The 13.56 MHz analog front-end circuit for ISO/IEC 15693-compatible radio frequency identification (RFID) trans- ponder IC presented in this paper converts RF power to DC and extracts clock and data from the interroga...The 13.56 MHz analog front-end circuit for ISO/IEC 15693-compatible radio frequency identification (RFID) trans- ponder IC presented in this paper converts RF power to DC and extracts clock and data from the interrogator by 10% or 100% ASK modulation. The transponder sends data back to the interrogator by load modulation technology. The electrostatic discharge (ESD) protection circuits function to limit RF voltage to a safe level. An inductive coupling simulation modelling for 13.56 MHz RFID system is presented, with simulation results showing that the transponder operates over a wide range of electromagnetic field strength from Hmin (150 mA/m) to Hmax (5 A/m). The transponder IC is implemented in SMIC 0.35-μm three-metal two-poly mixed signal CMOS technology with embedded EEPROM.展开更多
For the measurement of vertical profiles of sound speed in the sea using laser excited Brillouin scattering, a high resolution measurement of Brillouin frequency shift is required. In this work, a molecular absorption...For the measurement of vertical profiles of sound speed in the sea using laser excited Brillouin scattering, a high resolution measurement of Brillouin frequency shift is required. In this work, a molecular absorption cell was selected as the frequency shift discriminator and several kinds of absorption gases were tried. It was found that the strong line (#1095) of 127 I 2 at 18783.3297 cm -1 and two absorption lines of 129 I 2 located at the two sides of the #1095 line of 127 I 2 could be used as frequency shift discriminator to detect the changes of the Brillouin frequency shift. This selection is the best one within the range from 532.0131 nm to 532.5154 nm. But it is not perfect and there is a lot of work to do before its practical application.展开更多
Radio frequency interference （RFI） is a major problem in high-frequency （HF） radars. Conventional filtering-involved RFI suppression methods may introduce distortions to the target signals of interest and often de...Radio frequency interference （RFI） is a major problem in high-frequency （HF） radars. Conventional filtering-involved RFI suppression methods may introduce distortions to the target signals of interest and often demand extra hardware costs. In this paper, a novel method for RFI suppression by using linearly or randomly phase-modulated （PM） chirps is proposed, which enables independent analyses of the target signal and the RFI. Furthermore, the directions of arrival （DOA） of the interference are used as constraints to ensure a better DOA estimation of the target. The effectiveness of the method is demonstrated by numerical simulation results. The method can greatly improve the anti-interference capabilities of HF radars and is extremely applicable in the portable and low-cost radar systems.展开更多
文摘The 13.56 MHz analog front-end circuit for ISO/IEC 15693-compatible radio frequency identification (RFID) trans- ponder IC presented in this paper converts RF power to DC and extracts clock and data from the interrogator by 10% or 100% ASK modulation. The transponder sends data back to the interrogator by load modulation technology. The electrostatic discharge (ESD) protection circuits function to limit RF voltage to a safe level. An inductive coupling simulation modelling for 13.56 MHz RFID system is presented, with simulation results showing that the transponder operates over a wide range of electromagnetic field strength from Hmin (150 mA/m) to Hmax (5 A/m). The transponder IC is implemented in SMIC 0.35-μm three-metal two-poly mixed signal CMOS technology with embedded EEPROM.
文摘For the measurement of vertical profiles of sound speed in the sea using laser excited Brillouin scattering, a high resolution measurement of Brillouin frequency shift is required. In this work, a molecular absorption cell was selected as the frequency shift discriminator and several kinds of absorption gases were tried. It was found that the strong line (#1095) of 127 I 2 at 18783.3297 cm -1 and two absorption lines of 129 I 2 located at the two sides of the #1095 line of 127 I 2 could be used as frequency shift discriminator to detect the changes of the Brillouin frequency shift. This selection is the best one within the range from 532.0131 nm to 532.5154 nm. But it is not perfect and there is a lot of work to do before its practical application.
文摘Radio frequency interference （RFI） is a major problem in high-frequency （HF） radars. Conventional filtering-involved RFI suppression methods may introduce distortions to the target signals of interest and often demand extra hardware costs. In this paper, a novel method for RFI suppression by using linearly or randomly phase-modulated （PM） chirps is proposed, which enables independent analyses of the target signal and the RFI. Furthermore, the directions of arrival （DOA） of the interference are used as constraints to ensure a better DOA estimation of the target. The effectiveness of the method is demonstrated by numerical simulation results. The method can greatly improve the anti-interference capabilities of HF radars and is extremely applicable in the portable and low-cost radar systems.
