The fundamental aspects of digital broadcasting are its service flexibility and power savings, which make all-digital satellite broadcasting a viable and economic propositon compared with analog broadcasting. Tendenci...The fundamental aspects of digital broadcasting are its service flexibility and power savings, which make all-digital satellite broadcasting a viable and economic propositon compared with analog broadcasting. Tendencies in the development of digital television broadcasting are: (1) Stereophonic or two-language sound transmission with television in existing analog TV system, (2) Digital direct satellite broadcasting (D-DBS); (3)Digital high definition television (HDTV) Broadcasting.展开更多
China is a developing countrywith a large population and the e-conomic development level in theprovinces and the autonomous re-gions is quite different.On theother hand,the transmission ofthe broadcasting and TV pro-g...China is a developing countrywith a large population and the e-conomic development level in theprovinces and the autonomous re-gions is quite different.On theother hand,the transmission ofthe broadcasting and TV pro-grams via satellites has the follow-ing advantages:large coverage,high transmission quality and rea-sonable cost-effectiveness.There-fore,the satellite communicationsis the most advanced and effectiveway to realize full territory coverage of broadcasting and TV pro-grams in China. China began to develop com-munications satellites immediatelyafter it successfully launched展开更多
A continuous-time 7th-order Butterworth Gm-C low pass filter （LPF） with on-chip automatic tuning circuit has been implemented for a direct conversion DBS tuner in 0.35 μm SiGe BiCMOS technology. The filter＇s -3 dB...A continuous-time 7th-order Butterworth Gm-C low pass filter （LPF） with on-chip automatic tuning circuit has been implemented for a direct conversion DBS tuner in 0.35 μm SiGe BiCMOS technology. The filter＇s -3 dB cutoff frequency f0 can be tuned from 4 to 40 MHz. A novel on-chip automatic tuning scheme has been successfully realized to tune and Iock the filter＇s cutoff frequency. Measurement results show that the filter has -0.5 dB passband gain, ＋/- 5% bandwidth accuracy, 30 nV/Hz1/2 input referred noise, -3 dBVrms passband IIP3, and 27 dBVrms stopband IIP3. The I/Q LPFs with the tuning circuit draw 13 mA （with f0 = 20 MHz） from 5 V supply, and occupy 0.5 mm^2.展开更多
文摘The fundamental aspects of digital broadcasting are its service flexibility and power savings, which make all-digital satellite broadcasting a viable and economic propositon compared with analog broadcasting. Tendencies in the development of digital television broadcasting are: (1) Stereophonic or two-language sound transmission with television in existing analog TV system, (2) Digital direct satellite broadcasting (D-DBS); (3)Digital high definition television (HDTV) Broadcasting.
文摘China is a developing countrywith a large population and the e-conomic development level in theprovinces and the autonomous re-gions is quite different.On theother hand,the transmission ofthe broadcasting and TV pro-grams via satellites has the follow-ing advantages:large coverage,high transmission quality and rea-sonable cost-effectiveness.There-fore,the satellite communicationsis the most advanced and effectiveway to realize full territory coverage of broadcasting and TV pro-grams in China. China began to develop com-munications satellites immediatelyafter it successfully launched
文摘A continuous-time 7th-order Butterworth Gm-C low pass filter （LPF） with on-chip automatic tuning circuit has been implemented for a direct conversion DBS tuner in 0.35 μm SiGe BiCMOS technology. The filter＇s -3 dB cutoff frequency f0 can be tuned from 4 to 40 MHz. A novel on-chip automatic tuning scheme has been successfully realized to tune and Iock the filter＇s cutoff frequency. Measurement results show that the filter has -0.5 dB passband gain, ＋/- 5% bandwidth accuracy, 30 nV/Hz1/2 input referred noise, -3 dBVrms passband IIP3, and 27 dBVrms stopband IIP3. The I/Q LPFs with the tuning circuit draw 13 mA （with f0 = 20 MHz） from 5 V supply, and occupy 0.5 mm^2.
