3.5
3.5.1
Acceleration Signal Path
Transducer
ω n
s + 2 ? ξ ? ω n ? s + ω n
The transducer is an overdamped mass-spring-damper system defined by the following transfer function:
where:
2
H ( s ) = ---------------------------------------------------------
2 2
ζ = Damping Ratio
ω n = Natural Frequency = 2 ? Π ? f n
Reference Section 2.7 for transducer parameters.
3.5.2
ΣΔ Converter
A sigma delta modulator converts the differential capacitance of the transducer to a 1 MHz data stream that is input to the DSP
block.
g-CELL
C TOP
C BOT
α 1 =
V X
C INT1
FIRST
INTEGRATOR
z -1
1 - z -1
α 2
SECOND
INTEGRATOR
z -1
1 - z -1
1-BIT
QUANTIZER
ΣΔ _OUT
ADC
Δ C = C TOP - C BOT
β 1
β 2
V = Δ C x V X / C INT1
V = ± 2 × V REF
Figure 14. ΣΔ Converter Block Diagram
DAC
3.5.3
Digital Signal Processing Block
A Digital Signal Processing (DSP) block is used to perform signal filtering and compensation. A diagram illustrating the signal
processing flow within the DSP block is shown in Figure 15 .
ΣΔ _OUT
A
SINC FILTER
B
LOW-PASS FILTER
C
COMPENSATION
D
DOWNSAMPLING
E
OFFSET
OFFSET CANCELLATION CANCELLATION
LOW-PASS FILTER OUTPUT
F
OUTPUT
SCALING
G
INTERPOLATION
H OUTPUT
RATE LIMITING
Figure 15. Signal Chain Diagram
MMA52xxKW
Sensors
24
Freescale Semiconductor, Inc.
相关PDF资料
MMA6331LT SENSORS ACCELEROMETER 14LGA
MMA6341LT IC ACCELER 3G/8G XY-AXIS 14LGA
MMA6361LT IC ACCELER 1.5G XY-AXIS 14LGA
MMA6527KW IC ACCELEROMETER XY AXIS 16QFN
MMA6556KW IC ACCELEROMETER X AXIS 16QFN
MMA6826AKW IC ACCELEROMETER XY AXIS 16QFN
MMA6854KW IC ACCELEROMETER X AXIS 16QFN
MMA7331LR2 ACCELEROMETER 4G XYZ ENH 14-LGA
相关代理商/技术参数
MMA52XXAKW 制造商:FREESCALE 制造商全称:Freescale Semiconductor, Inc 功能描述:Xtrinsic MMA52xxAKW PSI5 Inertial Sensor
MMA52XXKW 制造商:FREESCALE 制造商全称:Freescale Semiconductor, Inc 功能描述:PSI5 Inertial Sensor
MMA52XXWR2 制造商:FREESCALE 制造商全称:Freescale Semiconductor, Inc 功能描述:PSI5 Inertial Sensor
MMA621010AEG 功能描述:加速计 - 板上安装 100/100G XY ANALOG RoHS:否 制造商:Murata 传感轴:Double 加速:12 g 灵敏度: 封装 / 箱体: 输出类型:Analog 数字输出 - 位数:11 bit 电源电压-最大:5.25 V 电源电压-最小:4.75 V 电源电流:4 mA 最大工作温度:+ 125 C 最小工作温度:- 40 C
MMA621010AEGR2 功能描述:加速计 - 板上安装 100/100G XY ANALOG RoHS:否 制造商:Murata 传感轴:Double 加速:12 g 灵敏度: 封装 / 箱体: 输出类型:Analog 数字输出 - 位数:11 bit 电源电压-最大:5.25 V 电源电压-最小:4.75 V 电源电流:4 mA 最大工作温度:+ 125 C 最小工作温度:- 40 C
MMA621010AKEG 功能描述:加速计 - 板上安装 100/100G XY ANALOG RoHS:否 制造商:Murata 传感轴:Double 加速:12 g 灵敏度: 封装 / 箱体: 输出类型:Analog 数字输出 - 位数:11 bit 电源电压-最大:5.25 V 电源电压-最小:4.75 V 电源电流:4 mA 最大工作温度:+ 125 C 最小工作温度:- 40 C
MMA621010AKEGR2 功能描述:加速计 - 板上安装 100/100G XY ANALOG RoHS:否 制造商:Murata 传感轴:Double 加速:12 g 灵敏度: 封装 / 箱体: 输出类型:Analog 数字输出 - 位数:11 bit 电源电压-最大:5.25 V 电源电压-最小:4.75 V 电源电流:4 mA 最大工作温度:+ 125 C 最小工作温度:- 40 C
MMA621010EG 功能描述:加速计 - 板上安装 100 /100 XY DIGITAL RoHS:否 制造商:Murata 传感轴:Double 加速:12 g 灵敏度: 封装 / 箱体: 输出类型:Analog 数字输出 - 位数:11 bit 电源电压-最大:5.25 V 电源电压-最小:4.75 V 电源电流:4 mA 最大工作温度:+ 125 C 最小工作温度:- 40 C