Investigations On Tuner And Broadband PLL Of DVB-T

With the promotion of information technology, analog TV will be substituted with digital TV in the next 10 years. International competition come with this upgrade will be extremely intense, especially in the field of Digital Television Terrestrial Broadcasting namely wireless transmission technology. Digital Television Terrestrial Broadcasting (DTTB) can not only receive digital video/audio and transmit broadband datum, but also implement interaction multimedia including long-distant education. Currently, there are three DTTB transmission standards abroad. They are ATSC in the USA, DVB-T in Europe and ISDB-T in Japan. Nowadays, 5 standard resolutions are available in China, and TDS-OFDM based DMB-T as well as ADTB-T are two competitive standards.This paper focuses on the research of RF receiver front-end module, which is a key component of DVB-T receiving system. This module can suitable not only for any digital video broadcasting-terrestrial Receivers or CATV system, but also for Cable Modems and Digital Set-Top Boxes.This paper presents a design of low-cost, broadband RF receiver front-end module which adopts dual-conversion topology bearing high image rejection. This module can process RF signal with amplitude from–90dBm to -10dBm, and the operating frequency range extends from 50MHz to 878MHz while providing over 80dB gain-control range and its noise figure is below 5dB. A dual synthesizer generates both local oscillator (LO) frequencies, providing superior phase noise performance of -82dBc/Hz at 1kHz. The HI-IF filter achieves over 50dBc of image rejection. A broadband PLL based on this tuner is implemented. This PLL can lock the frequency between 900MHz and 1800MHz and its stability and phase noise can satisfy the system specifications.The design scheme is presented first. According to the system specifications, the simulation of the tuner and PLL are realized with EDA software. Then the RF board hardware design is completed and finally excellent test results are given. All measurement results have good agreement with the simulation results, which satisfy the system requirements.