ST STV4100地面数字电视调谐方案
ST 公司的STV4100是超小型低功耗3.3V地面电视调谐器,具有正交输出的直接变换(零IF)接收器,主要用于数字电视广播.STV4100输入频率从174 到230MHz和470 到870 MHz,单电源3.3V工作,典型功耗625mW,全集成了VCO以及带RF功率监视的RF AGC,并具有谐波抑制级.它的可编程信道滤波器覆盖6-8MHz信道间隔.工作温度-10度到70度C,可用在地面电视机顶盒(STB),iDTV和PCTV.本文介绍了STV4100的主要特性,方框图和在DVB-T系统应用框图以及带与不带回路线入口的STV4100应用框图.
STV4100:Ultra-compact low-power 3.3-V terrestrial tuner IC The STV4100 terrestrial tuner is a directconversion (zero-IF) receiver with quadrature outputs intended for digital TV broadcasting.
On each VHF and UHF input is a low noise amplifier with both switchable and variable gain to ensure an optimal signal level for the two mixers.
Each mixer, which down-converts the signal to baseband, is followed by a low-pass filter and amplifier. The baseband gain is programmable via a dedicated pin.
The LO signals are provided by an integrated PLL which contains an on-chip voltage controlled oscillator meeting stringent phase noise requirements. The LO frequencies are programmable.
The comparison frequency for the phase/frequency detector is generated by dividing the crystal oscillator reference frequency. The crystal frequency can be from 16 MHz to 31 MHz depending on application...
