*Pages 1--2 from  Microsoft Word - 46801.doc*
 1 
 PUBLIC  NOTICE  FEDERAL  COMMUNICATIONS  COMMISSION  News  Media  Information:  (202)  418-  0500  445  12th  STREET,  S.  W.  Fax-  On-  Demand:  (202)  418-  2830  WASHINGTON,  D.  C.  20554  Internet:  http://  www.  fcc.  gov 
 ftp.  fcc.  gov 
 DA  05-  609  March  8,  2005 


 MM  Docket  No.  99-  325 
 COMMISSION  CLARIFIES  POLICY  REGARDING  MULTIPLE  AUDIO  STREAMS  IN  IBOC  TRANSMISSIONS 


 Experimental  authority  must  be  requested 
 On  October  10,  2002,  the  Commission  authorized  the  commencement  of  interim  operation  with  the  iBiquity  hybrid  1  IBOC  systems.  2  Under  these  interim  authorization  procedures,  stations  may 
 use  only  facilities  similar  to  those  evaluated  by  the  National  Radio  Systems  Committee  (NRSC).  Since  the  NRSC’s  initial  recommendations,  certain  modifications  to  the  IBOC  system  have  been  introduced 
 and  tested.  In  particular,  National  Public  Radio  (NPR)  has  sponsored  a  program  that  takes  advantage  of  advances  in  audio  coding  technology  to  offer  multiple  digital  program  channels  within  the  bandwidth 
 originally  used  for  a  single  digital  channel.  3  The  program,  known  as  “Tomorrow  Radio  SM  ,”  has  been  tested  extensively  on  several  NPR  affiliates. 


 NPR  has  filed  test  results  indicating  that  the  FM  IBOC  system  can  accommodate  both  a  main  and  a  secondary  digital  program  channel  with  good  quality  and  sufficient  robustness  for  mobile  service. 
 NPR  requests  that  the  Commission  expand  the  digital  notification  procedures  to  permit  immediate  implementation  of  IBOC  systems  with  multiple  digital  channels.  Multicast  operations  do  not  fall 
 within  the  scope  of  the  notification  procedures  authorized  by  the  IBOC  Order.  Thus,  until  the  Commission  modifies  these  procedures,  licensees  will  be  required  under  the  rules  to  obtain 
 experimental  authorizations.  We  also  recognize  that  the  extremely  encouraging  Tomorrow  Radio  SM 
 1  The  term  “hybrid”  refers  to  a  system  which  transmits  both  the  digital  and  analog  signals  within  the  spectral 
 emission  mask  of  a  single  AM  or  FM  channel. 
 2  See  Digital  Audio  Broadcasting  Systems  and  Their  Impact  on  the  Terrestrial  Broadcast  Service,  17  FCC  Rcd 
 19990,  20004  (2002)  (“  IBOC  Order”). 
 3  Other  participants  in  the  Tomorrow  Radio  SM  program  are  Kenwood  USA,  the  Corporation  for  Public 
 Broadcasting,  and  Harris  Corporation’s  Broadcast  Communications  Division. 
1
 2 
 test  results  establish  the  feasibility  of  multiple  digital  audio  transmissions  in  the  hybrid  mode.  Accordingly,  we  issue  this  Public  Notice  to  clarify  the  procedures  which  licensees  should  follow  to 
 commence  multicast  transmissions. 
 The  staff  will  continue  to  authorize  multiple  digital  audio  transmissions  as  experimental  operations  under  the  provisions  of  47  C.  F.  R.  §  73.  1510.  Requests  for  experimental  authority  pursuant  to  Section 
 73.1510  require  only  an  informal  application,  typically  a  letter,  and  include  no  fee  or  form.  The  staff  normally  approves  requests  to  participate  in  this  type  of  experimental  program  within  a  week  of  receipt. 
 The  matter  of  expanded  notification  procedures  will  be  addressed  in  the  next  Report  and  Order  in  this  proceeding.  For  additional  information,  contact  Susan  Crawford  or  Ann  Gallagher  at  the  Audio 
 Division,  Media  Bureau  at  (202)  418-  2700. 
 By:  Acting  Chief,  Media  Bureau 


 -FCC- 
2