A Broadcast Engineering Tutorial for Non-Engineers

Skip Pizzi, Graham Jones

• Publisher: Routledge
• Year: 2014
• Print ISBN: 9780415733380
• eBook ISBN: 9781317906827
• Edition: 4
• Topic: Technology & Engineering
• Subtopic: Communication Studies
• Index: Technology & Engineering

A Broadcast Engineering Tutorial for Non-Engineers is the leading publication on the basics of broadcast technology. Whether you are new to the industry or do not have an engineering background, this book will give you a comprehensive primer of television, radio, and digital media relating to broadcast—it is your guide to understanding the technical world of radio and television broadcast engineering. It covers all the important topics such as DTV, IBOC, HD, standards, video servers, editing, electronic newsrooms, and more.

This long-awaited fourth edition includes new standards and identifies and explains the emerging digital technologies that are revolutionizing the industry, including:

• HDTV—and "UltraHD"
• IP-based production and distribution and Internet delivery (including "over-the-top" TV)
• Connected/Smart TV, Mobile TV Second Screens and Social TV
• "Hybrid" broadcasting (over-the-air and online convergence)
• Podcasting and Mobile Apps
• Connected Cars

CHAPTER 1Introduction

DOI: 10.4324/9781315848426-1

Broadcasting is a communications service that possesses two fundamental and unique attributes: (1) Broadcasting is a point-to-multipoint service, meaning that a broadcast service originates from a single transmitter but is receivable by an unlimited number of receivers within the coverage zone of that transmitter. (Compare this to a point-to-point communications system, such as telephony, in which one device typically connects only to a single device at any given time.) (2) Broadcasting is a unidirectional service, meaning that it carries content only in a one-way path—from the broadcast station's transmitter to the listener's or viewer's receiver—with no provision for carrying signals back the other way. (Compare this to a bidirectional communications system, such as telephony, in which each user's device serves as both a transmitter and a receiver, and content can flow between users in both directions simultaneously.) These two characteristics have defined broadcasting since its origin and continue to do so today. Thus, all the systems described in this book will possess these two essential qualities.

Meanwhile, the business of Broadcasting has evolved to include its own two primary functions: (1) The generation of audio or audiovisual media content, and (2) the delivery of such content to audiences. All broadcasting facilities are organized around one or both of these two processes. Radio and television stations typically include one of each type of facilities. Often these are placed at two different physical locations, but occasionally they are collocated.

Therefore, in its simplest form, a radio or television broadcast station consists of two basic facilities: the studio site and the transmitter site. The studio is where the content is generated. The transmitter site is where the content is sent out over the air, in a point-to-multipoint, unidirectional fashion. If those two facilities are not physically in the same place, between them is a connection called the studio-transmitter link (or “studio-to-transmitter link”), often abbreviated as “STL.” But there are many individual components in each of these facilities that make up the chain from content generation to the reception of broadcast services by the viewer or listener. This tutorial provides an introduction to the technologies and equipment that make up these chains, and thereby constitute modern broadcasting systems.

Traditionally, broadcasting was based on analog techniques, but for the past quarter-century or so, there has been a steady migration to digital systems, which provide many technical and operational benefits for broadcasting processes. The increasing use of computer-based systems has revolutionized both radio and television studios, increasing the quality and efficiency of audio and visual media content creation. More recently, new standards have evolved that also allow application of digital techniques to the transmission of content to end users of both radio and television, improving the efficiency and quality of media content delivery, as well.

All types of broadcast stations used for domestic broadcasting (AM and FM radio, and television) are covered in this tutorial, with descriptions of both analog and digital studio and transmission systems. For completeness, satellite, cable, and Internet delivery are also briefly described, although this book does not cover them in detail.

Chapters in the first section of the book, “Broadcasting Basics,” discuss the main methods used for radio and television broadcasting and explain some of the basic science and the terms used later in the book. Chapters in the second section, “Studios, Production, and Playout Facilities,” describe radio and television studios and remote operations, covering the main items of equipment used and how they work together. Chapters in the third section, “Transmission Standards and Systems,” discuss the standards and technologies used for U.S. radio and television transmission and cover transmitter-site facilities and equipment. The penultimate chapter of this section discusses radio wave propagation and regulation of broadcasting by governmental authorities.

In each section or chapter, audio and radio topics are generally treated first, followed by video and television subjects.

Jargon words and phrases are shown in italics when these are used for first time in each section. The words and phrases may be defined in each section or covered in detail in other chapters. Some jargon words are unique to broadcasting, but some are regular words used in a special way that will be explained in each case.

BROADCASTING BASICS

CHAPTER 2Types of Broadcasting

DOI: 10.4324/9781315848426-3

For many years, the term broadcasting meant the transmission of audio or video content via radio-frequency (RF) waves, often referred to as “over-the-air.” More recently, with developments in advanced digital technology, the term applies to many different types of content distribution. Let's start with a summary of the main types of broadcasting in use today in the United States and elsewhere.

Many of the systems mentioned below differ only in the particular method of transmission or distribution used, whereas the studio systems used for generations of radio and television content have fewer variations. Don't worry if you don't fully understand all of the terms used in this chapter. They will be explained later in the appropriate sections.

Analog Radio

Traditional radio broadcasting for local stations in the United States and throughout the world generally falls into two main types: AM and FM—standing for amplitude modulation and frequency modulation, respectively. These are the particular methods of radio transmission used for many years in broadcasting audio signals to home, car, and portable receivers. In North America, AM is used in the medium frequency (MF)—also known as medium wave band—whereas FM uses the very high-frequency (VHF) band.

