用于数字电视调谐器的宽带CMOS频率综合器

A COMS wide band frequency synthesizer for digital TV tuners

介绍了一块用于数字电视调谐器的CMOS宽带频率综合器。该频率综合器集成了压控振荡器(VCO)、分频器(Divider)、鉴频鉴相器/电荷泵(PFD/CP)及4MHz晶振电路和整形电路。该芯片使用经典的单变频三波段结构,VCO通过片外谐振回路产生了从80MHz到840MHz的本振信号。为了保证频率综合器在很宽的频带内能正常工作并具有较为一致的性能,设计中VCO模块采用了独创的稳幅机制,并对预分频器结构进行了改进。该芯片采用了3.3V0.35μmCMOSRF工艺,所有电压信号路径均采用了差分结构,满足了DVB-CQAM64数字电视的低噪声要求,实现了清晰的数字电视接收,文章最后给出了测试结果。

A COMS wide-band frequency synthesizer in a DTV tuner IC is presented. It integrates VCOS, dividers, PFD/CP and a 4MHz crystal oscillator with a wave reshaper. The receiver chip adopts the conventional three band single conversion architecture. Off-chip resonator is used in VCO to generate local oscillation from 80 MHz to 840MHz. To ensure that the synthesizer works properly and has coherent performance in the wide band, a novel AAC module and an improved prescaler are designed. The synthesizer is implemented in 3.3V 0.35μm RF CMOS process. The performance of the synthesizer can satisfy the low noise requirement of DVB-C standard nearly in the whole band. Through the synthesizer, the receiver can receive cable DTV signals clearly, and the testing results are proposed at last.