iboc / hd radio tm : engineering concerns aaron read (g.m. : finger lakes public radio)
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No, your presenter is not “drinking the iBiquity Kool-Aid”
IBOC / HD RadioTM : Engineering ConcernsAaron Read (G.M. : Finger Lakes Public Radio)
Already decided HD RadioTM is right for you? Here’s a look at what you’ll
need to do.
A little housekeeping first…
CBI listserv: www.askcbi.orgOpening for Student position on CBI
executive board. E-mail app to exdir@askcbi.org by Nov.15th Must still be a student thru Dec.2011
Fill out a feedback form, dammit!!
Essential Questions
Session is not about operational issues / concerns.
It’s about the engineering of HD Radio, and how it applies to your situation.
Are you an AM station?
We’re not going to talk much about AM.
Has a lot of problems, is only sparsely implemented.
Download these slides: www.friedbagels.com/cbi/
What is HD Radio?Hint: “HD” doesn’t stand for anything
HD Radio=brand name Digital sidebands
straddling the analog carrier
Some RF energy on adjacent channels In-Band / On-Channel =
“IBOC” Backwards-compatible
Download these slides: www.friedbagels.com/cbi/
Is it required?
Unlike DTV in 2009, it’s optionalAll-digital possible, but not
authorized by FCC yetPressure to migrate comes from
listeners, marketplace, campus politics, etc.
Download these slides: www.friedbagels.com/cbi/
What happens with HD Radio?Analog > Buffer > Blend to Digital
Takes a few secondsAnalog delay for time-align
IBOC uses HDC (AAC) codec If HD is lost, blends back to analog
Or mutes for HD2, HD3, etc
Download these slides: www.friedbagels.com/cbi/
Simple FM IBOC Transmission Topology – All IBOC Gear at Transmitter Sitediagram courtesy of The IBOC Handbook, page 401
FM IBOC Transmission Topology – with Exporter and Exgine Modulesdiagram courtesy of The IBOC Handbook, page 405
FM IBOC Transmission Topology – with Exporter & Exgine Modules, plus Importerdiagram courtesy of The IBOC Handbook, page 413
What is HD Radio? (FM)
Digital carriers = bits & bytes 96kbps std (+12 or +24 ext.hybrid or “MP3”
mode; More carriers closer to analog carrier = no work with 92kHz SCA)
Multicasting (HD2, HD3…HD7) PAD/PSD, iTunes Tagging, Downloadable
Content, etc. 20kHz audio bandwidth No multipath interference or stereo hiss
Download these slides: www.friedbagels.com/cbi/
What is HD Radio? (AM)
Also just bits & bytes, just 32kbpsNo multicastingPAD/PSD, just barelyImproved audio quality
Download these slides: www.friedbagels.com/cbi/
Multicasting
Killer appExtra stations hidden in the signalRequire an HD tuner to hearSubdivides 96kbps total
Ext.Hybrid is separate
Download these slides: www.friedbagels.com/cbi/
iTunes Tagging
www.hdradio.com/iTunes_TaggingPress TAG buttonRadio saves tag to iPodNext time iPod synchs, iTunes
buys it automatically Very cool, but limited receivers /
stations doing it.
Download these slides: www.friedbagels.com/cbi/
More HD Radio power, pleez! Standard was -20dBc (1/100th) FCC blanket increase to -14dBc
Up to -10dBc in specific cases Hi-lvl combining / common amp – derating by 50%
-20dBc common amp TPO = 4.00kW (16.0kW) -14dBc common amp TPO = 2.65kW (10.6kW) -10dBc common amp TPO = 1.98kW (8.52kW)
Means a MUCH bigger transmitter is needed! MUCH better HD coverage – better for HD-n, too
Download these slides: www.friedbagels.com/cbi/
FM translators and boosters Boosters (Single Freq. Network)
NRSC-5 specs carrier synch, but no radios support it yet. Only prelim testing.
Translators require separate iBiquity license (i.e. $20k)Unless you get a heterodyning xlatorWEOS/W212BA case study
Download these slides: www.friedbagels.com/cbi/
FMeXtra?
Digital SCA (Subcarrier) service Compatible with hybrid IBOC, but not
all-digital IBOC. Transmits 64 – 156kbps
Stereo, RDS, analog SCA = less kbps avail. Transmits DATA, but architecture only
supports audio via AAC at the moment.
Shameless Self-PromotionThe IBOC Handbook : Understanding HD RadioTM Technology
Looking to really learn the engineering of IBOC / HD Radio? Read this book! First Overview of the Approved
NRSC-5 (IBOC) Standard. Authored by David Maxson Illustrated by Aaron Read
Available on Amazon.com
Final Thoughts
Questions – and please no: Rants, Screeds, Diatribes, Harangues, Raving, Tirades, Bullyragging,
Vociferation, Bloviating, Railing, Objurgating, Badgering, Molestation, Nettling, Ruffling, Badgering, Pestering, Heckling or Persecution.
Tell us your situation, we’ll opine if HD Radio or FMeXtra is right for you!
Aaron Read can be reached via www.friedbagels.com/blog Need an engineer? Yes you do! www.sbe.org
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