Kodak DirectView CR 800 System Theory Manual page 62

Important
The LASER power is known constantly by the Laser Reference data. With each sampling point (in time) that the LASER reads on the PLATE, the REF BD is reading
the reference signal. This data will be used later by the MCPU to make corrections to the image data.
Illustration
12–62
[2] The random light is picked up by the NOSEPIECE of the COLLECTOR
which reflects it toward the faces of the 5 PMTs
(a) For each line of the fast scan, a specific number of measurements is
made based on the plate size. This is known as the Sampling Rate.
The sampling rate defines the size of each pixel of infomration that is
read off the PLATE. The Sampling rate is programmed into the
DIGITIZER BD based on the size of the PLATE being scanned.
(b) While most of the LASER light is absorbed by the phosphors, a small
amount may bounce off and be directed toward the NOSEPIECE. A
Filter filters out any incipient red Laser light and lets only the blue light
emitted by the phosphors into the COLLECTOR.
[3] The PMTs convert the light energy?? into current signals. ??
[4] The output from each of the 5 pMTs is sent to the PMT/DAS BD where it is
converted and amplified to a proportional voltage signal.
[5] Gain control is applied to each of the voltage signals to correct for gain
variations from the 5 PMTs.
[6] The corrected signals are summed by the SUMMING AMPLIFIER. An offset
adjustment signal is added in and the summed signal is sent through a
LOW-PASS FILTER for noise reduction.
[7] The voltage signal is sent through a 16 bit A/D converter, converting it to a
16 bit digital signal.
Note
The LASER Reference signal has also passed through a current to voltage
amplifier, low-pass filter and A/D converter and been converted to a 16 bit laser
Reference signal. The function of the LASER reference signal is to tell the power
of the LASER at the particular moment that it reacted with the phosphor on the
PLATE; therefore it is essential that this signal has had identical operations
performed on it as has the LASER ?image?? signal.
[8] The 16 bit image data signal and the 16 bit laser reference signal arrive at
the DIGITIZER BD in 2 separate streams.
See "PMT Operation.".
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