Antennas and Combining

Analog FM Signals

Multi-station Combining

Combining Digital Signals in the FM Band

Common Amplification

        Co-Synthesis

        Low-Level Combining

High-Level Combining

        The High-Level Combiner

        Why a 10-dB Combiner?

        Efficiency and Heat Load

        Mismatch and Isolation

            Turn-around Loss

            Minimizing Unwanted Interaction

            Directivity

            Isolation

Split-level Combining

        Efficiency

        Considering the Options

        Isolation

Combining with Antennas

The IBOC-to-Antenna Path

Dual-Feed Antenna

Separate-Antenna Operation

        Separate-Antenna Research

        Separate-Antenna Regulation

Multi-Station Antenna Systems

        Common-Line IBOC to Multi-Station Combiners

        Separate-Line IBOC and Multi-Station Combining

Crest Factor and Peak Power in Hybrid IBOC Transmission

OFDM Peak to Average

Relate OFDM to Analog

OFDM Peak to Analog Peak

OFDM RMS to Analog RMS

Hybrid Crest Factor

Difference Between Hybrid and Analog Crest Factors

Chapter 13: TABLES
13.1 High-Level Combiner Power Budget
13.2 Comparison of Combining Efficiencies
13.3 IBOC-to-Antenna Paths
13.4 Three Stations Tested for Separate-antenna Performance
13.5 Multi-station IBOC Combining Options
13.6 Computation of Hybrid IBOC Peak-to-Average Power Ratio

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Chapter 13: FIGURES
13.1 Composite Baseband (Source: NRSC)
13.2 Creation of an FM Signal
13.3 Spectra of Frequency Modulated Broadcast Signals
13.4 Branch Combiner
13.5 Balanced Combiner
13.6 90-degree Hybrid
13.7 Co-synthesis and Low-Level Combining
13.8 High Level Combining Diagram (Courtesy of Shively Laboratories)
13.9 Combiner Signal Paths
13.10 Split-level Combining Diagram
13.11 Harris Coupling Coefficient Calculator on the World Wide Web
13.12 Common-Line and Separate-Line Topology
13.13 Quadrature-fed FM Antenna
13.14 Field Test Measurements of Digital-to-Analog Power Ratios for Combined- and Separate-Antenna Operation (Source: NAB)
13.15 IBOC and Multi-station Combiners
13.16 Illustration of Peak-to-RMS Relationships of Two Waveforms

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