Happy New Year! I993 The Year For SS?

Photo courtesy of Qualcornm Inc. and RF S: Microwaves Magazine

SSS Plans for 1993

We hope 1993 will be anexciting and eventful year for theSpread Spectrum community. Inour editorial this month, on page4, we make a few predictionsand prognostications about what

may happen in our business thi:year.

We have some interestingp l a n s f o r b o t h RF/SS (01.11consulting arm) and SSS for thisnew year. We share some ojthese plans with you in the “SSSPlans for 1993” article on page 7.

/PRE-SORTFIRSTCLASSU.S.POSTAGE

8pmd3~mmeAn RF/SS Publication

P.O. Box 2199El Granada, CA 94018-2199 PAID

PEFtMITNO.7ELGRANADA.CA

Article m

Rumors & Ramblings 4

IZecipherings 4

Editorial 4

The Aerial 5

SSS Plans for 1993 7

International Scene 7

Washington Scene 7

Cartoon 8

Equipment Corner 8

GPSS Xcvr-Part 3 9

Tale of Two Chips 11

February Preview 12

SPREAD SPECTRUM SCENE isdedicated to the Spread Spectrumprofessional and is committed tobeing the primary source for the lat-est news and information about thegrowth, regulation, and OppOrtUnitieSin this emerging science.

SSS provides a forum for publicationof technical information, advertising,editorials, opinions, and newsrelating to the emerging fields of ourcoverage and emphasis. SSS Is atargeted circulation publication. Wehave chosen a distinguished cadreof the most important decisionmakers in this new industry to bethe readers of SSS. SSS is sent byfirst class mail to this importantcadre of industry “movers andshakers” each month. SSS canpresent your advertising message tothe key designers, equipmentdevelopers, programmers, systemintegrators and end users in thisnew Industry. Call our 800 numberHotline to request a Media Kit

Editor & Publisher:Randy Roberts

Editorial Consultants:M. N. RobertsContributors:

Tom Diskin, Dan Doberstein,John Greene, Matthew

Johnson, Peter OnnigianR&D Staff:

Chris Kilgus

ISSN 1066 - 0550

Published bv: RFlSSP. 0. Box 2199

El Granada, CA 94018-2199

Telephone Numbers:Voice: 4157266849FAX: 41 S-726-01 18

InternetNUCP Email:hithr@well.sf.ca.us

Advertising & SubscriptionHotline:

Voice: 800-524-9285

SSS is published monthly and isavailable by subscription. You canreceive a complimentary copy bysending us a self addressed 9 x 12

1993 Predictions andPrognosticntions

1993 should be a greatyear for the SS c o m m u n i -ty/industry. After several yearsof more or less lackluster growth,economic meandering and vendorshake-out, 1993 looks to be avery promising year. The newPresident will appoint a new FCCChairperson and two other com-missioners. We will have a newfocus in the executive and legis-lative branches of governmentand with just a little luck we mayeven start to turn around thisrecession.

) Cirrus Logic Inc., Fremont, CAacquired Pacific Communicationsciences Inc. (PC%) of San Die-$0, last month. PCSI, anotherWA-Comm Linkabit spinoff, is aeading high tech supplier ofEuropean DECT and CT- 1,2 and3 cordless/cellular telephones.?CSI has long been known as a‘sleeper” in the SS business anda force to be reckoned with.They have many capabilities that Iparallel Qualcomm’s and theirmain engineering staff was alsotrained on the military projectsthat Linkabit pioneered. CirrusPCS1 exhibited at the WirelessExpo -- but their booth was sel-dom manned. What gives?@ Nippondenso of Carlsbad, CAdid not have a booth at the Wire-’less Expo, but they left flyersaround the registration area list-ing more than a half dozen open-ings for engineers and managers.ND did you know that you-canreach these folks directly throughthe pages of SSS at no cost?8 Heard a good rumor .-- want to“leak” some info to your compe-tition -- call our 800 number andwe may print it!

