IBOC AM Transmission Specification November 2001 iBiquity Digital Corporation 8865 Stanford Boulevard, Suite 202 20 Independence Boulevard Columbia, Maryland 21045 Warren, New Jersey 07059 AM Transmission Specification © 2001 iBiquity Digital Corporation 11/08/01 Doc. No. SY_TN_5010 Rev. 01 (410) 872-1530 (908) 580-7000 Table of Contents Contents 1 SCOPE ..............................................................................................................................................................1 2 ABBREVIATIONS, SYMBOLS, AND CONVENTIONS .................................................................................1 2.1 Introduction ...............................................................................................................................................1 2.2 Abbreviations and Acronyms ....................................................................................................................1 2.3 Presentation Conventions ..........................................................................................................................1 2.4 Mathematical Symbols ..............................................................................................................................1 2.4.1 Variable Naming Conventions ..............................................................................................................1 2.4.2 Arithmetic Operators.............................................................................................................................1 2.5 AM System Parameters .............................................................................................................................1 3 IBOC LAYERS..................................................................................................................................................1 3.1 Introduction ...............................................................................................................................................1 3.2 Waveforms and Spectra.............................................................................................................................1 3.2.1 Hybrid Waveform .................................................................................................................................1 3.2.2 All Digital Waveform............................................................................................................................1 3.3 System Control Channel............................................................................................................................1 3.4 Logical Channels .......................................................................................................................................1 3.4.1 Functional Components.........................................................................................................................1 3.4.2 L1 Service Access Point........................................................................................................................1 3.4.3 Scrambling ............................................................................................................................................1 3.4.4 Channel Encoding .................................................................................................................................1 3.4.5 Interleaving ...........................................................................................................................................1 3.4.6 System Control Processing....................................................................................................................1 3.4.7 OFDM Subcarrier Mapping ..................................................................................................................1 3.4.8 OFDM Signal Generation .....................................................................................................................1 3.4.9 Transmission Subsystem .......................................................................................................................1 4 FUNCTIONAL DESCRIPTION.........................................................................................................................1 4.1 Introduction ...............................................................................................................................................1 4.2 Functionality..............................................................................................................................................1 4.3 Transmission Subsystem ...........................................................................................................................1 4.3.1 Introduction...........................................................................................................................................1 4.4 Functional Components.............................................................................................................................1 4.4.1 Symbol Concatenation ..........................................................................................................................1 4.4.2 Diversity Delay .....................................................................................................................................1 4.4.3 Low Pass Filtering.................................................................................................................................1 4.4.4 Analog AM Modulator..........................................................................................................................1 AM Transmission Specification © 2001 iBiquity Digital Corporation 11/08/01 Doc. No. SY_TN_5010 Rev. 01 4.4.5 Analog/Digital Combiner......................................................................................................................1 4.4.6 Up-Conversion ......................................................................................................................................1 4.5 GPS Synchronization.................................................................................................................................1 5 WAVEFORMS AND SPECTRA.......................................................................................................................1 5.1 Introduction ...............................................................................................................................................1 5.2 Spectral Conventions.................................................................................................................................1 5.3 Hybrid Spectrum .......................................................................................................................................1 5.4 All Digital Spectrum..................................................................................................................................1 6 SUPPLEMENT A AM TRANSMISSION SPECIFICATIONS ........................................................................1 6.1 Introduction ...............................................................................................................................................1 6.2 Service Mode Switching............................................................................................................................1 6.3 Synchronization Tolerances.......................................................................................................................1 6.3.1 Analog Diversity Delay.........................................................................................................................1 6.3.2 Time and Frequency Accuracy and Stability ........................................................................................1 6.3.3 L1 Frame Timing Phase ........................................................................................................................1 6.3.4 AM Spectral Emissions Limits..............................................................................................................1 6.3.5 Alternative Spectral Emissions Limit for Hybrid Mode........................................................................1 6.3.6 Alternative Spectral Emissions Limit for All Digital Mode..................................................................1 6.4 Digital Sideband Levels.............................................................................................................................1 6.5 Analog Audio Source ................................................................................................................................1 List of Figures Figure 3-1 AM Air Interface L1 Functional Block Diagram ..................................................................................1 Figure 4-1 OFDM Signal Generation Conceptual Block Diagram.........................................................................1 Figure 4-2 Pulse Shaping Function.........................................................................................................................1 Figure 4-3 Hybrid Transmission Subsystem Functional Block Diagram ...............................................................1 Figure 4-4 All Digital Transmission Subsystem Functional Block Diagram..........................................................1 Figure 5-1 AM IBOC Hybrid Waveform Spectrum ...............................................................................................1