ACPR (adjacent channel power ratio), AltCPR (alternatechannel power ratio), and noise are important performancemetrics for digital communication systems thatuse, for example, WCDMA (wideband code division multipleaccess) modulation. ACPR and AltCPR are bothmeasures of spectral regrowth. The power in the WCDMAcarrier is measured using a 5MHz measurement bandwidth;see Figure 1. In the case of ACPR, the total powerin a 3.84MHz bandwidth centered at 5MHz (the carrierspacing) away from the center of the outermost carrier ismeasured and compared to the carrier power. The resultis expressed in dBc. For AltCPR, the procedure is thesame, except we center the measurement 10MHz awayfrom the center of the outermost carrier.
上传时间： 2013-11-02
上传用户：maricle
Frequently, voltage reference stability and noise defi nemeasurement limits in instrumentation systems. In particular,reference noise often sets stable resolution limits.Reference voltages have decreased with the continuingdrop in system power supply voltages, making referencenoise increasingly important. The compressed signalprocessing range mandates a commensurate reductionin reference noise to maintain resolution. Noise ultimatelytranslates into quantization uncertainty in A to D converters,introducing jitter in applications such as scales, inertialnavigation systems, infrared thermography, DVMs andmedical imaging apparatus. A new low voltage reference,the LTC6655, has only 0.3ppm (775nV) noise at 2.5VOUT.Figure 1 lists salient specifi cations in tabular form. Accuracyand temperature coeffi cient are characteristic ofhigh grade, low voltage references. 0.1Hz to 10Hz noise,particularly noteworthy, is unequalled by any low voltageelectronic reference.
上传时间： 2013-10-30
上传用户：wxhwjf
ISA总线概述 ISA总线: (Industry Standard Architecture:工业标准体系结构）是IBM公司为PC/AT电脑而制定的总线标准，为16位体系结构，只能支持16位的I/O设备，数据传输率大约是16MB/S。也称为AT标准。开始时PC机面向个人及办公室，定义了8位的ISA总线结构，对外公开，成为标准（ISO ISA标准）。第三方开发出许多ISA扩充板卡，推动了PC机的发展。1984年推出IBM-PC/AT系统，ISA从8位扩充到16位，地址线从20条扩充到24条。1988年，康柏、HP、NEC等9个厂商协同把ISA扩展到32位，即EISA总线(Extended ISA)。
上传时间： 2013-10-16
上传用户：dajin
SL811开发资料_包含源程序_电路图_芯片资料:SL811HS Embedded USB Host/Slave Controller.The SL811HS is an Embedded USB Host/Slave Controller capable of communicate with either full-speed or low-speed USB peripherals. The SL811HS can interface to devices such as microprocessors, microcontrollers, DSPs, or directly to a variety of buses such as ISA, PCMCIA, and others. The SL811HS USB Host Controller conforms to USB Specification 1.1.The SL811HS USB Host/Slave Controller incorporates USB Serial Interface functionality along with internal full-/low-speed transceivers.The SL811HS supports and operates in USB full-speed mode at 12 Mbps, or at low-speed 1.5-Mbps mode.The SL811HS data port and microprocessor interface provide an 8-bit data path I/O or DMA bidirectional, with interrupt support to allow easy interface to standard microprocessors or microcontrollers such as Motorola or Intel CPUs and many others. Internally,the SL811HS contains a 256-byte RAM data buffer which is used for control registers and data buffer.The available package types offered are a 28-pin PLCC (SL811HS) and a 48-pin TQFP package (SL811HST-AC). Both packages operate at 3.3 VDC. The I/O interface logic is 5V-tolerant.
上传时间： 2013-12-22
上传用户：a82531317
Synapse串口同步库。功能有：它不是控件，而只是代码库。适合编写控制台应用服务或其它应用；不需要安装；读写数据的方法和Synapse提供的TTCPBlockSocket一样；支持MODEM的AT指令；支持RTS驱动的通讯（例如：RS-485适配器）。功能无限制。源代码：包含。适用语言：CB3 CB4 CB5 D2 D3 D4 D5
上传时间： 2014-12-03
上传用户：朗朗乾坤
XComDrv是个通讯包，包含两个控件：TXComm，封装了一个通讯设备的若干特性；TXModem，MODEM与MODEM通讯的控件。最新的版本支持：定制流控制；任意波特率；完全的数据控制；指定事件字符；收/发数据；插件。TXModem可以用来：向MODEM设备发送AT指令；修改MODEM寄存器；拨号；连接；断开。最新版本包括XAsync v.1.2，异步（覆盖式）操作单元。功能无限制。源代码：包含，还有EXE演示。适用语言：CB4 CB5 D4 D5
上传时间： 2013-12-22
上传用户：Miyuki
CopyPwd is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. Usage of CopyPwd is at the risk of the person or company using this software
标签： distributed WARRANTY CopyPwd WITHOUT
上传时间： 2013-12-09
上传用户：sjyy1001
C# Network Programming by Richard Blum ISBN:0782141765 Sybex ?2003 (647 pages) This book helps newcomers get started with a look at the basics of network programming as they relate to C#, including the language抯 network classes, the Winsock interface, and DNS resolution.
标签： Programming 0782141765 Network Richard
上传时间： 2014-01-06
上传用户：WMC_geophy
We intend to develop a wifi enabled p2p file sharing system on a linux platform using jxta and java. The purpose is to build a system that can be ported to an embedded device at a later stage and be used for p2p file sharing using the 802.11b standard. 我们旨在Linux平台上使用jxta 和java来开发一个支持wifi的p2p文件共享系统。其目的是建造一个以后可以移植到嵌入式设备的系统，使用802.11b标准进行p2p文件共享。 来源: http://sourceforge.net/projects/linux-p2p-wifi/
标签： platform develop enabled sharing
上传时间： 2015-01-20
上传用户：Shaikh
开发GSM模块时，所要用到的AT命令
上传时间： 2015-02-05
上传用户：songnanhua