/DecipheringsEDUCATION IS WHAT SUFiVIVES

WHEN WHAT HAS BEENLEARNED HAS BEEN

FORGOTTEN.

- B. F. Skinner -

With this background Iwill look into my crystal ball andmake a few prdictions about whatis to come in this business in1993:

(1) Look for several key SShardware vendors (no names, orI’ll probably be sued) to run intofinancial difficulties if they insiston selling SS equipment thatcannot meet today’s FCC part15.247 rules.

(2) Look for more confusion,politicking and total lack of ciire-ction from Congress on legisla-tion required to enable the PCN-/PCS business in this country.

inch stamped (S.75 US postage)envelope.

SubscriDtion

(3) Look for the battle betweenRBOCS (regional Bell operatingcompanies or “Baby Bells”) andthe cable companies to heat up inthe US. Both sides will try tojump into the PCN/PCS businessin some way.

12 Months - US First Class Mail - $49.9512 Months - Foreign, AIR MAIL - ~70.00

US Funds

Don’t miss an issue ofSpread Spectrum Scene.

Subscribe now!(4) The FCC may start experi-mental licensing of un-used UHFTV channels to entities that want

Spread Spectrum Scene January, 1993

to try new technologies out onthe public. This prediction re-quires the FCC to proceed rapidly

with ~TV s tandard se t t ing,itself a rather risky business.

in 1993 -- who knows?

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7

(5) I predict that the newwireless PDAs from Apple, EOand others will hit the market thisyear and go over like leadballoons.

(6) I predict the appearance ofseveral new innovative SSwireless products on the market,that are targeted for the IndustrialSegment of this marketplace.They will not only meet currentFCC rules , they will berea sonab ly p r i ced , widelyavailable and fully functionalwhen announced.

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(7) I further predict that smokemirrors, FM and advertising hypewill continue in this business forsome time. The users and buyersof SS hardware don’t want it --but, just like the computer andsoftware sides of our high techbiz, this stuff is almostunavoidable.

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(8) Finally, I predict that Eshowdown and shakeout will starto form between those that hawkcellular telephone technology

i( l ike Motorola’s ARDIS) amothers who provide SS equipmenand services. I feel that pay b:Ythe minute or by the byt e

technology is a consume:rdeadend when SS is what ou .rcustomers want and need. T 0

make SS the technology c,fchoice will require more thansetting up groups like WinForum.It will take baptism by fire in themarketplace and Congress-ional/FCC action. Will we see it

*he Wireless Synzposirrnzand Exhibition Report

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We attended the Wirelessfmposium and Exposition, Jan-t-y 12 through 15 at the Sanse Convention Center. It wase first show concerning theireless area to be held by RFid Microwaves magazine, part’ Penton Publishing.

The show was a greatLccess -- with something like500 paid attendees. I was a ses-on chairman at the Friday mor-ing PCS session of five paper:Id attended every day of thelow. RF & Microwaves maga-ine and Mr. Jack Brown kindlylade available a display area forur seven foot by two foot SSSanner and allowed us to hand#ut sample issues and subscrip-ion flyers. More than 1500beople picked up on SSS. Thank‘ou one and all -- now let’s gelhose subscriptions and advertis:ments in!

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Seriously, with over lO(vendor display booths and some50 or 60 technical papers thiwas the wireless show of 1993in our opinion. This show wilbe hard to beat by any conferenctrying to cover wireless, PCS cLAN/MAN/WAN happeningthis year. Jack Brown didgreat job the first time out witthis effort!

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The conference digest wibe published soon and should 1available for purchase. Our ne:issue will summarize the most in-teresting papers.

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Peter Onnigian, P.E., W6QEU

In last months c01urn.n wevered antenna construction andrforrnance. This month we’ll dis-ss the installation of Spread Spec-un and other high frequency an-Inas, their supporting structuresd coaxial transmission lines tonnect to the electronics. A goodstallation, done properly will in-:re long term operation and pre-:nt damage to the equipment.Then it meets local building codes,will help you in defending your

r-m against damage suits in court!

A&ma Supports - Outdoors

Suitable pipe masts may besbtained from Radio Shack or fromRohn Mfg, Peoria, IL. Rohn sup-plies 30, 40, and 50 foot telescopicgalvanized masts, complete withbase plates, braces, guy wire assem-blies, roof anchors, etc.

The antenna should be lo-cated with two important criteria inmind. First, it should be placed soas to have line of sight conditionsto the other station with which com-munications are to be established.Secondly, the antenna must nothave a very long coaxial transmis-sion line run. This may be neces-sary in which event, larger sizecoaxial cable must be used to keep

January, 1993 Spread Spectrum scene 5

Not all antenna support in-Lallations are identical. Only 5-p:a1 planning considerations can be‘utlined here. Perhaps the easiestnethod of mounting is to put up agalvanized steel pipe or aluminumube, to which the antenna is moun-ed. Nearly all antennas for SS ap-)lications will easily mount to pipesvhose diameter varies from 3/4 tol-1/2 inches.

the RF efficiency high.

Indoor Instahtions

For LAN or for short range,say less than five miles, betweenthe LAN and the central station, theantenna may be placed indoors. Arather simple antenna installation ispossible. Indoor installations haveadvantages such as lower cost andfaster erection time. Such antennascan be placed between drop ceilingsand the next floor. Existing verticalstraps, pipe or even drop ceilingwires maybe used to hold theantenna in place and pointed in theright direction. Tests should bemade as to the best Yagi pointingdirection, as local reflections maybe very strong.

Outdoor Installations

For outdoor locations, theroof is probably the best location.Sefore installing, it must be de-rftnnined that a line of sight condi-tion exists to the station to whichcommunication is to be maintained.

Modern buildings havemany suitable objects such as airconditioning, window washing,exhaust fan housings, which may beused to hold these Yagis. Someare good, while others are not.Don’t attach anything on the roofun:il you have received permission,preferably in writing, to install theantenna? its support and coaxialtransmission line. Working withthe building manager is a must.

Installing Coax Cable

After the exact location ofthe antenna has been determined, itstime to run the coaxial transmissionline from the antenna to the elec-tronics.

There is a correct way antan in-correct way of uncoiling antor Pulling coaxial cable. Nearly al

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:able will be at least four tenths offn inch in diameter. The cablenust be reeled out. The reel must)e turned on its axis as the cable is-eeled out. It should not be playedlut so that the cable is twisted 360”:ach time one turn is removed from;he reel.

Don’t run the cable on theroof unprotected. Run it throughconduits. Use cheap PVC to protectthe cable from mechanical abuseand from being under foot. Thebuilding manager will probablyrequire you to run the cable in con-duit. Because of the very smallvoltage [14.15 volts RMS] any sortof pipe or wood grating maybeused, and will meet the UBC, NEC,and other codes.

Cable running verticallyshould also be protected andsupported by tying with plastic tiesevery two feet of height. Don’tover tighten these, so as to dent theouter cable jacket.

Entry into the roof requiresspecial precautions. Check with thebuilding maintenance people or witha roofer, on the best way to accom-plish this. Don’t ever drop the cableon the outside of the building andmake entry on the proper floorthrough a window!

Running coax inside thebuilding is an art, not a science.The electrical, telephone, or airconditioning duct work may beused. In this event, you’ll have tohave coax which is flameproof, andmeets fire codes. Beldon and otherscarry flame proof plenum cable inthe popular sizes, such as 9913,which is excellent electrically aswell as meeting this fire requi-rement.

Connectors

Either Type N or BNC ca-ble connectors can be used. Theycan be mixed, that is a N at the an-tenna, and BNC at the radio end. If

:ouplings must be made in the:able, type N males on the cables:an mate to a common N femalecarrel to make the splice.

Environmental Considerations

Due to the maximum ofTour watts maximum radiatedlower, there is no knownion-ionization hazard.

All outdoor exposed hard-pare should be of the stainless steelype. Some antenna firms use allstainless steel hardware while others30 not in order to cut costs. For atruly professional installation platedoutdoor hardware on the antenna, orsupporting structure, should beused.

In areas where icing occurs,the antenna wind load push plus icecoating increase niust be taken intoconsideration. The last thing you oryour firm would like to hear is thatyour antenna blew down, andcaused damage to personnel on theground, or damage to property.Outdoor antenna installations arenot places for in-experiencedinstallation people. The support,guying and/or mounting must bedone in. a good workmanlikemanner.

When in doubt, especiallyon high rise buildings, consult astructural engineer and go over yourplans with them. A couple of hun-dred dollars spent with structuralpeople is wisely spent, when con-sidering the alternative in ourlitigious times.

The writer has had experi-ence with this sort of thing, whichtook over four years to legallyresolve, cost thousands of manhoursin hearings and depositions, andmany thousands of dollars in legalfees. Be careful out there!

Send your antenna questions toPeter Onnigian, c/o SSS

6 Spread Spectrum Scene January, 1993

SSS Plans for 1993

m/SS and SSS h a v esome new plans for 1993. R.F/SSwill be making some strategicalliances with one or more BayArea engineering firms to furtherour product development andconsulting practice. These alli-ances will allow RF/SS to moreaggressively market our productsand services. It may also allowsome of R_F/SS’ associates tobecome a little busier than theyare today. SSS plans to grow incoverage, monthly page count,technical content and readership.

Effect ive February 1,1993 the domestic subscriptionprice for SSS will increase to$49.95. The Foreign Air Mailrate will also increase to $70.00(US funds). These rate increasesare necessary to offset the costsof printing, postage, handling andadministration. SSS will still no1make any real money until (or if:we secure a steady stream o:advertisers.

SSS will be starting twcnew columns in the Februar!issue:

(1) Ham Radio Happenings

(2) Consultant’s Comer

We have located a columconductor for the second columrbut still need someone to take othe “Ham” column -- anyone 01there interested? If you are jugive me a call or drop me a notr

Finally, we plan to addpart time Editor and AssocialPublisher, as well as someone I

help with advertising sales arother administrative choreAgain if you’re interested, ca’write or FAX.

l Mitsui Trading Company, Kin-zoku and a new Los Angelesstartup have announced the avail-ability of a group of SAW (Sur-face Acoustic Wave) convolversdesigned for SS applications.These devices and radios usingthem were shown at the WirelessSymposium and Exposition inSan Jose.

@ Science News recently ann-aunced the discovery of the 32ndMersenne prime number, thelargest prime yet discovered.Mersenne primes have mathemat-ical properties that make theminteresting for PN code genera-tion among other things.

Q SRI International is sponsoringyet another January Conferenceon subjects related to “wireless’and SS technology. To be helcJanuary 19-20 at the San Francisco Hilton, the “Portable Intelligence Expo” will feature exhibitby more than 50 companies antDr. Tom Stanley, FCC ChieEngineer will give the Keynotaddress. Call Mark Cummings 2415-326-6200 or FAX him 2415-326-5512 for more inform;tion.

l Look for a report from RustRushton, VE6TL, next month iSSS on the progress of the Cagary ham SS group.

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Apple Computer Inc.‘sNewton Personal Digital Assis-mt continues to stir up the press.Lpple has now signed partnershipgreements with R. R. Donnelley3 provide travel-based applica-ions using GeoSystem streetnaps and travel data; Motorola tolrovide a radio for Newton; andtierica Online to provide techn-,logy for future enhancements to9pple’s AppleLink on-line infor-nation service. We think it’swonderful -- Apple continues toprovide employment for mis-guided children who need littletoys.

Seriously, and in all fair-ness to Apple, the Newton seemsto be coming of age. Will any-body buy it? Will anybody useit? Will anybody care aboutNewton (beyond the press)? Wedon’t think so -- but we could bewrong. You the readers, theconsumers and the competitionApple will face will largely deter-mine Newton’s fate.

