US 6,982,948 B2
Method and apparatus for transmission and reception of FM in-band on-channel digital audio broadcasting
Brian William Kroeger, Sykesville, Md. (US); and Jeffrey S. Baird, Columbia, Md. (US)
Assigned to iBiquity Digital Corporation, Columbia, Md. (US)
Filed on Jan. 15, 2003, as Appl. No. 10/342,764.
Application 10/342764 is a continuation of application No. 09/438148, filed on Nov. 10, 1999, granted, now 6,549,544.
Prior Publication US 2003/0137928 A1, Jul. 24, 2003
This patent is subject to a terminal disclaimer.
Int. Cl. H04J 11/00 (2006.01)
U.S. Cl. 370—208 30 Claims
OG exemplary drawing
 
1. A transmitter for transmitting data in a digital audio broadcasting system comprising:
means for providing a plurality of orthogonal frequency division multiplexed sub-carriers, said sub-carriers including data sub-carriers and reference sub-carriers;
means for modulating said data sub-carriers with a digital signal representative of information to be transmitted, and for modulating said reference sub-carriers with a sequence of timing bits, said sequence of timing bits including an unambiguous block synchronization word, wherein number of bits comprising said block synchronization word is less than one half of the number of bits in said timing sequence; and
means for transmitting said orthogonal frequency division multiplexed sub-carriers.