Texas Instruments MULTICAM MC-1134P, Руководство пользователя

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Description of CCD Operation
B-22
5.1 Description of CCD Operation
The TC217 is a frame-transfer charge-coupled device (CCD) image sensor
with two field memories. It is suitable for use in NTSC-video or still-picture
photography applications. Its image-sensing area is configured into 488 lines,
486 of which are active and 2 of which are used for dark reference. Each line
is configured into 1158 pixels of which 1134 are active and 24 are for dark
reference. The TC217 has a standard aspect ratio of 4:3 and a standard
11-mm image-sensing-area diagonal. Its blooming protection, which is an
integral part of each pixel, is based on electron-hole recombination and is
activated by clocking the antiblooming gate.
One important advantage of this high-resolution sensor is its ability to capture
both fields of a TV frame simultaneously. Its two independently addressable
memories allow separate storage of each field and operation in a variety of
modes, including RS-170 with true interlace, RS-170 with pseudo-interlace,
and nonstandard pseudo-interlace with a resolution of 972 lines.
A unique multiplexer section in the TC217 rearranges the horizontal pixels into
vertical groups of three and separates and loads the image into the two field
memories. The independent addressing of each field memory provides
flexibility for different modes of operation. The interdigitated layout of the
memories allows each memory to share the same bank of three serial
registers and associated charge-detection amplifiers. Each register and
associated amplifier reads out every third column of the image area. The three
amplifiers are optimized dual-source followers that allow the use of off-chip
double-correlated clamp-sample-and-hold amplifiers for removing KTC noise.
The TC217 is built using TI-proprietary virtual-phase technology, which
provides devices with high blue response, low dark signal, good uniformity,
and single-phase clocking. The TC217 is characterized for operation from
–10
°
C to 40
°
C.