MC144144P 查看數據表（PDF） - Motorola => Freescale

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MC144144P

Enhanced Closed-Caption Decoder CMOS

Motorola => Freescale 

AC AND TIMING CHARACTERISTICS

Parameter

Conditions

Composite Video Input

Amplitude:

1.0 Vp–p, ± 3 dB

Polarity:

Sync tips negative

Bandwidth:

600 kHz

Signal Type:

Interlaced

Max Input R:

470 Ω

DC Offset:

Signal to be ac coupled with a minimum series capacitance of 0.1 µF.

Non–Standard Video Signals Must Have the Following Characteristics

Sync Amplitude:

200 mV min

Vert Pulse Width:

3H ± 0.5H

Vert Pulse Tilt:

20 mV max

H Timing:

Phase Step (head switch) ± 10 µs max

Fh Deviation (long term) ± 0.5% max

Fh p–p Deviation (short term) ± 0.3% max

Horizontal Signal Input (Preferably H Flyback)

Amplitude:

Video Lock Mode:

Polarity:

Frequency:

CMOS level signal, low ≤ 0.2 VCC, high ≥ 0.7 VCC

Any

15,734.263 Hz, ± 3%

HIN Lock Mode:

Polarity:

Frequency:

Any

Display HFB pulse

Line 21 Input Parameters ( at 1.0 Vp–p)

(Line 21 must be in its proper position to the leading edge of the vertical sync signal.)

Code Amplitude:

50 IRE ± 10 IRE

Code Zero Level:

– 5 IRE, + 15 IRE relative to back porch

Bit Rate:

Start of Code:

32 x Fh

10.5 ± 1.0 µs

(Measured from the midpoint of the leading edge of video H pulse to the midpoint

of the rising edge of the first clock run–in cycle.)

Start of Data:

3.972 µs, – 0.00 µs, + 0.30 µs

(Measured from the midpoint of the falling edge of the last clock run–in cycle to the

midpoint of the rising edge of the start bit.)

Input Signal–to–Random Noise Performance

Unit will function down to a 25 dB ratio One error per row or better at that level.

(CCIR weighted

Internal Sync Circuits

The internal sync circuits will lock to

all 525 line or 625 line signals having

a vertical sync pulse.

It is at least 2 H long.

It starts at the proper 2 H boundary for its field.

If equalizing pulse serrations are present they must be less than 0.125 H in width.

Timing Signals

Dot Clock:

Dot Period:

768 x FH = 12.0839 MHz

82.75 ns

Character Cell Width:

Width of Row (Box):

Width of Row (Char):

1.324 µs (tH ÷ 48)

45.018 µs (34 chars = 17/24 x tH)

42.370 µs (32 chars = 2/3 x tH)

MC144144

4

MOTOROLA

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