBOA-SIG together with the WiMedia Alliance, Wireless USB Promoter Group and 1394 Trade Association are demonstrating a high degree of broad industry commitment and cooperation for the MBOA UWB technology," said Stephen Wood, technology strategist for Intel R&D and a member of the MBOA-SIG promoter group. "This industry convergence around a single technology helps to ensure seamless interoperability between future products and will fuel the creation of a robust and fast-growing market."

The MBOA Ultrawideband TechZone will include eight live demonstrations of the wireless technology including bulk data transfers, quality-of-service based streaming video from various sources using wireless USB and wireless IP approaches.

The exhibiting companies in the TechZone will include: Alereon, Commstack, Focus Enhancement Semiconductors, General Atomics Advanced Wireless Group, HP, Intel Corporation, Mitsubishi Electric, Orangeware, Philips Electronics, Staccato Communications, Samsung Electronics, Texas Instruments, Taiyo Yuden R&D of America (TRDA), TDK, WiQuest and Wisair.

The exhibiting specification-building bodies, who are closely working together to ensure interoperability for MB-OFDM ultrawideband products, will include: the MultiBand OFDM Alliance (MBOA-SIG), WiMedia Alliance, 1394 Trade Association and the Wireless USB Promoter Group.

Other News

  • Sony Playing both sides of the UWB Fence?, Patrick Norton, Xtreme Tech, 12/17/04 Sony, a key player in the MBOA, is rumored to be demonstrating a direct sequence UWB chip at the International Solid-State Circuits Conference in February 2005.

  • Staccato Demonstrates Industry's First Complete Single-Chip All-CMOS MBOA UWB Chip

    San Diego, Calif., December 14, 2004 - Staccato Communications, wireless USB and ultrawideband (UWB) wireless silicon leader and pioneer, announced today that it has demonstrated to select customers the first version of Staccato's single-chip design for all major components of the RF and baseband specified by the newly completed MBOA PHY specification. This single-chip design is the latest in a series of all-CMOS test chips built by Staccato over the past 18 months but is the first to include all major components specified by the newly finalized MBOA specification. The chips have demonstrated the ability to transmit at the highest specified data rate of up to 480 Mbps. The all-CMOS implementation clears the path for low-cost, highly integrated silicon solutions for wireless USB and other UWB applications by taking advantage of mainstream generic CMOS foundry processes.

    "In terms of what it means for consumers, this achievement is significant," said Joyce Putscher, director and WPAN principal analyst for In-Stat/MDR. "Those familiar with the history of the Bluetooth and Wi-Fi markets can bear witness to the fact that all-CMOS solutions enable these technologies to be integrated into end products more quickly due to their significant price advantage. This can translate to early market share capture."

    "We are pleased by the results we have seen in the series of MBOA UWB test chips we have built so far," said Roberto Aiello, president and CEO, Staccato Communications. "We are now comfortable moving to production samples of the single-chip PHY for our customers as the next step and then quickly integrating the MAC and wireless USB functionality for a complete single-chip wireless USB chip in 2005."

    Staccato Communications' single-chip PHY products are expected to sample in early 2005, ready to accelerate retail PC, consumer electronic, and mobile phone products to market with ramping production later in the year. Complete single-chip wireless USB silicon will sample in late 2005. Both products will be available with complementary development kits to key customers.

  • Pulse~LINK Demonstrates 667 Megabit Wireless UWB Communications

    CARLSBAD, CALIF- December 13, 2004 -- Pulse~LINK, Inc. announced today that it has achieved the highest data rates ever transmitted and received for Ultra Wideband (UWB) wireless communications, demonstrating 667 Mbps of throughput after forward error correction. The new high-speed chipset architecture, capable of surpassing one Gigabit, presents CE manufacturers with DVI, HDMI and 1394b cable replacement opportunities for interconnectivity of high-end multimedia devices and wireless streaming of HDTV.

    "Our actual over-the-air data rate is at present 1.3 Gbps per second, with the data throughput presently at 667Mbps", states John Santhoff, Founder and CTO. "Over the next thirty to sixty days, optimization will bring the throughput to Gigabit data rates."