Apple Computer Inc.3 Newton Personal Digitalhsistant is capable of wired or wirelesscommunications

January, 1993 Spread Spectrum Scene 7

. /

E q u i p m e n tC o r n e r

by Chris Kilgus

Electrical Engineers andTechnicians have always used avariety of resources to obtain theparts for their projects. I startedwith ham radio at a young age inrural Kentucky. My link to theelectronic parts world was tearingup old TVs and my Allied Radiocatalog. I was always lookingfor the mailman. A local RadioShack is a resource that isunappreciated by anyone whohasn’t had to live without them.They are like 7-11 stores, youwouldn’t do your groceryshopping there, but what wouldwe do without them.

I have always beenfrustrated by distributors and repswho have their $50 minimumsand an unwillingness to providesmall quantities for prototyping.I think that more and more,engineers are being required tolocate their own parts. Every callto a distributer starts with thequestion about where you arecalling from. After a wait,someone comes on the line andasks you where you are callingfrom. Ten minutes later you findthey have the part but can’t sellless than a tube of 62 or that theyhave a $100 minimum. Therehas got to be a better way. Thereare some changes taking placeand one of the best is Digi-KeyCorporation (800-344-4539).They are aggressively providinga service to everyone who hasstruggled to find parts. They arethe one stop shop for SMD parts ,

“I dorii think our newesf nefwork configurafionis going fo work. All of our frmsmissions from

Ohio seem 10 be coming in over my eleciricpencil sharpener.”

in small quantities. They are HPIB) for $3400. Anybody whofast, have knowledgeable has looked into a synthesizedoperators, and no minimum. generator will know what a good _

There is a reasonable $5 handling deal that is. I think Test Lab hascharge on orders less than $25. a few more.

You can’t beat the surplus Designer kits are how youstores for a bargain, if you have really increase your productivitythe time. Nuts and Volts has in the lab. Nothing wastes moremany listings. The best surplus time than digging around in astore I’ve seen is Haltek in box of resistors looking for aMountain View, CA. (415-969- certain value and settling on05 10). Right next door to them something that is “close enough.”is a great place to get Digi-Key has the kits and Ireconditioned test equipment. recommend everyone get a l/8Test Lab Co. (800-442-5835) has watt resistor kit and a discracks and racks of prime HP and capacitor kit. Inductors are moreTEK equipment. One of the subtle, but I have found anguys there, Bill Pollard, will also excellent kit from 3L Globallocate hard to find stuff. My Electronics (813-343-2679). Forcompany picked up a HP8656A about $40 they provide 64 valuesRF Generator (.l - 990 MHz w/ from .l uH to 1000 uH, ten coils

8 Spread Spectrum Scene January, 1993

per value. For SMD coils thereis no way to beat the Cl00 Kitfrom Coilcraft (800-322~COIL).They have even supplied me withrefills at no cost.

MY a d v i c e t o alle l e c t r o n i c c o m p o n e n tmanufactures would be to providedesigner’s kits to engineers. Thatis the most effective way to gety o u r p a r t s des igned in toequipment.

While I am on my venderbandwagon, I would like to makea pitch for one more company,JAN Crystals (800-JAN-XTAL).Tlney can provide you wi thcrystals shipped the next workingday for only $15 extra percrystal. I have also used their $7deal where they ship in 3working days. That service haskept many of my projects onschedule. Add this cost to theirtypical unit price of $12, and youhave a Blue Ribbon Vendor.

Any SSS reader thatwould like to give a vendor therecognition they deserve (positiveor negative) send it along to me,cio sss.

Have you been to a goodelectronics trade show lately? Ican’t say I have. There was alarge turn out at Weston in LA a

couple months ago, but I didn’lcome away excited. Many of theExhibitors are interested in jus“running your card, so we carsend you more information.’Well, sure enough, thtinformation arrives months lateby 3rd class mail. By that timeI can’t remember why I wa,interested in the first place. T~Imost effective approach to gettinla product out there is to offesamples. I think they are wastin;their money on monogrammelgolf tees and key chains. Advic

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o salespeople, if you hand out a:atalog make sure it has yourlusiness card attached to it.

