AD9949 datasheet(11/36 Pages) AD

11 / 36 page

AD9949

Rev. B | Page 11 of 36

SYSTEM OVERVIEW

CCD

SERIAL

INTERFACE

DOUT

DIGITAL IMAGE

PROCESSING

ASIC

V-DRIVER

HD, VD

CLI

V1 TO Vx, VSG1 TO VSGx, SUBCK

H1 TO H4, RG

CCDIN

AD9949

INTEGRATED

AFE + TD

Figure 11. Typical Application

Figure 11 shows the typical system application diagram for the

AD9949. The CCD output is processed by the AD9949’s AFE

circuitry, which consists of a CDS, a PxGA, a VGA, a black level

clamp, and an ADC. The digitized pixel information is sent to

the digital image processor chip where all postprocessing and

compression occurs. To operate the CCD, CCD timing

parameters are programmed into the AD9949 from the image

processor through the 3-wire serial interface. From the system

master clock, CLI, provided by the image processor, the

AD9949 generates the high speed CCD clocks and all internal

AFE clocks. All AD9949 clocks are synchronized with VD and

HD. The AD9949’s horizontal pulses (CLPOB, PBLK, and

HBLK) are programmed and generated internally.

The H-drivers for H1 to H4 and RG are included in the

AD9949, allowing these clocks to be directly connected to the

CCD. The H-drive voltage of 3 V is supported in the AD9949.

Figure 12 shows the horizontal and vertical counter dimensions

for the AD9949. All internal horizontal clocking is programmed

using these dimensions to specify line and pixel locations.

H-COUNTER BEHAVIOR

When the maximum horizontal count of 4096 pixels is

exceeded, the H-counter in the AD9949 rolls over to zero and

continues counting. It is, therefore, recommended that the

maximum counter value not be exceeded.

However, the newer AD9949A version behaves differently. In

the AD9949A, the internal H-counter holds at its maximum

count of 4095 instead of rolling over. This feature allows the

AD9949A to be used in applications containing a line length

greater than 4096 pixels. Although no programmable values for

the horizontal blanking or clamping are available beyond pixel

4095, the H, RG, and AFE clocking continues to operate,

sampling the remaining pixels on the line.

MAXIMUM FIELD DIMENSIONS

12-BIT HORIZONTAL = 4096 PIXELS MAX

12-BIT VERTICAL = 4096 LINES MAX

Figure 12. Vertical and Horizontal Counters

CLI

MAX HD LENGTH IS 4095 PIXELS

MAX VD LENGTH IS 4095 LINES

Figure 13. Maximum VD/HD Dimensions

AD9949 датащи(PDF) 11 Page - Analog Devices

AD9949 датащи(HTML) 11 Page - Analog Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36

датащи скачать

ссылки URL