引言 在数字信息传输中，基带数字信号通常要经过调制器调制，将频率搬移到适合信息传输的频段上。2FSK就是用数字信号去调制载波的频率（移频键控），由于它具有方法简单、易于实现、抗噪声和抗衰落性能较强等优点，因此在现代数字通信系统的低、中速数据传输中得到了广泛应用。 直接数字频率合成技术(DDS)将先进的数字处理技术与方法引入信号合成领域。DDS器件采用高速数字电路和高速D/A转换技术，具备频率转换时间短、频率分辨率高、频率稳定度高、输出信号频率和相位可快速程控切换等优点，可以实现对信号的全数字式调制。
上传时间： 2014-12-27
上传用户：1427796291
IntroductionAs chip designers pack more functions into ICs,pin counts continue to grow and the space betweenpins keeps shrinking. Pin spacings of 0.5 mm and0.65 mm are not at all uncommon. The power ofthese new ICs is wonderful, to be sure, but trou-bleshooting them can be a chore because connect-ing scopes and logic analyzers has become muchmore difficult and less dependable.
标签： Agilent Probing Wedge High
上传时间： 2013-10-22
上传用户：蒋清华嗯
MPLAB C30用户指南(英文) HIGHLIGHTSThe information covered in this chapter is as follows:• About this Guide• Recommended Reading• Troubleshooting• The Microchip Web Site• Development Systems Customer Notification Service• Customer Support Document LayoutThe document layout is as follows:• Chapter 1: Compiler Overview – describes MPLAB C30, development tools andfeature set.• Chapter 2: Differences between MPLAB C30 and ANSI C – describes thedifferences between the C language supported by MPLAB C30 syntax and thestandard ANSI-89 C.• Chapter 3: Using MPLAB C30 – describes how to use the MPLAB C30 compilerfrom the command line.• Chapter 4: MPLAB C30 Runtime Environment – describes the MPLAB C30runtime model, including information on sections, initialization, memory models, thesoftware stack and much more.• Chapter 5: Data Types – describes MPLAB C30 integer, floating point and pointerdata types.• Chapter 6: Device Support Files – describes the MPLAB C30 header and registerdefinition files, as well as how to use with SFR’s.• Chapter 7: Interrupts – describes how to use interrupts.• Chapter 8: Mixing Assembly Language and C Modules – provides guidelines tousing MPLAB C30 with MPLAB ASM30 assembly language modules.
上传时间： 2013-10-21
上传用户：13925096126
This document describes the system hardware implementation for the OMAP3530 processor and theTPS65930/20 companion power integrated circuit (IC). The document concentrates on the powerconnectivity for the processor and the companion power IC. The document also briefly explains someother specifics related to power, such as the boot modes and the power-up sequence.
上传时间： 2013-11-14
上传用户：yeling1919
The HCS12X family is the successor to the HCS12family, with many additional features. One new feature isthe increased memory available to the CPU and themethods available to access it. This document focuses onthe improved memory map configuration.
上传时间： 2013-11-13
上传用户：王者A
本文介绍了一种基于单片机的健身车转速测量系统。该系统具有电路简单、使用方便等特点。文中详细介绍了该系统的工作原理,并且给出了它的硬件原理图和软件设计程序框图。关键词:转速 单片机 测量ABSTRACT :This paper introduces a measuring system of the rotational velocity of exercise bike based on single - chip microcomputer . It has such advantages : simple circuit ,convenient use and so on. The work principle is presented in detail in this paper and the block diagram of hardware and program flow chart are giv2 en as well .KEYWORDS :Rotational velocity Single - chip microcomputer Measuring
上传时间： 2013-11-02
上传用户：源弋弋
The PCA9516 is a BiCMOS integrated circuit intended forapplication in I2C and SMBus systems.While retaining all the operating modes and features of the I2Csystem, it permits extension of the I2C-bus by buffering both the data(SDA) and the clock (SCL) lines, thus enabling five buses of 400 pF.The I2C-bus capacitance limit of 400 pF restricts the number ofdevices and bus length. Using the PCA9516 enables the systemdesigner to divide the bus into five segments off of a hub where anysegment to segment transition sees only one repeater delay.
上传时间： 2013-11-21
上传用户：q123321
The PCA9517 is a CMOS integrated circuit that provides level shifting between lowvoltage (down to 0.9 V) and higher voltage (2.7 V to 5.5 V) I2C-bus or SMBus applications.While retaining all the operating modes and features of the I2C-bus system during thelevel shifts, it also permits extension of the I2C-bus by providing bidirectional buffering forboth the data (SDA) and the clock (SCL) lines, thus enabling two buses of 400 pF. Usingthe PCA9517 enables the system designer to isolate two halves of a bus for both voltageand capacitance. The SDA and SCL pins are over voltage tolerant and arehigh-impedance when the PCA9517 is unpowered.
标签： translating Level 9517 PCA
上传时间： 2013-12-25
上传用户：wsf950131
The PCA9518 is a BiCMOS integrated circuit intended forapplication in I2C and SMBus systems.While retaining all the operating modes and features of the I2Csystem, it permits extension of the I2C-bus by buffering both thedata (SDA) and the clock (SCL) lines, thus enabling virtuallyunlimited buses of 400 pF.
标签： Expandable 5channel 9518 PCA
上传时间： 2013-10-23
上传用户：dumplin9
The PCA9519 is a 4-channel level translating I2C-bus/SMBus repeater that enables theprocessor low voltage 2-wire serial bus to interface with standard I2C-bus or SMBus I/O.While retaining all the operating modes and features of the I2C-bus system during thelevel shifts, it also permits extension of the I2C-bus by providing bidirectional buffering forboth the data (SDA) and the clock (SCL) lines, thus enabling the I2C-bus or SMBusmaximum capacitance of 400 pF on the higher voltage side. The SDA and SCL pins areover-voltage tolerant and are high-impedance when the PCA9519 is unpowered.
标签： 4channel transla level 9519
上传时间： 2013-11-19
上传用户：jisiwole
