PCIe-FRM13 User’s Manual
8
2-3 Camera Link
Camera Link is a communication interface developed for use in vision applications. In the past,
we used proprietary connectors and cables between camera makers and frame grabber makers.
This caused a lot of confusion and cost increase for users. In order to resolve this confusion,
increasing data rate, and confusion in data transmission, the specifications of the Camera Link
interface are the specifications of cable or connector assembly, transmission speed and It was
made with regulations such as transmission method.
Many digital video solutions today use Low Voltage Differential Signal (LVDS) communication
defined by RS-644. RS-644 LVDS has become the Camera Link standard by improving the existing
RS-422 method, which had inconvenient cables and limited transmission speed. LVDS can transmit
data at high speed by using a differential signal with a low voltage swing. Compared to the
existing single-ended signal using one line, the differential signal transmits the signal using two
complementary lines. This transmission structure has the characteristics of large-scale common-
phase voltage rejection, low power consumption, and excellent noise immunity, which is
impossible with single-ended systems that only reference ground for data transmission.
An advanced LVDS technology for the transmission of digital data is a Channel Link. The channel
link can transmit parallel-to-serial and serial-to-parallel at 2.38 Gbps. Referring to [Figure 2-3], the
transmitter converts 28-bit CMOS/TTL data into 4 LVDS data streams. The converted signal is
transmitted to the MDR cable according to the Transmit Clock, and the opposite receiver converts
these four LVDS data into a 28-bit CMOS/TTL parallel signal according to the Receive Clock. This
channel link technology is being used as a low-cost chipset that is easy to learn and portable, so
that it can be used immediately.
Camera Link interface includes Base Configuration, Medium Configuration, and Full
Configuration. Base Configuration uses four RS-644 LVDS pairs for transmitter/receiver and camera
control as shown in [Figure 2-3], and uses two RS-644 LVDS pairs for communication between
camera and frame grabber. The data transmitted serially through the 26-Pin MDR Cable is
changed to 28-bit parallel image data at the Receive end of the frame grabber and used.
