收藏本站
MRF89XA
3.4.4
CHANNEL FILTERS
EQUATION 3-8:
The second mixer stages are followed by the channel
select filters. The channel select filters have a strong
influence on the noise bandwidth and selectivity of the
3 ? f c
ButterFilter
≤ BW passive,filter ≤ 4 ? f c
ButterFilter
receiver and hence its sensitivity. Each filter comprises
a passive and an active section.
3.4.4.2
Active Filter
3.4.4.1
Passive Filter
The “fine” channel selection is performed by an active,
Each channel select filter features a passive second-
order RC filter, with a bandwidth programmable
through the PASFILV<3:0> bits (FILCREG<7:4). As the
wider of the two filters, its effect on the sensitivity is
negligible, but its bandwidth must be set up to optimize
blocking immunity. The value entered into this register
sets the single side bandwidth of this filter. For optimum
performance it should be set to three to four times the
cut-off frequency (fc) of the active Butterworth (or
Polyphase) filter described in Section 3.4.4.2, Active
Filter , and as shown in Equation 3-8 .
third-order, Butterworth filter, which acts as a low-pass
filter for the zero-IF configuration (FSK), or a complex
Polyphase filter for the low-IF (OOK) configuration. The
POLFILEN bit (SYNCREG<7>) enables or disables the
Polyphase filter.
Figure 3-6 illustrates the required bandwidth of this
filter that varies between the two demodulation modes.
FIGURE 3-6:
ACTIVE CHANNEL FILTER DESCRIPTION
Low-pass filter for FSK (POLFILEN = 0)
- f c
0
f c
frequency
Polyphase filter for OOK (POLFILEN = 1)
Canceled side of
the polyphase filter
- f c
- f c
0
frequency
FSK mode : The 99% energy bandwidth of an FSK
modulated signal is approximated, as shown in
Equation 3-9 .
EQUATION 3-9:
EQUATION 3-10:
2 ? f c > BW 99%,fsk + LO drifts
= 2 ? f dev + -------
BW 99%,fsk
BR
2
Figure 3-11 illustrates an accurate overview of the filter
bandwidth vs. setting.
OOK mode : The 99% energy bandwidth of an OOK
modulated signal is approximated, as shown in
BW 99%,ook = ------- = 2 ? BR
The BUTFILV<3:0> bits from FILCREG set co the cut-
off frequency ( f c ) of the filter. In a zero-IF configuration,
the FSK lobes are centered on the virtual “DC”
frequency. The choice of co should be such that the
modulated signal falls in the filter bandwidth,
anticipating the Local Oscillator frequency drift over the
operating temperature and aging of the device as
shown in: Equation 3-10
Equation 3-11 .
EQUATION 3-11:
2
t bit
DS70622C-page 62
Preliminary
? 2010–2011 Microchip Technology Inc.
发布紧急采购，3分钟左右您将得到回复。

采购需求

(若只采购一条型号，填写一行即可)

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

*型号 *数量 厂商 批号 封装
添加更多采购

我的联系方式

*
*
*
相关PDF资料
MRF89XAM9A-I/RM IC TXRX MOD 915MHZ ULP SUB-GHZ
MRX-001-433DR-B MODULE RECEIVER 433MHZ 18DIP
MRX-002-433DR-B MODULE RECEIVER 433MHZ 18DIP
MRX-002SL-433DR-B MODULE RCVR 433MHZ SAW LN 24DIP
MRX-005-915DR-B MODULE RECEIVER 915MHZ 18DIP
MRX-005SL-915DR-B MODULE RCVR 915MHZ SAW LN 24DIP
MRX-007-433DR-B MODULE RECEIVER 433MHZ 18DIP
MRX-008-433DR-B MODULE RECEIVER 433MHZ 18DIP
相关代理商/技术参数
MRF89XAM8A-I 制造商:MICROCHIP 制造商全称:Microchip Technology 功能描述:Ultra Low-Power, Integrated ISM Band Sub-GHz Transceiver
MRF89XAM8A-I/RM 功能描述:射频模块 868MHz Sub-GHz transceiver module RoHS:否 制造商:Linx Technologies 产品:Transceiver Modules 频带:902 MHz to 928 MHz 输出功率:- 15.5 dBm to + 12.5 dBm 接口类型:UART 工作电源电压:- 0.3 VDC to + 5.5 VDC 传输供电电流:38.1 mA 接收供电电流:22.7 mA 天线连接器类型:U.FL 最大工作温度:+ 85 C 尺寸:1.15 mm x 0.63 mm x 0.131 mm
MRF89XAM8A-I/RM 制造商:Microchip Technology Inc 功能描述:, Leaded Process Compatible:Yes, Peak Re
MRF89XAM9A_12 制造商:MICROCHIP 制造商全称:Microchip Technology 功能描述:915 MHz Ultra Low-Power Sub-GHz Transceiver Module
MRF89XAM9A-I/RM 功能描述:射频模块 915MHz Sub-GHz Transceiver Mod RoHS:否 制造商:Linx Technologies 产品:Transceiver Modules 频带:902 MHz to 928 MHz 输出功率:- 15.5 dBm to + 12.5 dBm 接口类型:UART 工作电源电压:- 0.3 VDC to + 5.5 VDC 传输供电电流:38.1 mA 接收供电电流:22.7 mA 天线连接器类型:U.FL 最大工作温度:+ 85 C 尺寸:1.15 mm x 0.63 mm x 0.131 mm
MRF89XAM9AT-I/RM 制造商:Microchip Technology Inc 功能描述:915 MHz Ultra Low-Power Sub-GHz Transceiver Module
MRF89XAT-I/MQ 功能描述:射频收发器 868/915/950 MHz Sub-GHz transceiver 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
MRF8HP21080HR3 功能描述:射频MOSFET电源晶体管 HV8 2.1GHZ 160W NI780H-4 RoHS:否 制造商:Freescale Semiconductor 配置:Single 晶体管极性: 频率:1800 MHz to 2000 MHz 增益:27 dB 输出功率:100 W 汲极/源极击穿电压: 漏极连续电流: 闸/源击穿电压: 最大工作温度: 封装 / 箱体:NI-780-4 封装:Tray