参数资料
型号: CDS-1402MM
厂商: Electronic Theatre Controls, Inc.
英文描述: 14-Bit, Very Fast Settling Correlated Double Sampling Circuit
中文描述: 14位,非常快速沉降相关双采样电路
文件页数: 4/8页
文件大小: 203K
代理商: CDS-1402MM
CDS -1402
4
The fourth major contributor to pixel offset is a low-frequency
noise component (usually called 1/f noise or pink noise)
associated with the CCD's output buffer amplifier.
Due to all of these contributing factors, "pixel offsets" vary from
sample to sample in an inconsistent, unpredictable manner.
Traditional Approach to CDS
There are a number of techniques for dealing with the varying-
offset idiosyncrasy of CCD's. The most prevalent has been
what can be called the "sample-sample-subtract" technique.
This approach requires the use of two high-speed sample-hold
(S/H) amplifiers and a difference amplifier. The first S/H is
used to acquire and hold a given pixel's offset. Immediately
after that, the second S/H acquires and holds the same pixel’s
offset+video signal. After both the S/H outputs have fully
settled, the difference amplifier subtracts the offset from the
offset+video yielding the valid video signal.
CDS-1402 Approach (See Figure 1)
The DATEL CDS-1402 takes a slightly different, though clearly
superior, approach to CDS. It can be called the "sample-
subtract-sample" approach.
Note that the CDS-1402 has been configured to offer the
greatest amount of user flexibility. Its two S/H circuits function
independently. They have separate input and output pins.
Each has its own independent control lines. The control-line
signals are delayed, buffered, and brought back out of the
The floating capacitor is normally discharged (charged) via a
shunt switch (typically a FET structure) that has a non-zero
"on" resistance. When the switch is on, its effective series
resistance exhibits thermal noise (Johnson noise) due to the
random motion of thermally energized charge. Because the
shunt switch is in parallel with the floating capacitor, the
instantaneous value of the thermal noise (expressed in either
Volts or electrons) appears across the cap. When the shunt
switch is opened, charge/voltage is left on the floating cap.
The magnitude of this "captured noise voltage" is a function of
absolute temperature (T), the value of the floating capacitor
(C) and Boltzman’s constant (k). It is commonly referred to as
"kTC" noise.
The second contributor to the constantly varying pixel offsets
is the fact that, at high pixel rates, the floating capacitor never
has time to fully discharge (charge) during the period in which
its shunt switch is closed. There is always some "residual"
charge left on the cap, and the amount of this charge varies as
a function of what was the total charge held during the
previous pixel. This amount of residual charge is, in fact,
deterministic (if you know the previous charge and the number
of time constants in the discharge period), however, it is less
of a contributor than "kTC" noise.
The third major contributor to pixel offset is the fact that as the
shunt FET is turned off, the voltage across (and the charge
stored on) its parasitic junction capacitances changes. The
result is an "injection" of excess charge onto the floating cap
causing a voltage step normally called a "pedestal".
Figure 2. CDS-1402 Typical Timing Diagram
ANALOG INPUT FOR CDS
(Pins 3 and 4 are tied together)
S/H1 (Pin 11)
A/D CLOCK 1 (Pin 17)
S/H2 (Pin 12)
A/D CLOCK 1 (Pin 18)
A/D CLOCK 2 (Pin 19)
A/D CLOCK 2 (Pin 20)
VOLTAGE OUTPUT (Pin 22)
VIDEO SIGNAL N-1
VIDEO SIGNAL N
(CCD OUTPUT)
100ns typ.
30ns typ.
30ns typ.
NOTE: Not Drawn to Scale
RESET N
OFFSET N
OFFSET +
VIDEO N
RESET N+1
OFFSET N+1
OFFSET +
VIDEO N+1
100ns typ.
HOLD
HOLD
相关PDF资料
PDF描述
CDS15FD331J03 Miniature Dipped, Mica Capacitors
CDS15CD180J03 Miniature Dipped, Mica Capacitors
CDS15ED200J03 Miniature Dipped, Mica Capacitors
CDS15ED220J03 Miniature Dipped, Mica Capacitors
CDS15ED240J03 Miniature Dipped, Mica Capacitors
相关代理商/技术参数
参数描述
CDS14N 功能描述:SOCKET,1/4" DRIVE,7MM,6PT 制造商:apex tool group 系列:* 零件状态:在售 标准包装:1
CDS15 功能描述:保险丝 CARTRIDGE D 15A RoHS:否 制造商:Littelfuse 产品:Surface Mount Fuses 电流额定值:0.5 A 电压额定值:600 V 保险丝类型:Fast Acting 保险丝大小/组:Nano 尺寸:12.1 mm L x 4.5 mm W 安装风格: 端接类型:SMD/SMT 系列:485
CDS150 功能描述:保险丝 CNDIAN D-TYP 600V TD RoHS:否 制造商:Littelfuse 产品:Surface Mount Fuses 电流额定值:0.5 A 电压额定值:600 V 保险丝类型:Fast Acting 保险丝大小/组:Nano 尺寸:12.1 mm L x 4.5 mm W 安装风格: 端接类型:SMD/SMT 系列:485
CDS-15118B 功能描述:8 Ohm Magnetic Speaker 700mW 20Hz ~ 20kHz Top Rectangular 86dB 制造商:cui inc. 系列:CDS 零件状态:有效 类型:磁性 频率范围:20Hz ~ 20kHz 阻抗:8 欧姆 声压级:86dB 功率 - 额定值:700mW 功率 - 最大值:1W 端口位置:顶部 形状:矩形 材料 - 锥体:PET 材料 - 磁铁:Nd-Fe-B 端接:焊盘 大小/尺寸:15.00mm 长 x 11.00mm 宽 高度:3.10mm 标准包装:100
CDS-15118B-L100 功能描述:8 Ohm Magnetic Speaker 700mW 20Hz ~ 20kHz Top Rectangular 86dB 制造商:cui inc. 系列:CDS 零件状态:有效 类型:磁性 频率范围:20Hz ~ 20kHz 阻抗:8 欧姆 声压级:86dB 功率 - 额定值:700mW 功率 - 最大值:1W 端口位置:顶部 形状:矩形 材料 - 锥体:PET 材料 - 磁铁:Nd-Fe-B 端接:导线引线 大小/尺寸:15.00mm 长 x 11.00mm 宽 高度:3.10mm 标准包装:50