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AD9854是CMOS 300 MSPS Quadrature Complete DDS芯片（cmos工艺的可达300M速度的正交DDS芯片），主要特点有：

1.可以实现FSK（频移键控）, BPSK（二元相移键控）, PSK（相移键控）, chirp（脉冲调频）, AM（振幅调制） operation；

2.内部有两个12bits的DA转换器，超高速比较器；

3.可达3ps动态误差，在100Mhz情况下，达80dB的SFDR（无杂散动态范围）；

4.4× to 20× programmable reference clock multiplier（4倍到20倍的可编程时钟乘法器）；

5.Dual 48-bit programmable frequency registers（2个48bits的可编程频率寄存器）；

6.Dual 14-bit programmable phase offset registers（两个14bits的可编程相位偏移寄存器）；

7.12-bit programmable amplitude modulation and on/off output shaped keying function（一个12bits可编程幅度调制和通断整形按键功能）；

8.Single-pin FSK and BPSK data interfaces（单引脚的FSK和BPSK）；

9.PSK capability via input/output interface（PSK可由IO脚实现）；

10.Linear or nonlinear FM chirp functions with single-pin frequency hold function（带有引脚频率保持功能的线性和非线性的脉冲调频）；

11Frequency-ramped FSK（频率自增的FSK）；

12.<25 ps rms total jitter in clock generator mode（在时钟发生模式下有小于25ps rms的抖动误差）；

13.Automatic bidirectional frequency sweeping（自动的双向扫频）；

14.Sin(x)/x correction（Sin(x)/x 校正）；

15.Simplified control interfaces

   10 MHz serial 2- or 3-wire SPI compatible

   100 MHz parallel 8-bit programming

…

有如下应用场景

1.Agile, quadrature LO frequency synthesis（便携式频率分析）；

2.Programmable clock generators（可编程时钟发生器）；

3.FM chirp source for radar and scanning systems（应用在雷达和扫频领域的调频信号源）；

4.Test and measurement equipment（测试和测量设备）；

5.Commercial and amateur RF exciters（商业和普通的射频器）。

如下是其功能图

从左上开始看，有如下功能入口：

1.输入：reference clock in（参考时钟输入）；diff/single select（差分/单端选择）；

FSK/BPSK Hold Data In(FSK/BPSK数据保持输入)；BIDIRECTIONAL INTERNAL/EXTERNALI/OUPDATECLOCK（双向的内部或外部IO更新时钟输入）；

2.输出：ANALOG OUT(模拟输出)；clock out（时钟输出）；OSK（）；

OK，那么AD9854到底可以实现具体的什么呢，往下看概述。

When referenced to an accurate clock source, the AD9854 generates highly stable, frequency-phase, amplitude-programmable sine and cosine outputs that can be used as an agile LO in communications, radar, and many other applications.（当参考时钟源非常精准的时候，AD9854可以产生稳定的，频率、相位和幅度可调的sin和cos信号，当然可以应用在便携式频率分析意见和雷达等其他场合）。The innovative high speed DDS core of the AD9854 provides 48-bit frequency resolution (1 μHz tuning resolution with 300 MHz SYSCLK). Maintaining 17 bits ensures excellent SFDR.（得益于内部的高速DDS核，AD9854提供高达1uhz精度的分辨率和保证了17bits的SFDR）。The circuit architecture of the AD9854 allows the generation of simultaneous quadrature output signals at frequencies up to 150 MHz, which can be digitally tuned at a rate of up to 100 million new frequencies per second.（它的电路结构允许其产生高达150M的信号输出和100M的数字调频输出）。The sine wave output (externally filtered) can be converted to a square wave by the internal comparator for agile clock generator applications.（sin信号可以通过比较器转换为方波）。The device provides two 14-bit phase registers and a single pin for BPSK operation.（它提供两个14bits的相位寄存器和一个用作BPSK操作的引脚）。For higher-order PSK operation, the I/O interface can be used for phase changes.（对于更好要求的PSK操作，IO引脚可以用作相位改变功能）。The 12-bit I and Q DACs, coupled with the innovative DDS architecture, provide excellent wideband and narrow-band output SFDR.（12bits的I和Q通道DAC提供高带宽和窄带宽的SFDR）。The Q DAC can also be configuredas a user-programmable control DAC if the quadrature function is not desired. When configured with the comparator, the 12-bit control DAC facilitates static duty cycle control in high speed clock generator applications.（Q通道也可以配置为不使用正交功能，它由用户编程控制DA转换。配置为高速比较器时，12bits的DA可用来做时钟发生器）。Two 12-bit digital multipliers permit programmable amplitude modulation, on/off output shaped keying, and precise amplitude control of the quadrature oChirp functionality is also included to facilitate wide bandwidth frequency sweeping applications.utput.（内部的两个12bits的数字乘法器可以编程为调幅模块，通断按键整形，一个精确可控的方波）。Chirp functionality is also included to facilitate wide bandwidth frequency sweeping applications.（脉冲调制在高宽带扫频领域有重要应用）。The programmable 4× to 20× REFCLK multiplier circuit of the AD9854 internally generates the 300 MHz system clock from an external lower frequency reference clock.This saves the user the expense and difficulty of implementing a 300 MHz system clock source.（可倍频到300Mhz）。Direct 300 MHz clocking is also accommodated with either single-ended or differential inputs.（直接的300M也可以单端或者差分输入）。Single-pin conventional FSK and the enhanced spectral qualities of ramped FSK are supported. The AD9854 uses advanced 0.35 μm CMOS technology to provide a high level of functionality on a single 3.3 V supply.（提供常规的FSK和增强型斜率FSK.）。工作温度在−40°C to +85°C.