National Association of Broadcasters Engineering Handbook, 10th Edition

CHAPTER 4.7 FM and Digital Radio Broadcast Transmitters

GEOFFREY N. MENDENHALL*

Harris Broadcast Communications Division, Mason, Ohio

INTRODUCTION

Although the mathematical principles explaining frequency modulation (FM) have been known for many years, the advantages and practical application to radio broadcasting were not realized until the 1930s, when Major Edwin H. Armstrong conducted extensive developmental work proving that FM radio transmissions were possible and practical. Many theoreticians claimed to have proof that Armstrong’s experiments were impossible based on mathematical models claiming that an infinite transmission bandwidth would be required. He never received proper credit for his many contributions to the radio communications ...