c) Long Time Exposure Mode
- 12 -
In Long Time Exposure mode, the exposure time of shutter can
be controlled by a duration of ext. VD signal input.
CV-M90(rev.C) starts the exposure (=accumulation of electric
charge) after input of ext. VD signal, and ends the exposure
after the next input of ext. VD signal. The accumulated video
signal in one full frame (ODD/EVEN or EVEN/ODD) by 2:1
interlace mode can be output directly after every 2nd input of
ext. VD signal. Also the accumulated video signal in one field
(ODD or EVEN) either by 2:1 or Non-interlaced mode can be
output directly after every 2nd of input ext. VD signal.
To use Long time exposure mode, make the following procedure.
1. Make jumpers JP302 on PK8088 board short-circuited.
2. Set SW1-1, -2 and -3 on rear panel at OFF position.
3. Check SW1-4 on rear panel switch if it is set at OFF position
for normal shutter mode.
4. Set SW301 switch located on PK8088 board, for CCD
accumulation at optimum position either OFF for Field
accum. mode or ON for Frame accum. mode.
5. Set-SW1-5 on rear panel switch for scanning system at
optimum position either OFF for 2:1 Interlace mode or ON
for Non-interlace mode.
6. Input ext. VD signal (4.0Vp-p ± 2.0V at 75 Q terminated) at
pin no.7 of 12P Multi connector.
7. Timing of ext. VD signal in each accumulation mode has to
be set, as follow.
- 2:1 Interlace mode (Field accum. mode)
: 1VD or more
- 2:1 Interlace mode (Frame accum. mode) : 2VD or Integral time of 2VD
- Non-interface made (Field occum. mode) : 2VD or more
Note:
1VD In 2:1 Interlace
= 262.5H in EIA, 312.5H In CCIR
2VD in 2:1 Interlace
= 525.0H in EIA, 625.0H in CCIR
2VD in Non-Interlace
= 524.0H in EIA, 624.0H in CCIR
8. Refer to the following ”Timing Charts”, and also to ”Caution
on Long Time Exposure Mode”.
9. For more information, see ”5. Pin Assignment” and ”7. Mode
Setting”.
