Preface

There are two key inventions which have brought about this book, and neither of them are new. The digital computer is one of these, and turned from a curiosity into a powerful tool as early as the Second World War. The idea of pulse code modulation (PCM) which allows continuous signals to be handled by digital hardware is even older.

Digital video and audio are another form of data and so the convergence with computers and communications networks has always been inevitable, although it has taken 50 years to become an economic reality.

Now that convergence is a reality, products and systems combining audio, video, data processing and communications are emerging. Without adequate fundamental knowledge of the four core technologies, products could be flawed or even fail.

Traditional experience does not serve well in convergence. Computer engineers suddenly find they need to understand audio, imaging and data systems delivering with an accurate timebase. Audio and video engineers find they need to understand file servers and computer networks. This book is designed to meet those needs. Without assuming a background in any of them, the four core technologies of image reproduction, sound reproduction, data processing and communications are all treated here.

Specialist industries evolve their own buzzwords and acronyms in order to save time, but these terms have the side effect of making the technology incomprehensible to the outsider. Communications and networking are possibly the worst offenders in the acronym department, with MPEG and DVB close behind. In order to cross disciplines with any hope of success, the only approach which will work is to use plain English first and to introduce the inevitable buzzwords and acronyms later.

Another important aspect of this book is that the reader is asked to take very little on trust. Instead of presenting facts which are as likely to be challenged as they are to be forgotten, this book gives reasons which can be followed, supported by references. For example, all the criteria involved in image and sound quality should be based on studies of the human senses and so it is here.

These studies have advanced our knowledge considerably, but this has not always resulted in parallel improvements in television and hi-fi equipment because these have become commoditized and riddled with tradition. The reader from a computer background should not make the mistake of thinking that current audio and television practice represents the best that can be done. This book does not simply describe current television and audio practice. Instead it goes far beyond that to the limits of what can be done and how to do it.

John Watkinson
Burghfield Common, England