P R E L I M I N A R Y
Z86228
CPS DC-4243-00
P
RELIMINARY
C
USTOMER
P
ROCUREMENT
S
PECIFICATION
Z86228
L
INE
21 C
LOSED
C
APTION
C
ONTROLLER
(L21C)
GENERAL DESCRIPTION
The Z86228 (Line 21 Closed-Caption Controller) is a single
I.C. designed to provide the functional performance of a
L21C Decoder module. This Superintegration鈩?VLSI device
is completely self contained requiring only composite
video, a horizontal timing signal as input and an external
keyer (i.e., video switch between TV video and Closed-
Caption video) to produce captioned video. The Z86228
uses a wired logic approach to perform the functions
selected through its input control signals. It is fabricated
using standard CMOS technology and designed to achieve
the lowest possible cost.
The Z86228 is intended for use in a set-top decoder or in
any television receiver conforming to the NTSC standard.
It is capable of processing and displaying all standard
L21C format transmissions including the codes specified
by the FCC "Report and Order" on GEN Docket No. 91-1,
dated April 12, 1991. In addition, the device conforms to
the Electronic Industry Association's Recomended Practice
608, which provides supplemental guidelines for the
transmission of captions, text, and Extended Data Services
(EDS) on NTSC Field 2. Extended Data Services (EDS)
packets encoded on Field 2 , may be displayed in either of
two screen formats. If and when PAL and SECAM TV
standards define a protocol using the Line 21 format, this
design will be readily convertible to that standard.
The Line 21 Closed Captioning System
The L21C system provides for the transmission of CAPTION
information and other TEXT material as an encoded
composite data signal. This is during the unblanked portion
of Line 21, field 1, of the standard NTSC video signal. The
video signal conforms to the Standard Synchronizing
Waveform for Color Transmission given in Sub-part E, Part
73 of the FCC Rules and Regulations.
DC-4243-00
(2-18-94)
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