5
this section that the three channels of video must be "equalized" before they can be multiplexed
into a single channel of video. In order to accomplish this, two channels are provided with
variable gain and offset; one channel (considered the reference channel) has a fixed gain and
offset. The two variable channels are adjusted by means of the White Balance and Black
Balance potentiometers until all the three channels are properly matched.
3.3 Analog Video Processing:
The signal from the pre-processor stage is fed to the Video Processor which performs the
following functions related to the Analog (RS-170) video:
•
Gamma Correction
•
Gain and Offset Control
•
AGC & Auto-iris (optional)
•
Sync Insertion - the Composite Sync signal is added to the Output Video Signal to create
Composite Video.
•
Video Output Driver - The Video Processor is directly capable of driving a 75
Ω
co-axial
cable. It is recommended that the cable be terminated in its characteristic impedance of 75
Ω
at the receiving end (the monitor or other receiving device).
3.4 Video Digitization:
The low-level video signal voltage from the pre-processor is clamped (for black reference) and
amplified on the Sensor & Video Board before Analog-to-Digital conversion (on the optional
Analog to Digital board). The Digital Video Data is latched and converted to an RS-422 format
for transmission as a balanced, differential signal along a cable which consists of shielded
twisted pairs.
3.5 Sync and Power Board:
This board performs the following functions:
•
Voltage Regulation: Input voltages (+12V, -12V and +5V) are converted into several positive
and negative voltages required by the CCD and in the video processing circuits.
•
Generation of CCD timing signals
•
Generation of Video timing signals
•
Asynchronous Reset function
•
Genlock function
•
Electronic Shutter function
•
Pulse Driven Integration function
•
TTL to RS-422 conversion of digital video data, and all handshaking signals (clock, csync,
field index, enable line & enable frame).
Summary of Contents for DigitEyes Series
Page 14: ...9 Figure 4 3 TC 245 Gate Level Drawing Texas Instruments 1994 ...
Page 61: ...56 12 Appendix D Camera Mechanical Drawings Figure 12 1 Camera Mechanical Drawings ...
Page 63: ...58 Figure 13 2 Camera Noise Spectrum Min Gain Bandwidth 10kHz to 4 2MHz ...
Page 64: ...59 Figure 13 3 Camera Noise Spectrum Max Gain Bandwidth 100kHz to 4 2Mhz ...
Page 65: ...60 Figure 13 4 Camera Noise Spectrum Max Gain Bandwidth 10kHz to full ...