SprintScan 35LE Service Manual
Functional Description
6
From Figure 1-4 it can be seen that the CCD signal is smoother and the bias voltage is
independent of CCD characteristics.
The reference voltage is derived through a process called calibration. Because of the
characteristics of lamp and lens, the magnitude of the CCD’s output is lower toward the
beginning and end of a scan line than it is in the central portion, even when the input slide
is uniformly white. Calibration is used to compensate for this spatial variation.
Data Transfer Modules
In the third phase of scanner operation, the scanned data are transferred to the video ping-
pong buffer. Then the data in the buffer are moved out to the host computer via the SCSI
bus.
Command and Message Transfer
The scanner accepts commands from, and sends messages to, the host computer via the
SCSI bus. All commands and messages are transmitted in the form of records with a fixed
syntax. Command format and record syntax are described detail in the SprintScan 35LE
Command Set Manual.
