Cohu 4912-3000/0000 RS-170 Monochrome CCD Camera

The Cohu 4910 Series RS-170 and CCIR Monochrome CCD Cameras uses a 1/2-inch format interline transfer sensor with on-chip microlenses. This sensor offers lower dark current, image lag, and blooming than other types of sensors. It has improved dynamic range and spectral characteristics, too. A 1000:1 overload capacity prevents bright incidental light in a scene from deteriorating the video. The agc has a 20-dB range. Auto black can be turned on and off with an internal jumper.

Field transfer is the normal operating mode but frame transfer can be selected with an internal repositionable jumper.

The Camera is manufactured in RS-170 and CCIR versions.

When an RS-170 version of the Camera operates with internal crystal as the sync reference source, its field rate is 59.94 Hz. This is consistent with RS-170(A) specifications, making the Camera compatible with field and line rates for color systems. When genlocked the Camera operates at whatever field rate the input pulse supplies. A line-locked RS-170 version of the Camera operates at a 60-Hz field rate; a line-locked CCIR version operates at 50 Hz.

On the rear panel, a screwdriver adjustment for line-lock PHASE provides 180-degree control range. If additional adjustment range is required, the low-voltage ac power input leads to the rear panel can be reversed to provide a 180-degree phase shift.

A side-panel trim plate can be removed to access seven controls and switches.

Electronic shuttering is available to provide stop-action effect for moving scenes. Any one of eight shutter speeds from OFF (1/60, 1/50) to 1/10,000 second can be manually selected by a side-panel switch. (If the electronic iris option is installed it must be turned off before shuttering can be used.)

The electronic iris option allows a manual iris lens to be used in place of an auto-iris lens when viewing scenes with varying levels of light. This option can be switched on and off with a side panel ELECT IRIS switch. When turned on, it produces smooth electronic control of the sensor through an an eight-stop light control range-from 1/60 (1/50) to 1/15,000 second. The effect is a range of electronic shuttering of the sensor to control light from the scene much like the control produced by a mechanical auto iris lens. (It should be noted, though, that auto iris lenses have a much wider range of control.)

A SHARPNESS control on the side panel can be adjusted to increase the definition of white/black and black/white transitions in the scene to improve overall appearance in some situations.

Integration is controlled by application of a control pulse input on the rear panel AUX (auxiliary) connector. Two other pins of this connector provide a complementary grab-pulse output.

When internal jumpers are set to the reset (not normal/genlock) mode, the Camera can be asynchronously reset at any time by application of a reset pulse to the AUX connector at pin 6. This initiates a vertical-blanking interval 2.5 microseconds later. Video output from the BNC connector then follows the vertical blanking interval, which, for RS-170, is about 1.2 milliseconds (19 to 21 lines) wide. For CCIR, vertical blanking is about 1.6 milliseconds wide (25 lines). If in field mode, this first field of video will most likely be of reduced video level because the reset pulse will have cut the sensor integration period short. Subsequent fields will have a normal video level.

If in frame mode, the first two fields making up an interlaced frame will likely be of reduced (and different) video levels. Subsequent fields making up the frames, though, will be of normal video level.