    Pulse~LINK will begin making Gigabit wireless UWB evaluation kits available to partners in February 2005. The company's Gigabit RFIC is presently in fabrication and evaluation kits based on the sample RFIC are planned for release in April 2005. In addition to its high speed UWB technology, Pulse~LINK is introducing a new forward error correction technology for wireless communications that is far more efficient at extremely high data rates than the Viterbi forward error correction technology commonly used in other wireless communications.

    The high data rates achieved with Pulse~LINK's chipset will enable the first wireless solutions for DVI (Digital Visual Interface), HDMI (High Definition Multimedia Interface) and 1394b (Firewire) cabled devices. Cable replacement for these "video centric" interconnect technologies will allow wireless streaming of HDTV and high quality multi-channel audio for home theater systems. DVI, HDMI and 1394b are also used to interconnect multimedia electronics such as projectors, set-top boxes, high quality DVD players, video cameras, home theater systems and more.

    Along with providing higher data rate solutions, Pulse~LINK is pioneering longer-range UWB transmissions for Wireless LANs. "One of the primary requests we've heard from consumer electronics manufacturers of flat panel and high-end displays is for picture-in-picture HDTV wireless transmissions at 25 meters through at least one wall, which we have demonstrated." states Bruce Watkins, Pulse~LINK President and COO. "Pulse~LINK currently offers the only solution capable of sending multiple streams of HDTV wirelessly beyond a single room."

    In recent demonstrations, Pulse~LINK transmitted two simultaneous HDTV signals for "picture-in-picture" television through a combined seven inch thick concrete wall and an additional steel-frame drywall at ten meters and has demonstrated the same two streams at distances of 25 meters through one steel-frame drywall.

  • FCC Certifies Ubisense's UWB, By Mary Catherine O'Connor, RFID Journal Dec. 13, 2004. One of the first outlets of ultra-wideband RFID technology to get the FCC green light for commercial use, Ubisense is looking at applications as disparate as combat training and corporate office design.

  • Ultrawideband (UWB) Communications and Networking Symposium calls for papers by February 15, 2005. Wirelesscom 2005 will be held June 13-16, 2005 in Maui, Hawaii. Sponsored by IEEE, Wirelesscom is "The World's Premier International Conference on Wireless Networks, Communications, and Mobile Computing". For more information, see the Call for Papers and the general conference website.

  • Alereon Lays Claims To UWB Wireless Spec. Wireless broadband semiconductor house Alereon says it completed the industry's first over-the-air demonstration of 480 Mb/s and 320 Mb/s transmissions that meet the recently released Multi-Band OFDM Alliance (MBOA) ultra-wideband (UWB) specification. The company also says it took honors as the first company to demonstrate the mandatory 55 Mb/s-to-200 Mb/s data rates of the MBOA UWB specification.

  • Study sees trouble for UWB, By Mobile Pipeline News,, Nov 08, 2004. A lack of standards and high price are threatening to make a bust of ultra-wideband (UWB) wireless technology, according to an ABI Research study released November 8.

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Book Review: Dave Gorman's Googlewhack Adventure

by Jim Pearce, Pegasus Technologies, Inc.
Dave Gorman has a problem. He has been given a large advance by a publisher to write a novel and just cannot find it within himself to put pen to paper. Instead he becomes engrossed in extreme googlewhacking. Dave Gorman's Googlewhack! Adventure, published by Overlook Press on September 15, 2004, is the very personal and occasionally hilarious chronicle of his dilemma.

For those who are in the dark about googlewhacking, here is an explanation.

Google is the premier web search tool. It indexes billions of web pages and gives nearly instantaneous result when querying a word. It has become so indispensable to us webaddicts that searching using Google has become a verb: to google.

Often, googling any given word will turn up millions of pages that contain that word. Even unusual words will result in multiple thousands of hits. For example, I googled "kumquats" and found 76,900 pages, and "pentode" yielded 38,200. A googlewhack occurs when you find a combination of two words that only exist on one page in all of googledom. These two words must be English words (for English googlewhacking) that appear in There is just a single Google indexed page that contains both the words 'Kumquat' and 'Pentode.' This page isn't a list of random or ordered words, just a nice readable page with text on it, so it fully qualifies as a googlewhack.

