Pulnix TM-250 Manual de instrucciones descargar pdf (Pagina 31)

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Operation Mode

TM-250 Miniature CCD Camera

5.2.3 Pulse Width Asynchronous Shutter Mode

Pulse Width Mode Async Shutter enables exposure time to be controlled by the duration of VINIT. The

camera operates in the same way as it does Fast Mode Async Shutter or Pulse Width Mode Integration.

Unlike Pulse Width Mode Integration, the single pulse of discharge occurs only when the falling edge of

VINIT pulse is detected. The rising edge of VINIT resets camera, and photo-charge is transferred

simultaneously at the 1st line so only odd ﬁeld image is valid. SYNC signal is continuous when F2

switch is up (ON). SYNC is available only in the one ﬁeld right after VINIT when F2 is down (OFF).

FIGURE 16. Pulse Width Asynchronous Shutter Mode

5.2.4 Pre-Reset Asynchronous Shutter Mode

The purpose of this mode of operation is to maintain compatibility with the TM-7/6 and the TM-200/

300 series cameras. This shutter operation enables image capture at extremely high speeds with very

short exposure times and image output with a minimum of delay. In contrast with Post-Reset Mode, the

falling edge of the VINIT pulse ﬁrst resets internal counter logic to the beginning of the odd ﬁeld. The

discharge of photo-charge occurs at a predeﬁned period later after the reset, then the transfer pulse

occurs at the 11th line for the TM-250, and the 16th line for the TM-260. For this reason, the exposure

TABLE 10. Pulse Width Asynchronous Shutter Mode

OFF

ASY

CYC

TRIGGER

Polarity

Down Up Up Up Up Up Negative

F2 Up: SYNC signal is continuous.

F2 Down: SYNC signal is available in one ﬁeld right after

VINIT.

VINIT

Internal VD

Discharge pulse

Transfer

Exposure

Video Out

Not Valid

Reset Reset Reset

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Pulnix TM-250 Manual de instrucciones Pagina 31