OPERATION
TM-1300 Progressive Scanning High Resolution Camera
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4 - up16 dB
4 - down22 dB
3.1.5 (e) 5. Image Output Format Selection
The TM-1300 has three output connectors. The digital output is 10-bit or 8-bit from 31-pin connector
and the analog outputs are SVGA format (DB-15 connector) and composite video (BNC connector)
with sync.
When Image Selection (mode #5) is selected by pushing the switch up, the Direct Digital Output mode
is selected. This bypasses the memory buffer (cannot grab and freeze video images), and 10-bit 12
frame/sec digital output is generated. The analog output is scan-converted to SVGA speed
(47 frame/sec).
When the switch is down, Memory mode is selected. The digital signal goes through the memory buffer
for grabbing images and the output is 8-bit. The frame rate of both digital and analog is 12 frame/sec.
(no SVGA output).
3.1.5 (f) 6. and 7. A/D Reference Voltage Control
The CCD output itself has over 60 dB of dynamic range. However, the signal normally used to display
or capture does not have such a wide range. For instance, if the amp gain is set at 12 dB (4X) and the
display is 100 IRE in which saturation is 714 mV, the actual signal from the CCD is 714/4 = 178 mV.
This is 1/3 of the imager saturation. By adjusting Vref, the full dynamic range at a specific gain can be
obtained.
When low light and high sensitivity is required, the reference can be set to the narrow range so that the
small signal can be digitally amplified and the gray level can be shifted to the middle region for easy
observation and processing. The input signal to A/D is from 2.2 V to 3.7 V. The typical factory set is VL
= 2.2 V and VH = 3.2 V.
FIGURE 8.
A/D Dynamic Range
500 mV
CCD output
voltage
Input light
Vref high
Vref low
A/D dynamic range
Saturation
