ADI ADMV4540卫星通信K波段正交解调器解决方案

ADI公司的ADMV4540是集成了合成器的高度集成正交解调器,非常适合下一代K波段卫星通信.ADMV4540的RF前端包含两个低噪音放大器(LNA)通路,每个具有最佳的级联,在最大增益时双边带噪音5dB,同时最小化外接元件.双通路允许支持天线极化,而LNA通路的选择则通过SPI来进行.LNA输出采用相位和正交(I/Q)混合器下变换到基带.I/Q混合器输出提供给全差分低噪音和低失真可编滤波器和可变增益放大器(VGA).每路都能抑制大输出的波段干扰信号,而可靠提升所需要的信号,结果就降低模拟/数字转换器(ADC)系统的带宽和分辨率的要求.通路间的极好匹配和所有增益和带宽设定的高无杂散动态范围(SFDR)使得ADMV4540非常适合于具有密集星座,多个载波和邻近干扰的卫星通信系统.三个滤波器的滤角125 MHz, 250 MHz和500 MHz都可通过SPI可编程.滤波器提供六阶巴特沃斯滤波器响应,-3dB角频率为141 MHz, 282 MHz和565 MHz.当工作超过565MHz时,滤波器丧失能力,变成完全不能通过,因此要扩展-3dB带宽到高达900MHz.器件工作在3.3V电源,总功耗小于3.2W.采用48端ROHS兼容7x7mm LGA封装.工作温度−40℃到 +85℃.RF工作频率为17 GHz到 22 GHz, LO频率范围为17 GHz 到 21.5 GHz.主要用在卫星通信.本文介绍了ADMV4540主要特性,功能框图和系统框图以及评估板ADMV4540-EVALZ主要特性,多种实验室建立图,电路图,材料清单和PCB设计图.

The ADMV4540 is a highly integrated quadrature demodulator withintegrated synthesizer ideally suited for next generation K bandsatellite communication.

The RF front end of the ADMV4540 consists of two low noiseamplifier (LNA) paths, each with an optimal cascaded, 5 dB, doublesideband noise figure at maximum gain, while minimizing externalcomponents. The dual paths allow support for antenna polarization.

Selection of the LNA path can be done through the SPI.

The LNA output is then downconverted to baseband using aninphase and quadrature (I/Q) mixer. The I/Q mixer output is thenfed into fully differential low noise and low distortion programmablefilters and variable gain amplifiers (VGAs). Each channel is capableof rejecting large, out of band interferers while reliably boostingthe wanted signal, thus reducing the bandwidth and resolutio...