For more information and a fuller explanation of the rules of this strange game, see our Googlewhacking page.

But back to the book. Dave Gorman started googlewhacking to avoid thinking about his problems, and before he knew it he was deep into a challenge from another David Gorman (who he located by, of course, googleing his own name). He (Dave Gorman, NOT David Gorman) would form a chain of googlewhacks by meeting the authors of pages that contain the 'whacks and having them supply him with two 'whacks of their own. Dave would then go visit the authors of the new 'whacks and so on. This chain had to be ten steps deep and be completed by Dave's 32 birthday. This gave him just slightly more than two months and meant that he would get tons of frequent flyer miles!

Although he is an international award-winning comedian, I had never heard of Dave Gorman before the review copy of this book showed up in our mailbox. After reading the book, I now feel as though I am on very personal terms with him, for better or worse! He is brutally honest in describing his mood swings as the likely success of his quest wavers. The descriptions of the personalities of the 'whackers leaves me feeling like I know them too.

The book was a little slow to get into, but by the midpoint I knew enough about our intrepid English adventurer that I was genuinely anxious to know where the next set of 'whacks would take him.

Did he make it? Well, that would be giving it away, wouldn't it? I can just say that I now know that Dave is a stand-up comedian and is presently performing a live version of this book in an Off-Broadway production. How do I know this? I googled it, of course!

For more information or to purchase a copy of this bestseller in the U.K., go to one of the links below:

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Job Search Spotlight
Career Advice for New Graduates and Entry-level Job Seekers

by Teena Rose

Teena Rose is a certified and published resume writer with Resume to Referral and author of "Rèsumè Designs & Job-search Strategies for College Grads" published by CareerEpublications in September 2003/

One of the biggest mistakes that individuals make in their careers is to go aimlessly through school or work in an entry-level position with no clear direction (goals). They wait until the homestretch - graduation, layoff, or departure - before taking a stab at other opportunities. Finding a well-paying job or locating opportunities for advancement shouldn't be treated as an afterthought, rather one that has been planned and prepared for months or years.

Preparation, preparation, and more preparation! Imagine signing up for a marathon and waiting until the day prior to begin preparing for the race. Obviously, you're not ready because of lack of training, you didn't seek the assistance of a coach or mentor, and you didn't assess the resources you would need on the day of the race. Without proper preparation, what are your chances of completing the race?

Like any serious step you'll take in life, you must first determine the number of baby steps needed to get from one spot to the next. In other words, where are you headed and how will you get there? Outline every obstacle or challenge that will hinder your progress of taking these steps. Each small step (short-term goal) will take you closer to satisfying the big steps, known as long-term career goals.

First, take a good look at the types of positions you've held to date along with your college major. Ask yourself, do I like where I'm at and where do I see myself in 5 years? Don't be ashamed if you're not sure. Visit your favorite job bank, type in keywords for your intended career field, and examine those positions to determine if any meet your satisfaction.

Second, write down job and career goals (preferably 6 months before graduating or the start of your intended job search). Job goals pertain to the position you currently hold now, whereas, career goals are the 'big picture' (e.g. career change in less than two years or targeting a six-figure salary). Research 2 or 3 positions that you would love to obtain TODAY along with those you're striving for in a couple of years.

Third, prepare yourself, your credentials, and your résumé based on your predetermined career opportunities and goals. Prepare to go back to college, join business groups, serve on committees, or alter your résumé to encompass all (or any) of these.

In a career journal, make notations of the positions that interest you along with the skills required for each. Add other entries pertaining to outstanding credentials, and miscellaneous obstacles in the order that'll need to be completed, with resolutions and proposed dates of completion.

The object is to not stand still. Navigate your future by performing a self-assessment that will get you from a to z in your career. Jay Block says it best in the book, The End of the Job Search, Mastering the Art of Career Design: "Defining your career aspirations is an essential step in the process of transforming abstract thoughts into tangible realities. Everything ever accomplished by man or woman first started as a thought." I challenge you to assess yourself and create a master plan. It's ONLY your career!

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