The levels on these two terminals determine which of the four antiblooming modes is selected:

ABS1

ABS0

Operation

L

L

No ABG pulses

L

H

2-MHz burst of ABG pulses

H

L

1-MHz burst of ABG pulses

H

H

1-MHz continuous ABG pulses

SN28835

1/2-INCH NTSC TIMER

SOCS023B – FEBRUARY 1991

3

POST OFFICE BOX 655303

Terminal Functions

TERMINAL

I/O

DESCRIPTION

NAME

NO.

I/O

DESCRIPTION

ABIN

30

O

Antiblooming in

ABS0

10

I

ABS1

11

I

BCP1

1

O

Optical black clamp

BCP2

2

O

Optical black clamp

BF

7

O

Burst flag

CBLK

6

O

Composite blank

CLK2M

21

O

2-MHz clock

CP1

4

O

Clamp

CP2

3

O

Clamp

CSYNC

5

O

Composite sync

E/L

43

I

Delay select for S1, S2, S3. When E/L is high, the three serial-transfer pulses occur early relative to the

sample-and-hold pulses SH1, SH2, and SH3. When E/L is low, the three serial-transfer pulses occur

late relative to the sample-and-hold pulses.

FI

44

O

Field index

GND

33

Ground

GP

15

I

Exposure control: GP gates the PS and PI outputs (see the description of GPS)

GPS

13

I

When GPS is high, the timer operates in the normal-integration-time mode (tint = 16.67 ms) and VD is

connected internally to GP. To operate the imager in the variable-integration-time mode, GPS must be

held low and a user-defined logic circuit must be inserted between VD and GP to vary the integration

time (see Figure 1).

GT

29

O

TMS3473B parallel-driver MIDSEL input switch

GT1/SH3

38

O

GT1/SH3 is a logic signal for both Y gate 1 of the TL1051 video preprocessor and sample-and-hold

channel 3 of the TL1593 3-channel sample-and-hold circuit.

GT2

39

O

Y gate 2 for the TL1051 video preprocessor

GT3/SH2

37

O

GT3/SH2 is a logic signal for both Y gate 3 and sample-and-hold channel 2 of the TL1051 video

preprocessor.

HCR

41

I

Horizontal-counter reset

HGATE

20

O

Decoded H count signal. HGATE is a test point and is not used in normal operation.

HIGH

12

I

Not used (tie high)

MODE

32

I

TC243/TC245 CCD select. When MODE is low, the TC244/245 CCD imager is selected; when MODE

is high, the TC242/243 is selected (see the appropriate data sheets for imager differences).

PD

27

O

Power down. A low-logic level on PD causes the device to enter a low power-consumption mode.

PI

31

O

Parallel-image-area gate clock

PS

28

O

Parallel-storage-area gate clock

SB

14

I

Standby-mode select. When SB is high, normal operation is selected; when SB is low, the power-down

mode is selected.

SC

8

O

Subcarrier

SC(90)

9

O

Subcarrier phase shifted by 90 degrees

SH1

36

O

Sample and hold 1