In the United States, a given radio station frequently feeds only one transmitter and therefore is referred to as an AM station or an FM station. It is, however, quite possible for a station to feed both AM and FM transmitters in the same area, or to feed more than one transmitter covering different areas, in which case the term AM or FM may refer only to a particular transmitter and not to the station as a whole. The latter arrangement is more frequently encountered outside the United States, but is becoming increasingly common in the United States.

In some countries, AM radio also uses the long wave band, with frequencies somewhat lower than the MF band, and having slightly different propagation characteristics, better for broadcasting over wide areas. AM is also used for shortwave radio broadcasting—also known as “HF” for the high-frequency band that is used. This is used for broadcasting over very long distances (usually internationally).

We cover analog radio in more detail in Chapter 12.

Digital Radio

There are four standards for over-the-air digital radio systems in the world, all different from each other in several respects. They are commonly referred to by their acronyms: IBOC, DAB, ISDB-TSB, and DRM.

IBOC (In-Band On-Channel)

Digital radio broadcasting for local stations in the United States uses a system called In-Band On-Channel (IBOC, often pronounced “EYE-bock”). The IBOC digital radio system was developed and continues to be managed by a single company, iBiquity Digital Corporation, referring to its implementation of IBOC by the trademarked name of HD Radio. For this reason, the two terms are essentially interchangeable in most practical parlance, and so today, the HD Radio label is more commonly applied to the format. (The HD Radio trade name has led many to assume that the “HD” stands for high definition, but in fact, iBiquity Digital specifies that it is not an acronym and simply an identifier.)

The technology is called In-Band On-Channel because it places a radio station's digital signal within the same band (AM or FM) as the station's original analog system, and within the station's existing analog channel in each case. For this reason, IBOC digital radio does not require any additional spectrum, unlike most other digital broadcasting systems. Today's IBOC station therefore transmits two versions of its primary content—one analog and one digital—thereby serving both legacy and new receivers via the same broadcast channel. (The IBOC system also provides the capability of eliminating the analog component and moving to an all-digital channel, but this mode of operation is not currently allowed by FCC rules).

There are two variants of IBOC: one for AM radio services and one for FM. The major advantage for AM radio is a qualitative improvement in received audio and freedom from the ever-growing impact of audible interference that plagues AM reception. The FM IBOC system also provides better audio quality than traditional analog FM service, but with less noticeable effect since analog FM audio quality is already relatively good to begin with. The primary improvement with FM IBOC is quantitative, in that it also allows a station to include multiple audio services within the same broadcast channel (called “multicast services,” but often referred to as “HD-2” or “HD-3” services, owing to how the channels are identified on most IBOC receivers). FM IBOC also offers data services that stations can package with each audio service, providing text and other information associated with the audio program, such as song titles and performers' names—so-called “Program and Service Data” (PSD). In addition, FM IBOC can carry advanced data services such as “song tagging” (for identifying content in an online store, from which the listener can download to add the song to a personal music collection) and road-traffic information.

Of course, new HD Radio receivers are required to receive all these digital improvements, but such receivers also operate as analog radios (since both the digital and analog services currently occupy the same radio channels), allowing significant flexibility to broadcasters as they add digital services individually over time.

HD Radio was introduced for regular use in the United States in 2003 and at this writing, there are now more than 2,000 U.S. FM and AM stations carrying IBOC digital radio services, with several other countries considering its adoption. Most U.S. HD Radio stations are in the FM band, and the majority of those currently offer one or more multicast services.

Further detail on IBOC digital radio can be found in Chapter 13.

DAB

Outside the United States, another form of digital radio broadcasting called DAB is in use by some countries. DAB stands for Digital Audio Broadcasting, which is also known as Eureka 147, and in the United Kingdom, simply as Digital Radio. DAB has quality advantages similar to FM IBOC but is fundamentally different in its design. Unlike IBOC, DAB cannot share a channel with an analog broadcast, so new, dedicated spectrum is required. Each individual DAB transmission also requires much more spectrum because it contains multiple program services (typically 6 to 10, depending on quality and the amount of data carried). This makes it impractical for use by the typical local radio station, so it is generally implemented with the cooperation of several broadcasters, or by a third-party aggregator that acts as a transmission service operator for broadcasters.

DAB is most often transmitted using spectrum in the VHF band, which in some countries is becoming available as analog television is phased out. It can also be transmitted in UHF spectrum, or in the L-Band (see explanation of Frequencies, Bands, and Channels in Chapter 7).

In recent years, enhanced versions of DAB known as DAB+ and DAB-IP have been developed that increase the capacity of a DAB signal. At this writing, approximately 40 countries around the world have DAB services on air (most are in Europe), and others are considering adoption of DAB or one of its variants. A few countries where DAB is implemented have begun plans to shut down analog radio broadcasting and replace it with DAB service, but the format's success to date has varied widely in different regions. For example, in the United Kingdom, DAB receiver sales now outpace the sale of conventional radios, whereas in Canada, DAB service that the country initiated in 1999 was shut down in 2010 due to lack of consumer adoption.

ISDB-TSB

ISDB-TSB stands for Integrated Services Digital Broadcasting-Terrestrial Sound Broadcasting and is the digital radio system developed for Japan, where the first services started in 2003. Like DAB, ISDB-TSB is intended for multi-program services and is currently using transmission frequencies in the VHF band. One unique feature of this system is that the digital radio channels are intermingled with ISDB digital television channels in the same band.

DRM

DRM stands for Digital Radio Mondiale, a system developed primarily as a direct replacement ...

Table of contents

• Cover Page
• Half Title Page
• Title Page
• Copyright Page
• Contents
• Preface
• 1 Introduction
• BROADCASTING BASICS
• STUDIOS, PRODUCTION, AND PLAYOUT FACILITIES
• TRANSMISSION STANDARDS AND SYSTEMS
• Index