Audio Engineering

828 Chapter 28

reference signal consists of a four-word sequence, with the fi rst three words being a fi xed
preamble and the fourth containing the information defi ning:

First and second fi eld blanking;

State of the fi eld blanking;

Beginning and end of the line blanking.

This sequence of four words can be represented, using hexadecimal notation, in the
following manner:

FF 00 00 XY

in which XY represents a variable word. In binary form, this can be represented in the
following form:

Data bit

number

First word

(FF)

Second word

(00)

Third word

(00)

Fourth word

(XY)

7 1 0 0 1

6 1 0 0 F

5 1 0 0 V

4 1 0 0 H

3 1 0 0 P3

2 1 0 0 P2

1 1 0 0 P1

0 1 0 0 P0

The binary values of F, V, and H characterize the three items of information listed
earlier:

F  0 for the fi rst fi eld;

V  1 during the fi eld-blanking interval;

H  1 at the start of the line-blanking interval.