Z8623012SSG Datasheet, PDF (49/61 Pages) Zilog, Inc. – ADVANCED PROGRAM BLOCKING AND NTSC LINE 21 XDS DECODER

ELECTRICAL CHARACTERISTICS
ELECTRICAL CHARACTERISTICS
8.5.3 Line 21 Input Parameters (at 1.0V p-p)
Line 21 must be in its proper position to the leading edge of the Vertical Sync sig-
nal.
TABLE 40. LINE 21 INPUT PARAMETERS
Parameter
Conditions
Code Amplitude
Code Zero Level
Start of Code
50 IRE*
5 IRE, +15 IRE relative to Back Porch
10.5 ±0.5 µs (measure from the midpoint of the leading
edge of the composite video Hsync pulse to the
midpoint of the rising edge of the first clock run-in
cycle.)
Start of the Data
3.972 ms, –0.00 µs, +0.30 µs (measure from the
midpoint of the falling edge of the most recent clock
run-in cycle to the midpoint of the rising edge of the
start bit.)
NOTE: *A relative unit of measure developed by the Institute of Radio Engineers (IRE).
One IRE equals 1/140th of the composite video signal's peak-to-peak voltage. IRE is
the former name of what is now known as the Institute of Electrical and Electronics
Engineers (IEEE).
PS000401-TVC0699
Z86230—PRELIMINARY
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