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參數(shù)資料
| 型號(hào)： | AD538SD |
| 廠商： | ANALOG DEVICES INC |
| 元件分類： | 運(yùn)動(dòng)控制電子 |
| 英文描述： | Real-Time Analog Computational Unit ACU |
| 中文描述： | ANALOG MULTIPLE FUNCTIONS, 0.4 MHz BAND WIDTH, CDIP18 |
| 封裝： | SIDE BRAZED, CERAMIC, DIP-18 |
| 文件頁(yè)數(shù)： | 10/11頁(yè) |
| 文件大小： | 167K |
| 代理商： | AD538SD |
AD538
–10–
REV. C
TRANSDUCER LINEARIZATION
Many electronic transducers used in scientific, commercial or
industrial equipment monitor the physical properties of a device
and/or its environment. Sensing (and perhaps compensating for)
changes in pressure, temperature, moisture or other physical
phenomenon can be an expensive undertaking, particularly
where high accuracy and very low nonlinearity are important. In
conventional analog systems accuracy may be easily increased
by offset and scale factor trims, however, nonlinearity is usually
the absolute limitation of the sensing device.
With the ability to easily program a complex analog function,
the AD538 can effectively compensate for the nonlinearities of
an inexpensive transducer. The AD538 can be connected be-
tween the transducer preamplifier output and the next stage of
monitoring or transmitting circuitry. The recommended proce-
dure for linearizing a particular transducer is first to find the
closest function which best approximates the nonlinearity of the
device and then, to select the appropriate exponent resistor
value(s).
ARC-TANGENT APPROXIMATION
The circuit of Figure 17 is typical of those AD538 applications
where the quantity V
Z
/V
X
is raised to powers greater than one.
In an approximate arc-tangent function, the AD538 will accu-
rately compute the angle that is defined by X and Y displace-
ments represented by input voltages V
X
and V
Z
. With accuracy
to within one degree (for input voltages between 100
μ
V and
10 volts), the AD538 arc-tangent circuit is more precise than
conventional analog circuits and is faster than most digital tech-
niques. For a direct arc-tangent computation that requires fewer
external components, refer to the AD639 data sheet. The circuit
shown is set up for the transfer function:
V
V
(
V
V
(
V
REF
X
θ
θ
θ
=
)( )
)
1 21
.
where:
θ =
Tan
1
Z
X
The (
V
θ
REF
–
V
θ
) function is implemented in this circuit by
adding together the output,
V
θ
, and an externally applied refer-
ence voltage, V
θ
REF
, via an external AD547 op amp. The 1
μ
F
capacitor connected around the AD547’s 100 k
feedback
resistor frequency compensates the loop (formed by the ampli-
fier between V
θ
and V
Y
).
25k
V
25k
V
LOG
RATIO
100
V
25k
V
25k
V
ANTILOG
LOG
OUTPUT
100
V
AD538
INTERNAL
VOLTAGE
REFERENCE
V
u
= [V
u
REF
–V
u
]
3
(
)
u
= TAN
–1
( )
V
X
V
Z
Z
1.21
1
2
3
4
5
6
7
8
9
18
17
16
15
14
13
12
11
10
I
V
O
I
Z
V
Z
B
+10V
+2V
I
Y
A
D
I
X
V
X
SIGNAL
GND
C
PWR
GND
V
Y
–V
S
IN4148
RATIO MATCH 1% METAL
FILM RESISTORS FOR BEST
ACCURACY
*
+V
S
1
m
F
1
m
F
+15V
–15V
V
u
V
Z
AD547JH
R2
*
100k
V
+15V
–15V
0.1
m
F
100k
V
1
m
F
118k
V
R1
*
100k
V
10k
FULL-SCALE
ADJUST
R
A
931
V
, 1%
V
X
Figure 17. The Arc-Tangent Function
The V
B
/V
A
quantity is calculated in the same manner as in the
one-quadrant divider circuit, except that the resulting quotient
is raised to the 1.21 power. Resistor R
A
(nominally 931
) sets
the power or
m
factor.
For the highest arc-tangent accuracy the external resistors R1
and R2 should be ratio matched; however, the offset trim
scheme shown in other circuits is not required since nonlinearity
effects are the predominant source of error. Also note that insta-
bility will occur as the output approaches 90
°
because, by defini-
tion, the arc-tangent function is infinite and therefore, the AD538’s
gain will be extremely high.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| AD538ACHIPS | Real-Time Analog Computational Unit ACU |
| AD539 | AD539: Wideband Dual-Channel Linear Multiplier/Divider Data Sheet (Rev. A. 12/91) |
| AD539KN | Wideband Dual-Channel Linear Multiplier/Divider |
| AD539JCHIP | DIODE ZENER SINGLE 200mW 8.2Vz 20mA-Izt 0.05 3uA-Ir 6.5 SOT-323 3K/REEL |
| AD539JD | DIODE ZENER SINGLE 350mW 8.7Vz 20mA-Izt 0.05 3uA-Ir 6.5 SOT-23 3K/REEL |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| AD538SD/883B | 功能描述:增效器/分頻器 MULT/DIV ACU IC RoHS:否 制造商:Texas Instruments 產(chǎn)品:Multiplier 邏輯系列: 工作電源電壓: 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 安裝風(fēng)格:Through Hole 封裝 / 箱體:PDIP-14 |
| AD5390BCP-3 | 制造商:Analog Devices 功能描述:DAC 16-CH Resistor-String 14-bit 64-Pin LFCSP EP 制造商:Rochester Electronics LLC 功能描述:8/16-CHANNEL, 14/12-BIT, 3V/5V VOLTAGE OUT DAC - Bulk |
| AD5390BCP-3-REEL | 制造商:Analog Devices 功能描述:DAC 16-CH Resistor-String 14-bit 64-Pin LFCSP EP T/R |
| AD5390BCP-3-REEL7 | 制造商:Analog Devices 功能描述:DAC 16-CH Resistor-String 14-bit 64-Pin LFCSP EP T/R |
| AD5390BCP-5 | 制造商:Analog Devices 功能描述:DAC 16-CH Resistor-String 14-bit 64-Pin LFCSP EP 制造商:Analog Devices 功能描述:14BIT DAC 16CH 5V 5390 LFCSP-64 |
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