- 您现在的位置：买卖IC网 > Sheet目录474 > MAX7042EVKIT-433+ (Maxim Integrated)EVAL KIT MAX7042
308MHz/315MHz/418MHz/433.92MHz
Low-Power, FSK Superheterodyne Receiver
Data Filters
The data filter is implemented as a 2nd-order lowpass
Sallen-Key filter. The pole locations are set by the com-
Table 2. Coefficients to Calculate C F1 and
C F2
bination of two on-chip resistors and two external
capacitors. Adjusting the value of the external capaci-
tors changes the corner frequency to optimize for dif-
ferent data rates. The corner frequency in kHz should
be to approximately the fastest expected data rate in
kbps for NRZ and twice the fastest expected data rate
FILTER TYPE
Butterworth
(Q = 0.707)
Bessel
(Q = 0.577)
a
1.414
1.3617
b
1.000
0.618
in kbps for Manchester coding from the transmitter.
Keeping the corner frequency near the data rate
rejects any noise at higher frequencies, resulting in an
increase in receiver sensitivity.
The configuration shown in Figure 2 creates a Butterworth
or Bessel response. The Butterworth filter offers a very
flat amplitude response in the passband and a rolloff rate
of 40dB/decade for the two-pole filter. The Bessel filter
has a linear phase response, which works well for filter-
MAX7042
FSK DEMOD
ing digital data. To calculate the value of the capacitors,
use the following equations along with the coefficients in
Table 2:
100k ?
100k ?
C F 1 =
b
a ( 100 k ? )( π )( f C )
DS+
C F2
OP+
C F1
DF
C F 2 =
a
4 ( 100 k ? )( π )( f C )
Figure 2. Sallen-Key Lowpass Data Filter
where f C is the desired 3dB corner frequency.
For example, choose a Butterworth filter response with
C F 1 =
≈ 450 pF
C F 2 = ≈ 225 pF
a 5kHz corner frequency:
1 . 000
( 1 . 414 )( 100 k ? )( 3 . 14 )( 5 kHz )
1 . 414
( 4 )( 100 k ? )( 3 . 14 )( 5 kHz )
Choosing standard capacitor values changes C F1 to
470pF and C F2 to 220pF. In the Typical Application
Circuit, C F1 and C F2 are named C4 and C3, respectively.
Data Slicer
The purpose of a data slicer is to take the analog output
of a data filter and convert it to a digital signal. This is
achieved by using a comparator and comparing the ana-
log input to a threshold voltage. The threshold voltage is
set by the voltage on the DS- pin, which is connected to
the negative input of the data-slicer comparator. The pos-
itive input of the data-slicer comparator is connected to
the output of the data filter internally.
______________________________________________________________________________________
13
发布紧急采购，3分钟左右您将得到回复。
相关PDF资料
MAX7044EVKIT-433
EVAL KIT MAX7044
MAX7058EVKIT+
EVAL KIT MAX7058
MAX7060EVKIT+
EVAL KIT MAX7060
MAX8506EVKIT
EVAL KIT FOR MAX8506
MAX8582ETB+T
IC CONV 1.5MHZ CDMA 10-TDFN
MAX9635ESA+
IC AMBIENT LIGHT SENSOR 8NSOIC
MAX9930EVKIT+
KIT EVAL FOR MAX9930
MAX9947ETE+
TXRX AISG INTEGRATED 16TQFN
相关代理商/技术参数
MAX7043EUI+
功能描述:射频收发器 300MHz To 450MHz ASK FSK Superhtrdyne Rec RoHS:否 制造商:Atmel 频率范围:2322 MHz to 2527 MHz 最大数据速率:2000 Kbps 调制格式:OQPSK 输出功率:4 dBm 类型: 工作电源电压:1.8 V to 3.6 V 最大工作温度:+ 85 C 接口类型:SPI 封装 / 箱体:QFN-32 封装:Tray
MAX7043EUI+T
功能描述:射频收发器 300MHz To 450MHz ASK FSK Superhtrdyne Rec RoHS:否 制造商:Atmel 频率范围:2322 MHz to 2527 MHz 最大数据速率:2000 Kbps 调制格式:OQPSK 输出功率:4 dBm 类型: 工作电源电压:1.8 V to 3.6 V 最大工作温度:+ 85 C 接口类型:SPI 封装 / 箱体:QFN-32 封装:Tray
MAX7044
制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:300MHz to 450MHz High-Efficiency, Crystal-Based +13dBm ASK Transmitter
MAX7044_09
制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:300MHz to 450MHz High-Efficiency, Crystal-Based +13dBm ASK Transmitter
MAX7044_1
制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:Evaluation Kit
MAX7044_11
制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:300MHz to 450MHz High-Efficiency, Crystal-Based +13dBm ASK Transmitter
MAX7044AKA
制造商:Maxim Integrated Products 功能描述:300MHZ TO 450MHZ HIGH-EFFICIENCY C - Rail/Tube
MAX7044AKA+
制造商:Maxim Integrated Products 功能描述:RF TRANSMITTER ASK/OOK 2.5V/3.3V 8PIN SOT-23 - Rail/Tube