Smearless Mode, Smearless mode

CV-A11

6.10. Smearless Mode

This mode will reduce the unwanted smear signal from a highlighted scene when a short exposure time is used. The trigger mode is like edge pre-select, but a fast dump readout is performed before the active accumulation is started. It will remove the smear over the highlighted parts in the image, but there is still smear left below highlighted areas.

The trigger leading edge will start the dummy readout. It takes 28 H before the exposure start. The exposure stops and the resulting video signal is read out after the selected shutter time. It can be the 9 first steps normal or 1023 step programmable. SM=0 or SM=1.

This mode will operate with full and partial scanning. An EEN pulse will indicate the active accumulation time, and a WEN pulse indicates that the resulting video is read out.

To use this mode:
Set function:	Trigger mode “Smearless”	TR=6
	Shutter mode to “Normal” or “Programmable”	SM=0, SM=1
	Shutter Speed using fixed steps	SH=0 through 7
	or Programmable exposure	PE=1 through 1023
	Polarity and other functions
Input:	Ext. trigger to pin 5 on 6 pin connector (or 11 on 12 pin connector)
	Ext. HD to pin 6 on 12 pin connector. (If used).

Fig. 22. Smearless mode.

NOTE. Fig. 22 is omitted.

Important notes on using this mode.

•As the start of exposure will be synchronized with the internal H signal, the start of exposure may be shifted by max 1H. To avoid this shift (jitter), synchronize the camera with an external HD and make sure that the trigger pulse aligns to the HD signal as shown in Fig. 14.

•The duration of the external trigger pulse must be greater than 1H. It is recommended to make this longer, typically 9H. This is a TTL level pulse, which can be positive or negative going (the camera can be set to accept any polarity).

•Do not input ext. VD signal at pin 7 on 12 pin connector, as it may disturb the external trigger function.

•Do not input a new trigger before the previous video is read out. (WEN is high).

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