收藏本站
SX1223
4.2.3 Bit Rate Setting for MW1 and MW2
The bit rate is set by first dividing the crystal oscillator frequency by an integer in the range [1..63] in a
programmable divider, then this frequency is divided further by powers of two. The equation describing the bit rate
as a function of RefClk_K and BRn is
BR =
where:
f XTAL :
RefClk_K:
BRn :
f XTAL
Re fClk _ K ? 2 3 + BRn
Crystal oscillator frequency.
Integer in the range [1..63] (6 bit).
Integer in the range [0..5] (3 bit).
(4.1)
A procedure to determine the settings for the desired bit rate is described below:
1. Set BRn to 0.
2. Calculate RefClk_K by using this formula: Re fClk _ K =
f XTAL
BR ? 2 3 + BRn
.
3. If RefClk_K is too high, increment n by one, and repeat step 2, above
In some cases several combinations of RefClk_K and BRn will provide the required bit rate. In these cases BRn
should be chosen with the following in mind: A lower BRn offers better waveform shaping or spectral efficiency, but
may cause modulator saturation at some bit rates.
4.2.4 Deviation Setting for MW1 and MW2
Frequency deviation is controlled by user parameters RefClk_K , MOD_I , and MOD_A together with physical
parameters f XTAL and K VCO . All user parameters can be set in software, and f XTAL (crystal oscillator frequency) is set
when designing in the radio chip. K VCO (VCO gain) is a parameter of the radio chip, and is not controllable by the
user.
The crystal oscillator frequency, f XTAL , is divided by RefClk_K to generate the modulator clock. Since this modulator
clock is controlling the rise and fall times for the modulator, the frequency deviation is inversely proportional to this
clock. The relationship is shown in equation (4.2).
f DEV ∝
Re fClk _ K
f XTAL
(4.2)
It is assumed that K will be constant for most applications to keep bit-rate and shaping constant, although this is not
a requirement.
The control parameters of the frequency deviation are MOD_I and MOD_A . Of these two, MOD_I is the parameter
that controls the signal generation, while MOD_A controls attenuation of this signal. The reason for using an
attenuator is to be able to generate small deviations at high values of RefClk_K . The relationship is shown in
equation (4.3).
f DEV ∝
MOD _ I
2 MOD _ A
(4.3)
Finally, the VCO gain is given by equation (4.4).
where:
K VCO =
Const 1 + ( Const 2 ? f C ? ( 2 ? FreqBand ))
2 ? FreqBand
(4.4)
Const 1 :
Const 2 :
f C :
FreqBand :
? Semtech 2007
? 30 . 6324 × 10 9
54 . 7
Carrier frequency.
Frequency band. 0: 400MHz and 1: 900MHz.
12
www.semtech.com
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
SX1231-31SKB915 TVS
SX1240SKA433 TVS
SX1701BI085TRT IC AMP 2.5GHZ 5.3V 16-MLPQ
TA002-10002 LED HEATSINK W/FAN 12V 40X10MM
TC620HEPA IC TEMP SNSR 5V DUAL TRIP 8-DIP
TC623CVOA713 IC TEMP SNSR 3V DUAL TRIP 8-SOIC
TC624VOA IC TEMP SNSR PROG 2.7V 8SOIC
TC6501P125VCTTRG IC TEMP SWTCH OPEN DRAIN SOT23A5
相关代理商/技术参数
SX1223SK915 功能描述:KIT STARTER FOR XE1223 915MHZ RoHS:是 类别:RF/IF 和 RFID >> RF 评估和开发套件，板 系列:- 标准包装:1 系列:- 类型:GPS 接收器 频率:1575MHz 适用于相关产品:- 已供物品:模块 其它名称:SER3796
SX1230 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:Integrated Transmitter IC Narrow/wideband 315 MHz, 434 MHz 868 MHz and 915 MHz band Transmitter
SX1230-11SKA433 制造商:Semtech Corporation 功能描述:Evaluation Kit For SX1230-11SKA 433 mHz (SX1230SKA /SX1211SKA board) Transmitter
SX1230-11SKA868 制造商:Semtech Corporation 功能描述:NARROW/WIDEBAND RF TRANSMITTER 868MHZ
SX1230-11SKA915 制造商:Semtech Corporation 功能描述:NARROW/WIDEBAND RF TRANSMITTER 915MHZ 制造商:Semtech Corporation 功能描述:Evaluation Kit For SX1230-11SKA 915 mHz (SX1230SKA /SX1211SKA board)
SX1230-12SKA433 制造商:Semtech Corporation 功能描述:USB KIT - SX1230 433MHZ 制造商:Semtech Corporation 功能描述:Deluxe USB Starter Kit for SX1230, Includes Two USB Interface Boards at 433MHz
SX1230I066TRT 功能描述:IC TX UHF 433/868/916 MHZ 24-QFN RoHS:是 类别:RF/IF 和 RFID >> RF 发射器 系列:- 标准包装:4,000 系列:- 频率:310MHz ~ 440MHz 应用:- 调制或协议:UHF，ASK 数据传输率 - 最大:20 kBaud 功率 - 输出:1dBm ~ 5dBm 电流 - 传输:10mA 数据接口:PCB，表面贴装 天线连接器:PCB，表面贴装 存储容量:- 特点:- 电源电压:2.2 V ~ 4 V 工作温度:-40°C ~ 85°C 封装/外壳:16-LSSOP（0.154"，3.90mm 宽） 包装:带卷 (TR)
SX1230SKA 制造商:Semtech Corporation 功能描述: