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)： 35/37頁
文件大?。?/td> 479K
代理商： LM9812CCV
35
http://www.national.com
If 1.5 < Range < 2.0, then set the Multiplier Range bits (register
9, bits 3 and 2) to 01 (50%).
If 2.0 < Range < 3.0, then set the Multiplier Range bits (register
9, bits 3 and 2) to 00 (66%).
If Range > 3.0, then set the range is too large and the system
can not be calibrated.
4.5 Calculating the Pixel Rate Offset Coefficients
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.
The value of each pixel is the offset error for that pixel. Store
each pixel value into that pixel's offset correction RAM
location.
Set the Pixel Rate Offset Adder Source to external (register 9,
bit 0 = 0)
4.6 Calculating the Pixel Rate Multiplier Coefficients
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.
The equation for the multiplier gain is:
where:
x is the 10 bit multiplier gain coefficient (0 to 1023),
N = 2048 (Multiplier range = 1:1.5),
N = 1024 (Multiplier range = 1:2),
N = 512 (Multiplier range = 1:3).
Determine the multiplier gain for each pixel n so the result is
the Target Code:
The multiplier coefficient required is therefore:
Store the Multiplier Gain Coefficients for each pixel into that
pixel's offset correction RAM location.
Set the Pixel Rate Multiplier Source to external (register 9, bit
1=0)
CALIBRATION COMPLETE
4.7 Additional Calibration Information
The procedure detailed in sections 4.1 through 4.6 is only one of
many approaches to scanner calibration. In some approaches it
may be useful to use a model for the analog front end and actu-
ally measure V
OS1
and V
OS2
.
Figure 13 is a mathematical model of the analog front end of one
channel of the LM9812. The constant C (typically 2, given in the
Electrical Characteristics table) represents the total gain error
from Vin through D
with G = 1V/V (PGA register setting = 1).
To further simplify the model, the signal is always assumed to be
0V for black and increasing in the positive direction as pixel
brightness increases. In reality, black may be offset from ground,
and white may be negative (CCD) or positive (CIS) with respect to
black, but this is all taken care of by the CDS function and the cor-
rect setting of the Signal Polarity bit (Register 24, bit 7).
The analog front end’s transfer function is shown in Equation 18.
The typical values of C (2) and V
REFIN
(2V) cancel each other
out. It is also useful to convert all the voltages to ADC codes,
since that is the domain in which they will be seen by the calibra-
tion software. V
IN
(in ADC codes) = V
IN
(in V)*1024. Calibration
can be more easily accomplished using the simplified model of
Equation 19.
Measurement of the two offset voltages (V
OS1
and V
OS2
) is done
by measuring the ADC output, with a black image on the sensor
(if a black reference image is not available, it may be created sim-
ply by turning off the scanner’s illumination). In this example, V
IN
is considered to be 0V, and any offsets from the sensor are
lumped in with the LM9812’s V
OS1
. If the ADC output is measured
with a PGA gain of 1V/V and 3V/V, then the offset errors (V
OS1
and V
OS2
) can be determined from the following two equations:
V
ADC1
= 1V
OS1
+ V
OS2
+ V
DAC2
(PGA gain = 1V/V)
V
ADC2
= 3V
OS1
+ V
OS2
+ V
DAC2
(PGA gain = 3V/V)
Solving for V
OS1
and V
OS2
:
V
OS1
= (V
ADC2
- V
ADC1
)/2
V
OS2
= (3V
ADC1
- V
ADC2
)/2
5.0 POWER SUPPLY CONSIDERATIONS
5.1 General
The LM9812 should be powered by a single +5V source (unless
3V-compatible digital I/O is required-see Section 5.2). The analog
supplies (V
) and the digital supplies (V
and V
) are brought
out individually to allow separate bypassing for each supply input.
They should notbe powered by two or more different supplies.
Multiplier Gain
1
x
N
---
+
=
Equation 15: Multiplier Gain Equation
Gain(n)
pixel datan
=
Equation 16: Gain Calculation for Each Pixel
Multiplier Coefficent (n)
Integer(N(Gain(n) - 1))
Integer NTarget Code
--------------------------------
=
Equation 17: Multiplier Coefficient Calculation for Each Pixel
pixel datan
1
–
=
V
OD
DAC
Offset
G
Σ
+
+
Figure 13: Simplified Model of One Channel of the Ana-
log Front End
10 Bit
ADC
+
+
+
+
V
OS2
V
OS1
V
IN
Σ
Σ
D
OUT
V
REF IN
C
DOUT
1024C
--VIN
VOS1
+
(
)
G
VOS2
VOD
+
+
VREFIN
=
Equation 18: AFE Transfer Equation
DOUT
VIN
VOS1
+
(
)
G
VOS2
VOD
+
+
=
Equation 19: AFE Transfer Equation (units of ADC LSBs)
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(fù)。

采購需求

(若只采購一條型號，填寫一行即可)

發(fā)布成功！您可以繼續(xù)發(fā)布采購。也可以進入我的后臺，查看報價

發(fā)布成功！您可以繼續(xù)發(fā)布采購。也可以進入我的后臺，查看報價

*型號 *數(shù)量 廠商 批號 封裝
添加更多采購

我的聯(lián)系方式

*
*
*