TABLE OF CONTENTS In this chapter the various standardized interfaces for component and composite video will be detailed along with the necessary troubleshooting techniques.
Of all the advantages of digital video, the most important for production work is the ability to pass through multiple generations without quality loss. Digital interconnection between such production equipment is highly desirable to avoid the degradation due to repeated conversions.
Video convertors universally use parallel connection, where all bits of the pixel value are applied simultaneously to separate pins. Disk drives lay data serially on the track, but within the circuitry, parallel presentation is more common because it allows slower, and hence cheaper, memory chips to be used for timebase correction. Reed-Solomon error correction depends upon symbols assembled from typically eight bits. Digital effects machines and switchers typically operate upon pixel values in parallel.
The first digital video interfaces were based on parallel transmission. All that is necessary is a set of suitable driver chips, running at an appropriate sampling rate, to send video data down cables having separate conductors for each bit of the sample, along with a clock to tell the receiver when to sample the bit values. The complexity is trivial, and for short distances this approach represented the optimum solution at the time.
Parallel connection has drawbacks too; these come into play when longer distances are contemplated. A multicore cable is expensive, and the connectors are physically large. It is difficult to provide good screening of a multicore cable without it becoming...
