參數(shù)資料
型號: EVAL-AD5934EBZ
廠商: Analog Devices Inc
文件頁數(shù): 22/32頁
文件大?。?/td> 0K
描述: BOARD EVALUATION FOR AD5934
標(biāo)準(zhǔn)包裝: 1
主要目的: 計時,直接數(shù)字合成(DDS)
嵌入式:
已用 IC / 零件: AD5934
主要屬性: 12 位數(shù)模轉(zhuǎn)換器,24 位調(diào)節(jié)字寬
次要屬性: 16MHz 2.7 V ~ 5.5 V 圖形用戶界面
已供物品: 板,線纜,軟件
產(chǎn)品目錄頁面: 797 (CN2011-ZH PDF)
相關(guān)產(chǎn)品: AD5934YRSZ-ND - IC NTWK ANALYZER 12B 1MSP 16SSOP
AD5934YRSZ-REEL7-ND - IC CONV 12BIT 250KSPS 16SSOP
Data Sheet
AD5934
Rev. C | Page 29 of 32
SENSOR/COMPLEX IMPEDANCE MEASUREMENT
The operational principle of a capacitive proximity sensor is
based on the change of a capacitance in a RLC resonant circuit.
This leads to changes in the resonant frequency of the RLC
circuit, which can be evaluated as shown Figure 33.
It is first required to tune the RLC circuit to the area of resonance.
At the resonant frequency, the impedance of the RLC circuit is
at a maximum. Therefore, a programmable frequency sweep
and tuning capability is required, which is provided by the AD5934.
05325-
058
FREQUENCY (Hz)
PR
O
XI
MI
TY
IMPED
A
N
C
E
(
)
RESONANT
FREQUENCY
CHANGE IN
RESONANCE DUE
TO APPROACHING
OBJECT
FO
Figure 33. Detecting a Change in Resonant Frequency
An example of the use of this type of sensor is for a train proximity
measurement system. The magnetic fields of the train approaching
on the track change the resonant frequency to an extent that can
be characterized. This information can be sent back to a mainframe
system to show the train location on the network.
Another application for the AD5934 is in parked vehicle detection.
The AD5934 is placed in an embedded unit connected to a coil
of wire underneath the parking location. The AD5934 outputs a
single frequency within the 80 kHz to 100 kHz frequency range,
depending upon the wire composition. The wire can be modeled
as a resonant circuit. The coil is calibrated with a known impedance
value and at a known frequency. The impedance of the loop is
monitored constantly. If a car is parked over the coil, the impedance
of the coil changes and the AD5934 detects the presence of the car.
ELECTRO-IMPEDANCE SPECTROSCOPY
The AD5934 has found use in the area of corrosion monitoring.
Corrosion in a metal, such as aluminum, which is used in air
craft and ships, requires continuous assessment because the metal
is exposed to a wide variety of conditions, such as temperature and
moisture. The AD5934 offers an accurate and compact solution
for this type of measurement compared to the large and expensive
existing units on the market.
Mathematically the corrosion of a metal is modeled using a RC
network that consists of a resistance, RS, in series with a parallel
resistor and capacitor, RP and CP. A system metal would typically
have values as follows: RS is 10 to 10 k, RP is 1 k to 1 M,
and CP is 5 F to 70 F.
The frequency range of interest when monitoring corrosion is
0.1 Hz to 100 kHz.
To ensure that the measurement itself does not introduce a
corrosive effect, the metal needs to be excited with minimal
voltage, typically in the 200 mV region, which the AD5934 is
capable of outputting. A nearby processor or control unit, such
as the ADuc702x, would log a single impedance sweep from
0.1 kHz to 100 kHz every 10 minutes and download the results
back to a control unit. To achieve system accuracy from the
0.1 kHz to 1 kHz region, the system clock needs to be scaled
down from the 16.776 MHz nominal clock frequency to 500 kHz,
typically. The clock scaling can be achieved digitally using an
external direct digital synthesizer, such as the AD9834, as a
programmable divider that supplies a clock signal to MCLK
and that can be controlled digitally by the nearby microprocessor.
相關(guān)PDF資料
PDF描述
BQ2057CDGK IC LI-ION LDO CHRG MGMT 8-MSOP
VE-J7Y-EZ-F3 CONVERTER MOD DC/DC 3.3V 16.5W
VE-J7Y-EZ-F2 CONVERTER MOD DC/DC 3.3V 16.5W
MC34164P-3RPG IC SENSOR UNDERVOLT 3V TO-226AA
BQ2057TSN IC LITH-ION LDO CHRG MGMT 8-SOIC
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
EVAL-AD607EBZ 功能描述:BOARD EVALUATION FOR AD607 RoHS:是 類別:RF/IF 和 RFID >> RF 評估和開發(fā)套件,板 系列:- 標(biāo)準(zhǔn)包裝:1 系列:- 類型:GPS 接收器 頻率:1575MHz 適用于相關(guān)產(chǎn)品:- 已供物品:模塊 其它名稱:SER3796
EVAL-AD608EBZ 功能描述:BOARD EVALUATION FOR AD608 RoHS:是 類別:RF/IF 和 RFID >> RF 評估和開發(fā)套件,板 系列:- 標(biāo)準(zhǔn)包裝:1 系列:- 類型:GPS 接收器 頻率:1575MHz 適用于相關(guān)產(chǎn)品:- 已供物品:模塊 其它名稱:SER3796
EVAL-AD7021DBZ5 制造商:Analog Devices 功能描述:EVAL BOARD ((NS))
EVAL-AD7091RSDZ 功能描述:數(shù)據(jù)轉(zhuǎn)換 IC 開發(fā)工具 EVALUATION BOARD RoHS:否 制造商:Texas Instruments 產(chǎn)品:Demonstration Kits 類型:ADC 工具用于評估:ADS130E08 接口類型:SPI 工作電源電壓:- 6 V to + 6 V
EVAL-AD7091SDZ 功能描述:數(shù)據(jù)轉(zhuǎn)換 IC 開發(fā)工具 EVALUATION BOARD RoHS:否 制造商:Texas Instruments 產(chǎn)品:Demonstration Kits 類型:ADC 工具用于評估:ADS130E08 接口類型:SPI 工作電源電壓:- 6 V to + 6 V