THE OCULUS-F/64 FRAME GRABBER User's Manual

3.2 INPUT
DB9
1
2
3
4 (Diff)
CS
VS
Analog Input
HS/CS
Optional Camera
Adapter Module
34 Pin Header
Analog Input
Source
Selector and
Anti-alaising
Filter
Digital Interface
Control signals
Trigger
Clock
40 MHz A/D
8 Bits
Sync
Separator
and
Acquisition
Control
12 Bit Digital Data path
General I/O
3.2.1 ANALOG INPUT SELECTOR AND ANTI-ALAISING FILTER
8
Input
Look-Up
Table
8/16
Bit
Data
Four analog cameras can be connected via the male DB-9 input connector.
One input is capable of accepting a differential camera output signal typically
used in electrically noisy environments. The input selection is made by
software commands.
Two software selectable anti-alaising filters are available. One with low-pass
filter corner set at 20 Mhz and the second is programmable to have a corner
frequency from 1Mhz to 10 Mhz. Additionally, a filter by-pass selection is
available, if required.
Inputs are by default AC coupled but can be DC coupled. Selection of input
coupling is made by software.
3.2.2 ANALOG TO DIGITAL CONVERTER
Input video is digitized via the analog to digital converter at various standard
sampling rates or optionally at custom rates up to 40 million pixels per second.
The sampling clock frequency (pixel clock) can be varied from 510 kHz to 40
MHz in increments of less than 10 kHz, while maintaining pixel jitter to less
than 1/6th of a pixel.
A/D converter range and offset controls allow adjusting the digitized range of
the input video. As shown in the figures below any portion of the video input
can be selected for digitization to one of 256 gray levels, over the selected
range. The effects of range and offset on the acquired image are similar to
brightness and contrast controls on a video monitor.
Page 3-4 The OCULUS-F/64 User's Manual