I will be attending theJcrireless Symposium Exhibitionit the San Jose ConventionZenter this month and I amloping that this event breaks the:hain of boring shows. After all,RF is one of the few areas of:lectronic technology that isoffering something new. I amtaking a workshop by RichardWebb, “System and ReceiverDesign.” Included with thecourse is a software package ofanalysis programs. I will reviewthe course and software in anupcoming issue. They are alsohaving a workshop by the renowne x p e r t o n spread-spectrumsystems, Dr. Jack Holtzman.Unfortunately, both workshopswere scheduled for the same timeslot and I could only attend one.

I will continue next monthwith more practical informationthat I hope you find useful.

A 16 kbs Full DuplexSpreaci Spectrum RFData Link -- Part 3

by Dan Doberstein, PresidentDKD Instruments

Data Demod and AudioCircuitry

Last month we coveretthe code lock circuitry. Thi,month we examine the dat;demodula tor and the auditreconstruction using the CVSIdemodulator.

A Costas Loo:demodulator is used to recovethe data from the 455 Khz IIOf course we must have codlock before an IF would b

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Iresent. Assuming code lock the,55 KHz carrier has just the datanodulation on it, the remainingl i ther m o d u l a t i o n b e i n gnegligible. The incoming carriers first limited to remove anyamplitude variation. Since thenformation is carried in the?HASE o f t he ca r r i e r t h i soperation does not destroy anydata information. After limitingit is split and sent to twoidentical phase detectors. ClassicCostas loop demodulators usethree, four quadrant, multipliers.This design approximates thesemultipliers with two phasedetectors and one doublebalanced modulator. The Exarpart XR22 11 contains two phasedetectors, a VCO with 0 and 90degree outputs, Input limiter andthe Inphase limiter. The MC1496does the chopper/modulatorfunction. T h e t w o p h a s edetectors compare the phase ofthe carrier with the VCO output,one at 0 degrees, the other at 90degrees. Two channels are nowpresent, the I or Inphase, and theQ or Quadrature. The Inphasechannel carries the recovered dataas shown in the timing diagrams.

The output of the phasedetectors are lowpassed with thebandwidth approximately equal tothe data rate. T h e inphasechannel is now limited and sentto the MC1496. This limitedsignal is used to switch theoutput of the MC1496 frominvert to noninvert state. Hencethe chopper designation. Toachieve this the MC1496 is usedin its Double sideband,S u p p r e s s e d c a r r i e r m o d eEssentially the Inphase channelaffects only the SIGN of theMC 1496 output not itsmagnitude. The MC1496 outpu:

January, 1993 Spread Spectrum Scene r

is then lowpased by the Loopfilter and passed to the VCOcontrol point. The loop filterserves exactly the same functionas the loop filter in a standardPLL. The Loop, Inphase andQuadrature filters are all singlepole RC types. The Loop filtershould have a time constant ofabout 2 to 10 msec.

The timing waveforms showoperation assuming the loop hasacquired the carrier, in otherwords the f requency errorbetween the VCO and the IF iszero and the phase error is small.If there is any frequency offsetbetween the free running VCOfrequency and the IF (therealways is!) a small DC bias levelwill exist at the output of the

-Loop filter to correct out this

constant frequency error. If thisoffset is to large, or changes withtime i.e doppler shift caused byexcessive receiver or transmitterrelative movement, carrieracquisition will not be obtainedor ,in the changing case,maintained. This “bias” isillustrated in waveform 6.

