- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄384602 > LM9812CCV (NATIONAL SEMICONDUCTOR CORP) LM9812 30-Bit Color Linear CCD Sensor Processor PDF資料下載
參數(shù)資料
| 型號： | LM9812CCV |
| 廠商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分類： | 模擬信號調(diào)理 |
| 英文描述： | LM9812 30-Bit Color Linear CCD Sensor Processor |
| 中文描述： | SPECIALTY ANALOG CIRCUIT, PQCC52 |
| 封裝： | PLASTIC, LCC-52 |
| 文件頁數(shù)： | 34/37頁 |
| 文件大?。?/td> | 479K |
| 代理商： | LM9812CCV |
第1頁第2頁第3頁第4頁第5頁第6頁第7頁第8頁第9頁第10頁第11頁第12頁第13頁第14頁第15頁第16頁第17頁第18頁第19頁第20頁第21頁第22頁第23頁第24頁第25頁第26頁第27頁第28頁第29頁第30頁第31頁第32頁第33頁當前第34頁第35頁第36頁第37頁
34
http://www.national.com
Set the Multiplier Gain Range to 1:3 (register 9, bits 2 and 3 =
00)
4.2 Setting the Static Offset DACs
Scan one line of a pure black test pattern, or scan one line with
the light source turned off. (Caution: turning the light source on
and off may cause thermal drift in light intensity as the light
source warms up and cools down.) Scanning multiple black
lines and averaging each pixel from each line will reduce noise
and increase the accuracy of this step.
Find the minimum pixel value of the scanned black image
(Black
MIN
) for each color (Figure 8).
Reduce the Offset DAC value for each color so that the
minimum black pixel is close to 0, but still greater than 0
(Figure 9). One offset DAC code = ~4.2 ADC LSBs, so change
the DAC code to (31 - Black
MIN
/4.2).
Because the above equation is based on typical LM9812
performance, the new DAC settings should be verified. Scan
another black line(s) with the new DAC values and verify that
all the pixels are still above 0. If any pixels are equal to 0,
increment the DAC value by 1. If the minimum pixel is above 8,
consider decrementing the DAC value by 1. Repeat this step
until the minimum pixel value of the scanned black image
(Black
MIN
) for each color is greater than 0 but less than 9.
Black
MIN
values greater than 9 are acceptable (they will be
removed by the Pixel Rate Offset Subtractor), but will reduce
the dynamic range of the system.
4.3 Setting the Static PGAs
Decide on the Target Code for your scanner. This is the
maximum output code from the ADC for a pure white image.
This code may be as large as 1023, but this value could cause
clipping if the light source drifts and becomes brighter after
calibration. A value of 1000 allows for moderate light source
drift between calibration and image scan.
Scan one line of a pure white test pattern. Scanning multiple
white lines and averaging each pixel from each line will reduce
noise and increase the accuracy of this step.
Find the maximum white pixel value of the image data
(White
MAX
) for each color (Figure 10).
Program the PGA value for each color so that the maximum
white pixel is close to, but still less than the Target Code
(Figure 11). The PGA gain required to meet this condition is
equal to the Target Code divided by White
MAX
. Using the PGA
gain equation (Equation 1), the PGA code required is:
If the Blue channel requires a gain greater than 3 (Target
Code/White
MAX
is >3), then set register 2, bit 7=1 and use
Equation 14:
Program the calculated PGA values for each color into
configuration registers 3, 4, and 5.
Because the above equations are based on typical LM9812
performance, the new PGA settings should be verified. Scan
another white line(s) with the new PGA values and recalculate
White
MAX
and White
MIN
(the minimum ADC output code for the
white image) for each color. Verify that White
MAX
is near but
still below the Target Code. If White
MAX
is greater than or
equal to the target code, decrement that PGA value by 1.
4.4 Determining the Multiplier Correction Range Setting
For best performance, repeat Steps 4.2 and 4.3 before
proceeding. This will maximize the available dynamic range of
the ADC and ensure that all the pixels are in range.
Digitize another white line (or multiple lines) and calculate the
minimum and maximum pixels from that line (White
MIN
and
White
MAX
). Verify that White
MAX
is less than the Target Code.
The correction range required (Range) = White
MAX
/White
MIN
If Range < 1.5, then set the Multiplier Range bits (register 9,
bits 3 and 2) to 10 (33%).
Data Pixels
000
Figure 8: Finding Black
MIN
Black
MIN
008
004
010
00C
ADC
Output
Code
014
018
Data Pixels
000
Figure 9: Setting the Static Offset DACs
Black
= 13:
too high
008
004
010
00C
ADC
Output
Code
014
018
Black
= 6:
correct
Black
= 0:
too low
Data Pixels
Figure 10: Finding White
MAX
gain too high
Target Code
ADC
Output
Code
White
MAX
Data Pixels
Figure 11: CCD Input Signal In Range
Target Code
ADC
Output
Code
gain too low
gain correct
PGA code
Integer
WhiteMAX
0.94
–
2.137
=
Equation 13: PGA Code Calculation
PGA code
Integer
WhiteMAX
2.82
–
6.411
=
Equation 14: Blue PGA Code Calculation, x3 Bit Set
Data Pixels
Figure 12: Determining Correction Range Setting
Target Code
ADC
Output
Code
White
MAX
White
MIN
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LM9823CCWM | LM9823 3 Channel 48-Bit Color Scanner Analog Front End |
| LM9823CCWMX | LM9823 3 Channel 48-Bit Color Scanner Analog Front End |
| LMC13204 | Quad SPST High Voltage CMOS Analog Switches |
| LMC13334 | Quad SPST High Voltage CMOS Analog Switches |
| LMC13335 | Quad SPST High Voltage CMOS Analog Switches |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LM981-SC36 | 功能描述:基本/快動開關(guān) Foot Switch RoHS:否 制造商:Omron Electronics 觸點形式:SPDT 執(zhí)行器:Lever 電流額定值:5 A 電壓額定值 AC:250 V 電壓額定值 DC:30 V 功率額定值: 工作力:120 g IP 等級:IP 67 NEMA 額定值: 端接類型:Wire 安裝:Panel |
| LM981-ZZ | 功能描述:基本/快動開關(guān) Foot Switch RoHS:否 制造商:Omron Electronics 觸點形式:SPDT 執(zhí)行器:Lever 電流額定值:5 A 電壓額定值 AC:250 V 電壓額定值 DC:30 V 功率額定值: 工作力:120 g IP 等級:IP 67 NEMA 額定值: 端接類型:Wire 安裝:Panel |
| LM981-ZZ-1 | 功能描述:基本/快動開關(guān) Foot Switch RoHS:否 制造商:Omron Electronics 觸點形式:SPDT 執(zhí)行器:Lever 電流額定值:5 A 電壓額定值 AC:250 V 電壓額定值 DC:30 V 功率額定值: 工作力:120 g IP 等級:IP 67 NEMA 額定值: 端接類型:Wire 安裝:Panel |
| LM9820 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述: |
| LM9820CCWM | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:LM9810/20 10/12-Bit Image Sensor Processor Analog Front End |
發(fā)布緊急采購，3分鐘左右您將得到回復。