A 2.4GHz ASK transmitter suitable for a low power wireless capsule endoscope system is presented. A mixer-based frequency up-conversion transmitter architecture is employed to achieve a high data rate. A pseudodiffere...A 2.4GHz ASK transmitter suitable for a low power wireless capsule endoscope system is presented. A mixer-based frequency up-conversion transmitter architecture is employed to achieve a high data rate. A pseudodifferential stacked class-A power amplifier using the current reuse technique is proposed to save power. The transmitter mainly includes two parts： a 20MHz ASK modulator based on a constant amplitude phase lock loop （PLL） and a direct up-conversion RF circuit. This design, implemented in a TSMC 0.25μm CMOS process, achieves a - 23. 217dBm output power with a data rate of 1Mbps and dissipates 3.17mA of current with a single 2.5V power supply.展开更多
A new kind of glass-ceramic phosphor, which contains crystalline phases with green emissions, is explored. The glassceramic is prepared through semi-melt-quenching procedure with a nominal composition of （Ca0.99Eu0.0...A new kind of glass-ceramic phosphor, which contains crystalline phases with green emissions, is explored. The glassceramic is prepared through semi-melt-quenching procedure with a nominal composition of （Ca0.99Eu0.01）3Si2O7. The greenemitting crystals are precipitated and identified to be β-Ca2SiO4： Eu2＋ which is responsible for 510 nm-peaked much broader band emissions holding at 1550 ℃ for half an hour. In terms of the available light scattering theory, the appearance of opaque is discussed by closely associating with size and morphology of luminous β-Ca2SiO4 crystalline phase in glass.展开更多
文摘A 2.4GHz ASK transmitter suitable for a low power wireless capsule endoscope system is presented. A mixer-based frequency up-conversion transmitter architecture is employed to achieve a high data rate. A pseudodifferential stacked class-A power amplifier using the current reuse technique is proposed to save power. The transmitter mainly includes two parts： a 20MHz ASK modulator based on a constant amplitude phase lock loop （PLL） and a direct up-conversion RF circuit. This design, implemented in a TSMC 0.25μm CMOS process, achieves a - 23. 217dBm output power with a data rate of 1Mbps and dissipates 3.17mA of current with a single 2.5V power supply.
基金supported by the National Natural Science Foundation of China(Nos.50872091 and 21076161)the Key Discipline of Materials Physics and Chemistry of Tianjin(Nos.2006ZD30 and 10SYSYJC28100)
文摘A new kind of glass-ceramic phosphor, which contains crystalline phases with green emissions, is explored. The glassceramic is prepared through semi-melt-quenching procedure with a nominal composition of （Ca0.99Eu0.01）3Si2O7. The greenemitting crystals are precipitated and identified to be β-Ca2SiO4： Eu2＋ which is responsible for 510 nm-peaked much broader band emissions holding at 1550 ℃ for half an hour. In terms of the available light scattering theory, the appearance of opaque is discussed by closely associating with size and morphology of luminous β-Ca2SiO4 crystalline phase in glass.
