Fluke 54200, Руководство пользователя

Страница: 175 / 386

Function Reference
CLOSED CAPTION (CC)
5
5-33
Text Mode is a data service, generally not program related, which is also transmitted on
TV lines 21. The text service should use the channels T1 and T2 if possible but only
T3/T4 if T1/T2 is not sufficient. Text data are displayed as soon as they are received.
Table 5-10. Closed Caption Field Packets
Field 1 Packets Field 2 Packets
CC1 Primary Synchronous
Caption Service CC3 Secondary Synchronous
Caption Service
CC2 Special Non-synchronous
Use Captions CC4 Special Non-synchronous
Use Captions
T1 First Text Service T3 First Text Service
T2 Second Text Service T4 Second Text Service
XDS Extended Data Service
(not supported by Fluke 54200)
The television receiver must decode CC1 to CC4 captioning, and must display the cap-
tioning for whichever channel the user selects. The TV Mode of operation allows the
video to be viewed in its original form. The Caption and Text Modes define one or more
areas (boxes) in the screen within which Caption or Text characters are displayed. In
Text Mode the information is scrolled upwards through the window if it has been filled.
Caption mode possibilities are as follows:
•
Roll-up: 2, 3 or 4 continuous rows,
•
Pop-on: maximum of 4 rows, not necessarily continuously, displayed anywhere
on the screen. This data will be displayed after receipt of an End of
Caption command,
•
Paint-on: subsequent data are addressed immediately without the need of an End
of Caption command.
In the Fluke 54200 Closed Caption and Text Service are available for the following
TV systems:
NTSC, NTSC 4.43, PAL 625 and PAL 525 line systems, and SECAM.
The Caption and Text Data cannot be changed. All memory locations are pre-
programmed.
CC Sequence is an automatically continuous sequence of memory locations 1 to 8.
Remark:
During the Closed Caption mode (Line 21 Data Service) Teletext, Wide Screen Signal-
ling (WSS), Programme Delivery Control (PDC), and Video-Progamm-System (VPS)
are automatically switched off.