Chapter 2
Hardware Overview
2-2
ni.com
Video Acquisition
The NI 1405 can acquire analog color video in a variety of modes and then
store the images in the onboard SDRAM memory or transfer the images
directly to PCI system memory.
Video Decoder
The NI 1405 supports NTSC and PAL video standards in composite
format. The onboard video decoder converts the incoming video signal to
red, green, and blue (RGB) data.
The video decoder allows you to control numerous parameters to optimize
an acquisition. You can independently adjust parameters, such as analog
input range, brightness, contrast, saturation, or frequency range, which is
controlled by different filters. Refer to the
Measurement & Automation
Explorer Help for NI-IMAQ
, which is installed with NI-IMAQ, for a
complete description of the NI 1405 video parameters.
The video decoder also strips out all necessary clock and synchronization
signals included in the video signal and controls the acquisition conditions
automatically. High-quality circuitry can generate the synchronization
signals from poor timing signals. This allows you to acquire from, for
example, a video cassette recorder (VCR).
SDRAM
The NI 1405 has 16 MB of onboard high-speed synchronous dynamic
RAM (SDRAM). The NI 1405 can use the onboard RAM as a first-in
first-out (FIFO) buffer, transferring the image data as it is acquired or
acquiring the image data into SDRAM and holding it for later transfer
to main memory.
Trigger Control and Mapping Circuitry
The trigger control monitors and drives the external trigger line. You can
configure this line to start an acquisition on a rising or falling edge and
drive the line asserted or unasserted, similar to a digital I/O line. You can
also map many of the NI 1405 status signals to this trigger line and program
the trigger line in polarity and direction.