The CVSD demodulator isfed from the re-synced data andreconstructs the audio signal fromthe serial bit stream. The 16 kHzclock is only valid when the wehave code lock condition.Without code lock the 15 kHzclock will not be synchronouswith the transmitted data clock.One of the primary advantages tocoherent Direct sequence systemsis that data clock synchronism isachieved simultaneously with

code lock.Continuously Variable SlopeDemodulator/$lodulator convertsthe audio signal efficiently to andfrom a low bit rate serial datastreams. It also does anotherimportant job by insuring achanging bi t s t ream dur ing“quiet” periods. Excessively longstrings of all ones or zeros cancreate problems in receiveroperation. Next month we finishup this design article with somethoughts on microprocessorinterface for code selection, aserial data interface and using theFujitsu dual PLL MB 15 19 insteadof the Motorola MC145168, aswell as a “hints and kinks”section for those of you braveenough to n-y out some of these

The MC3417

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Spread Spectrum Sccnc Janury, 1993

A Tale of Two Chips

by R. H. Roberts, DirectorRF/Spread Spectrum

My apologies to CharlesDickens for the play on words inthe title -- but, this article willdescribe two radically differentchips that can be very useful inSS equipment designed for the915 MHz, FCC Part 15, ISMband. In this the first part of thisarticle I will describe the Moto-rola MC13 176D IC. In the sec-ond half of the article (to appearnext month) I will describe thePacific Monolithics PM-TRl 00 1Gallium Arsenide cellular tele-phone transceiver chip.

The Motorola MC13176DSilicon IC is finally here! Thechip’s pinout and block diagramis shown in the figure to theright. I’ve waited for it for nearlyt\yo years. You may have troublegetting a hold of production qua-ntities of the chip (it’s very popu-lar) but samples should be obtain-able, easily.

T h e MCl3176D -is de.scribed by Motorola as a “UHEFM/AM Transmitter” IC. I havtused only the surface mountetplastic packaged “D” suffix partsIn quantity these little guys se1for under $2.00 -- a real buy! /sister part, the MC 13 175, is alsoavailable. The only real difference between the two parts is thinternal frequency divider rati’used to compare the internal UH:VCO to the reference frequencyThe ‘175 uses a divide by Z

while the ‘176 uses a divide b32. I favor the ‘176 for use ;915 MHz because you can uzinexpensive, nominally 30 MHovertone crystals as the frequentreference.

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PIN COfiNECTIONS ANDFUNCTIONAL BLOCK DIAGRAM

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Motorola hIC13175/6 Pinout andBlock Diagram.

This nifty chip is veruseful for low power transmitter*eceiver local oscillators, lo??ower test signal sources andnost of other uses. The chip caae both amplitude and frequentmodulated, internally. Just aian outboard doubly balancemixer and you can apply BPSPN modulation for direct squence. Use a DDS or frequentsynthesizer for the reference intead of a crystal and you’ve gotfrequency hopper -- need I s;more?

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Motorola supplies a littledevelopment board designed toget you on the air quickly withthis chip -- call them, they arethere to help!

RF/SS has designed thischip into several recent applica-tions. Our customers love thechip and it’s highly simplifiedsupport circuitry. This chip trulymakes possible a variety of 10%power, low cost applications thaiwere heretofore impossible.

In a typical application a3.3 to 3.6 VDC, the chip draw:only about 35 milliamperes wher

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ctive, and can be powered d0Lx-nI standby to next to nothing.‘0~ can easily get a few milli-Jatts of RF power output at 915/1Hz, more at lower frequencies.

I think switched cvstals.re possible with a small mod-fication to this desi*m, so that atill function transmitter excir-:r/receiver local oscillator can belone with only a handful of)arts. We are using this chip int variety of Part 15 devicestwithout any amplification for10th transmit and receive andalmost sware by it’s reliable,-epeatable performance.

Motorola supplies a 323age application note (Rev. C --iated 9/1S/91) for this part -- besure you ask them for a copy ofit! . It will help overcome ar,ydoubts you may have about thispart. It will also show sey;erslother example circuits using thedevice that you may find interes:-ing.

The schematic on the nexlpage is a typical application circ-uit that we came up with afterstudying Motorola’s literature.The circuit is a straightfohardapplication of the chip in FMmode using a 30 MHz, thirdovertone crystal reference. Thecircuit easily deviates 10 kHzpeak at audio rates at 915 MHz.Remember you are modulatingoutside the PLL’s loop bandwidthin this application -- so limit thelow frequency end of your modu-lation, otherwise you may unlockthe PLL!

I have run several experi-ments, and blown up a few parts,tlying to power the chip downand trying to AM it -- be careful!The chip works on microamperelevels of control current -- I’mnot used to that!

Janunry, 1993 Spread Spcctrunl Scene 11

Jnnouncing:

The 1992 SSSAnthology

A Complete, indexed reprirll of uI1 1992SSS issues

Available in a Special“Pre-Print” Edition

Order # AN-2: only $17.95plus $3.00 Shipping Sr

Handling

Published by RF/SS1-500-524-9255415-726-6849

P 0 Box 2199. . 1El Granada, CA 94018-2199

The schematic below isbuilt on a two sided PCB, withboth “ground” and Vcc “groundplanes.” Motorola’s applicationnote uses the same technique.This microstrip constructionseems to work well with thesesmall SMT parts at 900 MHz.No other special precautions areneeded to use the MC13176D.Use good quality chip caps,resistors and the L3 coil. Coil Llis hand wound of 24 or 26 gauge,silver plated solid copper wire,air core, wide spaced. The onlyRF tuning required is to squeezeor stretch Ll to achieve a reliablelock with chip’s on-board VCO.

Good luck using this part!Please send us any feedback youmay have. More next month onPM’s GaAs chip alternative.

Second Half; “A Tale of twoChips,” highlights PacificMonolithic’s PAI-TR 1001GaAs cellular phone chip.

InterestinrJ; More on DSP,HDTV, The Aerial and ourother regular features.

Tutorial: Finally, the longawaited c o n t i n u a t i o n o fTechnical Tricks - this timewith the scoop on correlators.

News: L a t e s t n e w s o nSpread Spectrum regulatory,new products and reports ont h e l a t e s t w i r e l e s ssymposiums.

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ENGINEERShe you interested in a new and challenging career working for a company that develops products for theemerging wireless communications markets such as Digital Cellular, WLAN, PCS, PCN, and GPS?

FsI currently has the following opportunities available:

Digital Cellular VCO Design Engineer WLAN RF Transceiver Design EngineerDigital Cellular Synthesizer Design Engineer WLAN System ArchitectDigital Cellular Transceiver Design Engineer RF Test EngineerRF MIvfIC Applications Engineer Quality Engineer (SPC, SMT, PCB)RF GaAs/Si MIMIC Design Engineer Quality Manager (SPC. SMT, PCB)RF Communications Systems Engineer Analog&fixed Signal Design EngineerComponents Packaging Mechanical Engineer Analog VLSI IC Design EngineerSMT Manufacturing Engineer (Box Build) Cellular RF/Microwave Technicians

The Wireless Communications Division of TsI pas ,cializes in placement of RF/Microwave and

Communications professionals nationally.

To learn more about these and other opportunities in utmost confidence call or send/fax resume to:

Aaron WooExecutive Search InternationalWireless Communications DivisionPruneyard Towers1999 South Bascom Avenue, Suite 700

Campbell, CA 95008

(408) 879-237-IFAX (408) S79-2329

Wireless Opportunities:

RF Transceiver DesignRF Systems EngineerDSFVDigital Modem EngineersASIC Design / Group HeadMMIC DesignManagers / Business Deveiopment

M e t r o t e c h C o n s u l t a n t s i s al e a d e r in t h e s e a r c h o ft e c h n i c a l a n d e x e c u t i v etalent in the communicationsm a r k e t p l a c e .

Coniact:John Kratz, President

Ben Garfinkle, Executive V. P.714-380-7881 or FAX 774-458-3663

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Policy:

SSS will carry Help Wanted ads as afree service to readers if thefollowing three conditions are met:

(1) The jobs listed are in SSS’field of endeavor or related to it.

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